Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct answer of the following (any seven):
An unconfined aquifer is one in which
A unit hydrograph has one unit of
The instrument to measure wind velocity is
For a basin, in a given period $ \Delta t $, there is no change in the groundwater and soil water status. If P = precipitation, R = total runoff, E = Evapotranspiration and $ \Delta S $ = increase in the surface water storage basin, the hydrological water budget equation states
The instrument to measure humidity variation in atmosphere is
For a given storm, other factors remaining same
Most accurate method of finding average depth of rainfall over an area is
Base-flow separation is performed
Virgin flow means
Flow duration curve is the graph between
Q.2 Solve this question:
A stream size of 150 lit/sec was released from the diversion headwork to irrigate a land of area 18 hectare. The stream size when measured at the delivery to the field channels is 120 lit/sec. The stream was continued for 8 hours. The effective root zone depth is 1.80 m. The application losses in the field are estimated to be $ 440 \, m^3 $. The depth of water penetration was 1.80 m and 1.20 m at the head and tail of the run respectively. The available water holding capacity of the soil is 21 cm/m and irrigation was done at 60% depletion of available moisture $ (A_m) $. Find conveyance efficiency $ (E_c) $, water application efficiency $ (E_a) $, water storage efficiency $ (E_s) $ and water distribution efficiency $ (E_d) $. The stream size delivered to the plot was 100 lit/sec.
Q.3 Solve this question:
An irrigation channel is to be designed for a discharge of 50 cumecs adopting the available ground slope of $ 1.5 \times 10^{-4} $. The riverbed material has a median size of 2.0 mm. Design the channel and recommend the size of the coarser material to be excluded or ejected from the channel for its efficient functioning. Use Lacey theory. Assume side slope of 0.5 H: 1 V. The following are the rates of rainfall for successive 30 minutes period for storm duration of 210 minutes: 5.5; 6.0; 12.5; 8.0; 3.25; 3.25; 6.5 cm/hr. Take $ \phi $-index as 4.5 cm/hr. Calculate the total runoff (in cm) and total rainfall.
Q.4 Solve both questions:
Discuss SCS-CN method of estimating runoff volume.
Land use and corresponding runoff coefficient are as given below:
| Land use | Area (ha) | Runoff coefficient |
|---|---|---|
| Roads | 8 | 0.70 |
| Lawn | 17 | 0.10 |
| Residential area | 50 | 0.30 |
| Industrial area | 10 | 0.80 |
Calculate the equivalent runoff coefficient.
Q.5 Solve this question:
A 30 cm well completely penetrates an unconfined aquifer of saturated depth 40 m. After a long period of pumping at a steady rate of 1500 lpm, the drawdown, in two observation wells 25 m and 75 m from the pumping well were found to be 3.5 m and 2.0 m respectively. Determine the transmissivity of the aquifer. What is the drawdown at the pumping well?
Q.6 Solve this question:
Determine the location of closed tile drains below ground for the following data:
Root zone depth = 1.5 m
Capillary rise in soil = 0.3 m
Coefficient of permeability of soil = $ 1.5 \times 10^{-4} \, m/s $
Drainage capacity = $ 0.11 \, m^3/s/km^2 $
Spacing of drains = 200 m
Depth of impervious stratum below ground = 10.0 m
Q.7 Solve this question:
Discuss elementary profile of gravity. How are its dimensions fixed? Also derive normal stresses and principal stresses on the elementary profile.
Q.8 Solve this question:
Use the information from the table given below to find moisture content in the root zone at different depths, depth of water available in the root zone at different depths, total depth of water available in the root zone and the soil moisture deficit. Assuming peak rate of consumptive use as 8 mm/day also find the irrigation interval:
| Depth of sampling (m) | Wt. of moist soil sample (gm) | Oven dry wt. (gm) |
|---|---|---|
| 0.0 - 0.30 | 98.80 | 94.60 |
| 0.30 - 0.60 | 96.60 | 92.10 |
| 0.60 - 0.90 | 95.00 | 90.60 |
| 0.90 - 1.20 | 94.00 | 89.40 |
The bulk density of the soil in the root zone was 1.60 gm/cc. The moisture holding capacity of the soil at field capacity was 19.60 cm/m depth.
