WinSLAMM v 10 Theory and Practice Using WinSLAMM v10 to Meet Urban Stormwater Management Goals 1 We will cover... WinSLAMM Purpose, History and Unique Features Model Applications Small Storm Hydrology Basic Program Structure and Operation Treatment Practices Model Input/Output 2 1
WinSLAMM Can Answer These Types of Policy Questions... What are the base level pollutant loadings for different land uses with no controls? What flow and pollutant levels result from different development scenarios? What are the critical sources of flows and pollutants? How effective and cost effective are treatment practices in controlling pollutants and reducing flows? What combinations of stormwater controls will best meet regulatory requirements? 3 Background & History Development Began in mid-1970 s Early EPA street cleaning projects San Jose and Coyote Creek (CA) Castro Valley and other NURP projects Mid-1980 s - Model used in Agency Programs: Ottawa bacteria stormwater management program Toronto Area Watershed Management Strategy Wis. Dept. of Natural Resources: Priority Watershed Program Intensive data collection started in WI in early 1990s. First Windows version developed in 1995. Current graphical interface released, after three years of work, in 2012. Continuously being updated based on user needs and new research results. 4 2
Unique Features of WinSLAMM (and why it was developed!) WinSLAMM based on actual monitoring results at many scales and conditions. Early research project results in the 1970s did not conform to typical stormwater assumptions about rainfall runoff relationships and sources of pollutants. Initial versions of the model therefore focused on site hydrology and particulate sources and transport, and on public works practices. Other control practices added as data becomes available. 5 Controlled tests in small areas were used in conjunction with long term rainfall/runoff monitoring at larger parking lot areas to develop actual hydrological relationships for paved areas, the most significant source of runoff for most urban areas during small to intermediate sized rains. Pitt 1987 This is an example of a rainfallrunoff plot from one of many controlled street washoff and runoff tests. About 1/3 of the rainfall is infiltrated through the street pavement for many of these events (up to 20 mm rains in this plot). No further infiltration was observed for larger events, resulting in classical pavement Rv values of 0.8 to 0.95 for large rains of interest for drainage design. 6 3
Measured Particle Sizes, Including Bed Load Component, at influent to the Monroe St. Detention Pond, Madison, WI Very few of the large particles that enter the drainage systems are transported to the outfalls in typical urban drainage systems. Most (about 85% in this typical example) of the outfall 7 particulates discharged are less than 100 µm in size. Mass balance measurements in the drainage system and at the outfall used to determine the fate and transport of the urban particulates. Much of the larger particulates that are not washed off are lost from the paved surfaces by fugitive dust by winds and traffic turbulence. Measured fugitive dust losses from traffic (San Jose, Pitt 1979) Keyes, good 0.33 grams/vehicle mi asphalt Keyes, oil and 18 grams/vehicle mi screens asphalt Tropicana, good 2.5 grams/vehicle mi asphalt 8 4
We will cover... WinSLAMM Purpose, History and Unique Features Model Applications Small Storm Hydrology Basic Program Structure and Operation Treatment Practices Model Input/Output 9 Model Applications Model Can Be Applied on Multiple Levels Large Scale, City wide Analysis Site Development Analysis (Apartment Complex, Shopping Center, Hospital Complex, Residential Development) Analysis of Single Practice 5
