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2000 Progress Report: Water Quality Modeling in Urban Storm Water Systems
EPA Grant Number: R827933C024Subproject: this is subproject number 024 , established and managed by the Center Director under grant R825427
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Urban Waste Management and Research Center (University New Orleans)
Center Director: McManis, Kenneth
Title: Water Quality Modeling in Urban Storm Water Systems
Investigators: Hannoura, A. P. , Huber, Wayne C. , McCorquodale, J. A.
Institution: University of New Orleans , Oregon State University
EPA Project Officer: Krishnan, Bala S.
Project Period: December 1, 1999 through July 30, 2001
Project Period Covered by this Report: December 1, 1999 through July 30, 2000
RFA: Urban Waste Management & Research Center (1998)
Research Category: Targeted Research
Description:
Objective:The Storm Water Management Model (SWMM) is a dynamic rainfall-runoff simulation model that can describe single-event or long-term (continuous) effects of primarily urban storm water systems. Since its development in 1971, this model is updated regularly. However, several key areas that are critical to model application need further investigation. These are (1) relatively accurate simulation of surcharged conditions leading to regional flooding; (2) modeling of the sediment and water quality transport and fate; and (3) effective presentation of results utilizing recent advances in computations and information management systems. Therefore, the objectives of this project are to:
• Improve the current version of SWMM so that one can simulate the major
and minor systems simultaneously with minimum user interaction.
• Enhance the existing water quality code in SWMM for the adequate simulation
of the pollutant fate in drainage systems of urban areas.
• Enhance the data management, analysis, and visualization for the storm
water management systems.
The approach to improve the current version of SWMM, so that one can simulate the major and minor systems simultaneously with minimum user interaction, can be summarized in two phases.
The first phase has focused on investigating different possibilities for the modeling of the surface flow in a flooding situation. The main areas for review included computational geometry, digital elevation models, topographic analysis, and storm water management modeling.
After intensive review of computational geometry sources and testing several triangulation algorithms and tools (such as qhull, ACORD, Triangle and GEOMPACK), the Delaunay triangulation subroutines of GEOMPACK will be used in the overall methodology. Test runs of these FORTRAN subroutines are being performed, and they are being prepared to include in the code.
Work on DEM files has been in retrieving them in STDS format and converting them into ASCII files, which can be utilized in the proposed methodology. Other options, such as using C++ API classes directly, also are being investigated. Topographic analysis capabilities of the software, TOPAZ, also are being tested during this phase.
The next phase involved the development of the methodology and the preparation of the data, which will be used in the methodology. In this phase, a procedure is developed using Arcview to visualize overflow areas (i.e., flooded areas associated with different nodes in SWMM). Definition and creation of GIS layers of sub-basins in the study area along with possible divides (high lands) and storage areas (low lands) has begun, and the development of an area-elevation and storage-elevation relationship for study area has been accomplished.
The work on characterization of surface flow pathways for a realistic model of flooding and incorporation of the information management systems for the decisionmaking process continued in the following aspects:
• Construction of GIS layers for catchbasins in the study area.
• Implementation of the code for the algorithm to automatically find local
and global catchments (CATCH) (Martz, 1988).
• Testing and debugging of the code CATCH.
• Installation and testing of the Digital Elevation Model (DEM) for the
study area, which are developed from the Army Corps of Engineers' 1 foot contour
maps.
• Overall design of the "Automatic Detection of Drainage Paths"
algorithm.
• Integration of the AutoCAD design files containing manhole and link information
with DEM files for the study area.
• Design and implementation of Arcview Avenue scripts necessary for the
analysis.
• Conversion of the FORTRAN subroutines into DLL functions to facilitate
the integration with Arcview.
The methodology developed to model the surface flow in an urban area, requires A DEM of the study area, node map as point coverage, which corresponds to the manholes in the SWMM model and SWMM input file (not required for the initial analysis). The information received in this format will be utilized to perform the following analysis and synthesis tasks:
• Find the corresponding cells for each node-these are possible sources
and sink cells for the method.
• Generate the cost matrix for the study area (i.e., each cell is assigned
the negative of the maximum slope to its neighbors).
