INLAND EMPIRE ASCE & INLAND EMPIRE ASCE & APWA APWA LOW IMPACT DEVELOPMENT LOW IMPACT DEVELOPMENT (LID) SEMINAR (LID) SEMINAR LID FACILITY DESIGN Prepared by Eric Prepared by Eric Mosolgo October 14, 2009 October 14, 2009 Riverside, California Riverside, California
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INLAND EMPIRE ASCE & APWA LOW IMPACT DEVELOPMENT (LID) SEMINAR LID FACILITY DESIGN
INLAND EMPIRE ASCE & APWA LOW IMPACT DEVELOPMENT (LID) SEMINAR LID FACILITY DESIGN. Prepared by Eric Mosolgo October 14, 2009 Riverside, California. Background. Contra Costa Approach Stormwater treatment and flow control Minimize directly connected impervious areas - PowerPoint PPT Presentation
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INLAND EMPIRE ASCE & APWAINLAND EMPIRE ASCE & APWALOW IMPACT DEVELOPMENT LOW IMPACT DEVELOPMENT
(LID) SEMINAR(LID) SEMINAR
LID FACILITY DESIGN
Prepared by Eric Prepared by Eric Mosolgo
October 14, 2009October 14, 2009
Riverside, CaliforniaRiverside, California
BackgroundBackground
Contra Costa ApproachContra Costa Approach Stormwater treatment and flow controlStormwater treatment and flow control Minimize directly connected impervious areasMinimize directly connected impervious areas Avoid standing water / vector issuesAvoid standing water / vector issues
BackgroundBackground
San Diego HMP and Model SUSMP San Diego HMP and Model SUSMP UpdateUpdate
Sacramento HMPSacramento HMP
BackgroundBackground
Watershed and Stream ScaleWatershed and Stream Scale Site scaleSite scale
Reduce peak flowsReduce peak flows Detain runoff on siteDetain runoff on site
Increase time of concentrationIncrease time of concentration Slow runoff from leaving siteSlow runoff from leaving site
No runoff from small stormsNo runoff from small storms Infiltrate and evapotranspirate Infiltrate and evapotranspirate
Reduce duration of moderate flowsReduce duration of moderate flows Let runoff seep away very slowlyLet runoff seep away very slowly
Reduce runoff volumeReduce runoff volume Infiltrate where possibleInfiltrate where possible
Reduce runoff energyReduce runoff energy Detain and slow flowsDetain and slow flows
Increase groundwater storage and Increase groundwater storage and stream base flowsstream base flows
Facilitate infiltrationFacilitate infiltration
Reduce pollutants in runoffReduce pollutants in runoff Detain and filter runoffDetain and filter runoff
Protect against spills and dumpingProtect against spills and dumping Disconnect drainage and filter runoffDisconnect drainage and filter runoff
Modeling Approaches and Summary of Modeling Approaches and Summary of Existing SoftwareExisting Software Single-Event ModelingSingle-Event Modeling Continuous Simulation ModelingContinuous Simulation Modeling
Presentation OverviewPresentation Overview
Hydrologic and Hydraulic AnalysisHydrologic and Hydraulic Analysis Single Event Model ExampleSingle Event Model Example Continuous Simulation Model ExampleContinuous Simulation Model Example
Presentation OverviewPresentation Overview
Maintenance and Monitoring RequirementsMaintenance and Monitoring Requirements
WQ Storage in voids of sub-surface soil WQ Storage in voids of sub-surface soil layerlayerAmended soils; minimize soil compactionAmended soils; minimize soil compactionSoil infiltration rate should exceed 1.5 in/hrSoil infiltration rate should exceed 1.5 in/hr50% sand, 25% compost, 25% planting 50% sand, 25% compost, 25% planting soilsoil30% voids30% voidsSoil depth of 4 feet recommended for Soil depth of 4 feet recommended for bioretention areas with treesbioretention areas with trees
Conflict with water Conflict with water conservation goalsconservation goals
BMPs used in arid BMPs used in arid environments will require environments will require monitoring to assess monitoring to assess performanceperformance
Design ConsiderationsDesign ConsiderationsLID Hydromodification MitigationLID Hydromodification MitigationRainfall adjustmentsRainfall adjustmentsLocate LID in areas of Locate LID in areas of pervious (A or B) soilspervious (A or B) soilsSurface reservoir must fillSurface reservoir must fillDrawdown time Drawdown time requirementrequirementOffsite area restrictionsOffsite area restrictionsVarying lower flow Varying lower flow thresholdsthresholdsMinimum orifice size Minimum orifice size criteriacriteria
IMP Reduces Impervious Runoff to Less Than Pre-Project Levels
LID Modeling ApproachesLID Modeling Approaches
General sizing General sizing approach for approach for bioretention basins, bioretention basins, bioretention swales bioretention swales and rain gardensand rain gardens
Limit contributing Limit contributing watershed area watershed area (dispersed facilities)(dispersed facilities)
