Middle Potomac Watershed Plan Implementation

Bull Neck Run at Spring Hill Recreation Center Stream Restoration Project

Public Meeting

June 18, 2014

Stormwater Planning DivisionDepartment of Public Works and Environmental Services

Meeting Outline

• Fairfax County Stormwater Management• Countywide Watershed Plan Implementation• Project Introduction and Objectives• Existing Conditions• Proposed Improvements - Options• Example Projects• Questions?

Fairfax County Department of Public Works and Environmental Services (DPWES)

Department of Public Works and Environmental Services

Land Development

Services

CapitalFacilities

Solid Waste Stormwater

Stormwater Planning Division

Maintenance and Stormwater

Management Division

Wastewater

Stormwater Infrastructure

• Conveyance System– 1,600 miles pipe and

paved channel– 43,000 structures– 6,800 outfalls

• Management Facilities– 1,540 County Maintained – 3,720 Privately Maintained

• State Regulated Dams

Service Drivers

In response to The Clean Water Act of 1972

National Pollutant Discharge Elimination System (NPDES)Virginia Stormwater Management Program (VSMP)

RegulationsMunicipal Separate Storm Sewer Permit (MS4)Total Maximum Daily Loads (TMDLs)

Chesapeake BayLocal Streams

Countywide Watershed Planning

“Healthy Watersheds, Healthy Communities”

• 30 Designated Watersheds

• All 15 watershed plans have been adopted by Fairfax County

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

Middle Potomac Watershed Plan

• Watershed Characterization– Water Quality Monitoring– Land Use Change– Pollutant Loading

• Structural Project– 25 year plan

• Non-Structural Practices– Policy and Regulations

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

Bull Neck Run Watershed Plan

• Bull Neck Run has a drainage area of 2.5 mi2

• Projects identified in the watershed management plan

• Pond retrofits• LID Stormwater Enhancements• Stream Restoration• Neighborhood Stormwater

Improvementshttp://www.fairfaxcounty.gov/dpwes/stormwater/projects/project_list.htm

Goal is to provide water quality control and channel protection volume for the Spring Hill Recreation Center expansion project.

Partnership: LID Stormwater EnhancementsSpring Hill Rec-Center

26 Space Pavers and 1 Tree Box Filter

Partnership: LID Stormwater EnhancementsSpring Hill Rec-Center

Detention Pond Retrofit Before and After

Before

Wakefield Run Stream Restoration

After

Wakefield Run Stream Restoration

Before After

Rabbit Branch Stream Restoration

Before After

Bull Neck Run Stream Restoration

Next Steps

• Conceptual Design• Land Acquisition/Coordination• Preliminary Design• Public Meeting• Final Design• Project Construction (Phase I and II)

• Phase I Funding FY2016 or FY2017 • Phase II Funding to be allocated in future• Community Coordination: Pardon our Dust

• Maintenance and Operation

Bull Neck Run Project Area

Natural Channel Design

Background and Design Approach

Stream Design Approaches Natural Channel Design

3 design approaches 1)Analog 2)Empirical 3)Analytical

Phase 1

Bull Neck Runat Spring Hill

Phase 2

Bull Neck Runat Spring Hill

Instream Structures

Looking upstream at boulder rock toe and constructed riffle

Looking upstream at boulder rock toe – 2 and 3 courses

Modified Cross Vane

Modified Cross Vane

Click icon to add picture

Cross Vane Cross Vane

Cross Vane

Step Pool

Infill mix comprised of cobbles, gravels, sand, silt, topsoil

Larger material, usually cobble

Constructed Riffle(aka Reinforced Streambed)

Riffle

Access

During May 2010

BeforeFeb. 2010

AfterSept. 2010

Ratna Pottumuthu Ratna.Pottumuthu@FairfaxCounty.gov

Matt Meyers Matthew.Meyers@fairfaxcounty.gov

Stormwater Planning Division

Department of Public Works and Environmental Services

Fairfax County12000 Government Center Parkway, Suite 449

Fairfax, Virginia 22035

www.fairfaxcounty.gov/dpwes/stormwater

Questions ?

• Contact Information

A Fairfax County Publication, April 2014

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