• Obtain the depressionless DEM from the original DEM.
• Obtain the ultimate water ponding areas by subtracting the depressionless
DEM from the original one.
• For a given minimum ponding value, draw the regions with ponding and
calculate the volumes.
• The node cells within the ponding regions are called sink nodes and should
be ordered by ascending elevation. Beginning from the highest sink node, calculate
the volumes for each node elevation. The lowest elevation in the catchment is
not guaranteed to be a node, so the lowest point will be assigned a pseudo node.
Some of the sink node cells can be at the same elevation, then select one and
connect the others to it.
| Sets: | All nodes |
| Actual nodes and pseudo nodes | |
| Nodes in ultimate ponding areas | |
| Source nodes (outside ponding) | |
| Pseudo nodes (always in a ponding area and minimum elevation cell) | |
| Ordered set of sink nodes |
• For each region, the storage capacity of each node in the ordered set of sink nodes will be calculated. This will be used to estimate the physical dimension of the links. Minimum cost flow paths should be drawn to every node in a given ultimate ponding area and within the nodes in the ponding.
• The lowest elevation node will get all the flow if it is the lowest point within the ponding. If not, it can only receive water after the water elevation rises to its level.
• Using the cost matrix, create the cost flow direction grid for each node within the catchment (the lowest point within each catchment).
• Ponding areas without any node cell will be assigned a pseudo node, if the water ponding is above a given minimum storage volume.
• For every source node cell (non-sink cells), create minimum cost flow paths to the sink cells within the nearest ponding. Find criteria to eliminate some of these links (e.g., maximum allowable flow cost). The links should have a length and width. Width might be given as a parameter or set equal to the cell size (10 m in our case).
• Every region has a water elevation, after which it will discharge the additional water to another nearby region. Using the ultimately filled DEM map, identify possible links between regions and model them as conduits with weirs. Maximum distance criteria can serve to eliminate several links.
The principle task to enhance the existing water quality code in SWMM, for the adequate simulation of the pollutant fate in drainage systems of urban areas, is to develop water quality routines for common parameters (e.g., BOD, DO, TKN, NO2, NO3) and conservative or first-order nonconservative parameters of interest for incorporation into the Transport Block of SWMM. Currently, the Transport Block is the main choice for routing of quality parameters through the urban drainage system, as the Runoff Block does not include as sophisticated a flow and quality routing scheme, and the Extran Block does not simulate quality. Transport will currently simulate conservative and first-order nonconservative quality parameters, but will not perform interactive computations of the BOD-DO type. The goal of this research is to provide this interactive capability for BOD-DO and the nitrogen cycle.
FORTRAN coding will follow the coding currently in the WASP model. It will build on routines initiated in Subroutine QUAL of the Transport Block. The other issue is how to provide the new input to the model. A list summarizing the nature of the various parameters included in the water quality equations is prepared. This will be used to develop sensible input requirements for the revised Transport Block.
Future Activities:Current work focuses on the implementation of the surface flow modeling and on the FORTRAN coding necessary to implement water quality routines and on acquiring data with which to test them. The surface flow modeling involves the automatic generation of conduits between source and sink nodes to describe the surface flow and then converting this conduit information into SWMM format. In addition to the surface flow modeling, an emergency routing system will be designed and implemented. Also, the final report to the UWMRC and U.S. Environmental Protection Agency will be prepared in the last quarter of the next year.
