Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Stormwater Presentation to Friends of Lake Accotink Park 12-2019

133 views

Published on

Stormwater Management Program information

Published in: Environment
  • Be the first to comment

  • Be the first to like this

Stormwater Presentation to Friends of Lake Accotink Park 12-2019

  1. 1. A Fairfax County, VA, publication Department of Public Works and Environmental Services Working for You! December 19, 2019 Fairfax County's Stormwater Program Friends of Lake Accotink Park
  2. 2. Fairfax County's Stormwater Update Stormwater Management Stormwater Drivers a) MS4 Permit b) Chesapeake Bay Total Maximum Daily Load (TMDL) c) Local TMDL’s d) Dam Safety Regulations e) Maintenance of Existing Facilities f) Public Safety/Emergency Response 2October 16, 2019
  3. 3. History of Stormwater Funding $0.0 $10.0 $20.0 $30.0 $40.0 $50.0 $60.0 $70.0 $80.0 $90.0 $100.0 FY05 FY06 FY07 FY08 FY09 FY10 FY11 FY12 FY13 FY14 FY15 FY16 FY17 FY18 FY19 FY20 Budget Amounts Millions Operations (General Fund) Fringe (General Fund) Public Works Construction (Fund 308) Operations, Fringe & Contributory (Fund 125) Operations (Fund 318) Penny Dedication (Fund 318) Stormwater Service District (Fund 125) Stormwater Management Fairfax County's Stormwater Program October 16, 2019
  4. 4. Stormwater Management Fairfax County's Stormwater Program 4 (2%) NVSWCD, Occoquan Lab, Towns, $1.5 M (9%) Stormwater Regulatory Programs, $7.0 M (11%) Dam Saftey and Facility Rehabilitation, $9.0M (31%) Streams and Water Quality, $25.4M (10%) Conveyance Systems, $8.5M (31%) Operations, $25.6M (6%) Emergency and Flood Response, $5.0M 31% Operations 31% Streams and Water Quality 2% NVSWCD, Labs, Towns6% Emergency & Flood Response Fiscal Year 2020 Budget October 16, 2019
  5. 5. Fairfax County's Stormwater Program Stormwater Management Regulatory 5October 16, 2019 • MS4 Permit Compliance • Monitoring • Industrial High Risk Runoff Inspection • Illicit Discharge Response • Outreach and Education Grease Dumpster Grease Overflow
  6. 6. 66 Fairfax County's Stormwater Program Conveyance System Rehabilitation 6 Large fracture and joint offset Before After Conveyance System • 1,300 miles of pipe • 65,000 storm structures • 7,000+ MS4 regulated outfalls • 100+ miles of man-made channels (concrete, gabion, rip rap, etc.) • 10+ miles restored streams (natural channel design) Stormwater Management Deteriorated and eroded outfall restored with step pool and riffle bed mix October 16, 2019
  7. 7. Stormwater Management Dam Safety and Facility Rehabilitation 7 Fairfax County's Stormwater Program Typical State Dam Safety Regulation Requirements Routine maintenance • Annual inspections • Inspections after major storm events • Biannual inspections by a professional engineer (PE) • Non-Routine maintenance • Annual Emergency Action Plan (EAP) updates • 6-year certification cycle (Virginia) • Operation and Maintenance Plan • Inundation area mapping Maintenance of County’s flood warning system October 16, 2019 Stormwater Facilities • 2,200 Publically Owned SWM facilities • 20 State Regulated Dams • 4,800 Private SWM facilities
  8. 8. Stormwater Management Fairfax County's Stormwater Program Inventory of Stormwater Management Facilities 8 5,299 5,619 5,987 6,187 6,583 6,992 3,555 3,770 4,009 4,138 4,447 4,787 1,744 1,849 1,978 2,049 2,136 2,205 - 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 FY2014 FY2015 FY2016 FY2017 FY2018 FY2019 NO.OFFACILITIES YEAR Fairfax County Stormwater Management Facility Inventory Total Private Public Linear (Total) October 16, 2019
  9. 9. Stormwater Management 9 Fairfax County's Stormwater Program Inventory of Stormwater Management Facilities October 16, 2019
  10. 10. Fairfax County's Stormwater Program Stormwater Management Dam Safety and Facility Rehabilitation 10October 16, 2019 Stormwater Facility Challenges Before After
  11. 11. Fairfax County's Stormwater Program Stormwater Management Dam Safety and Facility Rehabilitation 11 Sealed Porous Asphalt Deteriorated Porous Concrete Replaced with Porous Concrete Slabs October 16, 2019 Stormwater Facility Challenges
