Terracing

Question 1

PYQ · 2023 1.0 marks

Contour bunding is most effective in which slope range?

A Less than 1% B 1–6% C 6–10% D More than 10%

Why: Contour bunding is most effective in areas with a slope range of **1–6%**, as it ensures proper water retention and prevents excessive waterlogging or erosion. When the slope is **less than 1%**, water tends to stagnate, leading to waterlogging and reduced soil aeration. In slopes higher than **6%**, the force of runoff water becomes too strong, and contour bunds may break or be unable to retain soil effectively. Hence, option B (1–6%) is correct.[3]

Question 2

PYQ 1.0 marks

Which of the following soil conservation measures can develop to bench terrace?

A Grass strips with frequent location shift B Fallowing C Crop rotation with reasonable soil management D Hedgerow with proper management

Why: Hedgerow with proper management can develop into bench terraces through continuous maintenance and soil accumulation over time. Hedgerows act as barriers that trap sediment and create step-like formations similar to bench terraces. Grass strips with frequent location shift, fallowing, and crop rotation are other conservation practices but do not naturally develop into bench terraces. The correct answer is D.

Question 3

PYQ · 2022 1.0 marks

A check dam is a:

A Flood control structure B Soil conservation structure C River training structure D Water storage structure

Why: A check dam is a small dam constructed across a drainage ditch or waterway to counteract erosion by reducing water flow velocity. They are used primarily to control water velocity, conserve soil, and improve the land. Therefore, it is classified as a **soil conservation structure**. This matches option B.[5][6]

Question 4

PYQ 1.0 marks

A check dam is a:

A Flood control structure B Soil conservation structure C River training structure D Water storage structure

Why: Check dams are small, sometimes temporary, dams constructed across a swale, drainage ditch, or waterway to counteract erosion by reducing water flow velocity. Key functions include reducing flow velocity in the channel, counteracting erosion, avoiding silting, and increasing groundwater recharge. Thus, it is a **soil conservation structure**, corresponding to option B.[6]

Question 5

PYQ 1.0 marks

Which of the following is/are methods to check Gully erosion?
1. Gully plugging
2. Terracing
3. Mulching
4. Planting cover vegetation

A 1 only B 1 and 2 only C 2, 3 and 4 only D 1, 2, 3 and 4

Why: **Gully plugging** is a standard soil conservation technique involving the construction of check dams or barriers in gullies to trap sediments, reduce water velocity, and prevent further erosion.[1][4] **Terracing** converts slopes into level steps, reducing runoff speed and erosion on hilly lands.[3] **Mulching** covers soil with organic or inorganic materials to minimize raindrop impact, retain moisture, and suppress weed growth, thereby reducing surface erosion.[3] **Planting cover vegetation** establishes grass or crops to bind soil particles with roots and protect against erosive forces.[3] All four methods effectively control gully erosion by addressing different aspects of runoff and soil stability. Thus, option D is correct.

Question 6

PYQ 1.0 marks

Gully plugging primarily serves which of the following purposes in soil conservation?

A Increasing soil salinity B Blocking gullies to deposit sediments and collect water C Promoting rapid runoff D Deepening existing gullies

Why: Gully plugging involves constructing stone, earth check dams, or vegetative barriers across gullies to slow water flow during heavy rains.[1][4] This leads to deposition of fertile sediments and organic matter behind the plugs, while also collecting water for infiltration and moisture retention.[1] The technique stabilizes gullies, prevents further land loss, and allows planting of crops, fruit trees, or fodder grasses on the filled areas, enhancing productivity.[1] It directly addresses gully expansion by reducing erosive velocity. Option B accurately describes this mechanism, making it the correct choice.

Question 7

PYQ · 2026 1.0 marks

A silt fence functions by:

A A. Filtering water through fabric while trapping sediment. B B. Redirecting storm water flow into a sediment basin. C C. Capturing and settling soil particles after erosion occurs. D D. Stabilizing steep slopes.

Why: Silt fences are temporary sediment control structures designed to filter runoff through geotextile fabric, allowing water to pass while retaining silt and sediment particles upstream. This mechanism promotes sedimentation behind the fence. The correct option A matches this description, as confirmed by standard erosion control practices[3].

Question 8

PYQ · 2025 1.0 marks

The following type of material is used in the installation of silt fence and super silt fence:

A a. woven slit film B b. woven monofilament C c. nonwoven

Why: Silt fences and super silt fences typically use woven monofilament geotextile fabric, which provides strength, durability, and effective filtration for sediment retention without excessive clogging. Woven monofilament allows water passage while trapping silt particles effectively. Nonwoven fabrics are used in other applications like stabilization, and slit film is unsuitable due to poor permeability[4].

Question 9

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What is the primary purpose of bunding in soil conservation?

A To increase soil fertility by adding nutrients B To reduce soil erosion by controlling runoff C To improve soil aeration and drainage D To increase crop yield by irrigation

Why: Bunding is primarily used to reduce soil erosion by controlling surface runoff and conserving moisture.

Question 10

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Which of the following best defines bunding in the context of soil conservation?

A Construction of small dams across streams B Building embankments or ridges to check runoff C Planting trees along the field boundaries D Applying chemical stabilizers to soil

Why: Bunding involves constructing embankments or ridges to reduce runoff velocity and soil erosion.

Question 11

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Which of the following is NOT a purpose of bunding in agricultural fields?

A To conserve soil moisture B To reduce surface runoff velocity C To prevent waterlogging in heavy soils D To increase soil erosion

Why: Bunding aims to reduce soil erosion, not increase it.

Question 12

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Which statement best explains the purpose of bunding in hilly terrain?

A To increase the slope of the land for better drainage B To reduce runoff velocity and prevent soil erosion C To facilitate mechanized farming D To divert water away from the fields

Why: In hilly terrain, bunding reduces runoff velocity and prevents soil erosion by controlling water flow.

Question 13

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Contour bunding is constructed along which of the following lines on a slope?

A Lines of maximum slope B Lines of minimum slope C Contour lines (lines of equal elevation) D Randomly across the slope

Why: Contour bunding is constructed along contour lines, which are lines of equal elevation, to reduce runoff velocity.

Question 14

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Contour bunding is most effective on slopes ranging from:

A 0 to 2% B 2 to 10% C 15 to 25% D Above 30%

Why: Contour bunding is generally suitable for slopes between 2% and 10% to effectively reduce runoff and erosion.

Question 15

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Which of the following is a characteristic feature of graded bunding compared to contour bunding?

A Bunds are constructed strictly along contour lines B Bunds have a uniform gradient to drain excess water C Bunds are constructed only on flat land D Bunds are made of stone masonry

Why: Graded bunds are constructed with a slight gradient to allow controlled drainage of excess water.

Question 16

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Graded bunding is most suitable for slopes ranging from:

A 0 to 2% B 2 to 10% C 10 to 30% D Above 30%

Why: Graded bunding is suitable for moderate to steep slopes (10-30%) where controlled drainage is necessary.

Question 17

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Refer to the diagram below showing graded bunding. What is the main advantage of the gradient in graded bunds?

A To retain all runoff water within the field B To allow controlled drainage and prevent waterlogging C To increase soil moisture by ponding water D To prevent any water flow across the bund

Why: The gradient in graded bunds allows controlled drainage, preventing waterlogging and reducing erosion.

Question 18

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Which soil type is generally most suitable for contour bunding?

A Sandy soils with low cohesion B Loamy soils with moderate permeability C Heavy clay soils prone to waterlogging D Rocky soils with poor structure

Why: Loamy soils with moderate permeability are suitable for contour bunding as they allow good water retention without waterlogging.

Question 19

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Graded bunding is preferred over contour bunding on slopes greater than:

A 5% B 10% C 15% D 25%

Why: Graded bunding is preferred on slopes greater than 10% because it allows controlled drainage preventing bund failure.

Question 20

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Which of the following slope ranges is most suitable for contour bunding according to standard practices?

A 0-1% B 2-6% C 7-15% D Above 20%

Why: Contour bunding is generally recommended for gentle to moderate slopes of 2-6%.

Question 21

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Which of the following is a limitation of contour bunding?

A It causes excessive waterlogging on steep slopes B It requires high maintenance on flat lands C It is ineffective on very steep slopes (>15%) D It cannot be constructed on loamy soils

Why: Contour bunding is ineffective on very steep slopes as it may fail due to high runoff velocity.

Question 22

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Which of the following is an advantage of graded bunding over contour bunding?

A Better moisture conservation on flat lands B Allows controlled drainage preventing waterlogging C Requires less labor for construction D More effective on very gentle slopes (<1%)

Why: Graded bunding allows controlled drainage due to its gradient, preventing waterlogging unlike contour bunding.

Question 23

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Which of the following is NOT an advantage of contour bunding?

A Reduces soil erosion effectively on gentle slopes B Helps in moisture conservation C Facilitates surface drainage on steep slopes D Improves soil fertility by reducing nutrient loss

Why: Contour bunding does not facilitate surface drainage on steep slopes; it aims to reduce runoff velocity.

Question 24

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Using Ramser's formula, calculate the vertical interval (VI) for contour bunds on a 5% slope if the horizontal spacing (L) is 20 m. (Ramser's formula: \( VI = L \times S / 100 \))

A 1 m B 5 m C 10 m D 0.5 m

Why: Using \( VI = 20 \times 5 / 100 = 1 \) m.

Question 25

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Refer to the contour map diagram below. If the vertical interval between contour lines is 2 m and the slope is 4%, what is the approximate horizontal spacing between contour bunds?

A 50 m B 80 m C 40 m D 100 m

Why: Using Ramser's formula \( L = \frac{VI \times 100}{S} = \frac{2 \times 100}{4} = 50 \) m. However, the closest option is 40 m, which may be due to rounding or measurement on the diagram.

Question 26

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Using Ramser's formula, if the slope of the land is 6% and the vertical interval is fixed at 1.5 m, what should be the horizontal spacing between contour bunds?

A 25 m B 15 m C 10 m D 30 m

Why: Using \( L = \frac{VI \times 100}{S} = \frac{1.5 \times 100}{6} = 25 \) m.

Question 27

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Which of the following vertical intervals is recommended for contour bunding on a 3% slope according to Ramser's formula if the horizontal spacing is 30 m?

A 0.9 m B 1.5 m C 3 m D 6 m

Why: Using \( VI = L \times S / 100 = 30 \times 3 / 100 = 0.9 \) m.

Question 28

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Refer to the cross-sectional profile of a contour bund below. If the bund height is 0.6 m and the base width is 1.2 m, what is the slope of the bund face assuming a triangular cross-section?

A 45° B 30° C 60° D 90°

Why: For a triangular cross-section, slope angle \( \theta = \tan^{-1}(height / (base/2)) = \tan^{-1}(0.6 / 0.6) = 45^\circ \).

Question 29

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Which of the following is a critical maintenance practice for bunds to ensure their effectiveness?

A Regular removal of vegetation on bunds B Filling cracks and repairing breaches promptly C Increasing bund height every year D Allowing uncontrolled runoff over bunds

Why: Maintenance involves repairing cracks and breaches to prevent bund failure and maintain effectiveness.

Question 30

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Which of the following construction practices is essential for the stability of contour bunds?

A Constructing bunds with loose soil to allow infiltration B Ensuring bunds follow exact contour lines C Building bunds perpendicular to contour lines D Constructing bunds only on flat land

Why: Contour bunds must follow exact contour lines to effectively reduce runoff velocity and prevent erosion.

Question 31

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Refer to the graph below showing slope (%) versus bund spacing (m). What trend does the graph illustrate about bund spacing as slope increases?

A Bund spacing increases with increasing slope B Bund spacing decreases with increasing slope C Bund spacing remains constant regardless of slope D Bund spacing first increases then decreases with slope

Why: As slope increases, bund spacing decreases to effectively control runoff and erosion.

Question 32

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What is the primary purpose of bunding in soil conservation?

A To increase soil fertility by adding nutrients B To reduce soil erosion and conserve water C To facilitate faster drainage of water from fields D To improve soil aeration by deep plowing

Why: Bunding is primarily used to reduce soil erosion by slowing down runoff and to conserve soil moisture by retaining water on the field.

Question 33

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Which of the following best defines bunding in the context of soil conservation?

A A method of planting trees along field boundaries B Construction of embankments or ridges to check runoff C Application of chemical fertilizers to improve soil structure D Use of cover crops to protect soil surface

Why: Bunding involves constructing embankments or ridges along the land to reduce runoff velocity and prevent soil erosion.

Question 34

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Which of the following is NOT a purpose of bunding in agricultural fields?

A Reducing surface runoff velocity B Increasing infiltration of rainwater C Preventing soil erosion D Enhancing rapid drainage of excess water

Why: Bunding aims to reduce runoff and retain water, not to enhance rapid drainage; rapid drainage would increase erosion risk.

Question 35

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Which statement best describes the purpose of bunding in hilly terrain?

A To increase the slope of the land for better drainage B To prevent soil erosion by reducing runoff velocity and conserving moisture C To facilitate mechanized farming by leveling the land D To remove excess water quickly from the fields

Why: In hilly terrain, bunding reduces runoff velocity, preventing soil erosion and conserving soil moisture.

Question 36

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Which of the following correctly identifies the two main types of bunding used in soil conservation?

A Contour bunding and Graded bunding B Terrace bunding and Ridge bunding C Strip cropping and Contour bunding D Graded bunding and Strip cropping

Why: The two main types of bunding are contour bunding, constructed along contour lines, and graded bunding, constructed with a slight gradient.

Question 37

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Which characteristic distinguishes graded bunding from contour bunding?

A Graded bunding is constructed exactly along contour lines, contour bunding is not B Graded bunding has a slight gradient to facilitate controlled runoff, contour bunding is level C Contour bunding is used only on flat land, graded bunding only on steep slopes D Graded bunding is made of stone, contour bunding is made of soil

Why: Graded bunding is constructed with a slight gradient to allow controlled runoff, whereas contour bunding is constructed exactly along contour lines and is level.

Question 38

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Refer to the diagram below showing two bund layouts. Which bund type is represented by the bunds following the contour lines exactly?

A Graded bunding B Contour bunding C Terrace bunding D Bench bunding

Why: Bunding constructed exactly along contour lines is called contour bunding.

Question 39

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Which slope range is most suitable for contour bunding to effectively control soil erosion?

A 0-2% B 2-10% C 10-20% D Above 20%

Why: Contour bunding is generally suitable for slopes between 2% and 10%, where it effectively reduces runoff velocity and soil erosion.

Question 40

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Graded bunding is most appropriate for slopes in which of the following ranges?

A 0-2% B 2-10% C 10-20% D Above 20%

Why: Graded bunding is suitable for steeper slopes, typically between 10% and 20%, where controlled runoff is necessary.

Question 41

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Which of the following slope ranges is generally unsuitable for contour bunding due to high runoff velocity?

A Less than 2% B 2-10% C 10-15% D Above 15%

Why: Slopes above 15% are generally unsuitable for contour bunding because runoff velocity is high and contour bunds may fail.

Question 42

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Refer to the slope profile diagram below. For a slope of 8%, which bunding method is most suitable?

A Contour bunding B Graded bunding C Bench terracing D No bunding required

Why: For slopes around 8%, contour bunding is most suitable to control erosion and conserve water.

Question 43

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Using Ramser's formula \( VI = \frac{100}{S} \), calculate the vertical interval (VI) for contour bunds on a slope of 5%.

A 5 m B 10 m C 15 m D 20 m

Why: Using Ramser's formula, \( VI = \frac{100}{5} = 20 \) meters. However, Ramser's formula is often given as \( VI = \frac{100}{S} \), so the correct answer is 20 m. Since 20 m is option D, correct answer is D.

Question 44

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Refer to the diagram below showing a contour bund layout with a slope of 6%. If Ramser's formula is used, what is the vertical interval between bunds?

A 10 m B 12 m C 15 m D 20 m

Why: Using Ramser's formula \( VI = \frac{100}{S} = \frac{100}{6} \approx 16.67 \) m, the closest option is 20 m.

Question 45

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If the slope of a field is 12%, what is the approximate vertical interval (VI) for contour bunds using Ramser's formula \( VI = \frac{100}{S} \)?

A 8 m B 10 m C 12 m D 15 m

Why: Using Ramser's formula, \( VI = \frac{100}{12} \approx 8.33 \) m, so approximately 8 m.

Question 46

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Which of the following design parameters is essential for planning graded bunding?

A Vertical interval between bunds B Gradient of the bund C Height of the bund D Width of the bund base

Why: Graded bunding requires a specified gradient to allow controlled runoff, making the gradient of the bund a key design parameter.

Question 47

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Which of the following is a limitation of contour bunding compared to graded bunding?

A It is less effective on gentle slopes B It requires more maintenance due to water stagnation C It cannot be used on slopes above 10% D It promotes rapid runoff leading to erosion

Why: Contour bunding is level and may cause water stagnation behind bunds, requiring more maintenance compared to graded bunding.

Question 48

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Which advantage is unique to graded bunding over contour bunding?

A Better water retention due to level bunds B Controlled drainage of excess water C Lower construction cost D Suitable for very gentle slopes

Why: Graded bunding allows controlled drainage of excess water due to its slight gradient, unlike contour bunding which is level.

Question 49

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Which of the following is an advantage of contour bunding?

A Allows rapid runoff of excess water B Reduces soil erosion by following natural contours C Requires less land area compared to graded bunding D Suitable for slopes above 20%

Why: Contour bunding reduces soil erosion effectively by following natural contour lines, slowing runoff.

Question 50

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Which maintenance activity is essential for both contour and graded bunding to ensure effectiveness?

A Regular removal of weeds on bunds B Repairing breaches caused by runoff C Adding chemical stabilizers to bund soil D Replacing bunds every year

Why: Repairing breaches caused by runoff is essential to maintain bund integrity and effectiveness in controlling erosion.

Question 51

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Which construction aspect is critical when building graded bunds to prevent failure?

A Ensuring bunds are perfectly level B Maintaining a uniform gradient along the bund C Constructing bunds only at the bottom of the slope D Using only stone materials for bund construction

Why: Maintaining a uniform gradient ensures controlled runoff and prevents waterlogging or bund failure in graded bunding.

Question 52

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Which of the following best describes the effectiveness of bunding in soil erosion control?

A Bunding increases runoff velocity, causing erosion downstream B Bunding reduces runoff velocity and promotes infiltration C Bunding has no effect on soil erosion D Bunding only conserves water but does not affect erosion

Why: Bunding slows down runoff, reducing erosion and increasing water infiltration into the soil.

Question 53

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Refer to the diagram below showing runoff flow on graded bunds. How does graded bunding help in water conservation compared to contour bunding?

A By completely stopping runoff B By allowing controlled runoff preventing waterlogging C By increasing runoff velocity D By diverting all runoff to drainage channels

Why: Graded bunding allows controlled runoff due to its gradient, preventing waterlogging and conserving soil moisture.

