Sunday, May 14, 2023

Why Validation in InfoDrainage, ICM SWMM and ICM InfoWorks is great for Good Model Building

 The built-in validation tool in InfoDrainage is an exceptional feature that significantly enhances the user experience and overall performance of the software. Here's why this feature is so beneficial:

  1. Efficiency: The validation tool speeds up the troubleshooting process by quickly identifying errors and potential issues that could affect the simulation. Instead of manually checking every aspect of the model, users can rely on this tool to pinpoint exactly where the problems lie. This can save a considerable amount of time, especially in large or complex models.

  2. Accuracy: By providing a list of problematic errors and warnings, the validation tool ensures that no issue goes unnoticed. This increases the accuracy of the simulations by reducing the risk of undetected errors that could skew the results.

  3. Guidance: Perhaps the most valuable aspect of the validation tool is its ability to provide suggestions for fixes. In certain situations, such as issues associated with levels, InfoDrainage doesn't just identify the problem; it also suggests a potential solution. This guidance can be invaluable, particularly for less experienced users who might struggle to determine the appropriate corrective action.

  4. User-friendly: When a suggested fix is available, users can implement it with the click of a button. This ease of use makes InfoDrainage more user-friendly and allows users to correct issues more quickly and easily.

  5. Improved results: By facilitating the identification and correction of errors, the validation tool can lead to more accurate and reliable simulation results. This can ultimately lead to better decision-making and improved outcomes in the real-world applications of the software.

In essence, the built-in validation tool in InfoDrainage is like having a built-in expert that's always ready to help you identify and fix issues, making the process of running and analyzing simulations significantly smoother and more efficient.

Treatment in BMP’s and LID’s for InfoSWMM and ICM SWMM

 Treatment in BMP’s and LID’s

5.1 Treatment

Excerpt from the EPA manual Storm Water Management Model Reference Manual Volume III – Water Quality (PDF) which can be found here

5.1.1 Background

Management of stormwater quality is usually performed through a combination of so-called “best management practices” (BMPs) and a form of hydrologic source control popularly known as “low impact development” (LID). Treatment of stormwater runoff, either by natural means or by engineered devices, can occur at both the source of the generated runoff or at locations within the conveyance network. Source treatment through LID is discussed in the next chapter. This section describes how SWMM models treatment applied to flows already captured and transported within a conveyance system.

Table 5-1, adapted from Huber et al. (2006), categorizes the different unit treatment processes used by various types of conveyance system BMPs. Ideally one would like to model these processes at a fundamental level, to be able to estimate pollutant removal based on physical design parameters, hydraulic variables, and intrinsic chemical properties and reaction rates. With a few exceptions, the state of our knowledge does not permit this, at least within the scope of a general purpose stormwater management model like SWMM. Instead one has to rely on empirical relationships developed from site-specific monitoring data.

Strecker et al. (2001) discuss the challenges of using monitoring data to develop consistent estimates of BMP effectiveness and pollutant removal. The International Stormwater BMP Database ( provides a comprehensive compilation of BMP performance data from over 500 BMP studies on 17 different categories of BMPs and LID practices. It is continually updated with new data contributed by the stormwater management community. Table 5-2 lists the median influent and effluent event mean concentrations (EMCs) for a variety of BMP categories and pollutants that were compiled from this database. The cells highlighted in yellow indicate that a statistically significant removal of the pollutant was achieved by the BMP category. A summary of the median removal percentages of several common pollutants treated by filtration, ponds, and wetlands published in the Minnesota Stormwater Manual is listed in Table 5-3. Most of these percentages are consistent with those inferred from median EMC numbers in the BMP database table 5-2.

Table 5-1 Treatment processes used by various types of BMPs

ProcessDefinitionExample BMPs
SedimentationGravitational settling of suspended particles from the water column.Ponds, wetlands, vaults, and tanks.
FlotationSeparation of particulates with a specific gravity less than water (e.g., trash, oil and grease).Oil-water separators, density separators, dissolved-air flotation.
FiltrationRemoval of particulates by passing water through a porous medium like sand, gravel, soil, etc.Sand filters, screens, and bar racks.
InfiltrationAllowing captured runoff to infiltrate into the ground reducing both runoff volume and loadings of particulates and dissolved nutrients and heavy metals.Infiltration basins, ponds, and constructed wetlands.
AdsorptionBinding of contaminants to clay particles, vegetation or certain filter media.Infiltration systems, sand filters with iron oxide, constructed wetlands.
Biological Uptake and ConversionUptake of nutrients by aquatic plants and microorganisms; conversion of organics to less harmful compounds by bacteria and other organisms.Ponds and wetlands.
Chemical TreatmentChemicals used to promote settling and filtration. Disinfectants used to treat combined sewer overflows.Ponds, wetlands, rapid mixing devices.
Natural Degradation (volatilization, hydrolysis, photolysis)Chemical decomposition or conversion to a gaseous state by natural processes.Ponds and wetlands.
Hydrodynamic SeparationUses the physics of flowing water to create a swirling vortex to remove both settleable particulates and floatables.Swirl concentrators, secondary current devices, oil-water separators.

Table 5-2 Median inlet and outlet EMCs for selected stormwater treatment practices

PollutantMedia FiltrationDetention BasinRetention PondWetland BasinManufactured Device
TSS mg/L52.78.766.824.270.713.520.49.0634.518.4
F. Coliform, #/100mL135054214801030192070713000614022102750
Cadmium, ug/L0.310.160.390.310.490.230.310.180.400.28
Chromium, ug/L2.  3.662.82
Copper, ug/L11.286.0110.625.679.574.995.613.5713.4210.16
Lead, ug/L10.51.696.083.108.482.762.
Nickel, ug/L3.512.205.643.354.462.19  3.844.51
Zinc, ug/L77.317.970.017.953.621.
Total P, mg/L0.
Orthophosphate, mg/L0.050.030.530.390.
Total N, mg/L1.060.821.402.371.831.
TKN, mg/L0.960.571.491.611.281.050.951.011.591.48
NOX, mg/L0.330.510.550.360.430.

Source: International Stormwater BMP Database, “International Stormwater Best Management Practices (BMP) Database Pollutant Category Summary Statistical Addendum: TSS, Bacteria, Nutrients, and Metals”, July 2012 (

Table 5-3 Median pollutant removal percentages for select stormwater BMPs

PollutantSand FilterPondsWetlands
Total Suspended Solids858473
Total Phosphorus775038
Particulate Phosphorus919169
Dissolved Phosphorus6000
Total Nitrogen353030
Zinc and Copper507070

Source: Minnesota Stormwater Manual (

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