Stormwater Management & Sewer Remediation

Streamline the design and analysis of stormwater management control strategies for minimizing events such as combined sewer overflows, sanitary sewer overflows, water in basements, surcharging, street flooding and/or rainfall-dependent inflow and infiltration.

To streamline the design effort involved in meeting US EPA regulations, including NPDES permits, CMOM, and/or TMDL requirements, PCSWMM provides an efficient set of tools for designing stormwater management control strategies for minimizing combined sewer overflows (CSO), sanitary sewer overflows (SSO), water in basements (WIB), surcharging, street flooding and/or rainfall-dependent inflow and infiltration (RDII). Powerful importing, QA/QC, and network building tools significantly reduce the development time for large models.

Model with as much detail as necessary, with optimized performance for large system wide models (100,000+ pipes/nodes)
Simulate valves, gates, inflatable dams, leaping weirs, and other complex flow structures
Accurately model force mains, lift stations and pumps
Account for seasonal and event-based groundwater interflow
Easily import data from all common GIS, CAD, database, spreadsheet formats
Quickly convert existing older EPA SWMM models to SWMM5
Automate network construction from imported data
Quickly perform comprehensive QA/QC on imported data
Data entry error checking, advanced error detection and consistency checks
Fill in missing values with a wide range of estimators
Estimate model parameters from spatial GIS data with powerful topological operations (area-weighting, spatial allocation, etc)
Quickly calibrate any/all model parameters with the exclusive, intuitive Sensitivity-based Radio Tuning Calibration (SRTC) tool
Simplify diurnal and seasonal dry weather flow (DWF) pattern creation with specialized tools and allocate loads and patterns with fast topological operations
Quickly determine and assign DWF loadings from lot level water usage data
Automate RDII unit hydrograph development with a unique, straightforward RDII calibration process
Model dynamic storms with high spatial and temporal variations in rainfall with rain-gage calibrated radar-rainfall
Optimize system storage and operation with global optimal (GO-RTC) and passive real-time control modeling
Assess the impact of multiple Low Impact Development (LID) practices on storm sewer relief
Check capacity requirements for compliance
Quickly perform comparative analyses of different "what-if" strategies with comprehensive scenario analysis graphs, profiles and reports
Easily create sub models for detailed studies, and update the macro model when completed
Keep track of all related documents, photographs, videos, etc. through geo-referenced points of interest (POIs) and the project notes manager
Easily assign and visualize confidence levels for all model parameters
Project model results and animations in Google Earth for client presentations

Spotlight Projects

Fostoria CSO Long-Term Control Plan

Date:

August 2016

Location:

Fostoria, Ohio, USA

Client:

City of Fostoria

Consultant:

Avetin Engineering Ltd.

Discussion

In order to mitigate Combined Sewer Overflows (CSOs) and their resulting waste, toxic materials and debris, the City of Fostoria started the development of the CSO Long-Term Control Plan (CSO LTCP) in 2007.

Avetin Engineering Ltd. worked with the City and developed a detailed hydrologic/hydraulic model using PCSWMM – with the objective of mimicking the sanitary and combined sewer system performance, determining the needed improvements and evaluating the mitigation effectiveness resulting from the proposed projects.

During the CSO LTCP development period, it was found that the City had experienced river intrusions through its CSO outfalls. A HEC-RAS model was then created to simulate the hydraulics of the East Branch Portage River.

In 2010, the City used PCSWMM’s river model importing tool to merge its HEC-RAS models into a practical watershed/sewershed model (which was updated two years later in 2012). The consistent updates to PCSWMM tools make it efficient for the City to evaluate the improvement results and re-prioritize the proposed projects if needed.

Shortly after the watershed/sewershed model became available, a flood control project located upstream to the City was developed. And, upon the completions of two major CSO LTCP projects, the integrated 1D-2D model was recently updated to incorporate all changes and improvements in 2016.

This model was then utilized as an important tool to develop system-wide dry/wet weather operational strategy for the City of Fostoria. The City takes the CSO LTCP as a living document and strives to comply with US EPA’s CSO policy as planned.

Mill Creek System Wide Model Enhancements

Date:

July 2016

Location:

Cincinnati, Ohio, USA

Client:

Metropolitan Sewer District of Greater Cincinnati

Consultant:

Wade Trim

For more information:

Read the JWMM paper

Discussion

The Metropolitan Sewer District of Greater Cincinnati’s (MSDGC's) Mill Creek System Wide Model (SWM) is one of the largest 1D stormwater management model (SWMM) projects in the world, with 19 sub-watersheds divided into 6,550 subcatchments, 28,000 nodes and 28,400 conduits. MSDGC and their consultants are consequently faced with long simulation run times while tackling the challenging task of managing ongoing work on various sub-watersheds.

Wade Trim is using PCSWMM to enhance the Mill Creek SWM by reducing run durations, making it easier to update the model moving forward and improving overall performance in simulating system flows. PCSWMM’s auditing tools are being used to review the large number of model elements and identify areas for improved performance or representation.

Once complete, the model will then be reviewed to identify points in the system where the overall Mill Creek SWM could be broken into smaller, more manageable sub-watershed models as well as an interceptor model. Portions of the system may also be impacted by receiving stream water levels during annual simulations, which would require development of boundary conditions at any impacted outfalls.

A check-out and check-in system will then be developed, and inter-submodel communication will be provided using interface files. The Mill Creek SWM enhancements are expected to support MSDGC’s Wet Weather Improvement Program Phase 2 planning efforts.

Integrated Dual Drainage Model for the City of Ottawa

Date:

2015

Location:

Ottawa, Ontario, Canada

Client:

City of Ottawa

Consultant:

Parsons

For more information:

Read the ICWMM abstract

Discussion

Faced with the risk of surcharging and surface flooding, the City of Ottawa conducted an Integrated Dual Drainage Study. The study supports city-wide comprehensive asset and wet weather infrastructure management plans by characterizing existing drainage conditions, identifying existing levels of service and defining constraints and opportunities within the study area.

PCSWMM was used to develop and evaluate a pipe-by-pipe model, and GIS and spreadsheet analysis were used to prepare input data, perform complex analyses and render results. Sewer hydraulic grade line and percent pipe full capacity were used to characterize the minor system performance. Major system classification was based on ponding depths/extents, conveyance system, private property crossing points and level of service within Collector roads.

Input rainfall was based on the City’s design storms (various return periods), while impacts of climate change were simulated by increasing storm intensities by 20%. To qualitatively validate the PCSWMM model, simulations of historical storms were run and the results were tested against flooding reports documented by the City.

The results indicated the minor and major systems had average levels of service of 1:5 and 1:100 years, respectively. A systematic approach was used to evaluate various alternatives to improve system performance, starting with those most basic and cost-effective and then gradually increasing the cost and complexity until the desired balance was achieved.

By restricting flows to the minor system with inlet control devices, average inlet capture rates could be reduced by 40 - 70%, significantly reducing the risk of sewer surcharging conditions during a 1:100-year storm. Reduced inlet capture translated into increases in surface flows and ponding duration, although these were effectively accommodated within the existing capacity of the major system.