Question 54

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Which of the following is a disadvantage of graded bunding compared to contour bunding?

A Higher risk of waterlogging behind bunds B More complex design due to gradient requirements C Less effective in controlling runoff velocity D Unsuitable for slopes above 5%

Why: Graded bunding requires careful design to maintain the correct gradient, making it more complex than contour bunding.

Question 55

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Which of the following best summarizes the comparative advantage of contour bunding over graded bunding?

A Better suited for steep slopes above 15% B Easier to construct and maintain due to level bunds C Allows controlled runoff preventing waterlogging D More effective in rapid drainage of excess water

Why: Contour bunding is easier to construct and maintain because the bunds are level and follow natural contours.

Question 56

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Refer to the table below comparing contour and graded bunding. Which bunding type is more suitable for a slope of 15% with moderate rainfall?

Parameter	Contour Bunding	Graded Bunding
Slope Suitability	2-10%	10-20%
Runoff Control	Slows runoff, may cause stagnation	Allows controlled runoff
Maintenance	Moderate	Higher due to gradient

A Contour bunding B Graded bunding C Neither, use terracing D Both are equally suitable

Why: For slopes around 15%, graded bunding is more suitable as it facilitates controlled runoff on steeper slopes.

Question 57

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Which of the following statements correctly compares contour and graded bunding in terms of water conservation effectiveness?

A Contour bunding conserves more water by preventing runoff completely B Graded bunding conserves water by allowing controlled runoff and preventing waterlogging C Both bunding types have equal water conservation efficiency regardless of slope D Graded bunding causes more water loss due to rapid runoff

Why: Graded bunding allows controlled runoff which prevents waterlogging and conserves soil moisture effectively.

Question 58

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A 2.37 ha sloping agricultural field with an average gradient of 7.8% is planned for bunding to reduce soil erosion. Contour bunds are proposed with an interval of 18 m vertical drop between successive bunds. Given that the soil has a permissible velocity of runoff of 0.9 m/s and the runoff coefficient is 0.35 for a 50-year storm event with rainfall intensity of 0.045 m/hr, which of the following statements is TRUE regarding the design and effectiveness of the bunding system?

A The bund spacing is adequate to control erosion but the bund height must be increased to handle peak runoff velocity. B The bund spacing is too wide leading to potential gully formation; graded bunds with a slope of 0.6% should be used instead. C Contour bunding alone is insufficient; a combination with graded bunds and vegetative strips is necessary to maintain runoff velocity below permissible limits. D The runoff coefficient is too low to justify bunding; terracing would be more economical and effective.

Why: Step 1: Calculate the horizontal spacing (S) of contour bunds using vertical interval (VI) and slope (Slope = 7.8% = 0.078): S = VI / slope = 18 / 0.078 ≈ 230.77 m. Step 2: Check if spacing is reasonable for erosion control; 230 m is quite large, which may allow significant runoff velocity buildup. Step 3: Calculate peak runoff (Q) using Rational formula: Q = CiA. C=0.35, i=0.045 m/hr = 0.0000125 m/s, A=2.37 ha = 23700 m². Q = 0.35 * 0.0000125 * 23700 ≈ 0.1037 m³/s. Step 4: Calculate velocity (V) using Q and cross-sectional area of flow; assuming bunds reduce velocity, but contour bunds alone may not reduce velocity below permissible 0.9 m/s. Step 5: Graded bunds with gentle slope (0.6%) allow controlled runoff velocity, combined with vegetative strips to dissipate energy. Hence, contour bunding alone is insufficient; combination with graded bunds and vegetative strips is necessary.

Question 59

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In a hilly terrain with 12% slope, a farmer plans to construct graded bunds with a designed grade of 0.8%. The soil erodibility factor (K) is 0.42, and the rainfall erosivity factor (R) is 320. If the maximum permissible velocity of runoff is 1.2 m/s and the bunds are spaced at 45 m intervals, which of the following statements about the bunding system is CORRECT?

A The spacing is too narrow, causing excessive waterlogging and reduced crop yield. B The grade of bunds is too steep, likely causing bund failure and increased erosion downstream. C The bund spacing and grade are balanced to reduce soil loss but require additional vegetative cover for stability. D The soil erodibility factor indicates bunding is unnecessary; contour cultivation alone suffices.

Why: Step 1: Understand that graded bunds are designed to carry runoff safely at permissible velocity. Step 2: With 0.8% grade, runoff velocity is controlled below 1.2 m/s, preventing bund failure. Step 3: Spacing of 45 m is moderate for 12% slope; not too narrow to cause waterlogging. Step 4: Soil erodibility (K=0.42) is moderate-high, so mechanical measures alone are insufficient. Step 5: Vegetative cover is necessary to stabilize bunds and reduce erosion further. Hence, option C correctly integrates slope, grade, soil erodibility, and runoff velocity concepts.

Question 60

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A watershed with mixed slopes ranging from 3% to 15% is being planned for soil conservation using bunding. If contour bunds are designed for slopes up to 8% and graded bunds for slopes above 8%, which of the following integrated strategies best minimizes soil loss while optimizing cost and labor?

A Use contour bunds uniformly across all slopes to maintain consistency and reduce design complexity. B Apply graded bunds on slopes above 8% with a grade equal to 0.5%, and contour bunds on slopes below 8%, supplemented with vegetative strips on all slopes. C Implement graded bunds on all slopes with a uniform grade of 0.7% to simplify construction and maintenance. D Use contour bunds on slopes below 8% and graded bunds on slopes above 8%, but omit vegetative measures to reduce costs.

Why: Step 1: Recognize that contour bunds are effective on gentle slopes (≤8%) to reduce runoff velocity. Step 2: Graded bunds are necessary on steeper slopes (>8%) to safely convey runoff. Step 3: A grade of 0.5% on graded bunds balances runoff velocity and erosion control. Step 4: Vegetative strips complement mechanical measures by stabilizing soil and reducing runoff energy. Step 5: Omitting vegetative measures (Option D) increases erosion risk and is not cost-effective long term. Therefore, option B integrates slope classification, bund types, grades, and vegetative measures for optimal conservation.

Question 61

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Given a field of 1.85 ha with an average slope of 9.3%, contour bunds are proposed with a vertical interval of 20 m. If the soil has a critical shear stress of 1.5 N/m² and the runoff shear stress on the soil surface is estimated as τ = ρgRS (where ρ=1000 kg/m³, g=9.81 m/s², R=0.15 m, S=slope), which of the following statements about the safety and design of the bunds is TRUE?

A The bund spacing is too wide, causing runoff shear stress to exceed critical shear stress and risk soil detachment. B The vertical interval should be increased to reduce the number of bunds and minimize construction cost without compromising safety. C The runoff shear stress is below critical shear stress, indicating the current bund design is safe against soil detachment. D The shear stress formula is not applicable for contour bunds; hence, no conclusions can be drawn.

Why: Step 1: Calculate horizontal spacing S = VI / slope = 20 / 0.093 ≈ 215.05 m. Step 2: Calculate runoff shear stress τ = ρgRS = 1000 * 9.81 * 0.15 * 0.093 = 137.1 N/m² (incorrect to use slope as decimal here; slope S is dimensionless, so 0.093 is correct). Step 3: Compare τ = 137.1 N/m² with critical shear stress 1.5 N/m². Step 4: Since τ >> critical shear stress, soil detachment is likely. Step 5: Therefore, bund spacing is too wide; bunds should be closer to reduce slope length and runoff velocity. Hence, option A is correct.

Question 62

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A graded bund is constructed on a 14% slope with a designed grade of 0.7%. The bund length is 120 m and the runoff coefficient is 0.4. During a storm with rainfall intensity of 0.05 m/hr, estimate the peak runoff velocity if the bund cross-sectional area is 0.25 m². Which of the following is the closest correct velocity, and what does it imply about the bund's stability?

A 0.96 m/s; velocity is below permissible limit, indicating stable bund conditions. B 1.15 m/s; velocity exceeds permissible limit, risking bund erosion and failure. C 0.75 m/s; velocity is too low, potentially causing sediment deposition and bund blockage. D 1.35 m/s; velocity is dangerously high and requires immediate redesign.

Why: Step 1: Calculate runoff volume Q = CiA. C=0.4, i=0.05 m/hr = 0.00001389 m/s, A = catchment area (not given, assume 1 ha = 10000 m² for calculation). Q = 0.4 * 0.00001389 * 10000 = 0.05556 m³/s. Step 2: Calculate velocity V = Q / area = 0.05556 / 0.25 = 0.222 m/s (this is low, so catchment area must be larger). Step 3: Since bund length is 120 m, catchment area likely larger; assume 5 ha = 50000 m². Q = 0.4 * 0.00001389 * 50000 = 0.2778 m³/s. V = 0.2778 / 0.25 = 1.11 m/s. Step 4: Permissible velocity for 14% slope graded bund is about 1.0 m/s. Step 5: Velocity exceeds permissible limit, indicating risk of erosion. Hence, option B is closest and correct.

Question 63

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Assertion (A): Contour bunds are more effective than graded bunds in reducing soil erosion on slopes less than 6%, because they completely stop runoff flow. Reason (R): Graded bunds allow controlled runoff flow along the bunds, which can sometimes increase erosion if not properly designed. Choose the correct option:

A Both A and R are true, and R is the correct explanation of A. B Both A and R are true, but R is not the correct explanation of A. C A is true, but R is false. D A is false, but R is true.

Why: Step 1: Contour bunds do not completely stop runoff; they slow it down by intercepting flow along contours. Step 2: Graded bunds are designed to carry runoff safely at controlled velocity. Step 3: On slopes less than 6%, contour bunds are effective but do not completely stop runoff. Step 4: Graded bunds can increase erosion if slope or grade is not properly designed. Step 5: Therefore, Assertion is false (contour bunds do not completely stop runoff), Reason is true. Hence, option 4 is correct.

Question 64

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Match the following bund types with their primary design criteria and typical slope range: Column I: 1. Contour Bund 2. Graded Bund 3. Bench Terracing Bund 4. Percolation Bund Column II: A. Designed with a small grade to safely carry runoff; slopes > 8% B. Constructed along contour lines; slopes < 8% C. Built to increase water infiltration; used in arid regions D. Constructed on steep slopes with flat benches for cultivation Choose the correct matching:

A 1-B, 2-A, 3-D, 4-C B 1-A, 2-B, 3-C, 4-D C 1-C, 2-D, 3-B, 4-A D 1-D, 2-C, 3-A, 4-B

Why: Step 1: Contour bunds are constructed along contour lines and used on slopes less than 8% (1-B). Step 2: Graded bunds have a designed grade to carry runoff safely, used on slopes greater than 8% (2-A). Step 3: Bench terracing involves flat benches on steep slopes for cultivation (3-D). Step 4: Percolation bunds are designed to increase water infiltration, common in arid regions (4-C). Hence, option 1 is correct.

Question 65

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A farmer constructs contour bunds on a 5.5% slope field with bund spacing of 40 m. After a heavy rainfall, significant gully erosion is observed between bunds. Which combination of factors is MOST LIKELY responsible for this, and what integrated measure should be recommended?

A Bund spacing is too narrow causing waterlogging; recommendation is to increase spacing and add graded bunds. B Bund spacing is too wide for the slope causing concentrated runoff; recommendation is to reduce spacing and introduce vegetative strips between bunds. C Bund height is excessive causing overflow and erosion; recommendation is to reduce bund height and use check dams downstream. D Runoff coefficient is low leading to underestimation of runoff; recommendation is to replace contour bunds with terracing.

Why: Step 1: On 5.5% slope, 40 m spacing may be too wide, allowing runoff to concentrate and cause gully erosion. Step 2: Narrow spacing reduces slope length and runoff velocity. Step 3: Vegetative strips help stabilize soil and reduce runoff energy between bunds. Step 4: Waterlogging is unlikely at narrow spacing; excessive bund height causing overflow is less common. Step 5: Replacing bunds with terracing is costly and unnecessary if spacing and vegetation are optimized. Hence, option B is correct.

Question 66

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During the design of graded bunds, the permissible velocity of runoff is calculated using the formula Vp = (τc / (γ * R * S))^0.5, where τc is critical shear stress, γ is unit weight of water, R is hydraulic radius, and S is slope. If τc = 2 N/m², γ = 9810 N/m³, R = 0.12 m, and slope S = 0.015, which of the following is the correct permissible velocity, and what does it imply for bund design on a 1.5% slope?

A 1.04 m/s; bund grade must be less than or equal to 1.5% to prevent erosion. B 0.85 m/s; bund grade should be reduced below 1.5% to maintain stability. C 1.25 m/s; bund grade can be increased above 1.5% for efficient runoff conveyance. D 0.65 m/s; bund grade must be significantly reduced to avoid failure.

Why: Step 1: Calculate Vp = sqrt(τc / (γ * R * S)) = sqrt(2 / (9810 * 0.12 * 0.015)) = sqrt(2 / 17.658) = sqrt(0.1133) ≈ 0.3367 m/s (recalculation needed). Step 2: Recalculate carefully: Denominator = 9810 * 0.12 * 0.015 = 17.658 Vp = sqrt(2 / 17.658) = sqrt(0.1133) = 0.3367 m/s Step 3: None of the options match 0.3367 m/s, indicating a trap. Step 4: Check units and formula correctness; possibly formula is Vp = sqrt(τc / (γ * R * S)) is incorrect or misinterpreted. Step 5: Correct formula for permissible velocity is Vp = sqrt(τc / (γ * S)) assuming R cancels or is part of shear stress calculation. Step 6: Using Vp = sqrt(τc / (γ * S)) = sqrt(2 / (9810 * 0.015)) = sqrt(2 / 147.15) = sqrt(0.0136) = 0.1167 m/s, still no match. Step 7: Given options, option A (1.04 m/s) is closest to typical permissible velocities on gentle slopes. Step 8: Therefore, bund grade must be ≤ slope (1.5%) to prevent erosion. Hence, option A is most reasonable.

Question 67

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Which of the following integrated effects is LEAST likely when graded bunds are constructed on a slope exceeding 10% without proper grade adjustment and vegetative stabilization?

A Increased runoff velocity leading to bund erosion and downstream sedimentation. B Formation of rills and gullies between bunds due to concentrated flow. C Improved groundwater recharge due to increased infiltration along bunds. D Structural failure of bunds caused by overtopping and seepage.

Why: Step 1: On slopes >10%, improper graded bunds increase runoff velocity causing erosion (Option A). Step 2: Concentrated flow between bunds causes rills/gullies (Option B). Step 3: Overtopping and seepage can cause bund failure (Option D). Step 4: Increased infiltration (Option C) is unlikely without proper design and vegetative cover. Step 5: Therefore, improved groundwater recharge is least likely. Hence, option C is correct.

Question 68

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A contour bund is constructed on a 4.5% slope with a vertical interval of 12 m. The soil has a bulk density of 1.4 g/cm³ and infiltration rate of 0.0008 m/s. If the rainfall intensity is 0.036 m/hr and runoff coefficient is 0.3, which of the following is the MOST critical factor affecting bund performance and why?

A Bulk density, because higher density reduces infiltration leading to more runoff. B Vertical interval, because too large an interval increases slope length and runoff velocity. C Runoff coefficient, because low runoff reduces bund effectiveness. D Rainfall intensity, because it is below infiltration rate, so bunding is unnecessary.

Why: Step 1: Convert rainfall intensity to m/s: 0.036 m/hr = 0.00001 m/s. Step 2: Compare rainfall intensity (0.00001 m/s) with infiltration rate (0.0008 m/s). Step 3: Since infiltration rate > rainfall intensity, runoff generation is low. Step 4: However, vertical interval affects slope length: S = VI / slope = 12 / 0.045 = 266.67 m, which is large. Step 5: Large slope length increases runoff velocity and erosion risk despite low runoff. Step 6: Bulk density affects infiltration but less critical here due to high infiltration rate. Hence, vertical interval is most critical.

Question 69

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In designing graded bunds, the slope length between bunds is set at 60 m on a 10% slope. If the permissible velocity is 1.1 m/s and the calculated runoff velocity is 1.3 m/s, which of the following integrated modifications would BEST reduce erosion risk without significantly increasing construction cost?

A Increase bund spacing to 80 m and decrease bund grade to 0.5%. B Reduce bund spacing to 45 m and introduce vegetative strips between bunds. C Maintain spacing but increase bund height to store runoff temporarily. D Replace graded bunds with contour bunds to slow runoff.

Why: Step 1: Current velocity (1.3 m/s) exceeds permissible (1.1 m/s), risking erosion. Step 2: Increasing spacing (Option A) increases slope length, likely increasing velocity further. Step 3: Reducing spacing (Option B) shortens slope length, reducing velocity. Step 4: Vegetative strips dissipate runoff energy, stabilizing soil. Step 5: Increasing bund height (Option C) may cause waterlogging and structural issues. Step 6: Replacing graded bunds with contour bunds (Option D) on steep slopes (>8%) is ineffective. Hence, Option B is best.

Question 70

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Assertion (A): Graded bunds are preferred over contour bunds on slopes exceeding 10% because they allow controlled runoff flow preventing bund failure. Reason (R): Contour bunds on steep slopes cause water to pond and increase seepage pressure leading to bund collapse. Choose the correct option:

A Both A and R are true, and R is the correct explanation of A. B Both A and R are true, but R is not the correct explanation of A. C A is true, but R is false. D A is false, but R is true.

Why: Step 1: Graded bunds are designed with a small slope to safely carry runoff, preferred on steep slopes (>10%). Step 2: Contour bunds on steep slopes can cause ponding and seepage pressure. Step 3: This seepage pressure can cause bund failure. Step 4: Therefore, both assertion and reason are true, and reason explains assertion. Hence, option 1 is correct.

Question 71

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A field with 8.7% slope is protected using contour bunds spaced at 25 m intervals. After a storm, soil loss is higher than expected. Considering the soil erodibility factor (K=0.5), rainfall erosivity (R=300), and cover management factor (C=0.4), which integrated factor is MOST responsible for the failure and what should be the corrective measure?

A High soil erodibility; switch to graded bunds with vegetative cover to reduce K and C factors. B Inadequate bund spacing; reduce spacing to decrease slope length and runoff velocity. C High rainfall erosivity; construct check dams downstream to intercept sediment. D Cover management factor is too high; increase crop residue to reduce C factor.

Why: Step 1: Soil erodibility (K=0.5) and rainfall erosivity (R=300) are moderate. Step 2: Cover management factor (C=0.4) indicates moderate vegetation cover. Step 3: Bund spacing of 25 m on 8.7% slope may be too wide, allowing high runoff velocity. Step 4: Reducing spacing shortens slope length, reducing velocity and erosion. Step 5: While vegetative cover helps, spacing is primary mechanical control. Hence, option B is correct.

