Fairfax County Stormwater Presentation for Penderbrook HOA

February 18, 2013

Oakton Swim & Racquet Club DF9045A

Oakton Estates DF9045B

Penderbrook DF9045D

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Tonight’s Meeting Agenda

• Stormwater Planning Division

• Environmental Services

• Watershed Planning

• Stormwater Project Goals & Objectives

• Project Information, Examples

• Next Steps- Q/A

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MAJOR COMPONENTS OF FAIRFAX COUNTY’S STORMWATER PROGRAM

• Conveyance Systems

• Dam Safety and Facility Rehabilitation

• Emergency and Flood Response Operations

• Stormwater Regulatory Program

• Streams and Water Quality

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STREAMS AND WATER QUALITY STRUCTURAL PROJECTS

• Detention Basin Retrofits • LID Implementation • Outfall Improvement • Stream Restoration

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Service Drivers

• Federal

– Clean Water Act of 1972

• Municipal Separate Storm Sewer (MS4) Permit

– Total Maximum Daily Loads (TMDL)

• Commonwealth

– Virginia Stormwater Management Act

– Chesapeake Bay Preservation Act

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Countywide Watershed Planning

POHICK

CREEK

DOGUE

CREEK

PIMMIT RUN

SANDY

RUN

MILL

BRANCH

BULL

RUN

WOLF

RUN

HIGH POINT

LITTLE ROCKY RUN

KANE CREEK

RYANS DAM

OCCOQUAN

OLD MILL BRANCH

JOHNNY MOORE CREEK

NICHOL

RUN

WASHINGTON DULLES

INTERNATIONAL AIRPORT

City of

Fairfax

Town of

Vienna

SUGARLAND RUN

DIFFICULT RUN

CAMERON

RUN

ACCOTINK

CREEK

BELLE

HAVEN

CUB RUN

Town of

Herndon

Arlington County

City of

Alexandria

Town of

Clifton

POND

BRANCH

BULL NECK RUN

POPES

HEAD

CREEK

SCOTTS RUN

DEAD RUN

TURKEY RUN

LITTLE

HUNTING

CREEK

FOUR MILE RUN

HORSEPEN

CREEK

Falls

Church

Poto

m

ac RiverOccoquan R

iver

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Difficult Run Watershed

• Drains to the Potomac River and into

the Chesapeake Bay

• 58.3 square miles

To view the Difficult Run Watershed

Management Plan please visit:

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

sheds/difficultrun_docs.htm

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Reasons for Countywide Watershed

Planning

To restore and protect the county’s streams, of which 80 percent are categorized as being in “fair” to “very poor” condition To help meet state and federal water quality standards by identifying strategies to prevent and remove pollution To support Virginia’s commitment toward cleaning up the Chesapeake Bay To replace the outdated watershed management plans and incorporate the use of new technologies To take a comprehensive approach in addressing multiple regulations, commitments, and community needs

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Community Goals & Objectives

• Open lines of communication with communities.

• Educate on project objectives and goals.

• Continue to coordinate and share information with the community.

Stormwater Projects

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Ecological Goals & Objectives

• Establish an ecologically balanced system

• Remove undesirable plants and replace with native vegetation

• Extend the stormwater flow path with retrofit features • Slow down the velocity of runoff decreasing erosion

• Infiltrate more runoff to reduce the quantity of stormwater runoff in streams which discharge to the bay

• Reduce future maintenance

• Reduce negative downstream impacts

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Current Site Conditions

3-locations

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Oakton Swim & Racquet Club Existing Conditions

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Oakton Swim & Racquet Club Existing Conditions

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Oakton Swim & Racquet Club Existing Conditions

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Oakton Swim & Racquet Club Existing Conditions

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Oakton Estates Existing Conditions

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Oakton Estates Existing Conditions

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Oakton Estates Existing Conditions

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Oakton Estates Existing Conditions

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Penderbrook Existing Conditions

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Penderbrook Existing Conditions

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Penderbrook Existing Conditions

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Project Information

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Proposed measures

• Install 3 rain gardens around the existing 3 drain inlets.

• In county easements only: use amended soils around the tennis courts and in other locations that

receive sheet flow and where acceptable.

• In county easements only: Install vegetated swales in areas that receive concentrated stormwater

runoff.

• Identify areas (amended soils and/or vegetated swales) that could be landscaped with native

plants and placed into a “do not mow” landscape feature.

• Add native seed mix to take areas out of the mowing cycle and let areas naturalize with native

plants where acceptable.

Oakton Swim & Racquet Club Project Phase IA

(this project must be approved before the

Oakton Estates Project Phase IIA can proceed)

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Oakton Estates Project Phase IIA

Across the street from Phase IA

(cannot proceed without Phase IA)

Proposed measures

• Work only within the Oakton Estates property. Location of the work to be

from a point south of the rip-rap to the property line. Rip-rap to remain in

place. Work to include: raising the stream bed elevation, stabilizing the

stream bed profile with riffle grade control structures, install grade control

structures to stop the head cut, and stabilize the banks by sloping (Avoid

mature trees) and install native vegetation and soil stabilization matting.

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Penderbrook Project Phase IB

Proposed measures

• Remove concrete ditch and install water quality improvements: extend the flow path, use micro-

pools, and plant native vegetation.

• Relocate spillway to Waples Mill side and plant screening vegetation on the Center Way side.

