dead run segments 2/3 stream restoration project public meeting

A Fairfax County, VA, publication

Department of Public Works and Environmental Services

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Dead Run Segments 2/3 Stream Restoration ProjectPublic MeetingDolley Madison Library

June 9, 2015

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Dead Run Segment 2/3 Stream Restoration Project

Stormwater Planning Division

Meeting Outline

• Project extent and timeline• Response to issues raised • Next steps• Outline of potential design refinements• Questions and answers• Walk to site

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Project Limits

Segment 2 – McLean Central Park• 800 Linear Feet

• Completely in Park

• Starts below previously restored section near library

Segment 3 – Dead Run Stream Valley Park• 1,500 Linear Feet

• Extends to Churchill Road

• Residential lots along Elizabeth Drive and Carol Rayes Street



Watershed Planning and Project Implementation

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

• Structural Project– 25 year plan

• Non-Structural Practices– Policy and Regulations

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



5Stormwater Planning Division

Watershed Planning and Project Implementation

• Dead Run has a drainage area just over 3 mi2

• 24 priority 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

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

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


Stormwater Program Regulatory Drivers

• National Pollutant Discharge Elimination System (NPDES)

• Virginia Stormwater Management Program (VSMP)– Municipal Separate Storm Sewer Permit (MS4)– 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


Dead Run– Stream Conditions


Dead Run– Stream Conditions

Fairfax County Annual Water Quality Report• http://www.fairfaxcounty.gov/hd/streams/strannualrpt.htm

Virginia Department of Environmental Quality • Water Quality Report (305b report)• http://www.deq.virginia.gov/Programs/Water.aspx

U.S. Geological Survey• Dead Run stream gage at Whann Avenue• Fairfax County Water Resource Monitoring• http://va.water.usgs.gov/fairfax/

http://www.fairfaxcounty.gov/hd/streams/strannualrpt.htm

http://www.deq.virginia.gov/Programs/Water.aspx

http://www.deq.virginia.gov/Programs/Water.aspx

http://va.water.usgs.gov/fairfax/

http://va.water.usgs.gov/fairfax/


Dead Run Stream Restoration

Project Benefits and Goals:• Improve water quality

– Reduce sediment and nutrient loads

• Stabilize stream banks – Reduce stream bank erosion– Protect property– Reduce tree loss

• Improve aquatic habitats• Restore and enhance vegetated stream

buffer (riparian corridor)Others:• Reduce frequent flooding



Project Time Line• Project initiated: Fall, 2013

• Surveys and assessment completed: Winter, 2013

• Pre-concepts submitted: April, 2014

• First public meeting: April 23, 2014

• Field walk with FCPA, MTF, Urban Forestry: August 15, 2014

• Pre-concept revisions to minimize tree loss completed: February, 2015

• Second public meeting: February 18, 2015

• Revised concept plan with alternative access options for Segment 3 completed: May 12, 2015

• First field walk with community: May 19, 2015

• Second field walk with community: June 9, 2015

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Next steps: Task Force

• We recommend that a citizens task force (“Stream Team”) be convened in coordination with Supervisor Foust’s office.

– The task force would be actively involved in revising the current concept plan to make sure it is acceptable to the community:

– Clearly understand community goals and expectations– Work with the design team to incorporate the community goals and establish a timeline– Be able to convey the details of design constraints and trade-offs to the community– Attend design charrette meetings– Perform detailed review of concept plan revisions to make sure it meets the community goals

before it is presented to the wider community– Recommend up to 10 representatives from the community

• We will continue to receive comments on the current concept through July 31st.

• We anticipate the task force will be convened by June 30th, and we will schedule a kick-off meeting with the task force in early July.



Next Steps With Target Dates

• Work with task force to develop final concept and publish to website - September, 2015

• Community meeting to present final concept - October, 2015

• Continue to work with task force to develop 95 percent design plans, and complete permitting - January, 2016

• Final design phase public meeting - Spring, 2016

• Final plan authorization and bidding phase – To be determined based on funding and approved budget

• Target is late spring/early summer, 2016

• Sequence with Dead Run Segment 1 (Dominican Retreat)

• Pardon Our Dust meeting with residents and contractor before issuing construction notice to proceed.



Response to Issues Raised – Tree and Canopy Loss -Proposed removal of more than 250 trees from McLean Central Park, including about 100 of the park's largest trees.-Proposed removal of virtually all other growth in a wide swath along the creek from Churchill Road to Elizabeth Drive. Current concept plan:

• 88 greater than 12 inch trees, up to 10 for access, 23 are at risk.

• 133 6 to 12 inch trees, up to 20 for access, 28 are at risk.

• Approximately 20 percent of trees proposed for removal are at risk.

• Estimated canopy loss is approximately 11 percent of area shown in red.