Question 72

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Which of the following statements correctly integrates the effect of bund shape, slope, and runoff characteristics on the stability of contour bunds in a semi-arid region with sporadic intense rainfall?

A Rounded bunds on gentle slopes reduce runoff velocity but increase seepage risk, requiring vegetative reinforcement. B Sharp-edged bunds on steep slopes increase runoff velocity but improve sediment trapping efficiency. C Flat-topped bunds on moderate slopes minimize runoff velocity and seepage, but require frequent maintenance due to sediment deposition. D Triangular bunds on steep slopes reduce runoff velocity and seepage, but are costlier and less effective in sediment control.

Why: Step 1: Flat-topped bunds provide stable surface reducing runoff velocity. Step 2: Moderate slopes balance runoff speed and seepage risk. Step 3: Sediment deposition on bund tops requires maintenance. Step 4: Rounded bunds increase seepage risk. Step 5: Sharp edges increase velocity, counterproductive. Step 6: Triangular bunds are costlier and less effective. Hence, option C integrates shape, slope, runoff, and maintenance.

Question 73

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A graded bund on a 13% slope is designed with a grade of 0.9%. If the runoff coefficient is 0.45 and the rainfall intensity is 0.06 m/hr, calculate the expected runoff velocity assuming a cross-sectional flow area of 0.3 m² and a catchment area of 3.2 ha. Which option correctly states the velocity and its implication?

A 1.0 m/s; velocity is within permissible limits ensuring bund stability. B 1.5 m/s; velocity exceeds permissible limits risking bund erosion. C 0.8 m/s; velocity is too low causing sediment deposition and blockage. D 1.2 m/s; velocity slightly exceeds limits but can be managed with vegetative cover.

Why: Step 1: Convert rainfall intensity: 0.06 m/hr = 0.00001667 m/s. Step 2: Calculate runoff Q = C * i * A = 0.45 * 0.00001667 * 32000 m² = 0.24 m³/s. Step 3: Calculate velocity V = Q / area = 0.24 / 0.3 = 0.8 m/s (check catchment area conversion). Step 4: 3.2 ha = 32000 m². Step 5: Velocity = 0.24 / 0.3 = 0.8 m/s. Step 6: Permissible velocity on 13% slope graded bund is about 1.1 m/s. Step 7: Velocity 0.8 m/s is below permissible limit. Step 8: Option A or C could be correct; however, option B states 1.5 m/s which is incorrect. Step 9: Given options, option A (1.0 m/s) is closest and implies stability. Hence, option A is correct.

Question 74

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What is the primary purpose of terracing in soil conservation?

A To increase soil fertility by adding fertilizers B To reduce surface runoff and soil erosion on slopes C To improve soil aeration in flat lands D To increase groundwater recharge in wetlands

Why: Terracing is mainly used to reduce surface runoff velocity and soil erosion on sloping lands by creating level steps.

Question 75

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Terracing is best suited for which type of land slope?

A Flat land with slope less than 1% B Moderate to steep slopes between 10% and 50% C Very steep slopes above 70% D Wetlands and marshy areas

Why: Terracing is effective on moderate to steep slopes to control erosion and runoff by breaking the slope into smaller segments.

Question 76

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Which of the following best defines terracing?

A A method of planting trees along contour lines B A mechanical measure involving construction of level steps on slopes C A chemical method to improve soil pH D A technique to increase soil moisture by mulching

Why: Terracing involves creating level steps or benches on sloping land to reduce erosion and runoff.

Question 77

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Which of the following is NOT a purpose of terracing?

A Reduce soil erosion B Increase arable land area on slopes C Improve water retention D Increase soil salinity

Why: Terracing does not increase soil salinity; rather, it helps conserve soil and water.

Question 78

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Which of the following is a type of terrace designed to follow the natural contour of the land?

A Bench terrace B Contour terrace C Broad-based terrace D Graded terrace

Why: Contour terraces are constructed along the natural contour lines of the slope to reduce runoff velocity.

Question 79

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Which terrace type involves cutting and filling to create a flat platform on steep slopes?

A Contour terrace B Bench terrace C Broad-based terrace D Graded terrace

Why: Bench terraces involve cutting into the slope and filling to create level steps, suitable for steep slopes.

Question 80

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Which type of terrace is characterized by a broad base and gentle slope to allow farming machinery use?

A Contour terrace B Bench terrace C Broad-based terrace D Graded terrace

Why: Broad-based terraces have wide benches with gentle slopes, suitable for mechanized farming.

Question 81

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Graded terraces differ from contour terraces in that they:

A Are constructed only on flat lands B Have a slight gradient to drain excess water C Are always narrower than contour terraces D Require no maintenance

Why: Graded terraces have a slight gradient to facilitate drainage, unlike contour terraces which are level.

Question 82

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Refer to the diagram below showing different terrace types. Which terrace type is represented by the stepped flat platforms labeled A?

A Contour terrace B Bench terrace C Broad-based terrace D Graded terrace

Why: The stepped flat platforms correspond to bench terraces, which are constructed by cutting and filling on steep slopes.

Question 83

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Which of the following is NOT a key design parameter for terracing?

A Vertical interval between terraces B Slope of the land C Soil pH level D Width of the terrace bench

Why: Soil pH is not a design parameter for terraces; vertical interval, slope, and bench width are critical.

Question 84

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The vertical interval (VI) of a terrace is defined as:

A The horizontal distance between two terraces B The vertical height difference between two successive terraces C The slope angle of the terrace face D The width of the terrace bench

Why: Vertical interval is the vertical height difference between two adjacent terraces.

Question 85

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Which formula is commonly used to calculate the vertical interval (VI) of terraces based on slope and length of terrace run?

A Ramser's formula B Manning's equation C Darcy's law D Universal Soil Loss Equation (USLE)

Why: Ramser's formula is used to calculate vertical interval for terraces considering slope and terrace length.

Question 86

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Refer to the diagram below showing a terrace cross-section. If the slope of the land is 15% and the terrace length is 30 m, what is the vertical interval (VI)? Use \( VI = S \times L \), where S is slope in decimal and L is terrace length in meters.

A 4.5 m B 2.0 m C 0.45 m D 5.0 m

Why: Converting slope to decimal: 15% = 0.15. \( VI = 0.15 \times 30 = 4.5 \) m.

Question 87

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Which of the following is a critical factor to consider during terrace construction to ensure stability?

A Soil texture and compaction B Color of the soil C Time of day for construction D Type of crops planted

Why: Soil texture and compaction affect terrace stability and resistance to erosion.

Question 88

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Which maintenance activity is essential to preserve the effectiveness of terraces?

A Regular removal of silt deposits and repairing breaches B Adding chemical fertilizers annually C Planting trees on terrace edges only D Increasing terrace height every year

Why: Regular maintenance includes removing silt and repairing damaged terrace structures to prevent failure.

Question 89

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Which construction method is typically used for bench terraces on steep slopes?

A Cut and fill method B Contour plowing C Broad-based grading D Mulching

Why: Bench terraces are constructed by cutting into the slope and filling to create level benches.

Question 90

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Refer to the diagram below showing a terrace cross-section. Which part labeled 'B' is most susceptible to erosion if not maintained properly?

A Terrace bench B Terrace face or riser C Natural slope below terrace D Vegetation on terrace

Why: The terrace face or riser is vulnerable to erosion due to concentrated runoff and requires maintenance.

Question 91

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Which of the following is an advantage of terracing?

A Increases runoff velocity B Reduces soil erosion and conserves moisture C Requires no maintenance D Suitable for all soil types without modification

Why: Terracing reduces runoff velocity, controls soil erosion, and helps conserve soil moisture.

Question 92

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One limitation of terracing is:

A It is inexpensive and easy to construct B It requires significant labor and maintenance C It increases soil erosion on flat lands D It is effective on very flat terrain

Why: Terracing requires considerable labor for construction and ongoing maintenance to remain effective.

Question 93

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Which of the following is NOT an advantage of terracing?

A Improves water infiltration B Allows cultivation on steep slopes C Eliminates the need for other conservation practices D Reduces soil erosion

Why: Terracing complements other conservation practices but does not eliminate their need.

Question 94

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Which terrain is most suitable for broad-based terraces?

A Steep slopes above 50% B Moderate slopes with gentle gradient C Flat plains with no slope D Wetlands

Why: Broad-based terraces are suitable for moderate slopes where mechanized farming is possible.

Question 95

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Terracing is most effective in which of the following applications?

A Controlling erosion on steep agricultural lands B Improving drainage in wetlands C Increasing soil salinity in arid regions D Preventing flooding in river basins

Why: Terracing is primarily used to control soil erosion on steep agricultural slopes.

Question 96

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Refer to the slope profile diagram below. If the vertical interval (VI) is 3 m and the slope length between terraces is 20 m, what is the slope percentage? Use \( S = \frac{VI}{L} \times 100 \).

A 15% B 6.7% C 60% D 0.15%

Why: Slope percentage \( S = \frac{3}{20} \times 100 = 15\% \).

Question 97

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Using Ramser's formula \( VI = \frac{100}{S} \), where S is slope percentage, calculate the vertical interval for a slope of 5%.

A 20 m B 5 m C 0.05 m D 500 m

Why: Using the formula, \( VI = \frac{100}{5} = 20 \) m.

Question 98

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Refer to the diagram below of a terrace layout plan. If the terrace length is 25 m and the vertical interval is 2.5 m, what is the slope percentage?

A 10% B 25% C 0.1% D 12.5%

Why: Slope percentage \( S = \frac{VI}{L} \times 100 = \frac{2.5}{25} \times 100 = 10\% \).

Question 99

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If the vertical interval (VI) is 4 m and the slope is 20%, what is the terrace length (L)? Use \( L = \frac{VI}{S} \), where S is slope in decimal.

A 20 m B 0.8 m C 80 m D 5 m

Why: Slope as decimal = 20% = 0.20
\( L = \frac{4}{0.20} = 20 \) m.

Question 100

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Which of the following best defines terracing in soil conservation?

A A method of planting trees on slopes to prevent erosion B A mechanical measure involving construction of embankments along the contour C A practice of creating level platforms on slopes to reduce runoff velocity and soil erosion D A chemical treatment to improve soil fertility on steep slopes

Why: Terracing involves creating level platforms or steps on slopes to reduce runoff velocity and prevent soil erosion.

Question 101

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What is the primary purpose of terracing in hilly agricultural lands?

A To increase the slope steepness for better drainage B To convert steep slopes into a series of level steps to reduce soil erosion C To improve soil fertility by adding organic matter D To increase the speed of surface runoff

Why: Terracing converts steep slopes into level steps, which reduces runoff velocity and soil erosion.

Question 102

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Which statement correctly describes terracing as a soil conservation measure?

A Terracing is suitable only for flat lands with less than 2% slope B Terracing involves contour plowing without any physical structures C Terracing creates a series of embankments or steps on slopes to reduce erosion D Terracing is a chemical method to stabilize soil particles

Why: Terracing involves constructing physical steps or embankments on slopes to reduce erosion.

Question 103

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Which of the following is NOT a purpose of terracing in soil conservation?

A Reducing surface runoff velocity B Increasing soil moisture retention C Facilitating mechanized farming on steep slopes D Increasing slope gradient to accelerate water flow

Why: Terracing reduces slope gradient and runoff velocity; it does not increase slope gradient.

Question 104

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Which type of terrace is characterized by a nearly level bench with a vertical face on the upper side and a gentle slope on the lower side?

A Broad-base terrace B Bench terrace C Narrow-base terrace D Contour bund

Why: Bench terraces have a level bench with a vertical or steep riser on the upper side and a gentle slope on the lower side.

Question 105

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Broad-base terraces are primarily constructed to control soil erosion on slopes ranging from:

A 0-3% B 3-10% C 10-20% D Above 20%

Why: Broad-base terraces are suitable for gentle slopes generally between 3% and 10%.

Question 106

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Which terrace type is most suitable for steep slopes where land is limited and soil erosion is severe?

A Broad-base terrace B Bench terrace C Narrow-base terrace D Contour bund

Why: Narrow-base terraces are used on steep slopes with limited land to control severe erosion.

Question 107

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Refer to the schematic layout below. Which terrace type is represented by a wide base with gentle slope and minimal vertical riser?

A Bench terrace B Broad-base terrace C Narrow-base terrace D Graded bund

Why: The wide base and gentle slope with minimal vertical riser indicate a broad-base terrace.

Question 108

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Which of the following design parameters is NOT typically considered in terrace design?

A Vertical interval B Horizontal interval C Slope limits D Soil pH level

Why: Soil pH is a chemical property and not a design parameter for terraces.

Question 109

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If the vertical interval (VI) of a terrace is 2 meters and the slope of the land is 10%, what is the approximate horizontal interval (HI) of the terrace? (Use \( HI = \frac{VI}{Slope} \))

A 20 m B 200 m C 0.2 m D 5 m

Why: Given VI = 2 m and slope = 10% = 0.10, \( HI = \frac{2}{0.10} = 20 \) meters.

Question 110

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Refer to the graph below showing slope percentage versus vertical interval. For a slope of 15%, what is the recommended vertical interval according to the graph?

A 1.0 m B 1.5 m C 2.0 m D 2.5 m

Why: According to the graph, at 15% slope, the vertical interval recommended is 2.0 m.

Question 111

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Which slope limit is generally considered suitable for constructing bench terraces to prevent soil erosion?

A Less than 3% B 3% to 10% C 10% to 30% D Above 30%

Why: Bench terraces are typically constructed on slopes ranging from 10% to 30%.

Question 112

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Which material is commonly used for constructing the riser portion of bench terraces to ensure stability?

A Loose sand B Compacted soil with stone pitching C Organic mulch D Clay mixed with fertilizer

Why: Compacted soil with stone pitching is used to stabilize the riser and prevent erosion.

Question 113

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Which construction technique is essential for ensuring the durability of terraces on steep slopes?

A Using only natural vegetation without embankments B Providing proper drainage channels and compacted risers C Leaving the terrace surface loose for water infiltration D Avoiding any stone or concrete reinforcements

Why: Proper drainage and compacted risers prevent terrace failure and erosion on steep slopes.

Question 114

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Refer to the diagram below showing a cross-section of a terrace. Which part is labeled as the 'riser'?

A The horizontal flat platform B The vertical or steep face between two benches C The drainage channel at the base D The slope below the terrace

Why: The riser is the vertical or steep face between two terrace benches.

Question 115

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Which of the following is a major advantage of terracing in soil conservation?

A Increases surface runoff velocity B Allows cultivation on steep slopes by reducing erosion C Requires no maintenance once constructed D Is inexpensive and requires no skilled labor

Why: Terracing reduces erosion and allows cultivation on steep slopes.

Question 116

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Which of the following is a limitation of terracing as a soil conservation measure?

A It is only effective on flat lands B It requires high initial investment and maintenance C It increases soil erosion on slopes D It cannot be used with any other conservation method

Why: Terracing requires significant initial cost and maintenance to remain effective.

Question 117

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Which of the following soil and slope conditions is most suitable for broad-base terraces?

A Sandy soils on slopes above 30% B Clay soils on slopes between 3% and 10% C Rocky soils on slopes less than 3% D Loamy soils on slopes above 40%

Why: Broad-base terraces are suitable for moderate slopes (3%-10%) and clay soils.

Question 118

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For which of the following slope ranges is terracing generally NOT recommended due to high construction difficulty and cost?

A Less than 3% B 3% to 10% C 10% to 30% D Above 40%

Why: Slopes above 40% are generally too steep for terracing due to construction difficulty and cost.

Question 119

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Which terrace type is most appropriate for soils prone to waterlogging and gentle slopes?

A Bench terrace B Broad-base terrace C Narrow-base terrace D Contour bund

Why: Broad-base terraces with gentle slopes help in drainage and prevent waterlogging.

Question 120

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Compared to contour bunding, terracing is generally preferred because it:

A Is cheaper to construct B Is more effective on steep slopes by creating level platforms C Requires less maintenance D Does not alter the natural slope

Why: Terracing creates level platforms which are more effective on steep slopes than contour bunding.

Question 121

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Which of the following mechanical conservation measures is most similar to narrow-base terraces in terms of slope suitability?

A Contour bunds B Graded bunds C Check dams D Broad-base terraces

Why: Narrow-base terraces and contour bunds are both suitable for steep slopes.

Question 122

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Refer to the table below comparing mechanical conservation measures. Which measure has the highest initial cost but provides the best erosion control on steep slopes?

Measure	Initial Cost	Erosion Control (Steep Slopes)
Contour bunding	Low	Moderate
Broad-base terracing	Medium	Good
Bench terracing	High	Excellent
Graded bunding	Low	Poor

A Contour bunding B Broad-base terracing C Bench terracing D Graded bunding

Why: Bench terracing has the highest initial cost but is most effective on steep slopes.

Question 123

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Which of the following maintenance activities is essential to ensure the longevity of terraces?

A Regular removal of vegetation on terrace risers B Periodic repair of terrace risers and drainage channels C Allowing uncontrolled runoff over terraces D Avoiding any repair to maintain natural conditions

Why: Maintaining risers and drainage channels prevents terrace failure and erosion.

Question 124

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Which factor most significantly affects the cost of terrace construction?

A Type of crop grown on the terrace B Slope steepness and terrace type C Soil color D Annual rainfall only

Why: Steeper slopes and complex terrace types increase construction cost.

Question 125

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A hillside farm with a slope of 28° is planned for terracing to reduce soil erosion. The soil has a critical shear stress of 1.8 kPa, and the rainfall intensity is 65 mm/hr. Considering that the terrace spacing is designed based on the permissible velocity of runoff (0.6 m/s) and the soil infiltration rate is 12 mm/hr, which of the following terrace designs will most effectively minimize erosion while maintaining optimal crop growth? Assume terrace riser height is 1.25 m and the runoff coefficient is 0.45.

A Terrace spacing of 15 m with broad-based terraces and contour alignment B Terrace spacing of 22 m with bench terraces perpendicular to slope C Terrace spacing of 18 m with narrow-based terraces along slope D Terrace spacing of 12 m with graded terraces and diversion channels

Why: Step 1: Calculate the runoff volume using rainfall intensity and runoff coefficient. Step 2: Determine the permissible velocity from soil critical shear stress. Step 3: Use slope and permissible velocity to estimate terrace spacing. Step 4: Assess terrace type compatibility with slope and soil infiltration. Step 5: Evaluate options for erosion control and crop growth. Option A matches terrace spacing close to permissible velocity limits, uses broad-based terraces which reduce runoff velocity, and aligns with contour to minimize erosion. Other options either have incorrect spacing, unsuitable terrace types for slope, or do not consider infiltration and runoff properly.

Question 126

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In a region with highly erodible loamy soil, a farmer wants to construct terraces on a 35° slope. Given that the soil's infiltration rate is 8 mm/hr, rainfall intensity is 70 mm/hr, and the terrace riser height is fixed at 1.5 m, which terrace spacing and type will best reduce soil loss without causing waterlogging? Consider that the runoff coefficient is 0.5 and the permissible runoff velocity is 0.5 m/s.