  12. 12. Stormwater Management Fairfax County's Stormwater Program Emergency and Flood Response 12 • FEMA National Flood Insurance Program • Community Rating System (CRS) • Mitigate Structural Flooding • Conveyance System Installation or Enhancement • Overland Relief • Voluntary Property Acquisition • Minor enhancements October 16, 2019
  13. 13. Fairfax County's Stormwater Program Stormwater Management Streams and Water Quality Improvements 13 13 Wakefield Park Tributary Accotink Creek WS Public Safety Headquarters Difficult Run WS October 16, 2019
  14. 14. Fairfax County's Stormwater Program Stormwater Management Stormwater Local Assistance Fund (SLAF) 14 14 Turkey Run at Truro Accotink Creek, WS October 16, 2019 County SLAF Awards • Up to 50% matching funds from State • 2014-2018 • $93 million budgeted for state wide projects • 20 County Projects Awarded • 4 Town of Vienna Projects Awarded • $17.2 Million in SLAF Grant Awards to County • $2.8 Million in SLAF Grant Awards to Town of Vienna • FY 2019 $10 million available (Solicitation closes on November 15, 2019)
  15. 15. Fairfax County's Stormwater Program Stormwater Management Project Selection and Prioritization 1. Project Selection Priority a) Public Safety b) Regulatory (MS4 Permit) I. Chesapeake Bay TMDL II. Local Stream TMDL’s c) Community Needs 2. Existing Project Metrics a) Cost Benefit Analysis a) Overall b) Trends 3. CIP Budget (Streams and Water Quality program) 15October 16, 2019 Accotink Tributary at Danburry Forest Accotink Creek WS
  16. 16. Fairfax County's Stormwater Program Stormwater Management Completed Facilities FY10-19 16October 16, 2019 Practices Number Installed TN TP TSS Stream Restoration 41 $1,800 $6,290 $21 Pond Retrofits 56 $3,440 $35,800 $28 Infiltration Swales & Trenches 16 $11,100 $138,000 $191 Dry Swales 13 $6,130 $69,000 $92 Bioretention (Rain Gardens) 31 $8,100 $71,600 $95 Pervious Pavement 28 $25,800 $241,000 $305 Capital Cost ($/(lb/yr) )
  17. 17. Fairfax County's Stormwater Program Stormwater Management Progress Towards Chesapeake Bay TMDL 17October 16, 2019
  18. 18. Fairfax County's Stormwater Program Stormwater Management 18October 16, 2019 Looking Forward And On the Horizon Changing Regulatory World Negotiation of New MS4 Permit Flood Mitigation Changing Weather Patterns Greater Advancement and Use of Technology Local Stream TMDLs Merging Similar WW and STW Functions Stormwater Runoff and Urban Stream Standards
  19. 19. Fairfax County's Stormwater Program Stormwater Management Completed Stormwater Projects in Braddock District Stream and Outfall Restoration • Accotink Tributaries at Wakefield Park (2) • Government Center Stream Restoration • Long Branch @ Long Branch Falls Park • Pohick Creek Tributary • Pohick Creek @ Queen Victoria Court • Rabbit Branch Tributary • Turkey Run @ Truro Subdivision Outfall Restoration • Babson Court • Inverchapel Road • Lenox Drive • Toll House Road • Ulysses Court Pond Retrofit • Brentwood West • Colony Park Drive • Fairfax Landbay C Section 2, Pond B • Herrity Building Wet Pond • Marymeade Section 1 and 2 • Patriot Village • University Square • Village Park Sec 2B 19October 16, 2019 Pohick Creek @ Queen Victoria Court Pohick WS
  20. 20. Fairfax County's Stormwater Program Stormwater Management Completed Stormwater Projects in Braddock District PL-566 Dam Rehabilitation and Dredging • Lake Barton • Royal Lake • Woodglen Lake 20October 16, 2019 Lake Barton Dredge Royal Lake Dam Rehabilitation
  21. 21. Fairfax County's Stormwater Program Stormwater Management Lake Dredging 21October 16, 2019 Lake Barton Dredging Pohick Creek WS AfterBefore
  22. 22. Stormwater Management Fairfax County's Stormwater Program Stream Restorations 22 22 2019 One year after Construction Before Turkey Run at Truro Accotink Creek WS October 16, 2019
  23. 23. Stormwater Management Fairfax County's Stormwater Program Stream Restorations 23 23 AfterBefore Long Branch Tributary at Long Branch Falls Park Accotink WS October 16, 2019
