Storage Volume vs Depth Equation in SWMM 5

Subject:  Storage Volume vs Depth Equation in SWMM 5

A storage node in SWMM 5 can have either a functional form or a tabular depth/area table.  The area functional form of a storage node is:

Area           =      A * Depth^B + C  and the Volume has the form in  node.c of the SWMM 5 of

Volume     =      A/(B+1)*Depth^(1+B) + C*Depth

For example if C is 25 square meters, A is 20 and the exponent B is 0.5 we get the following values for area and volume and you can also plot a Scatter Plot of Volume vs Depth in SWMM 5 (Figure 1).

Depth	Area	Volume
Meters	M^2	M^3
0	25.00	0.00
1	45.00	38.33
2	78.28	87.71
3	109.64	144.28
4	140.00	206.67
5	169.72	274.07
6	198.99	345.96
7	227.92	421.94
8	256.57	501.70
9	285.00	585.00
10	313.25	671.64
11	341.33	761.44
12	369.28	854.26

Table 1.  Area and Volume for a Storage Node in SWMM 5.

Figure 1.  You can use a Scatter Graph in SWMM 5 to show the relationship between Volume and Depth.