dead run segments 2/3 stream restoration project public meeting
TRANSCRIPT
A Fairfax County, VA, publication
Department of Public Works and Environmental Services
Working for You!
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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Dead Run Segment 2/3 Stream Restoration Project
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
Stormwater Planning Division
Stormwater Planning Division
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/
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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
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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)– 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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Dead Run– Stream Conditions
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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/
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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
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Dead Run Segment 2/3 Stream Restoration Project
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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Dead Run Segment 2/3 Stream Restoration Project
Stormwater Planning Division
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.
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Dead Run Segment 2/3 Stream Restoration Project
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.
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Dead Run Segment 2/3 Stream Restoration Project
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.
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Dead Run Segment 2/3 Stream Restoration Project
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.
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Dead Run Segment 2/3 Stream Restoration Project
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.
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Dead Run Segment 2/3 Stream Restoration Project
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.
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Dead Run Segment 2/3 Stream Restoration Project
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
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Dead Run Segment 2/3 Stream Restoration Project
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
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Dead Run Segment 2/3 Stream Restoration Project
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)
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Dead Run Segment 2/3 Stream Restoration Project
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.
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Dead Run Segment 2/3 Stream Restoration Project
Equipment Used During Construction
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Dead Run Segment 2/3 Stream Restoration Project
Equipment Used During Construction
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Dead Run Segment 2/3 Stream Restoration Project
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.
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Dead Run Segment 2/3 Stream Restoration Project
Churchill Road Bridge Backwater Area
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Dead Run Segment 2/3 Stream Restoration Project
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
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Dead Run Segment 2/3 Stream Restoration Project
Northern Virginia Stream Restoration Bank
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Dead Run Segment 2/3 Stream Restoration Project
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
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
Pre/Post Comparison – Existing Section 13552 year flow out of banks
• Typical Channel Segment Upper, ~90 SF Area
2 Design Refinement
Pre/Post Comparison – Existing Section 13552 year flow out of banks
• Nested Channel Segment Upper, ~60 SF Area
2 Design Refinement
Pre/Post Comparison – Existing Section 13552 year flow out of banks
• Comparison
Dead Run Segment 2/3 Stream Restoration Project
Stormwater Management
Stream Buffer Restoration Potential
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Dead Run Segment 2/3 Stream Restoration Project
Stormwater Management
Chesapeake Bay Preservation Ordinance Resource Protection Area (RPA)
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http://www.fairfaxcounty.gov/dpwes/environmental/cbay/
Dead Run Segment 2/3 Stream Restoration Project
Stormwater Management
Stream Buffer Existing Conditions
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Dead Run Segment 2/3 Stream Restoration Project
Stormwater Management
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
Dead Run Segment 2/3 Stream Restoration Project
Stormwater Management
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
Dead Run Segment 2/3 Stream Restoration Project
Stormwater Management
Stream Buffer Restoration - Example
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Shrub Layer
Typical ShrubSpecies
SpicebushAmerican ElderberryWitch HazelWinterberry HollySilky DogwoodButton Bush
Dead Run Segment 2/3 Stream Restoration Project
Stormwater Management
Stream Buffer Restoration - Example
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Understory Trees
Typical UnderstorySpecies
Sweetbay MagnoliaEastern RedbudAmerican HornbeamHazel AlderSlippery ElmSassafras
Dead Run Segment 2/3 Stream Restoration Project
Stormwater Management
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
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Dead Run Segment 2/3 Stream Restoration Project
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.
46Stormwater Planning Division
Dead Run Segment 2/3 Stream Restoration Project
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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Dead Run Segment 2/3 Stream Restoration Project
Stormwater Planning Division
Dipmani Kumar, P.E., CFMProject Manager
703-324-5500, TTY 711