Response to Issues Raised – Flash Flooding -Failure to address a related and major park problem: flash flooding from stormwater runoff that flows into the creek.

Tradeoff: Reduce channel size (to the low end of the range that still provides for a stable stream) and reduce tree impacts, but the reduction in flood levels will be smaller. If we continue to realign the channel away from lots (again, within an acceptable range), this will impact more trees.



Response to Issues Raised – Replacement Plantings and Trail Closure - Lack of provisions made by the county to maintain or protect replacement plantings from failure or encroachment of invasive species after the project is completed.This will be considered and made part of the final plan. We will work with the Park Authority and homeowners to create a final maintenance and invasive plant control plan for the reforestation measures in the park.

- Closure of large sections of the park and trail for approximately 9 to12 months.

This is inaccurate. We will try to keep the trails open – again this is a tradeoff. We can reduce the access impacts by using the trail but there will be some work-hour closures of the trails if we opt to use the trails for access. Temporary trails will be part of the project and we will work with the Park Authority to maintain access into the park provided by trails.



Response to Issues Raised – Public Notification --Woefully inadequate notification of the public about this project, its scope, and impact on the community; there has been no visible signage in the park that would notify park users.

We recognize that our standard public notification process was inadequate. The Park Authority has provided us with templates and examples of their public notification process for the park master planning process, and we will follow the same procedure for notification. This includes:

- Significantly expanding the area where meeting notification postcards/letters are sent.

- Posting signs in the park about upcoming meetings.



Response to Issues Raised – Water Quality Benefits - Insufficient evidence that this project, given the extensive damage it will do to the existing park environment, is the best way to achieve the proposed goals. In fact, no estimate has been released of how much the water quality will improve over what period of time.

A summary of this information was provided at the February meeting:

• Chesapeake Bay expert panel protocols used for estimating stream restoration nutrient credits.

• For Total Phosphorus (TP), as an example, the estimated reduction in loadings as a result of the proposed stream restoration for Segments 2/3 ranges from 0.063 to 0.261 pounds per linear foot per year (lbs/LF/yr.)

• This compares to a ‘default’ rate of 0.068 lbs/LF/yr. The high end of the estimated load reduction is 3 times the default rate.

• Total annual estimated reduction in erosion for Segment 2/3 is between 783 to 1,500 tons/year and the estimated reduction in TP loading is between 190 and 788 lbs/year



Response to Issues Raised in Petition: Projected Water Quality Improvements

400 600 800 1200 22000123456

Streams - Unit Cost

$/ft

Num

ber o

f pro

ject

sMean = $753/ft , Median = $601/ft

• Using the mean unit cost $753/ft, the cost per unit pound of annual TP reduction ranges from to $3,000 to $12,000



Response to Issues Raised in Petition: Projected Water Quality Improvements

Estimated range for proposed Dead Run Segment 2/3 restoration: $3,000 - $12,000 $/lb TP/yr

Practices NumberInstalled TP TN TSS

Stream Restoration 10 $ 25,583 $ 2,812 $ 13

Infiltration Swales & Trenches 3 $ 33,583 $ 5,765 $ 204

Pond Retrofits 32 $ 35,908 $ 7,928 $ 183

Soil Compost Amendment 9 $ 120,164 $ 16,797 $ 781

Dry Swales 7 $ 132,423 $ 22,732 $ 803

Bioretention (Rain Gardens) 18 $ 168,973 $ 28,935 $ 1,026

Pervious Pavement 4 $ 198,624 $ 33,631 $ 1,211

Capital Cost ($/lb/yr)



Additional Issues - Use smaller equipment to minimize impacts

It is possible to write limitations on equipment in the bid documents as a special condition, but potential problems include:

• Fewer bidders (possibly none)• Significantly higher cost• Significantly longer timeline

To reduce impacts we will consider/evaluate:• Access alignments that minimize tree disturbance• Design revisions that meet the overall goals but have less impact on trees• Equipment used by stream restoration contractors e.g. track equipment has less

compaction and other impacts and allows them to work in wetter areas.• Contractors generally use timber matting to further reduce soil compaction to

protect tree roots.



Equipment Used During Construction



Churchill Road Bridge Flooding

• VDOT inspection reports indicate no deficiencies with the bridge.• No current or future project is planned for the bridge. • Not subject to frequent closures because of overtopping.



Churchill Road Bridge Backwater Area



Response to Issues – Task Force Recommendation Therefore, we ask that Fairfax County:

1. Develop a new, much less invasive and impactful approach in order to preserve our park.2. Change and significantly extend the entire timetable for the new project to provide full opportunity for public response.3. Provide widespread notification, including visible signage in the park, that would notify park users and the community at large about the full scope of the new project proposal, its impact on the park, and flooding.

