Stormwater Management Model (SWMM) Information for watershed water quality, hydrology and hydraulics modelers (Note this Blog is not associated with the EPA). You will find Blog Posts and Twitter Embeds on the Subjects of SWMM5, InfoSWMM, InfoSewer, SWMMLive, InfoSWMM SUSTAIN, SWMM4 and SWMM in general.
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InfoSWMM (d/D v. Surcharge d/D)
Subject: InfoSWMM (d/Dv. Surcharged/D)
What is the difference between the output variables d/D and Surcharged/D in InfoSWMM and H2OMap SWMM
The d/D is calculated as link capacity based on the midpoint depth of water in the link orLink depth/ Link Maximum Depth
Since the depth in the link is restricted to the Maximum Depth the d/D value is always between 0 and 1
The Surcharged d/D is calculated from the end node depths at each end of the link
The two node depths are averaged and the value of Surcharged/D is the Average Node Depth / Link Maximum Depth,
The value of Surcharged/D varies from 0 to a large number depending on the maximum depths of the nodes and the possible surcharge depth of the nodes
The value of d/D is based on the middle of the link and the value of Surcharged/D is based on the average of the node depths at the end of the link. They may be and often are different. However, if you have a Surcharged/D greater than 1 it will indicate at least one end of the link is surcharged. A Surcharged/D may be greater than 1 with a d/Dless than 1 due to the ends of the node being surcharged and not surcharged.
· A Surcharged d/D indicates that at least one end of the link is Full, but · A d/D value less than 1 does not preclude that one end may be Surcharged.
Figure 1. Plot of d/D and Surcharged d/D in InfoSWMM.
Soffit Level (pipe technology)The top point of the inside open section of a pipe or box conduit. The soffit is the highest point of the internal surface of a pipe or culvert at any cross-section. The soffit is also referred to as the pipe obvert. So it is not quite the Crown of the Pipe. Here is an image I found that hopefully explains it better.
Comment: A really nice water analogy for the field properties Divergence, Curl and Gradient from the Blog Starts With a Bang
....it's pretty mathematically intensive, but what's missing from most textbooks and E&M courses are physical explanations of what the mathematics means. For instance, I've started teaching about fields, and pretty much every textbook out there goes on and on about the properties of fields. They say you can do three things to fields, take the gradient, divergence, orcurl of them. (Are you asleep yet? I'm sorry!) What do these things mean? An easy way to picture it is in terms of water. If you placed a drop of water anywhere on, say,Earth, the magnitude and direction of how it rolls down is the gradient of the Earth's elevation. If you let that drop of water flow, as it goes downhill, it can either spread out or converge to a narrower stream. When we quantify that, that's what the divergence of the field is. And finally, when that water is …
Engine Error NumberDescription ERROR 101: memory allocation error. ERROR 103: cannot solve KW equations for Link ERROR 105: cannot open ODE solver. ERROR 107: cannot compute a valid time step. ERROR 108: ambiguous outlet ID name for Subcatchment