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

0.00

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.