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Dead Run Stream Restoration Public Meeting June 9, 2015

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Dead Run Stream Restoration Public Meeting June 9, 2015

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Dead Run Stream Restoration Public Meeting June 9, 2015

  1. 1. A Fairfax County, VA, publication Department of Public Works and Environmental Services Working for You! Dead Run Segments 2/3 Stream Restoration Project Public Meeting Dolley Madison Library June 9, 2015
  2. 2. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division Meeting Outline 2 • Project extent and timeline • Response to issues raised • Next Steps • Outline of Potential Design Refinements • Q&A • Walk to site
  3. 3. Dead Run Segment 2/3 Stream Restoration Project Project Limits 3 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
  4. 4. 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 4 http://www.fairfaxcounty.gov/dpwes/watersheds/
  5. 5. Stormwater 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 Improvements 5 http://www.fairfaxcounty.gov/dpwes/stormwater/ projects/project_list.htm
  6. 6. Stormwater Planning Division 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 6
  7. 7. Stormwater Planning Division Dead Run– Stream Conditions 7
  8. 8. Stormwater Planning Division Dead Run – Stream Conditions 8 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/
  9. 9. Stormwater Planning Division Dead Run Stream Restoration Project Benefits and Goals: • Improve water quality – Reduce sediment and nutrient loads • Stabilize stream banks to – Reduce stream bank erosion – Protect property – Reduce tree loss • Improve aquatic habitat • Restore and enhance vegetated stream buffer (riparian corridor) Others: • Reduce frequent flooding 9
  10. 10. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Project timeline 10 • 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
  11. 11. 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 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 charette meetings – Perform detailed review of concept plan revisions to make sure it met 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. 11
  12. 12. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Next steps with target dates 12 • Work with task force to develop final concept and publish to website in September, 2015 • Community meeting to present final concept – October, 2015 • Continue to work with task force to develop 95% design plans, and complete permitting – January, 2016 • Final design phase public meeting – Spring 2016 • Final plan authorization and bidding phase – TBD 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.
  13. 13. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Response to issues raised – tree and canopy loss 13 -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 > 12” trees, up to 10 for access, 23 are at risk. • 133 6-12” trees, up to 20 for access, 28 are at risk. • Approximately 20% of trees proposed for removal are at risk. • Estimated canopy loss is approximately 11% of area shown in red.
  14. 14. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Response to issues raised – flash flooding 14 -Failure to address a related and major park problem: flash flooding from storm water 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.
  15. 15. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Response to issues raised – replacement plantings and trail closure 15 - 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 would be considered and made part of the final plan. We would work with the Park Authority and homeowners to come up with 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 9-12 months. This is inaccurate. We would always try to keep the trails open – again this is a tradeoff, we can reduce the access impacts by using the trail but there will some work hour closure of the trails if we opt to use the trails for access. Temporary trails would be part of the project and we would work with the Park Authority to maintain the access into the park provided by trails.
  16. 16. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Response to issues raised – public notification 16 --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.
  17. 17. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Response to issues raised – water quality benefits 17 - 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 in 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 lbs/LF/yr. • This compares to a ‘default’ rate of 0.068 lbs/LF/yr. The high end of the estimated load reduction is 3X 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
  18. 18. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Response to issues raised in petition: Projected Water Quality Improvements 18 0 2 4 6 400 600 800 1200 2200 Numberofprojects $/ft Streams - Unit Cost Mean = $753/ft , Median = $601/ft • Using the mean unit cost $753/ft, the cost per unit lb of annual TP reduction ranges from to $3,000 to $12,000
  19. 19. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Response to issues raised in petition: Projected Water Quality Improvements 19 Estimated range for proposed Dead Run Segment 2/3 restoration: $3,000 - $12,000 $/lb TP/yr Practices Number Installed 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)
  20. 20. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Additional issues 20 - 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 of an 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 and protect tree roots.
  21. 21. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Equipment used during construction 21
  22. 22. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Equipment used during construction 22
  23. 23. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Churchill Road Bridge Flooding 23 • VDOT inspection reports indicate no deficiencies with the bridge. • No current or future project planned for the bridge. • Not subject to frequent closures because of overtopping.
  24. 24. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Churchill Road Bridge Backwater area 24
  25. 25. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Response to issues – task force recommendation: 25 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 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 charette meetings - 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
  26. 26. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Northern Virginia Stream Restoration Bank 26
  27. 27. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Northern Virginia Stream Restoration Bank 27
  28. 28. 1Access Options 2Options for Refining the Design
  29. 29. 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.
  30. 30. 1Access – Alternative Study
  31. 31. 1Access – Alternative Study
  32. 32. 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
  33. 33. 2 Design Refinement Pre/Post Comparison – Existing Section 1355 2 year flow out of banks • Existing Conditions Analysis
  34. 34. 2 Design Refinement Pre/Post Comparison – Existing Section 1355 2 year flow out of banks • Typical Channel Segment Upper, ~90 SF Area
  35. 35. 2 Design Refinement Pre/Post Comparison – Existing Section 1355 2 year flow out of banks • Nested Channel Segment Upper, ~60 SF Area
  36. 36. 2 Design Refinement Pre/Post Comparison – Existing Section 1355 2 year flow out of banks • Comparison
  37. 37. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division Stream Buffer Restoration Potential 37
  38. 38. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division Chesapeake Bay Preservation Ordinance Resource Protection Area (RPA) http://www.fairfaxcounty.gov/dpwes/environmental/cbay/
  39. 39. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Divisiont Stream Buffer Existing Conditions 39
  40. 40. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division Stream Buffer Restoration Potential 40 Segment 3 Stream Buffer Concept Left Bank Left Bank Residential Residential 35 foot 50 foot 35 foot 50 foot Area (Acres) 1.14 1.55 0.46 0.87 Canopy Trees 114 155 46 87 Understory Trees 229 310 92 174 Shrubs 1,246 1,690 501 946 Estimate tree and shrub plantings for Segment 3: Left Bank Only
  41. 41. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division Stream Buffer Restoration - Example 41 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 Preservation Ordinance Dense planting will provide privacy screening and help mitigate tree loss
  42. 42. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division Stream Buffer Restoration - Example 42 Shrub Layer Typical Shrub Species Spicebush American Elderberry Witch Hazel Winterberry Holly Silky Dogwood Button Bush
  43. 43. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division Stream Buffer Restoration - Example 43 Understory Trees Typical Understory Species Sweetbay Magnolia Eastern Redbud American Hornbeam Hazel Alder Slippery Elm Sassafras
  44. 44. Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division Stream Buffer Restoration 44 Canopy Layer Canopy Tree Evergreen Understory Tree Deciduous Understory Tree Shrub Typical Canopy Tree Species Sugar Maple River Birch American Basswood Common Persimmon Swamp White Oak Pin Oak Willow Oak Black Gum
  45. 45. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Next steps: Task Force 45 - 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.
  46. 46. Stormwater Planning Division Dead Run Segment 2/3 Stream Restoration Project Next steps with target dates 46 • 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% design plans, permitting by January, 2015 • Final design phase public meeting, early spring 2016 • Final plan authorization and bidding phase – TBD 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
  47. 47. Additional Information For additional information, please contact www.fairfaxcounty.gov/dpwes Dead Run Segment 2/3 Stream Restoration Project Stormwater Planning Division 47 Dipmani Kumar, P.E., CFM Project Manager 703-324-5500 dkumar@fairfaxcounty.gov

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