# Blog

## Model Pump Station Force Mains in SWMM

A previous post about how to model a pump station can be found here and this post is about how to model a force main on the discharge side of…

## Junction Node and Storage Node in SWMM

SWMM uses a node-link scheme to represent storm sewer networks and the movement of water through such a network is governed by the mass and momentum conservation equations for conduits…

## Node Flooding, Surcharge, and Ponding in PCSWMM and EPA SWMM

In 1D storm sewer network modeling, it is important to understand how a modeling tool handles the system flooding or overflowing which will impact HGL and flow calculations in the…

## Modified Puls Storage Routing By Detention Basin Analysis Of Hydraulic Toolbox

The modified puls storage routing technique is widely used to size a detention basin by routing inflow hydrographs (Figure 1). The two unknowns, O2 and S2 , can be solved…

## HEC-RAS Lateral Structure (2 of 2)

A lateral structure (LS) in HEC-RAS, parallel to the centerline of a river, is often used to connect a river reach to a 2D flow area, a storage area, or…

## Raster DEM Slope Calculation Using GIS Slope Tool

A watershed average slope value is often needed in some hydrologic calculations, for example, Time of Concentration (TOC) estimation using NRCS Lag Time Method. The slope tool in AcrGIS or…

## Node Flooding and Ponding, Overland/Street Flow In 1D XPSWMM Modeling

Even if 2D modeling by XPSWMM, PCSWMM, HEC-RAS, and InfoWorks has become popular these days, 1D modeling still holds its ground on storm water management and flooding study due to…

## Pipe Entrance Loss And Exit Loss Coefficients In A Manhole For Modeling

Head Losses (or energy losses) associated with conduits in a storm sewer system include pipe friction losses and minor losses. Pipe friction losses are normally solved by Manning’s equation, while…

## Recondition And Pre-processing DEM For A Better Watershed Delineation

A DEM, before it can be used for watershed delineation, often needs to be reconditioned and pre-processed by “filling” any depressions or sinks (an area lower than its surroundings) to…