CivilStorm, SewerCAD, SewerGEMS
Low Impact Development (LID) controls can be modeled in CivilStorm, SewerGEMS and SewerCAD. LID does not apply to StormCAD and the GVF-Rational solver because it uses the Rational Method for peak flow (steady state) only. See more here: Can I use a low impact development (LID) controls in StormCAD?
Low-Impact Development (LID) is a term used mostly in the US and Canada to describe a more eco-friendly land planning and design approach to stormwater management. In the United Kingdom, this approach is referred to sustainable urban drainage systems (SUDS), and in Australia, it's called water-sensitive urban design (WSUD). The US terminology is used in this software and its documentation.
LID controls help developed watersheds or sites to retain or enhance pre-development hydrologic characteristics through the use of techniques that conserve natural systems and hydrologic functions.
Some of the goals of LID are to:
A number of government agencies, universities, and other groups publish educational information, research and design guidance for implementing LID and LID controls. Places to start include:
Note: LID elements can only be paired with catchments using the EPA-SWMM runoff method. If you have the CONNECT Edition Update 1 version of the storm-sewer products, you can also use a Time-Area runoff method.
Note: for underground storage chamber systems, use the pond element instead of LIDs. See more here.
LID control is represented by a combination of vertical layers, which may include (in top to bottom order):
Controls are defined in the LID Controls editor:
The model performs a moisture balance:
In a project, you would go to Components > Low Impact Development Controls. This is where you would enter the different LID Controls for the project. After these are set up, you can export them to the Engineering Libraries for use in other projects.
Note: The underdrain is only required on a rain barrel control. If using a rain barrel, you will notice that it has a Drain Delay. The drain delay is the number of dry weather hours that must elapse before the drain line in a rain barrel is opened (the line is assumed to be closed once rainfall begins).
After entering the Low Impact Development (LID) Controls, you will add the catchments and LID elements to the network.
What this might look like in an actual model:
In the SWMM Calculation Summary window that appears after computing the model, click "Runoff Summary" on the left side to review a summary of the mass balance.
In the "Output Options" field in the LID element properties, you can choose between Summary Results and Detailed Results.
Time series results can be viewed by graphing either the LID or the parent catchment. Right click on the LID or catchment polygon, choose Graph and select the parameter on the right side that you wish to graph.
Note: the "Infiltration" volume will be zero for a green roof that occupies the full catchment, as the rainfall in that case can either becomes runoff, is stored inside the LID or exits via an underdrain/undermat.
Urban Street Stormwater Guide
EPA SWMM manual