• Provide grade control and bed material at the mouth of the incoming channel to avoid potential for

head cutting due to removing the trickle ditch and changing elevations within the basin.

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Examples

Completed Projects

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Low Impact Development Walt Whitman Middle School – Rain Gardens

Area Treated

(acres)

Phosphorous

Removal

(lbs/yr)

Nitrogen Removal

(lbs/yr)

Sediment Removal

(tons/yr)

1.29 2.2 4.7 0.6 36

Low Impact Development

Sherwood Library - Permeable Pavers & Rain Garden - Now

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Outfall Restoration Big Rocky Tributary – Before & After

Drainage Area

(acres)

Phosphorous

Removal

(lbs/yr)

Nitrogen Removal

(lbs/yr)

Sediment Removal

(tons/yr)

96 4 68 1 38

Outfall Retrofits Sheffield Hunt– Before & After

Drainage Area (acres)

Phosphorous Removal (lbs/yr)

Nitrogen Removal (lbs/yr)

Sediment Removal (tons/yr)

29.25 63.92 188 145.7 39

Detention Basin Retrofits Foxfield Section 13 - Before & After

Area Treated (acres)

Phosphorous Removal (lbs/yr)

Nitrogen Removal (lbs/yr)

Sediment Removal (tons/yr)

111 49 383 14

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Detention Basin Retrofits Cinnamon Oaks Outfall into Basin - Before & After

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Sequoia Farms - Before & After

Area Treated (acres)

Phosphorous Removal (lbs/yr)

Nitrogen Removal (lbs/yr)

Sediment Removal (tons/yr)

92.25 50.48 361.16 3.88

Pond Retrofits

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Examples

Additional Projects

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Stream Restoration Dead Run – Before & After

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Stream Restoration Poplar Springs - Before & After

Drainage Area

(acres)

Phosphorous

Removal

(lbs/yr)

Nitrogen Removal

(lbs/yr)

Sediment Removal

(tons/yr)

230.4 7.5 141 1.25 45

Stream Restoration Government Center - Before & After

Drainage Area (acres)

Phosphorous Removal (lbs/yr)

Nitrogen Removal (lbs/yr)

Sediment Removal (tons/yr)

150 10.7 202 1.6 46

Next Steps… Feasibility study – winter 2013

Stakeholder meeting (if necessary)

Development of Conceptual Designs

Survey

Public Meeting

Preliminary Design – spring 2013

Develop the conceptual design into a plan set

Final Design – spring 2013

Public Meeting

Preliminary design is developed into a construction ready plan set.

Construction – TBD: fall/winter

Public bid process

Construction Notification

Estimated Construction: Time 1 to 1.5 months each project

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Post Construction Activity

Plantings – Within 30 days of construction completion

Maintenance – Annual inspection

– Monitoring to ensure proper function and identify

need for future maintenance

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Resources

Stormwater Planning Division Website

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

Fairfax County Watershed Planning

http://www.fairfaxcounty.gov/nvswcd/newsletter/planning.htm

Difficult Run Watershed Plan

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

EPA Water Quality Laws & Regulations

http://www.epa.gov/water/laws.html

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Fairfax County Vision Elements

•

To protect and enrich the quality of life for the people, neighborhoods and diverse communities of Fairfax County

by:

• Maintaining Safe and Caring Communities

The needs of a diverse and growing community are met through innovative public and private services, community

partnerships and volunteer opportunities. As a result, residents feel safe and secure, capable of accessing the range of

services and opportunities they need, and are willing and able to give back to their community.

• Building Livable Spaces

Together, we encourage distinctive "built environments" that create a sense of place, reflect the character, history and

natural environment of the community, and take a variety of forms -- from identifiable neighborhoods, to main streets, to town

centers. As a result, people throughout the community feel they have unique and desirable places to live, work, shop, play

and connect with others.

• Connecting People and Places

Transportation, technology and information effectively and efficiently connect people and ideas. As a result, people feel a

part of their community and have the ability to access places and resources in a timely, safe and convenient manner.

• Maintaining Healthy Economies

Investments in the workforce, jobs, and community infrastructure and institutions support a diverse and thriving economy. As

a result, individuals are able to meet their needs and have the opportunity to grow and develop their talent and income

according to their potential.

• Practicing Environmental Stewardship

Local government, industry and residents seek ways to use all resources wisely and to protect and enhance the County's

natural environment and open space. As a result, residents feel good about their quality of life and embrace environmental

stewardship as a personal and shared responsibility.

• Creating a Culture of Engagement

Individuals enhance community life by participating in and supporting civic groups, discussion groups, public-private

partnerships and other activities that seek to understand and address community needs and opportunities. As a result,

residents feel that they can make a difference and work in partnership with others to understand and address pressing public

issues.

• Exercising Corporate Stewardship

Fairfax County government is accessible, responsible and accountable. As a result, actions are responsive, providing

superior customer service and reflecting sound management of County resources and assets.

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Questions?

Thank You! 51

Contact Information

Holly Moran, P.E. – Project Engineer

703-324-5613 Holly.Moran@fairfaxcounty.gov

Justin Pistore – Project Manager 703-324-5685

Justin.Pistore@fairfaxcounty.gov

Fairfax County Stormwater Planning Division 703-324-5500 TTY 711

12000 Government Center Parkway Suite 449

Fairfax, Virginia 22035

www.fairfaxcounty.gov/dpwes/stormwater

To request this information in an alternate format call 703-324-5500, TTY 711 52