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.
Starting from the bottom of the manhole you have these regions of computational interest:
1. Manhole Invert to the lowest link invert – the node continuity equation is used with the area of the manhole being the default surface area of a manhole,
2. Lowest Link Invert to the Highest Link Crown Elevation – the node continuity equation is used with surface of the node being normally half of the surface area of the incoming and outgoing links,
3. Highest Manhole Pipe Crown Elevation to Manhole Rim Elevation – the node surcharge algorithm in which the surface area of the manhole is not used and the surcharge depth is iterated until the inflow and the outflows of the node are in balance,
4. The region above the Manhole Rim Elevation which can use one of four options to calculate the depth and/or flow out of or into the manhole:
1. No Surcharge Depth is entered and No Ponding area is used – the excess water into the manhole is lost to the network and shows up as internal outflow in the continuity tables,
2. A Ponding Area is used and the excess flow will pond on the surface of the manhole and later go back down into the conveyance pipes.
3. A Surcharge Depth is used and the depth will continue to be calculated using the node surcharge algorithm in which the surface area of the manhole is not used and the surcharge depth is iterated until the inflow and the outflows of the node are in balance,
4. A Dual Drainage system is simulated and the excess flow of the manhole is simulated in the street gutters or the actual street,
5. You use a 1D/2D linkage between the 1D manhole and 1D links to a 2D Mesh and simulate the flow out and the flow into the manhole using a bottom outlet orifice that switches automatically between weir and orifice flow based on the depth on top of the manhole.
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 …
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.
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