- We recommend that a citizen task force (“Stream Team”) be convened by Supervisor Foust’s office.

- The task force would be actively involved in revising the current concept plan to make sure it is acceptable to the community:

- Clearly understand community goals and expectations- Work with the design team to incorporate the community goals and establish a timeline- Be able to convey the details of design constraints and trade offs to the community- Attend design charrette meetings- Perform detailed review of concept plan revisions to make sure it meets the community

goals before it is presented to the wider community- Recommend approximately 10 representatives from the community



Northern Virginia Stream Restoration Bank

1 Access Options

2 Options for Refining the Design

1Access Options • Alternative 1 Approach

• Proposed some access along the left bank of the stream through Reach 3 adjacent to Elizabeth Dr.

• Alternative 2 Approach• Proposed access within the Park only, along the sanitary sewer

easement and two sections of trail. No access on private properties.

• Additional alternatives Explored• Access along sanitary sewer easement and trail. • Selecting route that has least amount of tree impacts.

1Access – Alternative Study

2 Design Refinement

• Options for Refinement of the Design

• Smaller Channel Cross-section in specific areas

• Transition from smaller to larger channel sections in areas, where possible

• Opportunities to save trees

• Still focus on less frequent storm events and improving the impacts of flooding especially in the Segment 3 Upper area

• Maintain overall channel stability

2 Design Refinement

Pre/Post Comparison – Existing Section 13552 year flow out of banks

• Existing Conditions Analysis

2 Design Refinement


• Typical Channel Segment Upper, ~90 SF Area

2 Design Refinement


• Nested Channel Segment Upper, ~60 SF Area

2 Design Refinement


• Comparison


Stormwater Management

Stream Buffer Restoration Potential

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Chesapeake Bay Preservation Ordinance Resource Protection Area (RPA)

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http://www.fairfaxcounty.gov/dpwes/environmental/cbay/



Stream Buffer Existing Conditions

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Stream Buffer Restoration Potential

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Segment 3 Stream Buffer Concept

Left Bank Left Bank Residential Residential35 foot 50 foot 35 foot 50 foot

Area (Acres) 1.14 1.55 0.46 0.87Canopy Trees 114 155 46 87Understory Trees 229 310 92 174Shrubs 1,246 1,690 501 946

Estimate tree and shrub plantings for Segment 3: Left Bank Only



Stream Buffer Restoration - Example

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Typical Planting Area

County Staff will coordinate with individual homeowners on plant selection and placement on their properties

Buffer Parameters

35’ Minimum from edge of stream bank

50’ Offset optional

Plant density determined by Chesapeake Bay PreservationOrdinance

Dense planting will provide privacy screening and help mitigate tree loss




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Shrub Layer

Typical ShrubSpecies

SpicebushAmerican ElderberryWitch HazelWinterberry HollySilky DogwoodButton Bush




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Understory Trees

Typical UnderstorySpecies

Sweetbay MagnoliaEastern RedbudAmerican HornbeamHazel AlderSlippery ElmSassafras



Stream Buffer Restoration

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Canopy Layer

Canopy Tree

EvergreenUnderstory

Tree

DeciduousUnderstory

Tree

ShrubTypical CanopyTree Species

Sugar MapleRiver BirchAmerican BasswoodCommon PersimmonSwamp White OakPin OakWillow OakBlack Gum



Next Steps: Task Force

- We recommend that a citizens task force (“Stream Team”) be convened by Supervisor Foust’s office.

- The task force would be actively involved in revising the current concept plan to make sure it was acceptable to the community:

- Clearly understand community goals and expectations- Work with the design team to incorporate the community goals and establish a

timeline- Be able to convey the details of design constraints and tradeoffs to the

community- Attend design charrette meetings and participate in field reviews- Perform detailed review of concept plan revisions to make sure it met the

community goals before it is presented to the wider community- Recommend approximately 10 representatives from the community

- We will continue to receive comments on the current concept through July 31st.

- We anticipate the task force will be convened by June 30th, and we will schedule a kick-off meeting with the task force in early July.



Next Steps With Target Dates

• Work with task force to develop final concept and publish to website in September, 2015

• Community meeting to present final concept in early October, 2015

• Develop 95 percent design plans, permitting by January, 2015

• Final design phase public meeting, early spring 2016

• Final plan authorization and bidding phase – To be determined based on funding and approved budget

• Target is late spring/early summer, 2016

• Sequence with Dead Run Segment 1 (Dominican Retreat)

• Pardon Our Dust meeting with residents and contractor before issuing construction notice to proceed.

Additional Information

For additional information, please contact

www.fairfaxcounty.gov/dpwes

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Dipmani Kumar, P.E., CFMProject Manager

703-324-5500, TTY 711

[email protected]

dead run segments 2/3 stream restoration project public meeting

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stream gage

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