scotts run tributary at windy hill road: stream stabilization project

A Fairfax County, VA, publication

Department of Public Works and Environmental Services

Working for You!

Scotts Run Tributary at Windy Hill Road

Stream Stabilization Project

May 2016

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Agenda

Project ScopeBackgroundGoals and ObjectivesExisting ConditionsProject ConceptNext StepsContact Information

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Stormwater Program Regulatory Drivers

• National Pollutant Discharge Elimination System (NPDES)

• Virginia Stormwater Management Program (VSMP)– Municipal Separate Storm Sewer Permit (MS4)– Discharge from approximately 7,000 storm drain outfalls– Includes watershed planning and project implementation

• Total Maximum Daily Loads (TMDLs)– Chesapeake Bay– Local Streams– Establishes pollutant loading budget for a given impaired water

body to meet water quality standards

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Scotts Run Watershed• 3,860 acres in Fairfax County• 30% impervious of mostly low

density residential land use• Drains significant commercial

and medium-density resident areas located near Tysons Corner

• Scotts Run discharges into the Potomac River

• Watershed Management Plan identifies frequent flooding at Scotts Run Road

http://www.fairfaxcounty.gov/dpwes/watersheds/middlepotomac.htm

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Project Objectives

Restore up to 650 linear feet of stream from Windy Hill Road to Box Elder Court:

Stabilize streambed and banks Reduce sediment and nutrient inputs into stream system

Improve habitat Maintain close coordination with stakeholders

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Social Goals1. Maintain open dialog and share information.2. Coordinate with all the stakeholders and the community.3. Design Team:

o Rinker Design Associates, P.C.o Utilities Design and Construction Divisiono Stormwater Management

o Stormwater Planning Divisiono Maintenance and Stormwater Management Division

o Urban Forestry

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Environmental Benefits

Improve watershed conditions and reduce downstream impacts through….

Controlling quantityMitigate flooding where possible

Controlling velocityReduce erosionProtect infrastructure

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Project Location

Windy Hill Road

Box Elder Court

Scotts Run RoadProject Limits

Lewinsville Road

495

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Drainage Area

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Existing Conditions

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Existing Conditions

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Existing Conditions

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Existing Conditions

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Existing Conditions

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Existing Conditions

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Existing Conditions

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Existing Conditions

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Existing Conditions

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Typical Structures Used – Plunge Pool

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Typical Structures Used – Cross Vanes

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Typical Structures Used – Rock Weirs

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Typical Structures Used – Boulder Toe

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Vegetation

• Coordinate tree preservation and removal with Urban Forestry

• Native trees, shrubs, and plugs will be planted

• Native seed mix

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Tentative Construction Access

Windy Hill RoadScotts Run Road

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Before and After Stream Restoration

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Construction Access

• Timber matting along the length of the access route

• Safety fencing around the site

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Construction Example

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Construction Example

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Construction Example

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Growing Season Following Construction Completion

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One Year After Construction Completion

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Three Years After Construction Completion

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Before and After Examples

Flatlick Confluence

January 2011 September 2015

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Before and After Examples

Big Rocky Run II

April 2011 September 2015

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2011

2013 2015

Before

Before and After Examples

Bridle Path

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Next Steps – Schedule

• Complete Preliminary Design- July 2016

• Complete 95% Design- September 2016

• Community Meeting- September 2016

• Complete Final Design- Late Fall 2016

• Construction:

• Start- Spring 2017

• Length- 3 to 4 months (constructed in phases)

• Planting may take place in the fall

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Online ResourcesStormwater Planning Division Websitehttp://www.fairfaxcounty.gov/dpwes/stormwater/

Fairfax County Watershed Planninghttp://www.fairfaxcounty.gov/nvswcd/newsletter/planning.htm

Scotts Run Watershed Planhttp://www.fairfaxcounty.gov/dpwes/watersheds/middlepotomac.htm

EPA Water Quality Laws & Regulationshttp://www.epa.gov/water/laws.html

Please sign in and provide your contact information to be included in project progress updates

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Contact InformationContact Information

DesignCatie Torgersen– Project Manager

703-324-5189Catherine.Torgersen@fairfaxcounty.gov

Fairfax County Stormwater Planning Division703-324-5500 TTY 711

12000 Government Center ParkwaySuite 449

Fairfax, Virginia 22035www.fairfaxcounty.gov/dpwes/stormwater

To request this information in an alternate format call 703-324-5500, TTY 711