## Friday, December 2, 2011

### 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. 