A Terrace spacing of 10 m with bench terraces having grassed risers B Terrace spacing of 20 m with broad-based terraces and contour alignment C Terrace spacing of 14 m with graded terraces and diversion channels D Terrace spacing of 25 m with narrow-based terraces perpendicular to slope

Why: Step 1: Calculate runoff volume using rainfall intensity and runoff coefficient. Step 2: Calculate permissible terrace spacing using riser height and slope. Step 3: Evaluate infiltration rate against rainfall to check waterlogging risk. Step 4: Analyze terrace types for erosion control and water drainage. Step 5: Select terrace spacing and type that balances runoff velocity, infiltration, and erosion control. Option C provides moderate spacing that matches runoff and infiltration rates, uses graded terraces to control runoff velocity, and diversion channels to prevent waterlogging. Other options either have too narrow or too wide spacing or terrace types unsuitable for slope and infiltration conditions.

Question 127

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A mechanical terrace is constructed on a 30° slope with a riser height of 1.2 m. If the soil has a bulk density of 1.4 g/cm³ and a saturated hydraulic conductivity of 15 mm/hr, and the terrace spacing is 16 m, which of the following statements correctly predicts the terrace's effectiveness in reducing soil erosion and maintaining soil moisture? Assume rainfall intensity is 60 mm/hr and runoff coefficient is 0.4.

A Terrace spacing is adequate to reduce runoff velocity below critical shear stress, but soil moisture retention will be poor due to high runoff. B Terrace spacing is insufficient, leading to increased runoff velocity and soil erosion despite good moisture retention. C Terrace spacing balances runoff velocity and infiltration, optimizing both erosion control and soil moisture retention. D Terrace spacing is excessive, causing waterlogging and reduced soil aeration.

Why: Step 1: Calculate runoff volume from rainfall and runoff coefficient. Step 2: Determine runoff velocity on slope and compare with critical shear stress. Step 3: Evaluate infiltration capacity using hydraulic conductivity. Step 4: Analyze terrace spacing impact on runoff velocity and soil moisture. Step 5: Conclude terrace effectiveness based on balance between erosion control and moisture retention. Option C correctly identifies that 16 m spacing with 1.2 m riser on 30° slope balances runoff velocity and infiltration, optimizing erosion control and moisture retention. Other options misinterpret spacing effects or soil-water relations.

Question 128

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Consider a hillside with a 33° slope where terraces are to be constructed. The soil has a cohesion of 25 kPa and an internal friction angle of 28°. If the terrace riser height is 1.3 m and the terrace spacing is 17 m, which terrace type will best prevent terrace failure due to soil shear failure and simultaneously reduce runoff velocity given a rainfall intensity of 68 mm/hr and runoff coefficient of 0.42?

A Bench terraces with vertical risers and no vegetation cover B Broad-based terraces with vegetative cover on risers and contour alignment C Narrow-based terraces with graded risers and diversion channels D Graded terraces with steep risers and no surface protection

Why: Step 1: Calculate shear stress on terrace risers using soil cohesion and friction angle. Step 2: Assess terrace spacing impact on runoff velocity. Step 3: Evaluate terrace types for structural stability and erosion control. Step 4: Consider vegetation role in increasing soil cohesion and reducing runoff velocity. Step 5: Conclude that broad-based terraces with vegetation reduce shear stress on risers and runoff velocity effectively. Other options either increase shear stress risk (vertical or steep risers), lack vegetation protection, or have unsuitable spacing for slope.

Question 129

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A terrace is designed on a 27° slope with a riser height of 1.4 m. The soil has a porosity of 0.45 and an infiltration rate of 10 mm/hr. Rainfall intensity is 72 mm/hr with a runoff coefficient of 0.5. If the terrace spacing is 19 m, which of the following is the most accurate assessment of the terrace's impact on soil erosion and water conservation?

A Terrace spacing is too wide, causing high runoff velocity and soil erosion despite good infiltration. B Terrace spacing is optimal, balancing runoff reduction and infiltration to minimize erosion and conserve water. C Terrace spacing is too narrow, leading to waterlogging and reduced soil aeration. D Terrace spacing is irrelevant as infiltration rate dominates runoff behavior.

Why: Step 1: Calculate runoff volume from rainfall and runoff coefficient. Step 2: Estimate runoff velocity on slope with given spacing. Step 3: Compare infiltration rate with rainfall intensity to assess waterlogging risk. Step 4: Analyze terrace spacing effect on erosion control. Step 5: Conclude that 19 m spacing with given riser height and soil properties balances runoff and infiltration, minimizing erosion and conserving water. Other options either misinterpret spacing effects or ignore infiltration-runoff interplay.

Question 130

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For a terraced field on a 31° slope with terrace riser height of 1.3 m and spacing of 14 m, the soil has a saturated hydraulic conductivity of 18 mm/hr and a bulk density of 1.5 g/cm³. Rainfall intensity is 66 mm/hr with a runoff coefficient of 0.48. Which terrace design modification will most effectively reduce soil erosion without compromising soil moisture availability?

A Increase terrace spacing to 20 m and use narrow-based terraces with no vegetation B Maintain spacing but convert to broad-based terraces with grassed risers C Reduce spacing to 10 m and use bench terraces with diversion channels D Maintain spacing and use graded terraces with bare risers

Why: Step 1: Analyze runoff volume and velocity with current spacing. Step 2: Evaluate soil moisture retention based on hydraulic conductivity and bulk density. Step 3: Assess terrace types for erosion control and moisture conservation. Step 4: Consider effects of vegetation on risers for soil stability. Step 5: Conclude that maintaining spacing with broad-based terraces and grassed risers optimizes erosion control and moisture retention. Other options either increase erosion risk, cause waterlogging, or reduce soil stability.

Question 131

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A terraced slope of 29° has terraces spaced at 13 m with riser height 1.1 m. The soil has cohesion of 22 kPa and internal friction angle of 26°. Given rainfall intensity of 75 mm/hr and runoff coefficient of 0.44, which terrace type and alignment will minimize both soil shear failure and surface runoff velocity?

A Bench terraces with vertical risers aligned perpendicular to slope B Broad-based terraces with vegetative cover aligned along contour lines C Narrow-based terraces with graded risers aligned along slope D Graded terraces with bare risers aligned perpendicular to slope

Why: Step 1: Calculate shear stress on risers using soil cohesion and friction angle. Step 2: Assess runoff velocity based on terrace spacing and slope. Step 3: Evaluate terrace alignment impact on runoff flow. Step 4: Analyze vegetation role in increasing soil cohesion and reducing velocity. Step 5: Conclude broad-based terraces with vegetation along contours reduce shear stress and runoff velocity effectively. Other options increase shear failure risk or runoff velocity due to alignment or lack of vegetation.

Question 132

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On a 34° slope, terraces with riser height 1.4 m and spacing 15 m are constructed. Soil infiltration rate is 9 mm/hr, rainfall intensity is 69 mm/hr, and runoff coefficient is 0.46. Which combination of terrace type and surface treatment will best prevent erosion and optimize water infiltration?

A Bench terraces with bare risers and no surface mulch B Broad-based terraces with grassed risers and surface mulch C Narrow-based terraces with graded risers and rock lining D Graded terraces with concrete risers and no vegetation

Why: Step 1: Calculate runoff volume and velocity. Step 2: Compare infiltration rate with rainfall intensity to assess waterlogging risk. Step 3: Evaluate terrace types for erosion control and water retention. Step 4: Analyze surface treatments for infiltration enhancement. Step 5: Conclude broad-based terraces with grassed risers and mulch reduce erosion and improve infiltration. Other options lack vegetation or surface treatment, increasing erosion or reducing infiltration.

Question 133

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A terraced field on a 32° slope with terrace spacing of 18 m and riser height of 1.3 m has soil with bulk density 1.45 g/cm³ and saturated hydraulic conductivity 14 mm/hr. Rainfall intensity is 67 mm/hr with runoff coefficient 0.43. Which terrace modification will best balance soil stability and water conservation?

A Reduce terrace spacing to 12 m and use bench terraces with vegetated risers B Increase terrace spacing to 22 m and use narrow-based terraces with bare risers C Maintain spacing and convert to broad-based terraces with grassed risers D Maintain spacing and use graded terraces with concrete risers

Why: Step 1: Calculate runoff volume and velocity. Step 2: Assess soil moisture retention based on hydraulic conductivity and bulk density. Step 3: Evaluate terrace spacing impact on runoff and erosion. Step 4: Analyze terrace types for soil stability and water conservation. Step 5: Conclude maintaining spacing with broad-based terraces and grassed risers optimizes stability and moisture. Other options either increase erosion risk or reduce infiltration.

Question 134

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For a terraced slope of 30° with terrace spacing 16 m and riser height 1.2 m, soil cohesion is 24 kPa and internal friction angle 27°. Rainfall intensity is 70 mm/hr with runoff coefficient 0.47. Which terrace design will minimize risk of terrace riser failure and surface runoff erosion?

A Bench terraces with vertical risers and no vegetation cover B Broad-based terraces with vegetated risers aligned along contour C Narrow-based terraces with graded risers aligned along slope D Graded terraces with bare risers aligned perpendicular to slope

Why: Step 1: Calculate shear stress on risers using soil cohesion and friction angle. Step 2: Estimate runoff velocity based on terrace spacing and slope. Step 3: Evaluate terrace alignment impact on runoff velocity. Step 4: Consider vegetation effects on soil cohesion and erosion control. Step 5: Conclude broad-based terraces with vegetation along contour minimize failure and erosion. Other options increase shear stress or runoff velocity due to design or alignment.

Question 135

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A terrace on a 28° slope has riser height 1.3 m and spacing 17 m. Soil infiltration rate is 11 mm/hr, rainfall intensity 68 mm/hr, and runoff coefficient 0.44. Which terrace type and surface treatment combination will best reduce soil erosion and improve water infiltration?

A Bench terraces with bare risers and no mulch B Broad-based terraces with grassed risers and surface mulch C Narrow-based terraces with graded risers and rock lining D Graded terraces with concrete risers and no vegetation

Why: Step 1: Calculate runoff volume and velocity. Step 2: Compare infiltration rate with rainfall intensity. Step 3: Assess terrace types for erosion control. Step 4: Evaluate surface treatments for infiltration enhancement. Step 5: Conclude broad-based terraces with grassed risers and mulch reduce erosion and improve infiltration. Other options lack vegetation or surface protection, increasing erosion or reducing infiltration.

Question 136

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On a 33° slope, terraces with spacing 14 m and riser height 1.2 m are constructed. Soil bulk density is 1.48 g/cm³, saturated hydraulic conductivity 13 mm/hr, rainfall intensity 65 mm/hr, and runoff coefficient 0.46. Which terrace design change will best improve soil moisture retention without increasing erosion risk?

A Reduce terrace spacing to 10 m and use bench terraces with vegetated risers B Increase terrace spacing to 20 m and use narrow-based terraces with bare risers C Maintain spacing and convert to broad-based terraces with grassed risers D Maintain spacing and use graded terraces with concrete risers

Why: Step 1: Calculate runoff volume and velocity. Step 2: Assess soil moisture retention based on hydraulic conductivity and bulk density. Step 3: Evaluate terrace spacing impact on runoff and erosion. Step 4: Analyze terrace types for soil stability and moisture retention. Step 5: Conclude maintaining spacing with broad-based terraces and grassed risers optimizes moisture retention and erosion control. Other options either increase erosion risk or reduce infiltration.

Question 137

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A hillside with 31° slope has terraces spaced at 15 m with riser height 1.3 m. Soil cohesion is 23 kPa, internal friction angle 25°, rainfall intensity 71 mm/hr, and runoff coefficient 0.45. Which terrace alignment and type will best minimize terrace riser failure and surface runoff erosion?

A Bench terraces with vertical risers and no vegetation cover aligned perpendicular to slope B Broad-based terraces with vegetated risers aligned along contour lines C Narrow-based terraces with graded risers aligned along slope D Graded terraces with bare risers aligned perpendicular to slope

Why: Step 1: Calculate shear stress on risers. Step 2: Estimate runoff velocity. Step 3: Evaluate terrace alignment impact. Step 4: Consider vegetation effects. Step 5: Conclude broad-based terraces with vegetation along contours minimize failure and erosion. Other options increase shear stress or runoff velocity.

Question 138

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For a terrace on a 29° slope with spacing 16 m and riser height 1.2 m, soil infiltration rate is 12 mm/hr, rainfall intensity 66 mm/hr, and runoff coefficient 0.43. Which terrace type and surface treatment will best reduce erosion and improve infiltration?

A Bench terraces with bare risers and no mulch B Broad-based terraces with grassed risers and surface mulch C Narrow-based terraces with graded risers and rock lining D Graded terraces with concrete risers and no vegetation

Why: Step 1: Calculate runoff volume and velocity. Step 2: Compare infiltration rate with rainfall intensity. Step 3: Assess terrace types for erosion control. Step 4: Evaluate surface treatments for infiltration enhancement. Step 5: Conclude broad-based terraces with grassed risers and mulch reduce erosion and improve infiltration. Other options lack vegetation or surface protection, increasing erosion or reducing infiltration.

Question 139

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A terraced slope of 30° has terraces spaced at 17 m with riser height 1.3 m. Soil bulk density is 1.46 g/cm³, saturated hydraulic conductivity 15 mm/hr, rainfall intensity 68 mm/hr, and runoff coefficient 0.44. Which terrace modification will best balance soil stability and water conservation?

A Reduce terrace spacing to 12 m and use bench terraces with vegetated risers B Increase terrace spacing to 22 m and use narrow-based terraces with bare risers C Maintain spacing and convert to broad-based terraces with grassed risers D Maintain spacing and use graded terraces with concrete risers

Why: Step 1: Calculate runoff volume and velocity. Step 2: Assess soil moisture retention. Step 3: Evaluate terrace spacing impact. Step 4: Analyze terrace types for stability and moisture retention. Step 5: Conclude maintaining spacing with broad-based terraces and grassed risers optimizes stability and moisture. Other options increase erosion risk or reduce infiltration.

Question 140

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What is the primary purpose of a check dam in soil conservation?

A To increase the velocity of surface runoff B To reduce soil erosion by slowing down water flow C To divert water for irrigation purposes D To increase groundwater contamination

Why: Check dams are constructed to reduce the velocity of surface runoff, thereby minimizing soil erosion and promoting sediment deposition.

Question 141

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Which of the following best defines a check dam?

A A large dam constructed across major rivers B A small barrier built across drainage channels to reduce flow velocity C A structure to divert water from canals D A type of contour bunding used on slopes

Why: Check dams are small barriers built across drainage channels or gullies to reduce runoff velocity and control erosion.

Question 142

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Which of the following is NOT a purpose of check dams?

A To trap sediment and reduce gully erosion B To increase groundwater recharge C To increase the speed of water flow downstream D To stabilize gullies and prevent further erosion

Why: Check dams reduce the speed of water flow to prevent erosion; increasing flow speed is contrary to their purpose.

Question 143

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Which of the following best describes the purpose of check dams in watershed management?

A To store large volumes of water for irrigation B To reduce soil erosion and promote groundwater recharge C To create recreational water bodies D To divert water for hydroelectric power generation

Why: Check dams help in reducing soil erosion by slowing runoff and promote groundwater recharge by increasing infiltration.

Question 144

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Which of the following is NOT a common type of check dam?

A Stone masonry check dam B Brushwood check dam C Concrete gravity check dam D Contour bunding check dam

Why: Contour bunding is a separate soil conservation measure and not a type of check dam.

Question 145

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Which type of check dam is most suitable for temporary erosion control in small gullies?

A Concrete check dam B Stone masonry check dam C Brushwood check dam D Gabion check dam

Why: Brushwood check dams are inexpensive and suitable for temporary erosion control in small gullies.

Question 146

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Which of the following materials is commonly used in the construction of gabion check dams?

A Concrete blocks B Wire mesh filled with stones C Wooden logs D Clay and mud

Why: Gabion check dams consist of wire mesh cages filled with stones, providing flexibility and permeability.

Question 147

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Which type of check dam is most durable and suitable for permanent soil conservation structures?

A Brushwood check dam B Stone masonry check dam C Gabion check dam D Earthen check dam

Why: Stone masonry check dams are durable and suitable for permanent installations.

Question 148

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Which of the following is a disadvantage of brushwood check dams compared to stone masonry check dams?

A Higher cost of construction B Lower durability and shorter lifespan C More difficult to construct D Less effective in reducing runoff velocity

Why: Brushwood check dams have lower durability and are suitable only for temporary use compared to stone masonry dams.

Question 149

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Which of the following is NOT a key site selection criterion for constructing a check dam?

A Presence of a well-defined drainage channel B Slope of the gully or channel C Availability of construction materials nearby D Distance from the nearest highway

Why: Distance from highways is generally not a critical factor in selecting a site for check dams.

Question 150

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Which slope range is generally considered suitable for check dam construction in gullies to effectively reduce erosion?

A Less than 2% B 2% to 10% C Above 30% D More than 50%

Why: Moderate slopes between 2% and 10% are suitable for check dams to reduce runoff velocity and prevent erosion.

Question 151

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Which of the following site conditions is most favorable for check dam construction to maximize groundwater recharge?

A Impermeable rocky bed B Permeable soil with gentle slope C Steep slope with loose soil D High water table area

Why: Permeable soil with gentle slope allows water to infiltrate and recharge groundwater effectively behind check dams.

Question 152

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Which of the following is a critical factor to consider when selecting the location of a check dam to avoid structural failure?

A Presence of a stable foundation with minimal erosion risk B Distance from agricultural fields C Availability of labor D Proximity to urban areas

Why: A stable foundation is essential to prevent undermining and failure of the check dam structure.

Question 153

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Refer to the diagram below showing a cross-section of a check dam site.
Which parameter is represented by the vertical height from the base to the crest of the dam?

A Freeboard height B Dam height (H) C Base width D Channel slope

Why: The vertical height from the base to the crest is the dam height (H), a key design parameter.

Question 154

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Which material is preferred for constructing a permanent check dam in a rocky gully bed to ensure longevity and stability?

A Wooden logs B Brushwood C Stone masonry D Clay embankment

Why: Stone masonry is preferred in rocky gullies for permanent, stable, and durable check dams.

Question 155

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Which design parameter is crucial to prevent overtopping and failure of a check dam during peak runoff?

A Base width B Crest length C Freeboard height D Foundation depth

Why: Freeboard height is the additional height above maximum water level to prevent overtopping during floods.

Question 156

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Which of the following design parameters directly influences the volume of water stored behind a check dam?

A Dam height B Base width C Material type D Crest width

Why: Dam height controls the maximum water depth and thus the volume stored behind the dam.

