IDEAL (Integrated Design, Evaluation, and Assessment of Loadings) is a post-construction water quality model for designing stormwater best management practices (BMP) (see Best management practice for water pollution) and calculating their effectiveness in removing common stormwater pollutants (sediments, bacteria, nitrogen and phosphorus). The model's runoff treatment algorithms are process-based by predicting runoff rates and pollutant loads and routing these loadings through BMPs using technologies which have been experimentally validated. Using isothermic relationships along with accepted decay, settling, and infiltration methods, pollutant trapping in BMPs is computed. The developers of the IDEAL model are Bill Barfield (Regents Professor at Oklahoma State University, Woolpert Inc.) and John Hayes of Clemson University. Currently, six BMPs can be modeled with IDEAL: sand filters, wet and dry detention basin, bioswales, bioretention cells, and vegetated filter strips. The ability to model engineered devices has recently been developed, but requires trapping efficiency information to be input. Rainwater tanks or cisterns can also be modeled. Currently, hydraulic modeling of closed systems and open channels is simplistic.
Contents
A recent (2003) article on the model was presented in Stormwater magazine. This article explains the development of the model and its use in Greenville County as an effort to address NPDES stormwater permit conditions. Another similar article was presented at the 2003 EWRI annual conference.
The U.S. Environmental Protection Agency (EPA) funded a Best Management Prcetice design manual developed in part by Barfield.
Development history
The IDEAL was conceived in 2000 in response to a request for proposals from the South Carolina Department of Health and Environmental Control (SCDHEC). SCDHEC is the state agency responsible for implementing the NPDES program of the Clean Water Act in South Carolina. The model was originally developed for coastal areas of South Carolina to help civil engineers meet state water quality standards. A version for Greenville County, SC, USA was released in 2004 and in currently supported. The model has recently been re-programmed into VB.net object-oriented programming framework after initially formulation as a spreadsheet.
Applications
The IDEAL model can be used in a number ways. The model was primarily developed to provide civil engineers with a new design tool to model stormwater BMPs, similar to how other engineering models are used to design water, santary sewer, and drainage networks. This is a big step toward provided better stormwater systems that reduce the discharge of pollutants into receiving waters. The IDEAL model can be used as a design tool for Low Impact Development, developing and/or showing compliance with regulation pertaining to impaired waters and TMDLs.
Current developments
There are currently versions that can be purchased and used in Greenville County, South Carolina, USA, and the southeastern states of Virginia, North Carolina, South Carolina, Georgia, and Florida. These versions, as well as a free demo of the model, are available from the StormOps website.
An AutoCAD interface is under development that will allow one to exchange information on a stormwater network to and from the IDEAL model.
Also under development is the incorporation of improved hydraulic computations using SWMM algorithms.