Q.9 Solve this question:
The GCA for a distributary is 5000 hectare (ha) 80% of which is CCA. The intensity of irrigation for Rabi is 50% and for Kharif is 30%. The average duty at the head of the distributary is 2000 ha/cumec for Rabi and 900 ha/cumec for Kharif. Determine discharge at the head of distributary. What will be design discharge if conveyance efficiency is 70%, time factor is 0.8 and capacity factor is 0.9?
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct answer of the following (any seven):
An unconfined aquifer is one in which
A unit hydrograph has one unit of
The instrument to measure wind velocity is
For a basin, in a given period $ \Delta t $, there is no change in the groundwater and soil water status. If P = precipitation, R = total runoff, E = Evapotranspiration and $ \Delta S $ = increase in the surface water storage basin, the hydrological water budget equation states
The instrument to measure humidity variation in atmosphere is
For a given storm, other factors remaining same
Most accurate method of finding average depth of rainfall over an area is
Base-flow separation is performed
Virgin flow means
Flow duration curve is the graph between
Q.2 Solve this question:
A stream size of 150 lit/sec was released from the diversion headwork to irrigate a land of area 18 hectare. The stream size when measured at the delivery to the field channels is 120 lit/sec. The stream was continued for 8 hours. The effective root zone depth is 1.80 m. The application losses in the field are estimated to be $ 440 \, m^3 $. The depth of water penetration was 1.80 m and 1.20 m at the head and tail of the run respectively. The available water holding capacity of the soil is 21 cm/m and irrigation was done at 60% depletion of available moisture $ (A_m) $. Find conveyance efficiency $ (E_c) $, water application efficiency $ (E_a) $, water storage efficiency $ (E_s) $ and water distribution efficiency $ (E_d) $. The stream size delivered to the plot was 100 lit/sec.
Q.3 Solve this question:
An irrigation channel is to be designed for a discharge of 50 cumecs adopting the available ground slope of $ 1.5 \times 10^{-4} $. The riverbed material has a median size of 2.0 mm. Design the channel and recommend the size of the coarser material to be excluded or ejected from the channel for its efficient functioning. Use Lacey theory. Assume side slope of 0.5 H: 1 V. The following are the rates of rainfall for successive 30 minutes period for storm duration of 210 minutes: 5.5; 6.0; 12.5; 8.0; 3.25; 3.25; 6.5 cm/hr. Take $ \phi $-index as 4.5 cm/hr. Calculate the total runoff (in cm) and total rainfall.
Q.4 Solve both questions:
Discuss SCS-CN method of estimating runoff volume.
Land use and corresponding runoff coefficient are as given below:
| Land use | Area (ha) | Runoff coefficient |
|---|---|---|
| Roads | 8 | 0.70 |
| Lawn | 17 | 0.10 |
| Residential area | 50 | 0.30 |
| Industrial area | 10 | 0.80 |
Calculate the equivalent runoff coefficient.
Q.5 Solve this question:
A 30 cm well completely penetrates an unconfined aquifer of saturated depth 40 m. After a long period of pumping at a steady rate of 1500 lpm, the drawdown, in two observation wells 25 m and 75 m from the pumping well were found to be 3.5 m and 2.0 m respectively. Determine the transmissivity of the aquifer. What is the drawdown at the pumping well?