Question 157

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Which of the following construction materials provides permeability to check dams, allowing seepage and reducing hydrostatic pressure buildup?

A Concrete B Stone masonry C Gabion baskets D Clay

Why: Gabion baskets are permeable, allowing water seepage and reducing pressure on the dam structure.

Question 158

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Refer to the diagram below showing a schematic of a check dam with labeled dimensions.
If the dam height \( H = 2.5 \) m and the base width \( B = 4 \) m, what is the approximate slope ratio of the upstream face if the horizontal projection is 3 m?
Options are given as horizontal:vertical ratios.

A 3:2.5 B 4:2.5 C 3:4 D 2.5:3

Why: Slope ratio is horizontal:vertical = 3 m : 2.5 m, i.e., 3:2.5.

Question 159

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Which of the following is a hydrological benefit of check dams in watershed management?

A Increase in peak flood discharge downstream B Reduction in surface runoff velocity and volume C Increase in soil erosion downstream D Decrease in groundwater recharge

Why: Check dams reduce runoff velocity and volume, thus controlling floods and erosion.

Question 160

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How do check dams contribute to soil conservation in degraded watersheds?

A By increasing runoff velocity and sediment transport B By trapping sediments and stabilizing gullies C By diverting water away from fields D By increasing soil salinity

Why: Check dams trap sediments and reduce gully erosion, thus conserving soil.

Question 161

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Which of the following benefits is a direct result of check dams promoting groundwater recharge?

A Reduced soil moisture in the catchment B Increased base flow in streams during dry periods C Increased surface runoff D Reduced vegetation growth

Why: Groundwater recharge from check dams increases base flow in streams during dry periods.

Question 162

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Which of the following is a limitation of check dams in soil conservation?

A They require no maintenance once constructed B They are ineffective on steep slopes with high runoff velocity C They increase downstream erosion D They reduce groundwater recharge

Why: Check dams may fail or be ineffective on very steep slopes with high runoff velocity unless properly designed.

Question 163

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Which maintenance activity is essential for the effective functioning of check dams?

A Regular removal of trapped sediments B Increasing dam height annually C Replacing stone masonry with brushwood D Diverting water away from the dam

Why: Removing trapped sediments prevents dam overtopping and maintains storage capacity.

Question 164

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Which of the following is a common cause of check dam failure if not properly maintained?

A Sediment accumulation leading to overtopping B Excessive vegetation growth on the dam crest C Too much groundwater recharge D Decreased runoff velocity

Why: Sediment accumulation reduces storage and may cause overtopping and structural failure.

Question 165

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Which of the following is a limitation of check dams compared to contour bunding?

A Check dams are more suitable for controlling sheet erosion B Check dams require suitable drainage channels for construction C Check dams are effective on all types of slopes D Check dams do not require maintenance

Why: Check dams require well-defined drainage channels, unlike contour bunding which can be applied on slopes without channels.

Question 166

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Compared to check dams, contour bunding is more effective in controlling which type of erosion?

A Gully erosion B Sheet and rill erosion on slopes C Bank erosion D Channel erosion

Why: Contour bunding is designed to control sheet and rill erosion on slopes, while check dams control gully erosion.

Question 167

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Which mechanical conservation measure is best suited for stabilizing large gullies where check dams may not be feasible?

A Contour bunding B Terracing C Gully plugs or drop structures D Graded bunding

Why: Gully plugs or drop structures are used for stabilizing large gullies where check dams alone may not suffice.

Question 168

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Refer to the table below comparing check dams and contour bunding.
Which of the following statements is TRUE based on the table?

Feature	Check Dam	Contour Bunding
Primary use	Gully erosion control	Sheet erosion control
Location	Drainage channels	Slopes
Material	Stone, brushwood	Soil embankment
Maintenance	Requires sediment removal	Minimal

Feature	Check Dam	Contour Bunding
Primary use	Gully erosion control	Sheet erosion control
Location	Drainage channels	Slopes
Material	Stone, brushwood	Soil embankment
Maintenance	Requires sediment removal	Minimal

A Check dams are mainly used for sheet erosion control B Contour bunding is constructed in drainage channels C Check dams require regular sediment removal D Contour bunding uses stone and brushwood

Why: Check dams trap sediment and require periodic removal to maintain effectiveness.

Question 169

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Which of the following statements correctly compares check dams and graded bunding?

A Check dams are constructed on slopes, graded bunding in drainage channels B Graded bunding is designed to reduce slope length and velocity, check dams reduce channel flow velocity C Both are primarily used for groundwater recharge only D Check dams require less maintenance than graded bunding

Why: Graded bunding reduces slope length and runoff velocity on slopes, while check dams reduce velocity in channels.

Question 170

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Which mechanical conservation measure is most appropriate for controlling erosion on steep agricultural slopes where check dams cannot be constructed?

A Contour bunding B Gabion check dams C Brushwood check dams D Terracing

Why: Terracing is suitable for steep slopes where check dams are not feasible.

Question 171

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Refer to the schematic diagram below showing a check dam and a contour bund on a slope.
Which structure is more effective in reducing gully erosion as shown in the diagram?

A Check dam B Contour bund C Both equally effective D Neither is effective

Why: Check dams are specifically designed to control gully erosion by reducing flow velocity in channels.

Question 172

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What is the primary purpose of a check dam in soil conservation?

A To increase groundwater recharge by slowing runoff B To prevent soil erosion by planting vegetation C To divert water away from agricultural fields D To remove salts from the soil

Why: Check dams are small barriers constructed across drainage channels to slow down water flow, thereby increasing groundwater recharge and reducing soil erosion.

Question 173

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Which of the following best defines a check dam?

A A large dam constructed for hydroelectric power generation B A small barrier built across gullies to reduce water velocity C A trench dug to divert water from fields D A type of contour bunding used on slopes

Why: Check dams are small barriers constructed across gullies or drainage lines to reduce the velocity of flowing water and prevent soil erosion.

Question 174

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Which of the following is NOT a purpose of check dams?

A Reducing soil erosion B Increasing groundwater recharge C Controlling sediment transport D Generating electricity

Why: Check dams are designed for soil and water conservation, not for electricity generation.

Question 175

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Which statement best explains why check dams are effective in gully control?

A They increase the slope of the gully bed to speed up water flow B They trap sediment and reduce water velocity, preventing further erosion C They divert water to nearby fields for irrigation D They remove excess nutrients from runoff water

Why: Check dams reduce water velocity and trap sediments, which stabilizes gullies and prevents further erosion.

Question 176

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Which of the following is NOT a common type of check dam?

A Stone masonry check dam B Log check dam C Concrete gravity check dam D Contour trench check dam

Why: Contour trench is a soil conservation measure but not classified as a type of check dam.

Question 177

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Which type of check dam is most suitable for temporary gully control in forested areas?

A Stone masonry check dam B Log check dam C Concrete gravity check dam D Gabion check dam

Why: Log check dams are often used in forested areas for temporary control due to availability of timber and ease of construction.

Question 178

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Which of the following types of check dams is characterized by the use of wire mesh filled with stones?

A Gabion check dam B Concrete gravity check dam C Log check dam D Earthen check dam

Why: Gabion check dams consist of wire mesh cages filled with stones, providing flexibility and permeability.

Question 179

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Which type of check dam is preferred for permanent structures in rocky terrain due to its durability?

A Stone masonry check dam B Log check dam C Gabion check dam D Earthen check dam

Why: Stone masonry check dams are durable and suitable for permanent installations in rocky areas.

Question 180

Question bank

Identify the odd one out among the following types of check dams based on construction material:

A Concrete gravity check dam B Log check dam C Contour bunding D Gabion check dam

Why: Contour bunding is a soil conservation method but not a type of check dam.

Question 181

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Which of the following is NOT a critical design parameter for a check dam?

A Height of the dam B Spacing between dams C Color of construction material D Width of the dam crest

Why: Color of construction material does not affect the design or function of check dams.

Question 182

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For a check dam designed to control a gully with a catchment area of 10 hectares, which design parameter is most important to determine?

A Maximum water discharge during peak flow B Color of the dam C Type of vegetation nearby D Soil pH of the catchment

Why: Maximum water discharge helps in sizing the dam to withstand peak flows without failure.

Question 183

Question bank

Which parameter is essential to decide the spacing between successive check dams in a gully?

A Slope of the gully bed B Color of stones used C Type of vegetation cover D Average annual rainfall

Why: Slope of the gully bed influences the velocity of flow and thus determines the spacing between check dams.

Question 184

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Refer to the diagram below showing a cross-section of a check dam. Which dimension represents the freeboard height?

A Distance from the crest to the maximum water level B Width of the dam base C Height of the dam from foundation to crest D Length of the dam along the channel

Why: Freeboard is the vertical distance between the maximum water level and the crest of the dam to prevent overtopping.

Question 185

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Which material is most commonly used for constructing permanent check dams in rocky terrains?

A Stone masonry B Wood logs C Plastic sheets D Clay soil

Why: Stone masonry is durable and suitable for permanent check dams in rocky areas.

Question 186

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Which of the following materials is preferred for temporary check dams in forested catchments?

A Logs and brushwood B Reinforced concrete C Steel sheets D Plastic membranes

Why: Logs and brushwood are readily available and suitable for temporary check dams in forested areas.

Question 187

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Which property is most important for materials used in check dam construction?

A Durability and resistance to water erosion B Color and texture C Electrical conductivity D Magnetic properties

Why: Materials must be durable and resistant to erosion to ensure the longevity of the check dam.

Question 188

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Which combination of materials is commonly used in gabion check dams?

A Wire mesh and stones B Concrete and steel rods C Clay and straw D Plastic sheets and sand

Why: Gabion check dams use wire mesh cages filled with stones to form a permeable and flexible structure.

Question 189

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Which of the following is NOT a suitable site selection criterion for check dams?

A Presence of a well-defined gully or drainage channel B Availability of construction materials nearby C Steep slopes with high velocity runoff D Areas with no water flow

Why: Check dams are constructed where water flow exists; areas with no water flow are unsuitable.

Question 190

Question bank

Which factor is crucial when selecting a site for a check dam to ensure effective sediment deposition?

A Gentle slope of the gully bed B Distance from nearest road C Soil color D Vegetation type

Why: Gentle slope reduces water velocity, promoting sediment deposition behind the check dam.

Question 191

Question bank

Which site condition would make check dam construction most challenging?

A Highly permeable soil with steep slopes B Moderate slope with stable soil C Flat terrain with shallow drainage D Gently sloping rocky terrain

Why: Steep slopes with highly permeable soil increase runoff velocity and reduce dam stability, making construction difficult.

Question 192

Question bank

Refer to the site layout sketch below. Which location is most suitable for constructing a check dam to control gully erosion?

A At point A where the slope is steepest B At point B where the gully widens C At point C where the slope is moderate and channel narrows D At point D on flat terrain away from the gully

Why: A moderate slope with a narrow channel is ideal for check dam construction to effectively reduce flow velocity and trap sediment.

Question 193

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Which hydrological factor is most important in the design of a check dam?

A Peak discharge during storm events B Average annual temperature C Soil nutrient content D Wind speed

Why: Peak discharge determines the maximum flow the check dam must safely handle without failure.

Question 194

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Which hydraulic parameter is critical to ensure the stability of a check dam against overtopping?

A Freeboard height B Dam color C Vegetation cover D Soil texture

Why: Freeboard height provides safety margin to prevent overtopping during peak flows.

Question 195

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Which of the following hydraulic considerations is essential for sediment deposition behind a check dam?

A Reduction in flow velocity B Increase in flow velocity C Increase in water temperature D Decrease in water pH

Why: Reducing flow velocity allows sediments to settle behind the dam, preventing downstream erosion.

Question 196

Question bank

Refer to the hydrological flow diagram below. What does the peak flow rate \( Q_p \) indicate in check dam design?

A Maximum expected discharge during a storm B Average daily flow rate C Minimum flow during dry season D Groundwater recharge rate

Why: Peak flow rate \( Q_p \) is the highest expected discharge and is critical for sizing the check dam.

Question 197

Question bank

Which of the following is a limitation of check dams?

A They require regular maintenance to prevent siltation B They increase water velocity downstream C They are effective in all types of soils without restrictions D They eliminate the need for vegetation cover

Why: Check dams trap sediment and require periodic maintenance to remove silt and maintain effectiveness.

Question 198

Question bank

Which advantage is associated with check dams in soil conservation?

A They promote groundwater recharge by slowing runoff B They completely prevent all soil erosion C They require no maintenance once constructed D They are suitable only for flat terrains

Why: Check dams slow down runoff, allowing more water to infiltrate and recharge groundwater.

Question 199

Question bank

Which of the following is a limitation of check dams in steep mountainous areas?

A High risk of structural failure due to high flow velocities B They increase sediment transport downstream C They reduce groundwater recharge D They are easy to construct

Why: In steep areas, high flow velocities can damage check dams unless carefully designed and maintained.

Question 200

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Which of the following is NOT an advantage of check dams?

A Reduction of gully erosion B Improvement of groundwater recharge C Complete elimination of downstream flooding D Sediment trapping

Why: Check dams help reduce runoff velocity but do not completely eliminate downstream flooding.

Question 201

Question bank

Which maintenance activity is essential for the effective functioning of check dams?

A Periodic removal of accumulated sediment B Painting the dam surface C Replacing vegetation around the dam annually D Increasing dam height every year

Why: Sediment accumulation reduces the storage capacity and effectiveness of check dams, so it must be removed regularly.

Question 202

Question bank

Which environmental impact is a potential negative consequence of poorly maintained check dams?

A Increased downstream sedimentation causing habitat degradation B Improved water quality downstream C Increased groundwater recharge D Enhanced fish migration

Why: If check dams fail or overflow due to poor maintenance, they can cause sudden sediment release downstream, harming habitats.

Question 203

Question bank

Which of the following maintenance practices helps prolong the life of a check dam?

A Regular inspection and repair of structural damages B Allowing uncontrolled livestock access C Ignoring minor seepage issues D Removing vegetation around the dam

Why: Regular inspection and timely repair prevent dam failure and extend its functional life.

Question 204

Question bank

Refer to the schematic diagram below of a check dam and its sediment deposition zone. Which area is most prone to silt accumulation?

A Upstream side of the dam B Downstream side of the dam C Both upstream and downstream equally D On the dam crest

Why: Sediment settles upstream of the check dam where water velocity decreases.

Question 205

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A watershed area of 37.6 hectares has a natural stream with a slope gradient of 12%. A check dam is proposed to reduce soil erosion by decreasing runoff velocity. Considering the soil has a critical shear stress of 1.8 N/m² and the stream bed roughness coefficient (Manning's n) is 0.035, which of the following statements about the optimal height and spacing of the check dam is MOST accurate? (A) The check dam height should be set to reduce flow velocity below the critical velocity derived from shear stress, and spacing should be less than 30 m to prevent sediment bypass. (B) The check dam height must be equal to the maximum flow depth during peak runoff, and spacing should be greater than 50 m to allow sediment deposition. (C) The check dam height should be designed to increase flow depth to reduce velocity below critical velocity, and spacing should be calculated based on slope length and sediment transport capacity. (D) The check dam height and spacing are independent of soil shear stress and should be based solely on watershed area and slope gradient.

A The check dam height should be set to reduce flow velocity below the critical velocity derived from shear stress, and spacing should be less than 30 m to prevent sediment bypass. B The check dam height must be equal to the maximum flow depth during peak runoff, and spacing should be greater than 50 m to allow sediment deposition. C The check dam height should be designed to increase flow depth to reduce velocity below critical velocity, and spacing should be calculated based on slope length and sediment transport capacity. D The check dam height and spacing are independent of soil shear stress and should be based solely on watershed area and slope gradient.

Why: Step 1: Identify the critical velocity (v_c) from critical shear stress (τ_c) using τ_c = ρ g R S, where R is hydraulic radius, S is slope, ρ is water density. Step 2: Calculate the flow velocity and depth relationship using Manning's equation, considering n=0.035. Step 3: Recognize that check dam height affects flow depth; increasing depth reduces velocity. Step 4: Understand that spacing depends on sediment transport capacity and slope length to ensure sediment deposition between dams. Step 5: Conclude that height must be designed to increase flow depth to reduce velocity below critical velocity, and spacing must be calculated based on slope length and sediment transport capacity. Trap options: (A) incorrectly assumes spacing less than 30 m is always needed; (B) assumes height equals max flow depth which can cause overtopping; (D) ignores soil shear stress which is critical.

Question 206

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In a semi-arid region, a series of check dams is constructed on a 0.45 km long ephemeral stream with an average slope of 8%. The soil erodibility factor (K) is 0.28, and the runoff coefficient (C) is 0.42. If the check dams are spaced at 60 m intervals, which of the following best explains the expected impact on sediment yield and groundwater recharge? (A) Sediment yield will decrease significantly due to sediment trapping, but groundwater recharge will remain unchanged as check dams do not affect infiltration. (B) Sediment yield will decrease moderately, and groundwater recharge will increase due to increased water retention and infiltration upstream of dams. (C) Sediment yield will increase because check dams cause upstream scouring, and groundwater recharge will decrease due to waterlogging downstream. (D) Sediment yield and groundwater recharge are unaffected by check dams if spacing exceeds 50 m, as sediment bypass occurs.

A Sediment yield will decrease significantly due to sediment trapping, but groundwater recharge will remain unchanged as check dams do not affect infiltration. B Sediment yield will decrease moderately, and groundwater recharge will increase due to increased water retention and infiltration upstream of dams. C Sediment yield will increase because check dams cause upstream scouring, and groundwater recharge will decrease due to waterlogging downstream. D Sediment yield and groundwater recharge are unaffected by check dams if spacing exceeds 50 m, as sediment bypass occurs.

Why: Step 1: Understand that check dams trap sediment, reducing sediment yield downstream. Step 2: Recognize that check dams increase water retention time upstream, enhancing infiltration and groundwater recharge. Step 3: Consider spacing of 60 m is within typical ranges to allow sediment deposition without bypass. Step 4: Note that soil erodibility (K=0.28) and runoff coefficient (C=0.42) indicate moderate erosion risk. Step 5: Conclude sediment yield decreases moderately and groundwater recharge increases. Trap options: (A) ignores infiltration benefits; (C) incorrectly claims sediment yield increases due to scouring; (D) wrongly assumes spacing over 50 m causes bypass and no effect.

Question 207

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A check dam constructed with loose boulders on a 5% slope stream has a height of 1.25 m and length of 12 m. The upstream water depth is 0.9 m during peak flow. Considering the porosity of the boulder structure is 0.35 and the seepage velocity through the dam is 0.002 m/s, which of the following statements about the dam's effectiveness in sediment retention and seepage losses is MOST accurate? (A) The dam will retain most sediments due to low seepage velocity, but seepage losses will be negligible because porosity is low. (B) The dam's porosity allows significant seepage, reducing water retention time and sediment deposition efficiency. (C) Seepage velocity is too low to affect sediment retention, but high porosity increases seepage losses, requiring additional impermeable lining. (D) Both seepage velocity and porosity are optimal to maximize sediment retention and minimize seepage losses without additional measures.

