What is Post-Construction Stormwater Management? Carrie J. Evenson, Ph.D. Environmental Programs Specialist IV Industrial Wastewater Enforcement Section Water Quality Division Department of Environmental Quality.
Download ReportTranscript What is Post-Construction Stormwater Management? Carrie J. Evenson, Ph.D. Environmental Programs Specialist IV Industrial Wastewater Enforcement Section Water Quality Division Department of Environmental Quality.
What is Post-Construction Stormwater Management? Carrie J. Evenson, Ph.D. Environmental Programs Specialist IV Industrial Wastewater Enforcement Section Water Quality Division Department of Environmental Quality Outline What is it? What does this mean for you? What’s out there? What’s been done in Oklahoma? Permit Requirements (1) Develop, implement, and enforce a program to address storm water runoff from new development and redevelopment projects that disturb greater than or equal to one acre, including projects less than one acre that are part of a larger common plan of development or sale, that discharge into your SMS4. Your program must ensure that controls are in place that would prevent or minimize water quality impacts; Permit Requirements (2) Develop and implement strategies which include a combination of structural and/or non-structural best management practices (BMPs) appropriate for your community; Structural = retention/detention ponds, grassed swales, etc. Non-structural = directing growth/development, protecting sensitive areas, minimizing impervious areas, etc. Permit Requirements (3) Use an ordinance or other regulatory mechanism to address post-construction runoff from new development and redevelopment projects to the extent allowable under State or local law; (4) Ensure adequate long-term operation and maintenance of BMPs. Address who, how, when, and what happens if not maintained So what IS it? Control of stormwater runoff after construction is complete Consists of: An ordinance May require post-construction hydrology not exceed pre-construction hydrology A method to ensure ordinance is followed (aka plan review and enforcement) A selection of ways to meet ordinance requirements A way to ensure that maintenance occurs long-term Post-Construction and Flood Control Are related Both address stormwater runoff from parking lots, streets, roofs, etc. as well as destination (i.e. infiltration or transport downstream) Do you have ordinances for both? Do they conflict? Can one or both be modified to encourage green over gray infrastructure? Green vs. Gray Infrastructure Traditional Street in OK Green Street in Portland, OR https://picasaweb.google.com/buildgreeninfrastructure/NewColumbiaPortlandOregon# What isn’t it? Simply a duplication of your construction stormwater management program Are closely tied but not the same Plan review may occur at the same time but different elements may need to be considered Establishing grass/vegetation on a site after construction is complete What’s on the horizon? EPA Stormwater Rulemaking Rule to be proposed by June 10, 2013 Addresses post-construction 1. Develop performance standards from newly developed and redeveloped sites to better address stormwater management as projects are built Retention of runoff from certain size storm event onsite 2. Evaluate options for establishing and implementing a municipal program to reduce discharges from existing development (aka “Retrofit”) What does this mean for you? Post-construction stormwater management will become a larger part of your stormwater program. You will need to develop a plan to comply with future and existing requirements. What’s out there? Non-structural controls Don’t involve physical construction Are planning and managementrelated Structural controls Involve physical construction Non-Structural Controls Review ordinances to remove barriers Street width requirements Parking requirements Prohibition on use of pervious concrete or asphalt Development design restrictions Others? Non-Structural Controls Direct growth Protect sensitive areas Maintain and/or increase open spaces Provide buffers along waterbodies Minimize impervious surfaces Encourage infill Educate builders/developers/public on green infrastructure Development Design http://www.illinoisfloods.org/documents/2011_Cost_of_Green_Workshop/2011-10-22-IAFSM_Green_vs_Gray.pdf EPA LID Video http://www.youtube.com/watch?v=EEvnxZtFu50&feature=related Structural Controls Retention/Detention Ponds Wet ponds Dry ponds Stormwater wetlands Structural Controls Rain Barrels and Cisterns Reduce runoff by disconnecting downspouts from storm sewer system Allows for reuse Complicated by water rights laws in Western states https://picasaweb.google.com/buildgreeninfrastructure/NewColum biaPortlandOregon#5347598378129283042 Rain Barrels in Oklahoma Oklahoma Gardening Feature http://www.youtube.com/watch?v=FeRO2MnH79M Structural Controls Rain Gardens/Bioretention Provide on-site treatment by filtering out pollutants Can be designed for infiltration or discharge via underdrain Suitable for small drainage area (≤ 5 acres) Can use drought-tolerant plant species Stillwater