Model Applications Large Scale, City wide Analysis Analysis Procedure Inventory drainage basins and land uses Evaluate existing pollutant loads and runoff volumes (base condition). Adjust base condition with existing stormwater control practices. Evaluate additional practices to costeffectively achieve pollutant reduction goals. Model Applications Large Scale, Regional Analysis More Red More Pollution More Green Less Pollution Pollution Load without Stormwater Control Measures12 6
Model Applications Large Scale, Regional Analysis Orange Catchbasins with Sumps Blue Wet Detention Ponds Green Grass Swales Pink Multiple Measures Implemented Stormwater Control Measures 13 Model Applications Large Scale, Regional Analysis Many areas went from red to green Can concentrate on areas that are still red Pollution Load with Implemented Stormwater Control Measures 14 7
Model Applications Site Development Analysis Analysis Procedure Inventory site characteristics (soil type, percent imperviousness, etc.) Locate selected stormwater controls throughout the site Determine volume and pollutant reduction achieved with selected stormwater control practices. Enter all the practices for a site and link them to determine the overall runoff and pollutant reductions Model Applications Site Development Analysis Porous Pavement Grass Swales Wet Ponds Biofilters 16 8
Model Applications Cost Analysis Capital Cost of Pond Achieving Different TSS Reductions at 100 Acre Mix of 40% Shopping Center and 60% Medium Residential Capital Cost, $ 200000 180000 160000 140000 120000 100000 80000 60000 40000 20000 0 Cost performance curves are usually not linear, with increasing unit costs as the overall treatment objective increases. For some situations, it may therefore be more costeffective to apply moderate levels of multiple controls. 0 20 40 60 80 100 TSS Reduction, % WinSLAMM can also calculate life cycle costs that include land costs, capital costs, and operational and maintenance costs, all adjusted for financing costs and inflation factors, and expected life of project. 9
We will cover... WinSLAMM Purpose, History and Unique Features Model Applications Small Storm Hydrology Basic Program Structure and Operation Treatment Practices Model Input/Output 19 Knowing the Runoff Volume is the Key to Estimating Pollutant Mass There is usually a simple relationship between rain depth and runoff depth in urban systems. Changes in rain depth affects the relative contributions of runoff and pollutant mass discharges: Directly connected impervious areas contribute most of the flows during relatively small rains Disturbed urban soils may dominate during larger rains 10
Monitored Milwaukee Rainfall and Runoff Distributions Small Large Medium 21 Monitored Milwaukee Pollutant Distribution Percent Associated with Rain, or less Small Medium Large Rain (inches) 22 11
Rainfall Sorts into Three Distinct Categories Small Rains Accounts for most events, by number Typically can be easily captured for infiltration or onsite beneficial uses Relatively low pollutant loadings, but frequent discharges Key rains associated with water quality violations, e.g. bacteria and total recoverable heavy metals Every time it rains, some numeric discharge concentration objectives may be exceeded. Therefore, try to eliminate the small events 23 Rainfall Sorts into Three Distinct Categories Medium Rains Responsible for most pollutant mass discharges Smaller events in this category can be easily captured and infiltrated or re used Larger events in this category need to be treated. Typically responsible for about 75% of pollutant discharges 24 12
Rainfall Sorts into Three Distinct Categories Large Rains Infrequent Large Events Not cost effective to treat all runoff Typically cause flooding and significant erosion Treatment practices designed for smaller storms will mitigate impacts of larger events to some extent 25 We will cover... WinSLAMM Purpose, History and Unique Features Model Applications Small Storm Hydrology Basic Program Structure and Operation Treatment Practices Model Input/Output 26 13