Q.6 Solve this question:
Determine the location of closed tile drains below ground for the following data:
Root zone depth = 1.5 m
Capillary rise in soil = 0.3 m
Coefficient of permeability of soil = $ 1.5 \times 10^{-4} \, m/s $
Drainage capacity = $ 0.11 \, m^3/s/km^2 $
Spacing of drains = 200 m
Depth of impervious stratum below ground = 10.0 m
Q.7 Solve this question:
Discuss elementary profile of gravity. How are its dimensions fixed? Also derive normal stresses and principal stresses on the elementary profile.
Q.8 Solve this question:
Use the information from the table given below to find moisture content in the root zone at different depths, depth of water available in the root zone at different depths, total depth of water available in the root zone and the soil moisture deficit. Assuming peak rate of consumptive use as 8 mm/day also find the irrigation interval:
| Depth of sampling (m) | Wt. of moist soil sample (gm) | Oven dry wt. (gm) |
|---|---|---|
| 0.0 - 0.30 | 98.80 | 94.60 |
| 0.30 - 0.60 | 96.60 | 92.10 |
| 0.60 - 0.90 | 95.00 | 90.60 |
| 0.90 - 1.20 | 94.00 | 89.40 |
The bulk density of the soil in the root zone was 1.60 gm/cc. The moisture holding capacity of the soil at field capacity was 19.60 cm/m depth.
Q.9 Solve this question:
The GCA for a distributary is 5000 hectare (ha) 80% of which is CCA. The intensity of irrigation for Rabi is 50% and for Kharif is 30%. The average duty at the head of the distributary is 2000 ha/cumec for Rabi and 900 ha/cumec for Kharif. Determine discharge at the head of distributary. What will be design discharge if conveyance efficiency is 70%, time factor is 0.8 and capacity factor is 0.9?
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct answer from the following (any seven):
The area below a direct runoff graph is
A confined aquifer is one in which
An unconfined aquifer is one in which
For a well penetrating an unconfined aquifer having permeability $ k = 4 \times 10^{-4} \,\, m/s $, the radius of influence for a drawdown of 5 m is approximately
If it rains between 2 p.m. and 3 p.m. and the entire basin area just starts contributing water at 3 p.m. to the outlet, then time of concentration will be
The area between the isohyets 45 cm and 55 cm is 100 square km and between 55 cm and 65 cm is 150 square km. The average depth of annual precipitation over the above basin of 250 square km will be
S-hydrograph is used to obtain unit hydrograph of
The runoff increases with
Infiltration rate is always
A rain gauge should preferably be fixed
Q.2 Solve both questions:
Discuss different infiltration indices.
The mass curve of rainfall of duration 180 minutes on a catchment is given below in the table. The catchment had an initial loss of 0.5 cm, the phi-index (index) of the catchment is known to be 0.4 cm/hr. Calculate the total surface runoff due to this storm.
| Time (minute) | 0 | 30 | 60 | 80 | 100 | 120 | 150 | 180 |
|---|---|---|---|---|---|---|---|---|
| Cumulative rainfall (cm) | 0 | 0.6 | 1.3 | 2.6 | 2.8 | 3.0 | 3.2 | 3.3 |
Q.3 Solve this question:
A small tube with a cross-sectional area of $ 40 \,\, cm^2 $ is filled with soil and laid horizontally. The open end of the tube is saturated, and after 15 minutes, $ 100 \,\, cm^3 $ of water have infiltrated into the tube. If the saturated hydraulic conductivity of the soil is $ 0.4 \,\, cm/hr $ determine how much infiltration would have taken place in 30 minutes if the soil column had initially been placed upright with its upper surface saturated. (Use Philip's equation).
Q.4 Solve this question:
The peak of flood hydrograph due to a 3-h duration isolated storm in a catchment is 270 cumecs. Total depth of rainfall is 5.9 cm. Assuming an average infiltration loss of $ 0.3 \,\, cm/h $ and a constant base flow of 20 cumecs, estimate the peak of 3-h unit hydrograph. If the area of catchment is given as 567 sq.km, determine the base width of 3-h unit hydrograph assuming it to be triangular in shape.
