Problem 10-1

Route the following triangular inflow hydrograph through a linear reservoir: peak inflow = 240 m³/s, baseflow = 0 m³/s, time-to-peak = 6 h, time base = 16 h, storage constant K = 2 h, and time interval Δt =1 h. Use a spreadsheet. Verify using ONLINE ROUTING 01.

Problem 10-2

Solve Problem 10-1 by the storage indication method. Use a spreadsheet. Verify using ONLINE ROUTING 02.

Problem 10-3

Determine the actual freeboard for the following dam, reservoir, and flood conditions: dam crest elevation = 125 m; emergency spillway crest elevation = 120 m; coefficient of spillway rating = 1.7; exponent of rating = 1.5; width of emergency spillway (rectangular cross section) = 20 m.

Elevation-storage relation:

Elevation (m)	120	121	122	123	124	125
Storage (hm3)	3.00	3.05	3.25	3.60	4.25	4.90

Inflow hydrograph to reservoir:

Time (h)	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23
Inflow (m3/s)	0	15	30	45	70	100	125	150	175	165	140	125	100	80	60	50	33	25	14	9	7	5	1	0

Assume the initial reservoir pool level at spillway crest. Use ONLINE ROUTING 03.

Problem 10-4

Design the emergency spillway width (rectangular cross section) for the following dam, reservoir, and flood conditions: dam crest elevation = 483 m; emergency spillway crest elevation = 475 m; coefficient of spillway rating = 1.7; exponent of spillway rating = 1.5. Elevation-storage relation:

Elevation (m)	475	477	479	481	483
Storage (hm3)	5.0	5.3	6.0	7.0	8.5

Inflow hydrograph to reservoir:

Time (h)	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24
Inflow (m3/s)	0	10	30	50	90	150	250	350	280	210	190	170	130	100	90	75	50	40	30	15	10	5	2	1	0

Assume design freeboard = 2 m (to within 0.01 m accuracy: 1.99-2.01 m) and initial reservoir pool level at spillway crest. Use ONLINE ROUTING 03. [Hint: Try several values of spillway length L (width). Determine width to an accuracy of 0.1 m].