Basic Program Structure WinSLAMM Calculation Process Calculate Runoff Volumes and Particulate Loadings for each Source Area Apply Appropriate Drainage System Treatment Practices Apply Appropriate Source Area Treatment Practices Sum Resulting Source Area Outputs Route Totals to the Outfall for Volume and Pollutant Discharge to Receiving Waters Route Totals to the Drainage System 27 Medium Density Residential Land Use ROW Residential Land Use Source Areas Pitched Roofs Driveways Sidewalks Small Landscaped Areas Streets Storm Sewer Drainage System Grass Swale Drainage System Residential Land Use Source Areas Pitched Roofs Driveways Small Landscaped Areas Streets Low Density Residential Land Use Freeway Land Use Source Areas Paved Lane and Shoulders Large Turf Areas ROW Commercial Land Use Source Areas Flat Roofs Parking Driveways Sidewalks Small Landscaped Areas Streets Strip Commercial Land Use Outfall Park Land Use Other Urban Land Use Source Areas Playground Sidewalks Large Landscaped Areas Streets 28 14
Modeled Drainage System from Previous Slide 29 The Basic Program Structure Information is Entered in the Land Development Characteristic (.mdb) database file: 1. Appropriate Parameter Files 2. Land Use type and area 3. Size of all Source Areas 4. Source Area parameters and characteristics (soil type, connected imperviousness, street texture, etc.) 5. Control Practice designs 30 15
Rainfall Parameter File Can Include Many Years/Decades of Rainfall Information 31 SLAMM runoff coefficient file -.rsv Runoff coefficient 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Connected pitched roofs Rough textured streets Clay soils Sandy soils 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Connected flat roofs Connected Pitched Roofs Directly connected impervious areas Directly connected unpaved areas Pervious areas - A soils Pervious areas - B soils Pervious areas - C/D soils Smooth textured streets Intermediate textured streets Rough textured streets Rainfall (in) Not much difference between the different source areas for the large, drainage design storms, but much larger differences for the small and intermediate sized rains. 32 16
Particulate Solids Concentration File Depicts the particulate solids concentrations for source areas and land uses based upon rainfall depth. Default files available, or may be user defined. File extension: *.pscx 33 Street Dirt Washoff and Accumulation Sawtooth Pattern Associated with Deposition and Removal of Particulates on Urban Street Street Dirt Accumulation Street Dirt Washoff or Cleaning Pitt 1979 17
Pollutant File Depicts the pollutant concentrations (and variability) for source areas and land uses. Regionally calibrated files available, or may be user defined based on local data. File extension: *.ppdx 35 Basic Program Operation Critical Particle Size Files For devices using sedimentation such as wet detention ponds, catchbasins, hydrodynamic devices, biofilters, grass swales, grass filters, media filters, etc. 80% A number of.cpz files are included with the program, or can be created using locally available psd data 3 um For 80% reduction, the particle size for control is 3 um 36 18
We will cover... WinSLAMM Purpose, History and Unique Features Model Applications Small Storm Hydrology Basic Program Structure and Operation Treatment Practices Model Input/Output 37 Model Input/Output Model Output 1. Output Summary 2. Receiving Water Impacts 3. Land Uses and Source Area Detail 4. Control Device Detail 5. Analyzed as a single file or in batch mode 6. Many output options i. Control Device Detailed Output ii. Hydrograph and Particle Size Distribution at each Control Practice, Land Use and Junction 38 19