Q.5 Solve this question:
At a certain point in an unconfined aquifer of $ 3 \,\, km^2 $ area, the water table was at an elevation of 102.00 m. Due to natural recharge in a wet season, its level rose to 103.20 m. A volume of $ 1.5 \,\, mm^3 $ of water was then pumped out of the aquifer causing the water table to reach to a level of 101.20 m. Assuming the water table in the entire aquifer to respond to a similar way, estimate (i) the specific yield of the aquifer and (ii) the volume of recharge during wet season.
Q.6 Solve this question:
Find the probable life of a reservoir with initial capacity of 4000 ha-m if the average annual inflow is 8000 ha-m and the average annual sediment inflow is $ 2 \times 10^5 $ tons. Assume a specific weight of sediment as $ 1120 \,\, kg/m^3 $. The useful life of reservoir is terminated when 80% of its initial capacity is filled with sediment. The values of trap efficiency for different values of capacity inflow ratio is given in the table below:
| Capacity inflow ratio | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 |
|---|---|---|---|---|---|---|---|---|---|---|
| Trap efficiency, % | 87 | 93 | 95 | 95.5 | 96 | 96.5 | 97 | 97.3 | 97.4 | 97.5 |
Q.7 Solve this question:
A 12-hectare land is to be irrigated by a pump working for 12 hours a day. Root zone depth is 0.9 m and the field capacity of the soil is 28% while permanent wilting point is 17%. Density of soil is $ 1.36 \,\, gm/cm^3 $ and the water application efficiency is 70%. The soil is to be irrigated when 50% of the available water has depleted. The peak evapotranspiration is $ 5.0 \,\, mm/day $ and the system is to run for 10 hours a day. Determine (a) net irrigation depth, (b) gross irrigation depth, (c) irrigation period, (d) area to be irrigated per day and (e) the system capacity.
Q.8 Solve this question:
Use the information from the table given below to find moisture content in the root zone at different depths, depth of water available in the root zone at different depths, total depth of water available in the root zone and the soil moisture deficit. Assuming peak rate of consumptive use as $ 8 \,\, mm/day $, also find the irrigation interval:
| Depth of sampling (m) | Wt. of moist soil sample (gm) | Oven dry wt. (gm) |
|---|---|---|
| 0 - 0.30 | 98.80 | 94.60 |
| 0.30 - 0.60 | 96.60 | 92.10 |
| 0.60 - 0.90 | 95.00 | 90.60 |
| 0.90 - 1.20 | 94.00 | 89.40 |
The bulk density of the soil in the root zone was $ 1.60 \,\, gm/cc $. The moisture holding capacity of the soil at field capacity $ 19.60 \,\, cm/m $ depth.
Q.9 Write short notes on the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct answer from the following (any seven):
The area below a direct runoff graph is
A confined aquifer is one in which
An unconfined aquifer is one in which
For a well penetrating an unconfined aquifer having permeability $ k = 4 \times 10^{-4} \,\, m/s $, the radius of influence for a drawdown of 5 m is approximately
If it rains between 2 p.m. and 3 p.m. and the entire basin area just starts contributing water at 3 p.m. to the outlet, then time of concentration will be
The area between the isohyets 45 cm and 55 cm is 100 square km and between 55 cm and 65 cm is 150 square km. The average depth of annual precipitation over the above basin of 250 square km will be
S-hydrograph is used to obtain unit hydrograph of
The runoff increases with
Infiltration rate is always
A rain gauge should preferably be fixed
Q.2 Solve both questions:
Discuss different infiltration indices.