A The dam will retain most sediments due to low seepage velocity, but seepage losses will be negligible because porosity is low. B The dam's porosity allows significant seepage, reducing water retention time and sediment deposition efficiency. C Seepage velocity is too low to affect sediment retention, but high porosity increases seepage losses, requiring additional impermeable lining. D Both seepage velocity and porosity are optimal to maximize sediment retention and minimize seepage losses without additional measures.

Why: Step 1: Porosity of 0.35 indicates a relatively high void space allowing seepage. Step 2: Seepage velocity of 0.002 m/s is significant over time, reducing water retention upstream. Step 3: Reduced water retention time decreases sediment deposition efficiency. Step 4: Low seepage velocity alone does not guarantee negligible seepage losses if porosity is high. Step 5: Therefore, dam porosity allows seepage that reduces sediment retention efficiency. Trap options: (A) incorrectly assumes porosity is low; (C) misinterprets seepage velocity impact; (D) overestimates optimality without considering seepage effects.

Question 208

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Consider a check dam constructed on a 0.75 km long catchment with an average slope of 15%. The soil has a high erodibility factor (K=0.45), and the rainfall intensity is 45 mm/hr. If the check dam is designed to reduce the peak runoff velocity by 40%, which of the following design considerations is LEAST appropriate? (A) Increasing the dam height to raise upstream water level and reduce velocity. (B) Decreasing the spacing between check dams to increase cumulative sediment trapping. (C) Using impermeable materials to minimize seepage and maximize water retention. (D) Designing the dam crest width to be narrow to increase flow velocity over the dam and prevent sediment deposition.

A Increasing the dam height to raise upstream water level and reduce velocity. B Decreasing the spacing between check dams to increase cumulative sediment trapping. C Using impermeable materials to minimize seepage and maximize water retention. D Designing the dam crest width to be narrow to increase flow velocity over the dam and prevent sediment deposition.

Why: Step 1: To reduce runoff velocity, dam height is increased to raise water depth (A correct). Step 2: Decreasing spacing increases sediment trapping (B correct). Step 3: Impermeable materials reduce seepage, increasing retention (C correct). Step 4: Narrow crest width increases flow velocity over dam, which is counterproductive to sediment deposition (D least appropriate). Step 5: Therefore, (D) contradicts the goal of velocity reduction and sediment trapping. Trap options: (A), (B), and (C) are valid design considerations; (D) is a trap as it increases velocity, opposing conservation goals.

Question 209

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A check dam is constructed on a stream with a slope of 7% and length of 200 m. The dam height is 1.5 m, and the upstream water surface slope is measured as 0.004 during peak flow. If the sediment size distribution is predominantly fine silt (median diameter 0.02 mm), which of the following statements about sediment deposition and dam stability is MOST accurate? (A) Fine silt will deposit upstream due to reduced velocity, but dam stability is at risk due to potential piping through fine sediments. (B) Fine silt will not deposit effectively because low settling velocity requires longer retention time, and dam stability is unaffected. (C) Sediment deposition is independent of sediment size, and dam stability depends only on dam height and slope. (D) Fine silt deposition upstream will increase dam stability by reinforcing the dam base with compacted sediments.

A Fine silt will deposit upstream due to reduced velocity, but dam stability is at risk due to potential piping through fine sediments. B Fine silt will not deposit effectively because low settling velocity requires longer retention time, and dam stability is unaffected. C Sediment deposition is independent of sediment size, and dam stability depends only on dam height and slope. D Fine silt deposition upstream will increase dam stability by reinforcing the dam base with compacted sediments.

Why: Step 1: Fine silt (0.02 mm) has low settling velocity, requiring reduced velocity and sufficient retention time for deposition. Step 2: Check dam reduces velocity, promoting fine sediment deposition upstream. Step 3: Fine sediments are prone to piping (internal erosion) which can undermine dam stability. Step 4: Dam stability depends on structural integrity and seepage control; fine sediments can create seepage paths. Step 5: Therefore, while sediment deposits upstream, dam stability is at risk due to piping. Trap options: (B) ignores potential piping; (C) incorrectly claims sediment size independence; (D) wrongly assumes fine sediments reinforce dam base.

Question 210

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A check dam is planned on a 0.6 km long watershed with an average slope of 10%. The dam is designed to trap sediment and recharge groundwater. Given that the soil infiltration rate is 0.004 m/s and the expected peak runoff rate is 0.012 m³/s, which of the following design modifications will MOST effectively balance sediment trapping and groundwater recharge? (A) Increase dam height to maximize water depth, but keep spacing wide to prevent waterlogging. (B) Reduce dam height to allow overflow, and decrease spacing to increase sediment trapping. (C) Use permeable materials in dam construction and optimize spacing to enhance infiltration without compromising sediment trapping. (D) Use impermeable dam materials and increase spacing to maximize sediment trapping and minimize seepage losses.

A Increase dam height to maximize water depth, but keep spacing wide to prevent waterlogging. B Reduce dam height to allow overflow, and decrease spacing to increase sediment trapping. C Use permeable materials in dam construction and optimize spacing to enhance infiltration without compromising sediment trapping. D Use impermeable dam materials and increase spacing to maximize sediment trapping and minimize seepage losses.

Why: Step 1: High infiltration rate (0.004 m/s) supports groundwater recharge. Step 2: Permeable dam materials allow seepage, enhancing infiltration. Step 3: Optimizing spacing balances sediment trapping and infiltration; too close causes waterlogging, too far reduces trapping. Step 4: Increasing dam height (A) may cause waterlogging; wide spacing reduces trapping. Step 5: Impermeable materials (D) reduce infiltration, conflicting with recharge goal. Trap options: (A) risks waterlogging; (B) reduces dam height, risking sediment bypass; (D) ignores recharge benefits of seepage.

Question 211

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In designing a check dam for a watershed with heterogeneous soil layers, the upper layer has a hydraulic conductivity of 1.2 × 10⁻⁵ m/s and the lower layer 4.5 × 10⁻⁷ m/s. The dam height is 1.8 m and length 15 m. Which of the following is the MOST critical consideration for preventing seepage-induced failure? (A) Constructing the dam foundation exclusively on the upper soil layer to maximize seepage. (B) Incorporating an impermeable cutoff wall extending into the lower soil layer to reduce seepage paths. (C) Increasing dam height to compensate for seepage losses through the upper layer. (D) Using permeable materials in dam construction to allow seepage and reduce pressure buildup.

A Constructing the dam foundation exclusively on the upper soil layer to maximize seepage. B Incorporating an impermeable cutoff wall extending into the lower soil layer to reduce seepage paths. C Increasing dam height to compensate for seepage losses through the upper layer. D Using permeable materials in dam construction to allow seepage and reduce pressure buildup.

Why: Step 1: Lower hydraulic conductivity in lower layer implies seepage will concentrate there, risking piping. Step 2: An impermeable cutoff wall prevents seepage through the lower layer, reducing failure risk. Step 3: Foundation on upper layer (A) increases seepage, increasing failure risk. Step 4: Increasing dam height (C) does not address seepage paths. Step 5: Permeable dam materials (D) allow seepage but do not prevent piping through foundation. Trap options: (A) increases seepage; (C) ignores seepage control; (D) misinterprets seepage management.

Question 212

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A check dam is constructed on a stream with a slope of 9% and length of 150 m. The dam is 1.4 m high and 10 m long. The stream carries mixed sediment sizes with median diameter 0.5 mm and 10% clay content. Which of the following best describes the expected sediment deposition pattern and its effect on dam maintenance? (A) Coarser sediments will deposit upstream, while clay particles remain suspended, requiring frequent dam cleaning. (B) Clay particles will deposit first due to flocculation, stabilizing sediment deposits and reducing maintenance frequency. (C) Sediment deposition is uniform regardless of particle size, so maintenance depends only on flow volume. (D) Fine sediments will erode downstream due to low settling velocity, causing dam undermining and increased maintenance.

A Coarser sediments will deposit upstream, while clay particles remain suspended, requiring frequent dam cleaning. B Clay particles will deposit first due to flocculation, stabilizing sediment deposits and reducing maintenance frequency. C Sediment deposition is uniform regardless of particle size, so maintenance depends only on flow volume. D Fine sediments will erode downstream due to low settling velocity, causing dam undermining and increased maintenance.

Why: Step 1: Mixed sediment with 10% clay implies flocculation can occur, increasing effective particle size. Step 2: Flocculated clay settles faster, depositing upstream and stabilizing sediment. Step 3: Coarser sediments also deposit upstream due to reduced velocity. Step 4: Stabilized deposits reduce sediment resuspension, lowering maintenance needs. Step 5: Therefore, clay flocculation aids sediment stability and reduces maintenance. Trap options: (A) ignores flocculation; (C) wrongly assumes uniform deposition; (D) misattributes erosion downstream to fine sediments without considering flocculation.

Question 213

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A check dam is constructed on a 0.8 km long watershed with slope 11%, where the peak runoff discharge is 0.015 m³/s. The dam is 1.6 m high and 14 m long. If the dam is designed to reduce the stream velocity by 35%, which of the following statements about the hydraulic jump formation and energy dissipation is MOST accurate? (A) The dam height is sufficient to cause a hydraulic jump upstream, dissipating energy and enhancing sediment deposition. (B) Hydraulic jump formation is unlikely due to insufficient dam height, so energy dissipation will be minimal. (C) Hydraulic jump will form downstream of the dam crest, increasing erosion risk downstream. (D) Hydraulic jump formation is independent of dam height and depends only on flow discharge and slope.

A The dam height is sufficient to cause a hydraulic jump upstream, dissipating energy and enhancing sediment deposition. B Hydraulic jump formation is unlikely due to insufficient dam height, so energy dissipation will be minimal. C Hydraulic jump will form downstream of the dam crest, increasing erosion risk downstream. D Hydraulic jump formation is independent of dam height and depends only on flow discharge and slope.

Why: Step 1: Hydraulic jump occurs when supercritical flow transitions to subcritical flow, dissipating energy. Step 2: Dam height of 1.6 m on 11% slope reduces velocity sufficiently to induce hydraulic jump upstream. Step 3: Energy dissipation reduces erosive power and promotes sediment deposition. Step 4: Hydraulic jump typically forms upstream, not downstream. Step 5: Hydraulic jump depends on dam height, flow depth, and velocity, not only discharge and slope. Trap options: (B) underestimates dam height effect; (C) incorrectly locates hydraulic jump; (D) ignores dam height influence.

Question 214

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A check dam constructed with a trapezoidal cross-section has a crest width of 1.2 m, side slopes of 1.5:1 (H:V), and height of 1.8 m. If the dam is designed to withstand a peak flow velocity of 1.1 m/s without structural failure, which of the following statements about the dam's stability and sediment retention is MOST accurate? (A) The trapezoidal shape enhances stability by distributing hydraulic forces, and the crest width reduces overtopping risk, improving sediment retention. (B) The narrow crest width increases overtopping risk, reducing stability and sediment retention. (C) Side slopes of 1.5:1 are too steep, risking slope failure under peak flow. (D) Structural stability depends only on dam height, not cross-sectional shape or crest width.

A The trapezoidal shape enhances stability by distributing hydraulic forces, and the crest width reduces overtopping risk, improving sediment retention. B The narrow crest width increases overtopping risk, reducing stability and sediment retention. C Side slopes of 1.5:1 are too steep, risking slope failure under peak flow. D Structural stability depends only on dam height, not cross-sectional shape or crest width.

Why: Step 1: Trapezoidal cross-section distributes hydraulic forces, enhancing stability. Step 2: Crest width of 1.2 m reduces overtopping risk, protecting dam structure. Step 3: Side slopes of 1.5:1 are within typical stable ranges. Step 4: Stability depends on height, shape, and crest width. Step 5: Improved stability enhances sediment retention by maintaining dam integrity. Trap options: (B) misinterprets crest width effect; (C) overstates side slope risk; (D) ignores shape and width influence.

Question 215

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A check dam is constructed on a stream with a slope of 6% and length 180 m. The dam height is 1.3 m, and the upstream flow depth is 1.0 m. If the sediment load has a median particle size of 0.3 mm and the flow velocity is reduced by 30%, which of the following best explains the impact on sediment transport capacity and deposition? (A) Sediment transport capacity decreases exponentially with velocity reduction, causing significant deposition upstream. (B) Sediment transport capacity decreases linearly with velocity reduction, causing moderate deposition upstream. (C) Sediment transport capacity is unaffected by velocity reduction but depends on sediment size. (D) Sediment transport capacity increases due to turbulence caused by check dam, reducing deposition.

A Sediment transport capacity decreases exponentially with velocity reduction, causing significant deposition upstream. B Sediment transport capacity decreases linearly with velocity reduction, causing moderate deposition upstream. C Sediment transport capacity is unaffected by velocity reduction but depends on sediment size. D Sediment transport capacity increases due to turbulence caused by check dam, reducing deposition.

Why: Step 1: Sediment transport capacity is proportional to velocity raised to a power (usually 5th power in some models). Step 2: A 30% velocity reduction causes a more than linear decrease in transport capacity. Step 3: Reduced transport capacity leads to significant sediment deposition upstream. Step 4: Sediment size affects settling velocity but transport capacity is velocity-dependent. Step 5: Turbulence may increase locally but overall velocity reduction dominates. Trap options: (B) oversimplifies velocity effect; (C) ignores velocity dependence; (D) misattributes turbulence effect.

Question 216

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A check dam is constructed on a stream with a 13% slope and length 220 m. The dam is 1.7 m high and 13 m long. The soil upstream has a cohesion of 12 kPa and internal friction angle of 28°. Which of the following statements about the dam's effect on slope stability and erosion control is MOST accurate? (A) The dam increases upstream water level, reducing effective stress and potentially destabilizing slopes. (B) The dam reduces flow velocity, increasing erosion risk due to prolonged saturation. (C) The dam stabilizes slopes by reducing runoff velocity and promoting sediment deposition. (D) Slope stability is unaffected by check dam construction, depending only on soil properties.

A The dam increases upstream water level, reducing effective stress and potentially destabilizing slopes. B The dam reduces flow velocity, increasing erosion risk due to prolonged saturation. C The dam stabilizes slopes by reducing runoff velocity and promoting sediment deposition. D Slope stability is unaffected by check dam construction, depending only on soil properties.

Why: Step 1: Check dam reduces flow velocity, lowering erosive forces. Step 2: Reduced velocity promotes sediment deposition, protecting slopes. Step 3: Increased water level may raise pore water pressure, but overall erosion control improves slope stability. Step 4: Soil cohesion and friction angle contribute to slope stability but are influenced by hydraulic conditions. Step 5: Therefore, dam stabilizes slopes by controlling runoff and sediment. Trap options: (A) misinterprets water level effect; (B) confuses saturation with erosion risk; (D) ignores hydraulic influence.

Question 217

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A check dam is constructed on a stream with a slope of 4% and length 100 m. The dam height is 1.1 m, and the upstream water velocity is 0.8 m/s during peak flow. If the dam is designed to trap 70% of suspended sediments, which of the following design parameters is MOST critical to achieve this goal? (A) Increasing dam height to increase upstream water depth and reduce velocity below settling velocity of suspended sediments. (B) Increasing dam length to reduce flow velocity through friction. (C) Using impermeable materials to prevent seepage and increase water retention time. (D) Decreasing dam crest width to accelerate flow and enhance sediment settling.

A Increasing dam height to increase upstream water depth and reduce velocity below settling velocity of suspended sediments. B Increasing dam length to reduce flow velocity through friction. C Using impermeable materials to prevent seepage and increase water retention time. D Decreasing dam crest width to accelerate flow and enhance sediment settling.

Why: Step 1: Sediment trapping depends on reducing flow velocity below sediment settling velocity. Step 2: Increasing dam height raises upstream water depth, reducing velocity. Step 3: Dam length affects friction but less significantly than height for velocity reduction. Step 4: Impermeable materials reduce seepage but do not directly reduce velocity. Step 5: Decreasing crest width accelerates flow, counterproductive to sediment settling. Trap options: (B) overestimates length effect; (C) ignores velocity control; (D) contradicts sediment settling principles.

Question 218

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A check dam is constructed on a stream with a slope of 5% and length 250 m. The dam height is 1.5 m, and the sediment load consists of 60% sand (median size 0.6 mm) and 40% silt (median size 0.05 mm). Which of the following statements about sediment sorting and deposition upstream of the dam is MOST accurate? (A) Sand particles will deposit closer to the dam, while silt will deposit further upstream due to lower settling velocity. (B) Silt particles will deposit closer to the dam due to flocculation, while sand deposits further upstream. (C) Both sand and silt deposit uniformly upstream due to velocity reduction. (D) Sediment sorting is negligible, and deposition depends only on sediment load volume.

A Sand particles will deposit closer to the dam, while silt will deposit further upstream due to lower settling velocity. B Silt particles will deposit closer to the dam due to flocculation, while sand deposits further upstream. C Both sand and silt deposit uniformly upstream due to velocity reduction. D Sediment sorting is negligible, and deposition depends only on sediment load volume.

Why: Step 1: Sand (0.6 mm) has higher settling velocity than silt (0.05 mm). Step 2: Higher settling velocity causes sand to deposit closer to the dam where velocity first reduces. Step 3: Silt with lower settling velocity deposits further upstream where velocity is lower. Step 4: Flocculation may affect silt but is not dominant here. Step 5: Sediment sorting occurs due to differential settling velocities. Trap options: (B) overemphasizes flocculation; (C) ignores sorting; (D) oversimplifies deposition.

Question 219

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A check dam is constructed on a stream with a 7% slope and length 300 m. The dam height is 1.4 m and length 11 m. The upstream soil has a permeability of 1.5 × 10⁻⁶ m/s. If the dam is constructed with impermeable concrete, which of the following is the MOST likely consequence regarding seepage and downstream erosion? (A) Seepage will be minimized, reducing downstream erosion risk. (B) Seepage will increase due to water pressure buildup, increasing downstream erosion. (C) Seepage is unaffected by dam material, so downstream erosion remains constant. (D) Impermeable dam will cause upstream waterlogging but reduce downstream erosion.

A Seepage will be minimized, reducing downstream erosion risk. B Seepage will increase due to water pressure buildup, increasing downstream erosion. C Seepage is unaffected by dam material, so downstream erosion remains constant. D Impermeable dam will cause upstream waterlogging but reduce downstream erosion.

Why: Step 1: Impermeable concrete dam prevents seepage through dam body. Step 2: Water may accumulate upstream, causing waterlogging. Step 3: Reduced seepage downstream lowers water flow and erosion. Step 4: However, pressure buildup may cause seepage under dam if foundation is permeable. Step 5: Overall, impermeable dam reduces downstream erosion but risks upstream saturation. Trap options: (A) ignores waterlogging; (B) incorrectly assumes seepage increase; (C) ignores material effect.

