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Wetlands and Stormwater Management
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Wetlands and Stormwater Management

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  • The stormwater treatment practices presented in this slide show fall into five major categories: stormwater ponds, stormwater wetlands, infiltration practices, filtering practices, and open channels. Within each category, there are several design variations.
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    • 1. Balancing Wetland and StreamBalancing Wetland and Stream Preservation with StormwaterPreservation with Stormwater Management:A Case StudyManagement:A Case Study Presentation for National Association of Environmental Professionals 39th Annual Conference St. Petersburg, Florida April 8, 2014 Andrew T. Der & Associates, LLC Environmental Consulting 1000 Fell Street | Baltimore, MD 21231 1.410.491.2808 | AndrewTDer@comcast.net
    • 2. Habitat Avoidance – can be -Habitat Avoidance – can be - InsufficientInsufficient
    • 3. What HappensWhat Happens
    • 4. Secondary Impacts = NewSecondary Impacts = New Construction SWMcriteriaConstruction SWMcriteria Disturbance to Surface water resources • State nontidal waters and wetlands including 100 year floodplain and water quality criteria • State tidal waters and wetlands • Federally regulated waters of the United States Disturbance to Land (nonpoint source pollution) • State stormwater management regulations – includes delegated point and nonpoint source federal criteria • State and local erosion and sediment control criteria • Special state tidal water criteria
    • 5. Classification of State Waters inClassification of State Waters in MarylandMaryland • Use I & I-P:Water Contact Recreation and Protection of Aquatic Life • Use II: Shellfish Harvesting Waters • Use III & III-P: Natural Trout Waters • Use IV & IV-P: Recreational Trout Waters
    • 6. State WaterQuality StandardsState WaterQuality Standards Numerical • Dissolved Oxygen,Temperature, pH,Turbidity, Fecal Coliform,Toxics Narrative include CWA •...Protection of Aquatic Life ...Fishable ...Swimmable...Includes EPA Anti- Degradation Policy (ADP): “...To accomplish the objective of maintaining existing water quality...Nonpoint sources shall achieve all cost effective and reasonable best management practices for nonpoint source control...”
    • 7. What is a Best ManagementWhat is a Best Management Practice (BMP)?Practice (BMP)? BMPs are policies, practices, procedures, or structures (engineered practices) implemented to mitigate the adverse environmental effects on surface water quality resulting from rain water runoff. BMPs are categorized as structural or non-structural. • Early Planning/ Avoidance • “Low Impact Development”, or “Better Site Design”, or “Environmental Site Design” • Local stream buffers and setbacks • Minimize or disconnect impervious surfaces sheet flow, open section pavement • Devices or engineered practices (ponds, bioretention, etc.) Most significant factor affecting performance is construction and maintenance
    • 8. Hierarchy of Engineered PracticesHierarchy of Engineered Practices Smaller Volumes “First Flush” Preferred and most compatible with ESD at-source and/or pretreatment quality control • Infiltration – trench/basin • Filtering – sand filter/bioretention • Hydrodynamic Devices above or underground – Curb & gutter vortex/filter basin • “Newer”Technology – pervious surfaces/green roofs Larger Volumes When preferred is Insufficient for quantity and quality • Stormwater Ponds – wet pond – wet ED pond – dry ED pond (for cold water w/ pre-treatment) – multiple pond system • StormwaterWetlands – shallow marsh – ED shallow wetland – pond/wetland systems
    • 9. Location of Example Project AreaLocation of Example Project Area
    • 10. Location of Project AreaLocation of Project Area
    • 11. Watershed and InitialWatershed and Initial Development at Low PointDevelopment at Low Point
    • 12. Initial Permit Review StepsInitial Permit Review Steps • Higher Quality Use I-PWater • Purpose and Need • Avoidance and Minimization of Waters of the U. S. from Roads, Utilities, and Other Disturbances • Nonpoint Source Pollution Management: Quality • Stormwater Management (SWM): Quantity • Coordination with Local Authorities, NGOs, and Stakeholders • How to Address ADP and SWM
    • 13. Apply Hierarchy of SWMApply Hierarchy of SWM Preferences to Site CharacterPreferences to Site Character • Vegetative buffers, disconnects, open section pavement • Infiltration Practices if Soils Allow • Bioretention, Swales,Wetland Filtering • Retention or Extended Detention Pond with Wetlands (to include quantity management)
