Question

chow 8.2.1:

Storage vs. outflow characteristics for a proposed reservoir are given below.
Calculate the storage-outflow function 2S/At + Q vs. Q for each of the tabulated
values if Ar = 2 h. Plot a graph of the storage-outflow function.
Storage (10^6 m3) 75 81 87.5 100 110.2
Outflow (m3/s) 57 227 519 1330 2270

Answer 1

SOLUTION:

The storage vs outflow characteristics are already given and the value of $\Delta$t is also given.

Here $\Delta$t = 2 h = 2 x 60 x 60 = 7200 sec = 0.0072 * 10⁶ sec

Now we need to use the values of S, Q and $\Delta$t to find out the values of  

2S

The data are tabulated below:

Storage S (106 m3)	Outflow Q (m3/sec)	(2S/Δt +Q ) (m3/sec)
75	57	20890
81	227	22727
87.5	519	24825
100	1330	29108
110.2	2270	32881

Now we have to plot the graph of storage-outflow function. Here   is taken along x-axis and outflow Q is taken along y-axis

2S

The graph is as following