Supplemental Keywords:storm water management, flooding, water quality, Digital Elevation Model. , Ecosystem Protection/Environmental Exposure & Risk, Water, Scientific Discipline, Waste, RFA, Ground Water, Civil/Environmental Engineering, Wet Weather Flows, Environmental Engineering, Municipal, Monitoring/Modeling, Urban and Regional Planning, runoff, water quality, chemical transport models, fate and transport, water management, hydrologic modeling, community water quality information system, storm water, Storm Water Management Model, urban storm water, sediment transport, flood control, storm drainage, stormwater, urban runoff, stormwater runoff, model-based analysis, storm drainage systems, hydrodynamic modeling, municipal wastewater, ecological models
Relevant Websites:
Progress and Final Reports:
Original Abstract
Main Center Abstract and Reports:
R825427 Urban Waste Management and Research Center (University New Orleans)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825427C001 Comprehensive Evaluation of The Dual Trickling Filter Solids Contact Process
R825427C002 Issues Involving the Vertical Expansion of Landfills
R825427C003 Deep Foundations on Brownfields Sites
R825427C004 Ambient Particulate Concentration Model for Traffic Intersections
R825427C005 Effectiveness of Rehabilitation Approaches for I/I Reduction
R825427C006 Urban Solid Waste Management Videos
R825427C007 UWMRC Community Outreach Multimedia Exhibit
R825427C008 Including New Technology into the Investigation of Inappropriate Pollutant Entries into Storm Drainage Systems - A User's Guide
R825427C009 Investigation of Hydraulic Characteristics and Alternative Model Development of Subsurface Flow Constructed Wetlands
R825427C010 Beneficial Use Of Urban Runoff For Wetland Enhancement
R825427C011 Urban Storm and Waste Water Outfall Modeling
R827933C001 Development of a Model Sediment Control Ordinance for Louisisana
R827933C002 Inappropriate Discharge to Stormwater Drainage (Demonstration Project)
R827933C003 Alternate Liner Evaluation Model
R827933C004 LA DNR - DEQ - Regional Waste Management
R827933C005 Landfill Design Specifications
R827933C006 Geosynthetic Clay Liners as Alternative Barrier Systems
R827933C007 Used Tire Monofill
R827933C008 A Comparison of Upflow Anaerobic Sludge Bed (USAB) and the Anaerobic Biofilm Fluidized Bed Reactor (ABFBR) for the Treatment of Municipal Wastewater
R827933C009 Integrated Environmental Management Plan for Shipbuilding Facilities
R827933C010 Nicaragua
R827933C011 Louisiana Environmental Education and Resource Program
R827933C012 Costa Rica - Costa Rican Initiative
R827933C013 Evaluation of Cr(VI) Exposure Assessment in the Shipbuilding Industry
R827933C014 LaTAP, Louisiana Technical Assistance Program: Pollution Prevention for Small Businesses
R827933C015 Louisiana Environmental Leadership Pollution Prevention Program
R827933C016 Inexpensive Non-Toxic Pigment Substitute for Chromium in Primer for Aluminum Sibstrate
R827933C017 China - Innovative Waste Composting Plan for the City of Benxi, People's Rupublic of China
R827933C018 Institutional Control in Brownfields Redevelopment: A Methodology for Community Participation and Sustainability
R827933C019 Physico-Chemical Assessment for Treatment of Storm Water From Impervious Urban Watersheds Typical of the Gulf Coast
R827933C020 Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region
R827933C021 Characterizing Moisture Content Within Landfills
R827933C022 Bioreactor Landfill Moisture Management
R827933C023 Urban Water Issues: A Video Series
R827933C024 Water Quality Modeling in Urban Storm Water Systems
R827933C025 The Development of a Web Based Instruction (WBI) Program for the UWMRC User's Guide (Investigation of Inappropriate Pollutant Entries Into Storm Drainage Systems)
R827933C027 Legal Issues of SSO's: Private Property Sources and Non-NPDES Entities
R827933C028 Brownfields Issues: A Video Series
R827933C029 Facultative Landfill Bioreactors (FLB): A Pilot-Scale Study of Waste Stabilization, Landfill Gas Emissions, Leachate Treatment, and Landfill Geotechnical Properties
R827933C030 Advances in Municipal Wastewater Treatment
R827933C031 Design Criteria for Sanitary Sewer System Rehabilitation
R827933C032 Deep Foundations in Brownfield Areas: Continuing Investigation
R827933C033 Gradation-Based Transport, Kinetics, Coagulation, and Flocculation of Urban Watershed Rainfall-Runoff Particulate Matter
R827933C034 Leaching and Stabilization of Solid-Phase Residuals Separated by Storm Water BMPs Capturing Urban Runoff Impacted by Transportation Activities and Infrastructure
R827933C035 Fate of Pathogens in Storm Water Runoff
R87933C020 Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region