The mass curve of rainfall of duration 180 minutes on a catchment is given below in the table. The catchment had an initial loss of 0.5 cm, the phi-index (index) of the catchment is known to be 0.4 cm/hr. Calculate the total surface runoff due to this storm.
| Time (minute) | 0 | 30 | 60 | 80 | 100 | 120 | 150 | 180 |
|---|---|---|---|---|---|---|---|---|
| Cumulative rainfall (cm) | 0 | 0.6 | 1.3 | 2.6 | 2.8 | 3.0 | 3.2 | 3.3 |
Q.3 Solve this question:
A small tube with a cross-sectional area of $ 40 \,\, cm^2 $ is filled with soil and laid horizontally. The open end of the tube is saturated, and after 15 minutes, $ 100 \,\, cm^3 $ of water have infiltrated into the tube. If the saturated hydraulic conductivity of the soil is $ 0.4 \,\, cm/hr $ determine how much infiltration would have taken place in 30 minutes if the soil column had initially been placed upright with its upper surface saturated. (Use Philip's equation).
Q.4 Solve this question:
The peak of flood hydrograph due to a 3-h duration isolated storm in a catchment is 270 cumecs. Total depth of rainfall is 5.9 cm. Assuming an average infiltration loss of $ 0.3 \,\, cm/h $ and a constant base flow of 20 cumecs, estimate the peak of 3-h unit hydrograph. If the area of catchment is given as 567 sq.km, determine the base width of 3-h unit hydrograph assuming it to be triangular in shape.
Q.5 Solve this question:
At a certain point in an unconfined aquifer of $ 3 \,\, km^2 $ area, the water table was at an elevation of 102.00 m. Due to natural recharge in a wet season, its level rose to 103.20 m. A volume of $ 1.5 \,\, mm^3 $ of water was then pumped out of the aquifer causing the water table to reach to a level of 101.20 m. Assuming the water table in the entire aquifer to respond to a similar way, estimate (i) the specific yield of the aquifer and (ii) the volume of recharge during wet season.
Q.6 Solve this question:
Find the probable life of a reservoir with initial capacity of 4000 ha-m if the average annual inflow is 8000 ha-m and the average annual sediment inflow is $ 2 \times 10^5 $ tons. Assume a specific weight of sediment as $ 1120 \,\, kg/m^3 $. The useful life of reservoir is terminated when 80% of its initial capacity is filled with sediment. The values of trap efficiency for different values of capacity inflow ratio is given in the table below:
| Capacity inflow ratio | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 |
|---|---|---|---|---|---|---|---|---|---|---|
| Trap efficiency, % | 87 | 93 | 95 | 95.5 | 96 | 96.5 | 97 | 97.3 | 97.4 | 97.5 |
Q.7 Solve this question:
A 12-hectare land is to be irrigated by a pump working for 12 hours a day. Root zone depth is 0.9 m and the field capacity of the soil is 28% while permanent wilting point is 17%. Density of soil is $ 1.36 \,\, gm/cm^3 $ and the water application efficiency is 70%. The soil is to be irrigated when 50% of the available water has depleted. The peak evapotranspiration is $ 5.0 \,\, mm/day $ and the system is to run for 10 hours a day. Determine (a) net irrigation depth, (b) gross irrigation depth, (c) irrigation period, (d) area to be irrigated per day and (e) the system capacity.
Q.8 Solve this question:
Use the information from the table given below to find moisture content in the root zone at different depths, depth of water available in the root zone at different depths, total depth of water available in the root zone and the soil moisture deficit. Assuming peak rate of consumptive use as $ 8 \,\, mm/day $, also find the irrigation interval:
| Depth of sampling (m) | Wt. of moist soil sample (gm) | Oven dry wt. (gm) |
|---|---|---|
| 0 - 0.30 | 98.80 | 94.60 |
| 0.30 - 0.60 | 96.60 | 92.10 |
| 0.60 - 0.90 | 95.00 | 90.60 |
| 0.90 - 1.20 | 94.00 | 89.40 |
The bulk density of the soil in the root zone was $ 1.60 \,\, gm/cc $. The moisture holding capacity of the soil at field capacity $ 19.60 \,\, cm/m $ depth.