Summary of Existing Summary of Existing LID Modeling SoftwareLID Modeling Software
Single-Event ModelsSingle-Event Models
Continuous Simulation ModelsContinuous Simulation Models HSPFHSPF HEC-HMSHEC-HMS SWMMSWMM Contra Costa LID Sizing CalculatorContra Costa LID Sizing Calculator San Diego HMP / LID Sizing CalculatorSan Diego HMP / LID Sizing Calculator
Summary of Existing LID SoftwareSummary of Existing LID SoftwareContra Costa Sizing CalculatorContra Costa Sizing Calculator
Sizing Factor Sizing Factor DevelopmentDevelopmentSoil GroupSoil GroupLand UseLand UseTreatment / Mitigation Treatment / Mitigation ApproachApproachSoil Physics at BMP Soil Physics at BMP Layer InterfacesLayer InterfacesWQ only sizing factorsWQ only sizing factorsWQ + Flow Control Sizing WQ + Flow Control Sizing FactorsFactors
Varying Conditions Soils (NRCS A, B, C, D) Land Cover Precipitation
Non-Structural Measures Pervious Pavement Self-Retaining Areas
Summary of LID Modeling Software Summary of LID Modeling Software
San Diego HMP / LID CalculatorSan Diego HMP / LID CalculatorDetention Basin Calculator (low flow orifice Detention Basin Calculator (low flow orifice and overflow weir)and overflow weir)
Pond configuration and outlet structure Pond configuration and outlet structure criteriacriteria
LID credit to reduce pond sizingLID credit to reduce pond sizing
Graphical Output of Peak Flow Frequency Graphical Output of Peak Flow Frequency and Flow Duration Responseand Flow Duration Response
Summary of LID Modeling SoftwareSummary of LID Modeling SoftwareSan Diego HMP / LID CalculatorSan Diego HMP / LID CalculatorInfiltration Devices for Parking Infiltration Devices for Parking Lots (scaling factor that varies Lots (scaling factor that varies with depth / bottom area ratio)with depth / bottom area ratio)Infiltration strips and tree wellsInfiltration strips and tree wellsTreatment only option for Treatment only option for vegetated swalesvegetated swalesExtended detention basin Extended detention basin optionoptionIncorporation of generic LID Incorporation of generic LID options for BMP manufacturersoptions for BMP manufacturersPervious pavementPervious pavement
Water Quality Only Flow Control Bioretention Cistern + Bioretention Bioretention + Vault Flow-Through Planter Dry Well Detention Basins Vegetated Swales Extended Detention Basins
Regulatory Levels Varying Lower Control Threshold
Performance and Output Summary Output for Plan Reviewers Performance Curves for Pond Sizing Integrated Help System
Summary of ExistingSummary of ExistingLID Modeling SoftwareLID Modeling Software
Treatment & Flow ControlTreatment & Flow Control NRCS Soil GroupNRCS Soil GroupAA BB CC DD
Hydrologic and Hydraulic AnalysisHydrologic and Hydraulic Analysis
Single-Event ExampleSingle-Event Example
0.2 inches/hour
BMP Area/Impervious Area =0.2/5 = 0.04
Planting mediumi = 5 inches/hour
Hydrologic and Hydraulic AnalysisHydrologic and Hydraulic Analysis
Continuous simulation Continuous simulation model examplemodel example
Match pre-project flows Match pre-project flows and durations in the and durations in the geomorphically significant geomorphically significant flow rangeflow range
Peak flow frequency Peak flow frequency statistics based on partial statistics based on partial duration calculationsduration calculations
Hydrologic and Hydraulic AnalysisHydrologic and Hydraulic AnalysisInput SummaryInput Summary
Hydrologic and Hydraulic AnalysisHydrologic and Hydraulic AnalysisOutput SummaryOutput Summary
Maintenance RequirementsMaintenance Requirements
HOA maintenanceHOA maintenanceRegular inspections to verify Regular inspections to verify vegetative establishment and vegetative establishment and prevent invasive vegetationprevent invasive vegetationRemoval of accumulated Removal of accumulated sediment sediment Replacement of dead Replacement of dead vegetation, erosion repair at vegetation, erosion repair at inflow, unclogging the inflow, unclogging the underdrainunderdrainChecks for standing waterChecks for standing waterVector controlVector control
Monitoring RequirementsMonitoring Requirements
Collect data for minimum of 2 rainy seasonsCollect data for minimum of 2 rainy seasons
Monitoring sites should cover range of Monitoring sites should cover range of development types, have applicable rain gage development types, have applicable rain gage data, be located in headwaters of watersheds, data, be located in headwaters of watersheds, be located upstream of variety of receiving be located upstream of variety of receiving channel types.channel types.
Obtain facility inflows and outflowsObtain facility inflows and outflows
Compare collected data to predicted dataCompare collected data to predicted data