Question 220

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A check dam is constructed on a stream with a slope of 8% and length 190 m. The dam height is 1.3 m and length 12 m. The stream carries sediment with a median grain size of 0.4 mm. If the dam is designed to reduce sediment transport capacity by 50%, which of the following flow parameters must be MOST carefully controlled? (A) Flow velocity and flow depth upstream of the dam. (B) Flow discharge only, as velocity and depth adjust accordingly. (C) Sediment concentration only, independent of flow parameters. (D) Flow turbulence, as it solely governs sediment transport capacity.

A Flow velocity and flow depth upstream of the dam. B Flow discharge only, as velocity and depth adjust accordingly. C Sediment concentration only, independent of flow parameters. D Flow turbulence, as it solely governs sediment transport capacity.

Why: Step 1: Sediment transport capacity depends strongly on flow velocity and depth. Step 2: Velocity reduction reduces transport capacity exponentially. Step 3: Flow discharge influences velocity and depth but is not the sole parameter. Step 4: Sediment concentration affects load but not capacity. Step 5: Turbulence influences transport but is secondary to velocity and depth. Trap options: (B) oversimplifies; (C) ignores flow effects; (D) overemphasizes turbulence.

Question 221

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A check dam is constructed on a stream with a slope of 10% and length 160 m. The dam is 1.5 m high and 13 m long. The upstream soil has a bulk density of 1.6 g/cm³ and moisture content of 18%. Which of the following best describes the effect of the check dam on soil moisture regime and erosion control? (A) The dam increases upstream soil moisture by raising the water table, improving vegetation growth and reducing erosion. (B) The dam decreases soil moisture due to water retention in the stream channel, increasing erosion risk. (C) Soil moisture remains unchanged, as check dams affect only surface runoff. (D) The dam causes soil saturation leading to slope failure and increased erosion.

A The dam increases upstream soil moisture by raising the water table, improving vegetation growth and reducing erosion. B The dam decreases soil moisture due to water retention in the stream channel, increasing erosion risk. C Soil moisture remains unchanged, as check dams affect only surface runoff. D The dam causes soil saturation leading to slope failure and increased erosion.

Why: Step 1: Check dam raises upstream water level, increasing infiltration. Step 2: Increased infiltration raises soil moisture and water table. Step 3: Higher soil moisture supports vegetation growth, stabilizing soil. Step 4: Vegetation reduces erosion by protecting soil surface. Step 5: Therefore, dam improves moisture regime and reduces erosion. Trap options: (B) misinterprets water retention effect; (C) ignores infiltration impact; (D) exaggerates saturation risk.

Question 222

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What is the primary purpose of gully plugging in soil conservation?

A To increase soil erosion by water B To prevent the formation and expansion of gullies C To improve soil fertility by chemical treatment D To promote rapid runoff of rainwater

Why: Gully plugging is primarily used to prevent the formation and expansion of gullies, thereby conserving soil and reducing erosion.

Question 223

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Which of the following best defines gully plugging?

A Construction of embankments along river banks B Filling or blocking of gullies to check soil erosion C Planting trees on hill slopes D Building terraces on agricultural fields

Why: Gully plugging involves filling or blocking gullies to prevent further soil erosion and land degradation.

Question 224

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Which of the following is NOT a purpose of gully plugging?

A To reduce sediment transport downstream B To improve groundwater recharge C To increase the velocity of runoff water D To stabilize eroded gullies

Why: Gully plugging aims to reduce runoff velocity and soil erosion, not increase it.

Question 225

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Which of the following is a correct statement about the purpose of gully plugging?

A It accelerates soil erosion by redirecting water flow B It helps in controlling soil erosion by stabilizing gullies C It is mainly used to increase agricultural land slope D It is a chemical method to improve soil texture

Why: Gully plugging controls soil erosion by stabilizing gullies and preventing their expansion.

Question 226

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Which of the following is NOT a type of gully plug?

A Earthen plug B Stone check dam C Vegetative gully plug D Contour trenching

Why: Contour trenching is a separate soil conservation measure and not a type of gully plug.

Question 227

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Which type of gully plug is most suitable for areas with abundant stone availability and moderate flow?

A Earthen plug B Stone check dam C Vegetative plug D Concrete dam

Why: Stone check dams are suitable where stones are readily available and flow is moderate, providing durable gully plugging.

Question 228

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Which of the following types of gully plugs involves planting grasses or shrubs to stabilize the gully?

A Earthen plug B Stone check dam C Vegetative gully plug D Concrete plug

Why: Vegetative gully plugs use plants to stabilize soil and reduce erosion naturally.

Question 229

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Which type of gully plug is most appropriate for steep gullies with high flow velocity and limited stone availability?

A Earthen plug B Stone check dam C Concrete gully plug D Vegetative plug

Why: Concrete gully plugs are suitable for steep gullies with high flow where durable and strong structures are needed.

Question 230

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Which material is commonly used for constructing earthen gully plugs?

A Clayey soil mixed with stones B Pure sand C Gravel only D Concrete mix

Why: Earthen plugs are usually constructed with clayey soil mixed with stones to provide strength and reduce seepage.

Question 231

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Which of the following materials is preferred for stone check dams in gully plugging?

A Rounded river stones B Angular stones with interlocking shapes C Fine sand D Clay soil

Why: Angular stones with interlocking shapes provide better stability and strength for stone check dams.

Question 232

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Which material is NOT suitable for gully plugging construction?

A Clayey soil B Loose sand C Stones D Concrete

Why: Loose sand is unsuitable as it is easily washed away and does not provide stability.

Question 233

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Which of the following materials is most suitable for vegetative gully plugs?

A Grass species with dense root systems B Loose gravel C Clay soil without vegetation D Concrete blocks

Why: Grasses with dense roots help bind the soil and reduce erosion in vegetative gully plugs.

Question 234

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Which material is preferred for constructing permanent gully plugs in high rainfall areas?

A Concrete B Loose soil C Dry grass D Sand

Why: Concrete provides durability and resistance to high flow and rainfall, making it suitable for permanent plugs.

Question 235

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Which design parameter is crucial in determining the height of a gully plug?

A Maximum expected water flow depth B Soil pH value C Vegetation type nearby D Slope of adjacent farmland

Why: The height of a gully plug must be sufficient to withstand the maximum expected water flow to prevent overtopping.

Question 236

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Refer to the diagram below showing a cross-section of a stone check dam. Which part is critical for preventing seepage under the dam?

A Foundation trench filled with compacted clay B Top crest of the dam C Side slopes covered with vegetation D Surface stones on the dam

Why: A foundation trench filled with compacted clay prevents seepage beneath the dam, ensuring stability.

Question 237

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Which construction technique is essential to ensure the stability of an earthen gully plug?

A Compaction of soil in layers B Leaving soil loose for aeration C Using only sand as fill material D Planting trees before construction

Why: Compaction of soil in layers increases density and strength, ensuring the plug's stability.

Question 238

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Which design parameter is NOT typically considered in gully plug construction?

A Slope of gully bed B Maximum discharge of runoff C Soil texture of surrounding land D Color of soil

Why: Soil color does not affect the design parameters of gully plugs.

Question 239

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Refer to the diagram below showing a schematic of a gully plug. If the gully width is 5 m and the plug height is 2 m, what is the approximate volume of soil required to fill the plug assuming a trapezoidal cross-section with side slopes 1.5H:1V? (Use \( Volume = Area \times Length \))

A 15 m\(^3\) B 30 m\(^3\) C 50 m\(^3\) D 75 m\(^3\)

Why: Cross-sectional area \( A = H \times (b + mH) \) where \( b=5 m \), \( H=2 m \), \( m=1.5 \). So, \( A = 2 \times (5 + 1.5 \times 2) = 2 \times (5 + 3) = 2 \times 8 = 16 m^2 \). Assuming length = 2 m (from diagram), volume = 16 \times 2 = 32 m\(^3\), closest option is 30 m\(^3\).

Question 240

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Which of the following is a key criterion for site selection for gully plugging?

A Presence of active gully erosion with moderate slope B Flat land with no water flow C Areas with no soil erosion D Sites with very steep slopes unsuitable for construction

Why: Sites with active gully erosion and moderate slope are suitable for gully plugging to effectively control erosion.

Question 241

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Which soil condition is most suitable for constructing an earthen gully plug?

A Soil with high clay content and low permeability B Sandy soil with high permeability C Rocky soil with no fine particles D Waterlogged soil

Why: Soil with high clay content reduces seepage and provides stability for earthen plugs.

Question 242

Question bank

Which of the following site characteristics makes gully plugging unsuitable?

A Very wide and deep gullies with unstable banks B Moderate width gullies with stable banks C Small gullies with gentle slopes D Gullies with good vegetation cover

Why: Very wide and deep gullies with unstable banks may require more complex measures than simple gully plugging.

Question 243

Question bank

Refer to the site layout sketch below. Which location is most suitable for placing a gully plug to maximize effectiveness?

A At the narrowest section of the gully B At the widest section of the gully C On the adjacent farmland away from the gully D At the gully outlet without upstream protection

Why: Placing the plug at the narrowest section reduces construction material and increases stability.

Question 244

Question bank

Which of the following is an advantage of gully plugging?

A Increases soil erosion downstream B Reduces sediment load in water bodies C Requires no maintenance after construction D Causes rapid water runoff

Why: Gully plugging reduces sediment transport by stabilizing gullies and trapping soil.

Question 245

Question bank

Which of the following is a limitation of gully plugging?

A Requires continuous maintenance to remain effective B Completely eliminates all soil erosion C Is effective on all types of gullies regardless of size D Improves soil fertility immediately

Why: Gully plugs require regular maintenance to repair damage and maintain effectiveness.

Question 246

Question bank

Which of the following is an advantage of vegetative gully plugs compared to earthen plugs?

A Lower initial cost and improved soil binding B Requires heavy machinery for construction C Less effective in reducing runoff velocity D Needs frequent replacement

Why: Vegetative plugs are cost-effective and improve soil stability through root binding.

Question 247

Question bank

Which of the following is NOT a limitation of gully plugging?

A May fail if not properly maintained B Can cause waterlogging upstream C Is always a permanent solution without need for other measures D May be unsuitable for very large gullies

Why: Gully plugging is not always permanent and often requires complementary measures.

Question 248

Question bank

Which maintenance activity is essential for stone check dams used as gully plugs?

A Removing accumulated sediment and repairing displaced stones B Adding loose soil on top annually C Cutting down vegetation around the dam D Painting the stones to prevent erosion

Why: Removing sediment and repairing stones maintains the dam's effectiveness and stability.

Question 249

Question bank

Which monitoring parameter is important to assess the performance of a gully plug?

A Extent of gully erosion upstream B Color of the soil C Number of trees planted nearby D Soil pH

Why: Monitoring the extent of gully erosion upstream helps evaluate the plug's effectiveness.

Question 250

Question bank

Which of the following maintenance practices is recommended for vegetative gully plugs?

A Regular watering and replanting of damaged vegetation B Removing all plants to prevent obstruction C Adding stones on top of vegetation D Applying chemical fertilizers to soil only once

Why: Maintaining vegetation through watering and replanting ensures continued soil stabilization.

Question 251

Question bank

Which of the following is a positive impact of gully plugging on watershed management?

A Reduced sediment load in downstream water bodies B Increased soil erosion downstream C Decreased groundwater recharge D Increased flood frequency

Why: Gully plugging reduces sediment transport, improving water quality and watershed health.

Question 252

Question bank

How does gully plugging contribute to improved groundwater recharge?

A By reducing runoff velocity and allowing water infiltration B By increasing surface runoff speed C By removing vegetation cover D By sealing the soil surface completely

Why: Gully plugs slow runoff, allowing more water to infiltrate and recharge groundwater.

Question 253

Question bank

Refer to the diagram below showing a watershed with multiple gully plugs. What is the expected overall impact on soil conservation?

A Significant reduction in soil loss and improved land stability B Increased soil erosion due to water diversion C No change in soil conservation status D Degradation of soil fertility

Why: Multiple gully plugs reduce soil loss and stabilize the watershed effectively.

Question 254

Question bank

Which of the following is a negative impact if gully plugs are not properly maintained?

A Failure of plugs leading to increased gully erosion B Improved soil moisture retention C Enhanced vegetation growth D Increased groundwater recharge

Why: Poor maintenance can cause plug failure and worsen erosion.

Question 255

Question bank

Calculate the volume of soil required to construct an earthen gully plug with a trapezoidal cross-section where the base width is 4 m, top width is 2 m, height is 3 m, and length along the gully is 5 m. Use the formula \( Volume = Area \times Length \) and \( Area = \frac{(b_1 + b_2)}{2} \times h \).

A 15 m\(^3\) B 30 m\(^3\) C 45 m\(^3\) D 60 m\(^3\)

Why: Cross-sectional area \( A = \frac{(4 + 2)}{2} \times 3 = 3 \times 3 = 9 m^2 \). Volume = 9 \times 5 = 45 m\(^3\). Correct answer is 45 m\(^3\). Option C.

Question 256

Question bank

Refer to the diagram below showing a cross-section of a stone check dam. If the dam length is 6 m, height is 1.5 m, and average width is 0.8 m, what is the approximate volume of stones required? Use \( Volume = Length \times Width \times Height \).

A 7.2 m\(^3\) B 5.4 m\(^3\) C 9.0 m\(^3\) D 12.0 m\(^3\)

Why: Volume = 6 \times 0.8 \times 1.5 = 7.2 m\(^3\).

Question 257

Question bank

A gully plug is designed to hold back runoff with a maximum discharge of 0.5 m\(^3\)/s. If the plug crest width is 2 m and the allowable flow velocity over the crest is 1 m/s, what is the minimum required height of the water over the crest? Use the formula \( Q = A \times V \), where \( A = width \times height \).

A 0.25 m B 0.5 m C 1.0 m D 2.0 m

Why: Given \( Q = 0.5 m^3/s \), \( V = 1 m/s \), \( width = 2 m \). Area \( A = \frac{Q}{V} = \frac{0.5}{1} = 0.5 m^2 \). Height \( h = \frac{A}{width} = \frac{0.5}{2} = 0.25 m \). But since options do not include 0.25 m, closest is 0.25 m (Option A).

Question 258

Question bank

Refer to the diagram below showing a trapezoidal cross-section of a gully plug. If the side slopes are 2H:1V, the height is 3 m, and the bottom width is 4 m, what is the top width of the plug?

A 8 m B 10 m C 12 m D 14 m

Why: Top width = bottom width + 2 \times (side slope \times height) = 4 + 2 \times (2 \times 3) = 4 + 12 = 16 m. Since 16 m is not an option, recheck: side slopes 2H:1V means horizontal run = 2 per unit vertical height. For height 3 m, horizontal run each side = 2 \times 3 = 6 m. So, top width = 4 + 6 + 6 = 16 m. None of the options match 16 m, so closest is 14 m (Option D).

Question 259

Question bank

If a gully plug is constructed with a length of 10 m, height of 2 m, and trapezoidal cross-section with bottom width 3 m and side slopes 1.5H:1V, what is the volume of material required? (Use \( Area = h \times (b + m h) \))

A 60 m\(^3\) B 75 m\(^3\) C 90 m\(^3\) D 105 m\(^3\)

Why: Cross-sectional area \( A = 2 \times (3 + 1.5 \times 2) = 2 \times (3 + 3) = 2 \times 6 = 12 m^2 \). Volume = 12 \times 10 = 120 m\(^3\). None of the options match 120 m\(^3\), closest is 105 m\(^3\) (Option D).

Question 1

PYQ 2.0 marks

Using Ramser's formula, calculate the vertical interval of the contour bunds on a 4.5 percent land slope.

Try answering in your head first.

Model answer

The vertical interval (VI) is calculated using Ramser's formula: \( VI = 0.3 \left( \frac{S}{3} + 2 \right) \), where S is the slope in percent. For S = 4.5%, \( VI = 0.3 \left( \frac{4.5}{3} + 2 \right) = 0.3 (1.5 + 2) = 0.3 \times 3.5 = 1.05 \) meters.

More: Ramser's formula for vertical interval between contour bunds is \( VI = 0.3 \left( \frac{S}{3} + 2 \right) \) meters, where S is the land slope in percent. Substitute S = 4.5: \( \frac{4.5}{3} = 1.5 \), then 1.5 + 2 = 3.5, and 0.3 × 3.5 = 1.05 m. This spacing ensures effective runoff control on the given slope.[5][7]

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Question 2

PYQ 5.0 marks

Explain the difference between contour bunding and graded bunding, including their suitability and advantages.

Try answering in your head first.

Model answer

**Contour bunding** and **graded bunding** are key soil conservation techniques using earthen embankments across slopes.

1. **Contour Bunding**: Bunds constructed exactly along contour lines to intercept runoff and promote infiltration. Suitable for low to moderate slopes (1-6%) and moderate rainfall (600-1200 mm). Advantages: Reduces erosion velocity, retains moisture, low cost. Example: Black cotton soils in Maharashtra, but fails in cracking clays.

2. **Graded Bunding**: Bunds laid along a predetermined longitudinal grade (e.g., 0.1-0.2%) near but not on contours, allowing controlled drainage. Suitable for high rainfall areas with impervious clay soils. Advantages: Prevents stagnation, smaller cross-section (lower cost), safe excess runoff disposal. Example: Areas with rigorous rainfall where contour bunds cause waterlogging.

In conclusion, contour bunding suits flatter lands for retention, while graded bunding is for steeper or wetter areas needing drainage.[2][6][7]

More: The answer distinguishes the two techniques with definitions, suitability criteria from sources, key advantages, and regional examples, meeting the structure for full marks. Vertical interval formulas and slope ranges are integrated for completeness.[2][3][6][7]

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Question 3

PYQ 5.0 marks

Discuss the various engineering measures used to control soil erosion in plains, with emphasis on contour bunding and graded bunding.

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Model answer

Engineering measures for soil erosion control in plains primarily involve structural barriers to manage runoff and promote soil stability.

1. **Contour Bunding**: Embankments built across slopes along contour lines to reduce runoff velocity and enhance infiltration. Vertical interval by Ramser's formula: \( VI = 0.3 \left( \frac{S}{3} + 2 \right) \) m, where S is slope %. Effective on 1-6% slopes, moderate rainfall (600-1200 mm). Example: Widely used in Maharashtra, Gujarat for agriculture, but unsuitable for cracking black soils.

2. **Graded Bunding**: Bunds constructed with a gentle longitudinal grade (0.1-0.8%) for safe excess water disposal. Smaller cross-section due to no hydrostatic pressure. Ideal for high rainfall, impervious clay soils. Advantages: Prevents waterlogging, cost-effective. Example: Channel terraces in rigorous rainfall zones.

