CE-603-A Water Resources Engineering - May 2023 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aExplain Thiessen polygon method of calculating mean precipitation over an area.
   How to answer

   • Definition of mean precipitation and need for areal average
   • Construction of Thiessen polygons by joining stations and drawing perpendicular bisectors
   • Formula $P_{avg} = \sum P_i A_i / \sum A_i$ with weights
2. 7 Marks
   bWhat is Infiltration? What are various factors affecting infiltration?
   How to answer

   • Definition of infiltration
   • Process of water entry into soil
   • Factors: soil type, moisture, vegetation, rainfall, temperature etc.
   • Effect of each factor on rate
3. 7 Marks
   aWhat are various factors affecting the shape of runoff hydrograph?
   How to answer

   • Definition of runoff hydrograph
   • Climatic factors: rainfall intensity, duration, distribution
   • Physiographic factors: area, shape, slope, drainage density
   • Effect on peak, base width and shape
4. 7 Marks
   bGive steps to derive UH from a runoff hydrograph.
   How to answer

   • Isolation of direct runoff by baseflow separation
   • Measurement of runoff volume and depth
   • Division of ordinates by runoff depth to get UH ordinates
   • Steps for adjustment and verification
5. 7 Marks
   aMention methods of improving duty.
   How to answer

   • Definition of duty
   • Methods: proper crop selection, rotation, lining of channels
   • Water management and reduction of losses
   • Soil and agronomic practices
6. 7 Marks
   bAfter how many days will you apply water to soil, if: Assume additional data if necessary.

   1. i)Field capacity of soil = 28%
   2. ii)Permanent wilting point = 13%
   3. iii)Apparent density of soil = 1.3
   4. iv)Effective depth of the root zone = 70 cm
   5. v)Daily consumptive use of water for the crop = 12mm
   How to answer

   • Formula for depth of readily available water using field capacity and wilting point
   • Compute available moisture depth with density and root depth
   • Compute irrigation interval = depth / daily consumptive use
   • Assume allowable depletion if necessary and state result in days
7. 7 Marks
   aDefine followings:

   1. i)GCA
   2. ii)CCA
   3. iii)kor period
   4. iv)paleo irrigation
   5. v)cash crops
   How to answer

   • Define GCA - gross command area
   • Define CCA - culturable command area
   • Define kor period, paleo irrigation, cash crops
   • Distinguish with examples where needed
8. 7 Marks
   bDerive the relation between duty and delta. Determine the delta of a crop, having duty as 432 hectare/cumec, on the field and 45 days its base period.
   How to answer

   • Derive $\Delta = 8.64 B / D$ with units conversion
   • Define duty $D$, delta $\Delta$ and base period $B$
   • Substitute $D=432$ hectare/cumec, $B=45$ days
   • Compute delta in metres
9. 7 Marks
   aWhat is an Aqueduct? Explain in brief its design procedure.
   How to answer

   • Definition of aqueduct as cross-drainage work
   • Conditions where canal passes over drainage
   • Types and components
   • Brief design steps: hydrologic, hydraulic and structural
10. 7 Marks
    bDesign a regime channel for a discharge of 50 cumecs, with a silt factor = 1.0, by using Lacey's theory.
    How to answer

    • Lacey's regime formulas: $V$, $R$, $S$, $A$, $P$
    • Compute hydraulic mean radius and velocity for $Q=50$, $f=1.0$
    • Determine width, depth and slope
    • Check regime conditions
11. 7 Marks
    aExplain various factors of affecting the selection of suitable type of cross drainage work.
    How to answer

    • Definition of cross drainage works
    • Factors: relative levels, discharge, foundation, cost
    • Factors: construction, maintenance, traffic
    • Selection criteria for aqueduct, siphon, superpassage etc.
12. 7 Marks
    bDesign an irrigation channel to carry a discharge of 50 cumecs at a slope of 1/5000. Take Kutter's N = 0.0225 and m = 0.9.
    How to answer

    • Kutter's formula for velocity with $N$ and $m$
    • Assume trapezoidal section with side slopes
    • Solve for $B$ and $D$ for $Q=50$, $S=1/5000$
    • Check velocity and final dimensions
13. 7 Marks
    aWrite a note on rain water harvesting.
    How to answer

    • Definition and need for rain water harvesting
    • Methods: rooftop, surface runoff, recharge pits
    • Components and advantages
    • Suitability and limitations
14. 7 Marks
    bWhat are specific yield and specific retention? Explain.
    How to answer

    • Definitions of specific yield and specific retention
    • Relation with porosity: $n = S_y + S_r$
    • Factors affecting values
    • Significance in groundwater yield
15. 7 Marks
    aMention advantages and disadvantages of well irrigation.
    How to answer

    • Advantages: control, quality, low loss, perennial supply
    • Disadvantages: high cost, limited discharge, over-exploitation
    • Comparison with canal irrigation
    • Suitability conditions
16. 7 Marks
    bExplain Recuperation test for open well. What is the purpose of this test?
    How to answer

    • Procedure of recuperation test: pumping and recovery observation
    • Formula for specific capacity / yield $Q = C A (H)/T$
    • Purpose: determine yield and safe pumping rate
    • Interpretation of recovery curve