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.

Buildings 30.1% Sidewalks 8.4% Roads 33.8% Paved median 0.6% Parking lot 15.7% Handicap ramp 0.1% Driveway 7.4% Alley 0.2% Airport 3.8%

Impervious cover in Arlington County - 2007

Impervious cover in Arlington = 42% or 7125 acres

Impervious surface Runoff speed and volume Water Quality Groundwater supply

Effect of Urbanization on Watersheds

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
• pportunities 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%
• f 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
• 30th 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 33rd St N)
• 32nd St N (at Kensington Blvd)
• John Marshall Dr median
• Patrick Henry Dr (at 9th Rd N) – in construction
• 8th St S (at Monroe St S)
• $2 million budgeted for FY 11-16

Resources for Homeowners

Rain Barrel(s) 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

Incentive Program for Homeowners

• Partnership with Arlingtonians for a Clean

Environment

• In pilot year, providing 40 matching grants
• f $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