Community Center Rain Garden Demonstration Project Rain Gardens in Oklahoma http://www.newson6.com/story/13360322/volunteerscreate-broken-arrow-rain-garden ?redirected=true www.muskogeephoenix.com/features/.../Rain-gardens-good-for-home Rain Gardens in Oklahoma www.news9.com/story/19513628/okcoffers-classes-on-rain-gardens http://npaper-wehaa.com/oklahoma-gazette/2011/04/20/#?article=1236329 Rain Gardens in Oklahoma Oklahoma Gardening Feature http://www.youtube.com/watch?v=PJSuHxcxyDg Structural Controls Botanical Research Institute of Texas Green Roofs Reduce peak flow discharge Reduces urban heat island effect Use drought-tolerant plant species Difficult to retrofit structures Winnie May House in Oklahoma City – originally installed in 1951 http://www.okc.gov/planning/greenroof/#TOUR_LOCATIONS Green Roofs in Oklahoma Oklahoma Gardening Feature http://www.youtube.com/watch?v=rzIBYWs09-c Structural Controls Green Parking Reduce parking lot contribution to stormwater runoff by reducing impervious surfaces and increasing infiltration Combination of porous paving, reduced lot/space size, and bioretention http://www.streamteamok.net/Doc_link/Green%20P arking%20Lot%20Guide%20(final).PDF Structural Controls Narrower Streets Reduces impervious surface Applicable to low traffic volume streets Areas of successful implementation Portland, OR Boulder, CO Parts of New Jersey https://picasaweb.google.com/buildgreeninfrastructure/SeattleStreetEdgeAlternativesSEA#5279034770289654642 Structural Controls Permeable/Pervious/Porous Materials Includes pavers, concrete, and asphalt Allow water to drain through to a storage/infiltration layer Used for parking lots, sidewalks, and residential streets Pervious Parking at Beaver Water District in NWA Overflow parking area with grass parking pavers with plastic reinforcing grid. Pervious concrete parking lot Structural Controls Grassed Swales Aka bioswales, biofilters, grassed channel, etc Designed to treat and infiltrate runoff Modified versions of drainage ditches Conveyance only vs treatment and conveyance Vegetated filter strip between parking spaces at Beaver Water District in NWA Structural Controls Infiltration Basins Shallow impoundment or depression Designed to allow infiltration Treats runoff via detention and filtration Suitable for small drainage area (≤ 10 acres) Infiltration Basin at Beaver Water District in NWA Structural Controls Infiltration Trench Rock-filled trench without an outlet Stores and infiltrates runoff Treats stormwater through filtration through soil Clogging may be issue http://cfpub.epa.gov/npdes/stormwater/menuofbm ps/index.cfm?action=browse&Rbutton=detail&bmp =70&minmeasure=5 Structural Controls Catch Basin Inserts Placed in catch basins to remove oil and grease, sediment, trash, and other pollutants Requires regular maintenance Examples from Idaho DEQ Storm Water BMP Catalog Resuspension may occur http://www.deq.idaho.gov/media/618062-6.pdf Structural Controls Sand and Organic Filters Directs stormwater through sand bed Removes floatables and pollutants Primarily used for water quality improvement Requires regular maintenance and filter media replacement Sand filter under construction http://www.dcr.virginia.gov/stormwater_management/do cuments/Chapter_3-12.pdf Structural Controls Vegetated Filter Strips Designed to treat sheet flow from adjacent surfaces Adapted from agricultural practices Slow runoff velocity Filter sediment Need to maintain sheet flow for proper treatment http://www.oh.nrcs.usda.gov/programs/lake_erie _buffer/images/grass_fs_seneca_co.jpg What’s going on in Oklahoma? City of Norman Trail Woods Addition Rain gardens, rain barrels, and downspout disconnection on one side Traditional construction on other side Runoff will be monitored by University of Oklahoma researchers What’s going on in Oklahoma? City of Stillwater Rain garden at Stillwater Public Library Rain harvesting sand cistern at Skyline Elementary What’s going on in Oklahoma? City of Stillwater Rain garden demonstration project at Stillwater Community Center Built in 2009 Rain barrel building workshop Conducted in June 2010 What’s going on in Oklahoma? City of Bixby Rain garden at Bentley Park Roundabout Designed in-house by Jared Cottle and Bea Aamodt What’s going on in Oklahoma? City of Owasso Used ENKE mat at the Rayola Park project Wetland mitigation project at the Garnett regional detention facility What’s going on in Oklahoma? City of Broken Arrow Living Green LID program Voluntary Provides incentive for LID implementation through recognition Can achieve Bronze, Silver, Gold, or Platinum LID Certification Level based on types of LID implemented Available for four types of development Residential Non-Residential Existing Residential Existing Non-Residential What’s going on in Oklahoma? City of Tulsa Pervious concrete test 5 different concrete companies in area poured test patches at Public Works maintenance yard Infiltration rate changes are being monitored by OSU quarterly What’s going on in Oklahoma? http://www.youtube.com/watch?v=QijdlarzVnI What’s going on in your MS4? Questions, Comments, Discussion