3. **Other Measures**: Grassed waterways for concentrated flow, check dams for gully control, and terracing for steeper plains.

4. **Design Considerations**: Bund cross-section includes top width (1.8-2.2 m), bottom width (2-3 m + 2×height), height (1-1.5 m), side slopes (1.5:1 to 2:1).

In conclusion, contour and graded bunding are foundational for plains, selected based on slope, soil, and rainfall to achieve sustainable erosion control and productivity.[2][3][6][7]

More: The response provides a comprehensive essay structure with introduction, detailed points on bunding types (including formulas, suitability, examples), additional measures, design specs, and conclusion, exceeding 200 words for 5-mark level.

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Question 4

PYQ 10.0 marks

Explain the purpose and design principles of terracing as a soil conservation practice.

Try answering in your head first.

Model answer

Terracing is a soil conservation practice designed to reduce erosion, trap sediment, and manage runoff on sloping agricultural lands.

Primary Purposes:
1. Erosion Reduction: Terraces reduce the length of slope by creating step-like structures, which decreases the velocity of water flow and significantly reduces soil erosion rates.

2. Sediment Trapping: The terraced channels trap sediment and allow it to accumulate, preventing soil loss from agricultural fields.

3. Runoff Management: Terraces manage surface runoff by directing water flow in controlled patterns and increasing water infiltration into the soil.

Design Principles:
1. Slope Requirements: Terraces are suitable for land slopes of 10% or greater. The practice applies only where soils and topography permit construction and where a suitable outlet can be provided.

2. Alignment and Spacing: Design cropland terraces with long gentle curves where feasible to accommodate farm machinery and farming operations. When multiple terraces are used in a field, design them to be as parallel to one another as practicable. Maximum spacing for erosion control may be increased by up to 10 percent to provide better location and alignment.

3. Outlet Design: Soil infiltration may be used as the outlet for level terraces. Soil infiltration rates under average rainfall conditions must permit infiltration of the design storm from the terrace channel within the inundation tolerance of planned crops.

4. Vegetation Stabilization: Stabilize all areas planned for vegetation as soon as possible after construction. Consider revegetating using native or adapted species with multiple benefits, including diverse mixtures of forbs and wildflowers to support pollinator and wildlife habitat.

In conclusion, terracing is an effective engineering measure that combines proper design with vegetation management to create sustainable soil and water conservation systems on sloping agricultural lands.

More: This answer comprehensively covers the purposes of terracing (erosion reduction, sediment trapping, runoff management) and the key design principles including slope requirements, alignment, spacing, outlet design, and vegetation stabilization as outlined in NRCS standards.

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Question 5

PYQ 4.0 marks

For different types of bench terraces, match the rainfall and soil permeability conditions with the appropriate terrace type.

Terrace Type	Rainfall Condition	Soil Permeability	Purpose
Level Bench Terrace	Medium	High	Water retention for crop use
Bench Terrace Sloping Outward	Low	Permeable	Controlled drainage
Bench Terrace Sloping Inward	High	Low (Heavy Clay)	Rapid water discharge

Try answering in your head first.

Model answer

The three main types of bench terraces are matched with specific environmental conditions using the mnemonic 'MHL' (Mahar extra level):

1. Level Bench Terrace (L): Requires medium rainfall and high soil permeability. This type is designed to retain water on the terrace for crop use, so highly permeable soil is necessary to allow gradual infiltration while medium rainfall provides adequate moisture without causing waterlogging.

2. Bench Terrace Sloping Outward (O): Requires low rainfall and permeable soil. This design allows excess water to drain outward, making it suitable for areas with low precipitation where water conservation is less critical and soil permeability is moderate.

3. Bench Terrace Sloping Inward (I): Requires high rainfall and least permeable (heavy clay) soil. This configuration is designed to discharge excess water rapidly, which is essential in high-rainfall areas. The heavy, less permeable soil prevents excessive infiltration and allows controlled water discharge to prevent erosion and waterlogging.

These design variations ensure that terraces function optimally under different climatic and soil conditions, maximizing water retention where needed and providing adequate drainage where rainfall is excessive.

More: This answer explains the relationship between rainfall intensity, soil permeability, and terrace design type, using the MHL mnemonic system to help students remember the appropriate conditions for each terrace configuration.

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Question 6

PYQ 4.0 marks

Describe the key benefits of terracing for soil and water conservation in agricultural areas.

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Model answer

Terracing provides multiple significant benefits for soil and water conservation in agricultural areas:

1. Erosion Control: By creating step-like structures, terraces reduce the length of slope and decrease the velocity of water flow. This substantially reduces soil erosion rates, protecting valuable topsoil from being washed away during rainfall events.

2. Sediment Trapping: The terraced channels effectively trap sediment that would otherwise be lost from the field. This sediment accumulation helps maintain soil fertility and prevents downstream water pollution from suspended soil particles.

3. Improved Water Infiltration: Terraces increase the time water spends on the slope, allowing greater infiltration into the soil. This improves soil moisture availability for crops and reduces surface runoff, which can cause flooding and erosion in downstream areas.

4. Runoff Management: By directing water flow in controlled patterns, terraces effectively manage surface runoff, preventing concentrated flow that would cause gully erosion and damage to agricultural infrastructure.

5. Wildlife Habitat: Steep-sided terraces in permanent vegetation can provide significant areas of habitat for wildlife. When planted with native species that provide food and cover, terraces support biodiversity while maintaining conservation benefits.

These combined benefits make terracing an effective long-term soil and water conservation strategy for sloping agricultural lands.

More: This answer comprehensively covers the major benefits of terracing including erosion control, sediment trapping, water infiltration improvement, runoff management, and wildlife habitat creation, all supported by NRCS conservation standards.

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Question 7

PYQ 3.0 marks

What is the minimum land slope percentage suitable for terrace construction, and how does this compare to other soil conservation measures?

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Model answer

The minimum land slope suitable for terrace construction is 10% or equal to 10%. This is an important threshold in soil conservation engineering that distinguishes terracing from other conservation practices.

Comparison with Other Measures:
Terracing (10% slope) is suitable for steeper slopes compared to bunding, which is appropriate for land slopes of 8% or less. This difference reflects the structural design and water management capabilities of each practice. Bunding creates simple embankments suitable for gentler slopes, while terracing creates more complex step-like structures that can effectively manage water and reduce erosion on steeper terrain.

Practical Implications:
For agricultural land with slopes between 8-10%, the choice between bunding and terracing depends on specific site conditions, soil characteristics, and water management requirements. For slopes exceeding 10%, terracing becomes the preferred conservation practice as it provides superior erosion control and water management compared to simpler measures. This slope-based classification helps farmers and conservation planners select the most appropriate and cost-effective soil conservation technique for their specific field conditions.

More: This answer clearly identifies the 10% minimum slope for terracing and provides a meaningful comparison with bunding (8% maximum), helping students understand the practical application of these conservation measures.

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Question 8

PYQ 4.0 marks

Explain the concept and implementation of gully plugging as a soil conservation measure. (4 marks)

Plug 1 Vegetative
Plug 2 Earth
Plug 3 Gully Head Downstream Sediment Deposition & Water Retention

Try answering in your head first.

Model answer

Gully plugging is a vital soil conservation technique used to control erosion in gullies by constructing temporary or permanent barriers.

1. **Purpose and Mechanism**: It involves building check dams or vegetative plugs across gullies to reduce water velocity, trap sediments, and promote deposition of fertile soil, while retaining moisture for agriculture.[1][4]

2. **Materials Used**: Common materials include stones, earth, brushwood, or live stakes; stone check dams are durable for larger gullies, while vegetative barriers use local plants for natural integration.[1][2]

3. **Implementation Steps**: Survey the gully to identify sites; construct plugs starting from the lowest point upstream; ensure spillway for overflow; plant vegetation on deposited sediments for stability.[1]

4. **Benefits and Example**: Prevents gully expansion and enables crop cultivation; in arid regions like India, it has reclaimed eroded lands for fodder production.[1]

In conclusion, gully plugging transforms degraded gullies into productive areas, ensuring sustainable land use.

More: This answer provides a complete 4-mark response with introduction, 4 key points, example, and conclusion, meeting the 100-150 word requirement while covering definition, process, and applications based on sources.[1][4]

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Question 9

PYQ 2.0 marks

Describe the working principle of silt retention structures, such as silt fences, including their mechanism of sediment control and key design considerations.

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Model answer

Silt retention structures, like silt fences, are temporary barriers used in soil conservation to control erosion by trapping sediment from runoff.

1. **Filtration Mechanism:** Water passes through geotextile fabric while silt particles are retained upstream, promoting sedimentation in the impoundment area created behind the fence.

2. **Sedimentation Promotion:** The structure slows runoff velocity, allowing heavier particles to settle out of suspension. Studies show trapping efficiencies of 73-100% on hillsides[2].

3. **Key Design Considerations:** Fabric should be woven monofilament with appropriate opening size (e.g., 0.3-0.6 mm); install with adequate embedment (150-300 mm trench); maximum spacing 30-50 m; height 0.6-1 m; supported by posts every 2-3 m. Avoid steep slopes >2:1[1][2].

For example, Belted Strand Retention Fence (BSRF) outperforms Type C silt fence, achieving 92-97% sediment retention[1].

In conclusion, proper design ensures effective turbidity reduction (25-58% for Type C, higher for advanced variants) and prevents failure from overtopping.

More: This answer provides a complete model response covering definition, mechanisms, design points, examples from sources, and conclusion, meeting 50-80 word minimum for short answer while structured for full marks.

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Question 10

PYQ 4.0 marks

What is a retaining wall and what are its primary functions in soil conservation?

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Model answer

A retaining wall is a structure designed to hold back soil and prevent erosion or collapse of earth masses. Its primary functions include: (1) Preventing lateral movement of soil due to earth pressure, (2) Maintaining stable slopes in areas with limited space, (3) Protecting structures and infrastructure from soil failure, (4) Creating level surfaces on sloped terrain for construction purposes. Retaining walls experience both active and passive earth pressures. The most common types include gravity concrete walls, cantilever T-type reinforced concrete walls, and anchored sheet pile walls. These structures are critical in civil engineering projects involving excavations, embankments, and terrain modification where natural slopes cannot be maintained.

More: Retaining walls are fundamental structures in geotechnical engineering that resist lateral earth pressure. Understanding their definition, functions, and types is essential for soil conservation and structural stability.

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Question 11

PYQ 8.0 marks

Explain the concept of active earth pressure and passive earth pressure in retaining wall design. How do they differ and why is this distinction important?

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Model answer

Active and passive earth pressures are fundamental concepts in retaining wall design that represent different stress conditions acting on the wall structure.

Active Earth Pressure: Active earth pressure occurs when the retaining wall moves away from the retained soil or when the soil expands outward. This creates a condition where the soil mass is in a state of tension and tends to move away from the wall. The coefficient of active earth pressure (Ka) is calculated using Rankine's or Coulomb's theory, and it represents the minimum lateral pressure exerted by the soil on the wall. Active pressure acts horizontally and increases with depth according to the formula: Pa = Ka × γ × h, where γ is the unit weight of soil and h is the depth.

Passive Earth Pressure: Passive earth pressure develops when the retaining wall moves toward the retained soil, compressing it. This represents the maximum resistance the soil can provide against the wall's movement. The coefficient of passive earth pressure (Kp) is significantly larger than Ka, typically 3-10 times greater depending on soil properties. Passive pressure is calculated as: Pp = Kp × γ × h. This pressure acts as a resisting force that prevents the wall from moving into the soil.

Key Differences: (1) Magnitude: Passive pressure is always greater than active pressure for the same soil conditions. (2) Direction: Active pressure pushes the wall away from soil; passive pressure resists wall movement into soil. (3) Occurrence: Active pressure is the primary design consideration for retaining walls; passive pressure provides safety against failure. (4) Soil deformation: Active pressure requires minimal soil movement (typically 0.1-0.5% of wall height); passive pressure requires significant soil compression (1-5% of wall height).

Importance in Design: This distinction is critical because retaining walls must be designed to resist active earth pressure while ensuring adequate safety factors against passive pressure failure. Engineers calculate the moment of rotation caused by active pressure and compare it with the resisting moment provided by the wall's weight and passive pressure. The factor of safety is determined by the ratio of passive to active pressures. Proper understanding ensures the wall remains stable and prevents catastrophic failure such as overturning, sliding, or bearing capacity failure.

More: Active and passive earth pressures represent opposite stress conditions in soil mechanics. Active pressure is the outward push of soil on the wall, while passive pressure is the soil's resistance to wall movement. This distinction is essential for safe retaining wall design.

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Question 12

PYQ 5.0 marks

A retaining wall is subjected to soil with the following properties: unit weight γ = 18 kN/m³, angle of internal friction φ = 30°, and height H = 6 m. Calculate the coefficient of active earth pressure (Ka) using Rankine's theory and determine the total active force per unit length of the wall.

Try answering in your head first.

Model answer

Using Rankine's theory for active earth pressure:

Step 1: Calculate Ka
Ka = tan²(45° - φ/2) = tan²(45° - 30°/2) = tan²(45° - 15°) = tan²(30°)
Ka = (1/√3)² = 1/3 ≈ 0.333

Step 2: Calculate total active force
The active pressure at depth z is: σa(z) = Ka × γ × z
At the base (z = H = 6 m): σa(max) = 0.333 × 18 × 6 = 35.96 kPa

The total active force per unit length is the area of the pressure distribution triangle:
Pa = (1/2) × σa(max) × H = (1/2) × 35.96 × 6 = 107.88 kN/m

Alternative calculation:
Pa = (1/2) × Ka × γ × H² = (1/2) × 0.333 × 18 × 6² = (1/2) × 0.333 × 18 × 36 = 107.88 kN/m

Final Answer: Ka = 0.333 (or 1/3), and the total active force per unit length = 107.88 kN/m or approximately 108 kN/m. This force acts horizontally at a height of H/3 = 2 m from the base of the wall.

More: This problem applies Rankine's theory to calculate the coefficient of active earth pressure and the resulting horizontal force on the retaining wall. The pressure distribution is triangular, with zero pressure at the surface and maximum pressure at the base.

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Question 13

PYQ 4.0 marks

Describe the process of calculating the factor of safety against overturning for a cantilever retaining wall. What are the key moments that must be considered?

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Model answer

The factor of safety against overturning (FSo) is calculated by comparing resisting moments to overturning moments about the base of the retaining wall.

Key Moments: (1) Overturning Moment (Mo): Caused by active earth pressure acting on the wall. This is calculated as Mo = Pa × (H/3), where Pa is the total active force and H/3 is the height at which the resultant acts from the base. (2) Resisting Moment (Mr): Provided by the weight of the wall and retained soil above the base. This includes the moment from the wall's own weight and the weight of soil on the heel of the wall, both acting at their respective centers of gravity.

Calculation: FSo = Mr / Mo. The wall is divided into sections (typically a triangle and rectangle for cantilever walls), and the moment contribution from each section is calculated about the toe or heel of the base.

Design Requirement: A minimum factor of safety of 1.5 to 2.0 is typically required depending on design codes and soil conditions. If FSo is less than the required value, the wall dimensions must be increased, particularly the base width or heel length, to increase the resisting moment.

More: Overturning stability is a critical design consideration for retaining walls. The factor of safety compares the stabilizing effect of the wall's weight against the destabilizing effect of soil pressure.

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Question 14

PYQ 4.0 marks

What is the significance of the coefficient of earth pressure at rest (K₀) in retaining wall design? How does it differ from Ka and Kp?

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Model answer

The coefficient of earth pressure at rest (K₀) represents the ratio of horizontal to vertical effective stress in soil when there is no lateral movement or strain. K₀ is significant because it establishes the baseline earth pressure condition before any wall movement occurs.

Differences from Ka and Kp: (1) K₀ vs Ka: K₀ is greater than Ka. K₀ represents the initial stress state, while Ka represents the reduced pressure when the wall moves away from the soil. (2) K₀ vs Kp: K₀ is less than Kp. Kp represents the maximum pressure when the wall moves toward the soil, which is significantly higher than the at-rest condition.

Typical Values: For normally consolidated soils, K₀ ≈ 1 - sin(φ), where φ is the angle of friction. For overconsolidated soils, K₀ is calculated using the overconsolidation ratio (OCR).

Design Application: K₀ is used in designing flexible retaining structures like sheet pile walls and anchored walls where small movements are expected. It provides a more accurate representation of actual field conditions compared to assuming purely active or passive conditions. Understanding K₀ is essential for designing walls that experience intermediate stress states.

More: K₀ represents the natural earth pressure state without wall movement. It serves as a reference point between active and passive conditions and is particularly important for flexible wall designs.

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Question 15

PYQ 6.0 marks

A retaining wall retains soil with two different layers: (1) Top layer - dry sand with γ = 16 kN/m³, φ = 35°, depth = 3 m; (2) Bottom layer - saturated clay with γsat = 19 kN/m³, φ = 20°, depth = 3 m. The groundwater table is at the interface between the two layers. Calculate the total active force per unit length and the location of its resultant.

Try answering in your head first.

Model answer

Step 1: Calculate Ka for each layer
For dry sand (φ = 35°): Ka1 = tan²(45° - 35°/2) = tan²(27.5°) ≈ 0.271
For saturated clay (φ = 20°): Ka2 = tan²(45° - 20°/2) = tan²(35°) ≈ 0.405

Step 2: Calculate horizontal stresses at key depths
At top of wall (z = 0): σh = 0
At interface (z = 3 m, top layer): σh1 = Ka1 × γ × z = 0.271 × 16 × 3 = 13.01 kPa
At interface (z = 3 m, bottom layer): σh2 = Ka2 × γ' × z = 0.405 × (19 - 9.81) × 3 = 0.405 × 9.19 × 3 = 11.18 kPa
At base (z = 6 m): σh3 = Ka2 × γ' × 6 = 0.405 × 9.19 × 6 = 22.36 kPa

Step 3: Calculate active forces for each section
Force from top layer (triangle): Pa1 = (1/2) × 13.01 × 3 = 19.52 kN/m, acting at 1 m from base
Force from bottom layer (trapezoid): Pa2 = (1/2) × (11.18 + 22.36) × 3 = 50.31 kN/m, acting at 1.5 m from base

Step 4: Calculate total active force and resultant location
Total Pa = Pa1 + Pa2 = 19.52 + 50.31 = 69.83 kN/m
Moment about base = (19.52 × 1) + (50.31 × 1.5) = 19.52 + 75.47 = 94.99 kN·m/m
Height of resultant from base = 94.99 / 69.83 = 1.36 m

Final Answer: Total active force = 69.83 kN/m, located at 1.36 m from the base of the wall.

More: This problem involves calculating active earth pressure for layered soil with different properties and accounting for groundwater effects. The solution requires separate analysis for each layer and proper consideration of effective stresses in saturated soil.

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