Output Summary Drainage System and Outfall Results: 39 Model Input/Output Receiving Water Impacts 40 20
Model Input/Output Detailed Output Information 41 Control Practice Summary Table 42 21
RR0 7000 PR12000 NL0300 1 Nonreg RR13000 NL03002 NL02000 NL03006 NL01000 NL03000 Nonreg NL03004 NL03003 NL0 300 5 NL04000 NL0 801 9 NL05000 NL06001 NL08018 NL06000 NL06004 NL06002 NL06003 NL08023 IW01000 NL0 801 5 NL07001 NL07000 NL0 801 7 NL0 801 6 NL08000 NL08021 RR0 6000 NL08020 NL0 802 2 NL08004 Nonreg RR0 600 0 NL0800 6 NL08001 NL0900 0 NL08002 Nonre g RR01000 NL08003 RR03000 RR0 2000 NL08005 NL0 800 7 NL08014 NL08008 RR0400 0 NL08011 NL08010 NL1 0003 NL10001 NL1 000 2 NL10000 NL08009 NL08012 RR4 600 3 NL0 801 3 RR4700 2 RR4 7001 RR4 6004 RR46002 RR53000 RR08000 RR0 9000 NL11000 RR4 7000 RR5000 0 RR46001 RR1 000 0 RR61000 Nonreg RR4 8000 RR1 100 0 RR49000 RR1 2003 RR22000 RR46000 RR5100 0 RR15012 RR22001 RR4 5000 RR1200 0 RR15014 RR5700 0 RR59000 RR2 1000 RR44000 RR56000 SL12000 RR12002 RR5 800 0 RR14000 RR5 5000 RR52000 RR15013 RR34000 RR4 3000 SL13000 RR12001 RR1500 0 RR23000 RR3300 0 RR1 5005 RR15000 RR1600 0 RR24000 SL14000 RR1 7000 Nonreg RR15001 RR3 2000 RR15011 RR54000 RR15010 RR1500 6 RR25000 RR1 5002 RR18000 RR2 600 0 SL16000 RR15004 SL15000 RR1 500 8 RR15003 RR19000 RR3 100 0 RR2 7000 RR3 5000 RR36000 RR29000 RR2 8000 RR30000 RR20000 RR38000 SL 17000 RR1 5016 RR1500 7 RR20001 RR15009 RR60000 RR36001 RR1 5017 RR41000 RR42000 SL17001 RR4 000 0 RR39000 RR37002 RR37001 RR3 7000 RR37003 SL17002 RR36002 RR3 7007 RR3 7006 RR3 7004 RR37008 RR37005 RR3701 2 RR37011 RR37009 SL25000 RR37030 RR37010 RR4 000 1 SL18000 SL19003 RR3 7013 RR37014 SL19005 RR3701 5 SL19000 SL19004 SL19002 Non reg SL19001 RR3 7017 RR3 7016 RR3701 9 RR3 7018 SL19006 SL20000 RR3 7025 RR37022 RR3 702 1 SL23019 SL23032 RR37023 SL23016 SL23015 SL22001 SL21000 PR08001 RR3 7024 SL 230 35 SL23002 SL22000 PR08002 SL23033 RR3 7028 SL23002 PR07000 SL23004 SL23017 SL 23034 RR3702 6 RR37027 SL 230 02 PR08003 PR08000 SL23036 SL23018 SL23000 PR08001 SL 23013 SL23005 SL23028 SL23029 PR01000 1600 0 1600 3200 4800 Feet SL23014 SL23030 RR3 7029 SL23006 SL23012 SL 230 03 SL23021 SL23020 SL 230 08 SL23011 SL23027 SL 23007 SL 23010 SL23011 SL23024 SL23025 SL23023 SL 23024 SL23026 SL23024 PR02000 SL23023 PR06004 PR06004 SL 23022 PR03000 SL24001 SL23024 PR06004 Nonreg PR06003 PR06000 PR09000 PR04000 Nonreg PR1 0000 PR11000 Non reg PR05000 PR06002 PR06001 SL23001 SL23001 Tab 2 B WinSLAMM Theory and Practice 1/8/2014 Model Input/Output Similar Output for Particulate Solids Concentration Particulate Solids Yield Pollutant Concentration Pollutant Yield 43 The WinSLAMM batch editor can be used to automatically run a large number of files, usually for integration into a GIS-based map. Critical Loading Rates N High Subbasins MH Water Moderate ML Corporate Limits Low 43247 November, 2002 Critical Loading Rates Stormwater Investigation City of Racine, Wisconsin 22
Lincoln, NE, WinSLAMM project to identify sources and controls for bacteria (runoff volume was the critical tool) Commercial Areas Flow Contributions Rains: 1: 0.01 ; 2: 0.05 ; 3: 0.1 ; 4: 0.25 ; 5: 0.5 ; 6: 0.75 ; 7: 1 ; 8: 1.5 ; 9: 2 ; 10: 2.5 ; 11: 3 ; 12: 4 45 Control Program for Commercial Strip Mall Land Use Volume Reduction (% reduction compared to base conditions for clay loam conditions in the biofilters) Total Annual Costs ($/100 acres/yr) Porous pavement (in half of the parking areas) 25% $180,400 Curb cut biofilters (along 80% of the curbs) 29 $166,500 Biofilters in parking areas (10 percent of the source area) 29 $314,000 Small wet pond plus biofilters in parking areas (10 29 $341,800 percent of the source area) Biofilters in parking areas (25 percent of the source area) 40 $785,000 Small wet pond plus biofilters in parking areas (10 43 $424,600 percent of the source area) and curb cut biofilters (along 40% of the curbs) 46 23