Assignment (10)

Reservoirs

1. For the reservoir of the following figure, how much water may be

stored between the minimum operating level and the spillway crest

level? How much water may be stored as surcharge storage?

Solution

2. What is reservoir capacity required for the demand rates of example 1 (page 76-77) if pumping is to be limited to off-peak night hours (7 p.m. to 7 a.m.)? What pump capacity is required? Solved in Book

time demand pumping hr outflow inflow O - I O - I

1 273 529.3

-256

2 206 529.3

-323

3 256 529.3

-273

4 237 529.3

-292

5 257 529.3

-272

6 312 529.3

-217

7 438 529.3

-91.3

8 627 529.3 97.7

9 817 529.3 287.7

10 875 529.3 345.7

11 820 529.3 290.7

12 773 529.3 243.7

13 759 529.3 229.7

14 764 529.3 234.7

15 729 529.3 199.7

16 671 529.3 141.7

17 670 529.3 140.7

18 657 529.3 127.7

19 612 529.3 82.7

20 525 529.3

-4.3

21 423 529.3

-106

22 365 529.3

-164

23 328 529.3

-201

24 309 529.3

-220

12703 12703

inflow rate 529.29

reservoir capacity = 2422.4 -2423

Solution of Problem first option

0

200

400

600

800

1000

0102030

demand outflow

pumping inflow

time demand pumping

hr outflow inflow O - I O - I

1 273 0

273

2 206 0

206

3 256 0

256

4 237 0

237

5 257 0

257

6 312 0

312

7 438 0

438

8 627 1059 -432

9 817 1059 -242

10 875 1059 -184

11 820 1059 -239

12 773 1059 -286

13 759 1059 -300

14 764 1059 -295

15 729 1059 -330

16 671 1059 -388

17 670 1059 -389

18 657 1059 -402

19 612 1059 -447

20 525 0

525

21 423 0

423

22 365 0

365

23 328 0

328

24 309 0

309

12703

inflow rate 1058.58 reservoir capacity

=

-3934 3929

Solution of Problem –second option

0

200

400

600

800

1000

1200

0102030

demand outflow

pumping inflow

time demand pumping

hr outflow inflow O - I O - I

1 273 1059

-786

2 206 1059

-853

3 256 1059

-803

4 237 1059

-822

5 257 1059

-802

6 312 1059

-747

7 438 1059

-621

8 627 0 627

9 817 0 817

10 875 0 875

11 820 0 820

12 773 0 773

13 759 0 759

14 764 0 764

15 729 0 729

16 671 0 671

17 670 0 670

18 657 0 657

19 612 0 612

20 525 1059

-534

21 423 1059

-636

22 365 1059

-694

23 328 1059

-731

24 309 1059

-750

12703

inflow rate 1058.58 reservoir capacity

=

8774 -8779

0

200

400

600

800

1000

1200

0102030

demand outflow

pumping inflow