    • 14. ProposedProposed Site-specificSite-specific MitigationMitigation and BMP’sand BMP’s • Stream/wetland impacts limited to necessary roads/utilities • In-stream SWM in marginal/poor areas only • Minimum stream buffer of 100‘ (30.5 meters) • Wetland mitigation and replanting in cropped riparian buffer areas • “First flush” stormwater quality management in uplands • Infiltration/filtration where feasible (permeable soils and depth) • Primary quantity stormwater management in “horseshoe” pond • Water pooling areas planted with wetland vegetation
    • 15. BMPs and Mitigation – Forest andBMPs and Mitigation – Forest and Wetlands – Workwith SiteWetlands – Workwith Site
    • 16. BMPs and Mitigation - MaximizeBMPs and Mitigation - Maximize Site CharacterSite Character
    • 17. BMPs and Mitigation - Pond andBMPs and Mitigation - Pond and Wetlands ManagementWetlands Management
    • 18. BMPs and Mitigation – ImpactBMPs and Mitigation – Impact Avoidance and Wetland FiltrationAvoidance and Wetland Filtration
    • 19. BMPs and Mitigation - SensitiveBMPs and Mitigation - Sensitive ResourcesResources
    • 20. BMPs and Mitigation - TransitionBMPs and Mitigation - Transition HabitatHabitat
    • 21. BMPs and Mitigation - SWM&BMPs and Mitigation - SWM& LandscapingLandscaping
    • 22. BMPs and Mitigation – SWMandBMPs and Mitigation – SWMand LandscapingLandscaping
    • 23. BMPs and Mitigation – UrbanBMPs and Mitigation – Urban AreasAreas
    • 24. BMPs and Mitigation – UrbanBMPs and Mitigation – Urban AreasAreas
    • 25. BMPs and Mitigation – UrbanBMPs and Mitigation – Urban AreasAreas
    • 26. BMPs and Mitigation - StreamBMPs and Mitigation - Stream Stabilization and RestorationStabilization and Restoration • Can be effective watershed sediment control practice • Can be local approval requirement • Can be a traded credit • Can be out-of-kind wetland mitigation
    • 27. Public & NGO InvolvementPublic & NGO Involvement • Public Notice • Waters may have Use III or IV (higher quality trout water) potential • Temperature and ponds potential concern • EPA Antidegradation Policy may apply • Implemented stream Rapid Bioassessment • Findings - no Use III or IV standards but higher quality Use I
    • 28. Additional Mitigation and WaterAdditional Mitigation and Water Quality Management PracticesQuality Management Practices • Water Quality Monitoring Plan • Stream Reach Temperature Model and Percent Contribution of “QED” 2, 10 year event to Stream Flow • Maximum 20% Diversion Base Flow • Shade Planting of SW Conveyance and Management Areas •Toe Drain Pipes Under Embankment Fill
    • 29. Streamand WaterQualityStreamand WaterQuality MonitoringMonitoring Can be used for state Watershed Compliance Can be used for state natural resource studies Preconstruction, construction and post- construction Macroinvertebrate studies (more common examples are WWTP & mining requirements) Chemistry Geomorphology Groundwater
    • 30. Primary Monitoring ComponentPrimary Monitoring Component
    • 31. Historic Bioassessment DataHistoric Bioassessment Data Rapid Bioassessment Metric Comparisons to Pre-Construction Scores Year ST2 ST6 ST10 1993 Non Impaired ** Non Impaired ** 1994 Non to Mod. Impaired Non Impaired Non Impaired ** 1995 Non to Mod. Impaired Non to Mod. Impaired Non Impaired 1996 Non to Mod. Impaired Moderately Impaired Non to Mod. Impaired 1997 Non to Mod. Impaired Non to Mod. Impaired Moderately Impaired 1998 Moderately Impaired Non to Mod. Impaired 1999 Moderately Impaired Moderately Impaired Moderately Impaired 2000 Moderately Impaired Non to Mod. Impaired 2001 Non to Severely Impaired Moderately Impaired Non Impaired 2002 Non to Mod. Impaired Mod. to Severely Impaired ** Non Impaired value is given to the first (reference) date for comparison purposes; the streams on those dates are not necessarily truly non-impaired.
    • 32. Historic Dissolved Oxygen DataHistoric Dissolved Oxygen Data Piney Branch Mean Dissolved Oxygen Levels for Stations 2, 6 and 10 0 2 4 6 8 10 12 14 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year mg/l ST. 2 Mean D.O. ST. 6 Mean D.O. ST. 10 Mean D.O. Use I Min. D.O.
    • 33. Historic Temperature DataHistoric Temperature Data Piney Branch Instream Peak Temperatures Stations 2, 6 and 10 0 5 10 15 20 25 30 35 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Temperature(oC) ST. 2 ST. 6 ST. 10
    • 34. Lessons LearnedLessons Learned • Basis for “how we do it now” • Basis for groundbreaking county Special Protection Area legislation • Basis for local, state, federal coordinating committees and public processes • Basis for initial findings for CWA Section 402 Phase I MS4 NPDES Municipal Permit Compliance

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