Watershed Planning Workshop Upper Four Mile Run, Gulf Branch and - PowerPoint PPT Presentation

Watershed Planning Workshop Upper Four Mile Run, Gulf Branch and Donaldson Run February 1, 2011 Langston Brown Community Center

Arlington’s watersheds Chesapeake Bay watershed

Watershed Planning  Initiated May 2008; first planning meeting for these watersheds in March 2010  Contracted to Center for Watershed Protection  For each watershed, result is an inventory of potential stormwater retrofit projects.  Part of Arlington’s Stormwater Master Plan Update  Anticipates Chesapeake Bay clean-up requirements  http://www.arlingtonva.us/departments/Environm entalServices/epo/page67082.aspx

Stormwater Master Plan Update  Stormwater Master Plan (1996) and Watershed Management Plan (2001) will be updated and combined into a comprehensive Master Plan.  Storm Sewer Capacity Analysis to study the County's current storm sewer pipes.  County-wide stream inventory to assess stream conditions and prioritize stream restoration projects.  Watershed retrofit plans to identify locations where stormwater treatment facilities can be added to help slow down and filter stormwater runoff.

Stormwater Retrofits A retrofit is a stormwater management facility designed to store, infiltrate, and/or filter stormwater runoff from a contributing drainage area for which a stormwater management facility currently does not exist.

Impervious cover in Arlington County - 2007 Airport Alley 3.8% 0.2% Handicap ramp 0.1% Driveway 7.4% Buildings 30.1% Parking lot 15.7% Paved median 0.6% Sidewalks 8.4% Impervious cover Roads 33.8% in Arlington = 42% or 7125 acres

Effect of Urbanization on Watersheds Impervious surface Runoff speed and volume Water Quality Groundwater supply Stream Corridor Restoration, FISRWG, 1998

Effect of Urbanization on Watersheds

Severe streambank erosion and habitat degradation

Why Stormwater Retrofits?  County streams are impacted.  Most development occurred before regulations that protect water quality and streams were enacted.  Stormwater retrofits provide our best opportunities to improve watershed health, along with redevelopment and stream restoration.  Will be required to meet Chesapeake Bay clean-up goals.

Why Stormwater Retrofits? Stormwater retrofits will help:  Clean and filter pollutants from runoff  Slow and temporarily store stormwater runoff  Improve water quality in our local streams

Limitations of Watershed Retrofits  Time and funding limitations mean projects will be implemented incrementally.  On average, assessments indicate about 15% of impervious area can be retrofitted.  Retrofits alone cannot solve current flooding, infrastructure and stream erosion problems.  County must and will fund and implement infrastructure updates and stream restoration projects in addition to retrofits.  Implementation on private property is essential for significant change.

Considerations and Challenges Gulf Branch/Donaldson Run  Both watersheds are “built-out”  Impervious area less than County average (Gulf Branch – 29%; Donaldson Run – 23%).  High proportion of public land in the Donaldson Run watershed (40%).  Both watersheds primarily single-family residential (Gulf Branch – 78%; Donaldson Run – 57%)  Streets and private roofs contribute 75% of the impervious area. Driveways are also significant (14-18%).  Steep topography

Considerations and Challenges Crossman Run, Westover Branch and Torreyson Run  All watersheds are “built-out”  High percentage impervious cover – 42%; low percentage of public land.  Primarily single family residential (72%) but also some commercial area (3%).  Commercial areas include pollutant “hotspots.”  Streets and private/commercial roofs, make up the majority of the impervious area (av 73%) . Parking lots also significant (11-13%).  Both public and private efforts are needed!

Next Steps  Concepts designs under development for 3 Donaldson Run sites: • County compost facility • Water tower • 30 th Street N @ Military Road  Select additional projects for concept development (24 total)  Additional field work to develop concept designs  Final report

Plan Implementation  7 Green Streets projects in design  8.1 acres of impervious area to be treated • Williamsburg Blvd median (Old Dominion to 35th St N) • Williamsburg Blvd median (Harrison to Edison N) • Kensington Blvd (at 33 rd St N) • 32nd St N (at Kensington Blvd) • John Marshall Dr median • Patrick Henry Dr (at 9 th Rd N) – in construction • 8 th St S (at Monroe St S)  $2 million budgeted for FY 11-16

Resources for Homeowners Rain Gardens for Homeowners Workshops Learn how to properly locate, design, construct and maintain a small-scale rain garden. http://www.novaregion.org/index.aspx?NID=977 Build Your Own Rain Barrel Workshops & Rain Barrel Sales http://www.arlingtonenvironment.org/barrel.php Green It! Workshop Series http://www.arlingtonva.us/portals/topics/Climateevents.aspx Chesapeake Conservation Landscaping Council http://www.chesapeakelandscape.org Rain Barrel(s)

Incentive Program for Homeowners  Partnership with Arlingtonians for a Clean Environment  In pilot year, providing 40 matching grants of $500-$1000 to homeowners for sustainable stormwater projects.  Launching spring or summer 2011.  http://www.arlingtonva.us/departments/En vironmentalServices/epo/page74076.aspx

Questions??  Contact info:  Phone: (703) 228-3588  Email: cjolicoeur@arlingtonva.us  Web: www.arlingtonva.us Residents Environment Watershed Management http://www.co.arlington.va.us/departments/Environ mentalServices/epo/page74076.aspx