  24. 24. Stormwater Management Fairfax County's Stormwater Program Stream Restorations 24 24 AfterBefore Pohick Creek Tributary at Queen Victoria Pohick Creek WS October 16, 2019
  25. 25. Stormwater Management Fairfax County's Stormwater Program Stream Restorations 25 25 2018 6 years after Construction Before Government Center Stream Restoration Difficult Run WS October 16, 2019
  26. 26. Fairfax County's Stormwater Program Stormwater Management Outfall Restorations 26October 16, 2019 Toll House Road Accotink Creek WS AfterBefore
  27. 27. Fairfax County's Stormwater Program Stormwater Management Stormwater Retrofit 27October 16, 2019 Kings Park West Accotink Creek WS AfterBefore
  28. 28. Fairfax County's Stormwater Program Stormwater Management Stormwater Projects Currently in Construction in Braddock District Stream and Outfall Restoration • Flag Run @ Elgar Street (Braddock) Pond Retrofit • Government Center Pond GSI/LID • Herrity Building Concrete Fountain Replacement 28 Flag Run @ Elgar Street Accotink Creek WS October 16, 2019
  29. 29. Fairfax County's Stormwater Program Stormwater Management FY 2020 and Ongoing Design Projects in Braddock District Stream and Outfall Restoration • Accotink Creek at Wakefield Park* • Accotink Tributary @ Danbury Forest • Difficult Run Tributary @ Fairfax Govt. Center • Long Branch Stream Restoration • Rabbit Branch Tributary @ Collingham Drive • Long Branch Central Watershed Management Area Lake Dredge • Lake Barton* • Lake Accotink * Scheduled for Construction in FY 2020 29 Long Branch Stream Restoration Accotink Creek WS October 16, 2019
  30. 30. DPWES Stormwater Planning Division Long Branch Central Watershed Management Area 30 Long Branch Central Watershed Management Area Long Branch Central Watershed 3.71 Square Miles - 8 Miles of Streams Braddock Road Little River Turnpike (236) Capital Betway (495) Burke Station Road Project Location
  31. 31. DPWES Stormwater Planning Division Project Overview Project Goals: • Achieve Long Branch Central TMDL waste load reduction requirements. • Provide long-term stability and have low maintenance. • Improve water quality within the Long Branch Central watershed. • Improve habitat and environmental health (ecological lift). 31 Failed Stream Bank: Long Branch near Olde Creek Elementary School Degraded Outfall: Long Branch at Laurel Street Long Branch Central Watershed Management Area
  32. 32. DPWES Stormwater Planning Division Project Schedule • Begin Assessment – Winter 2020 • Complete Restoration Work Plan – Fall 2020 • Complete First Construction Plans – Summer 2021 • Construction Begins – Fall 2021 • Construction Ongoing – Through 2027 • Warranty, Monitoring and Maintenance – 2022 through 2030 32 Long Branch Central Watershed Management Area Massive Bank Erosion: Long Branch Tributary in Old Forge Park Long Branch Central Watershed Management Area
  33. 33. DPWES Stormwater Planning Division 33 Long Branch Central Watershed Management Area Lake Accotink Dredging Project Location Lake Accotink • Lake Accotink Drainage Area 31 mi2 • Stream Length 60.5 miles • Impervious Cover in Watershed 30% • Amount of Sediment Trapped Each Year ~22,000 cubic yards
  34. 34. DPWES Stormwater Planning Division • Remove ~350,000 cubic yards of sediment in initial dredge • Pump sediment to Wakefield Park to avoid truck traffic in communities • Process sediment in Wakefield Park • Truck sediment to disposal sites • Establish permanent dredge program to maintain lake depth 34 Long Branch Central Watershed Management Area Lake Accotink Dredging Project Overview
  35. 35. DPWES Stormwater Planning Division Project Schedule 35 Long Branch Central Watershed Management Area Lake Accotink Dredging Sept, 2019 Advertised for Design Consultant - Complete Sept 19, 2019 Public Master Plan Meeting – Complete Oct 29, 2019 BOS Meeting Scope and Funding Strategy for Approval - Complete Feb 28, 2020 Award Consultant Contract for Design & Permitting March 31, 2020 Submit Request for VCWRLF Loan June 30, 2020 Park Authority Complete Master Plan Sept 30, 2020 State Approve VCWRLF Loan Jan 31, 2021 Award Dredging Contract March 1, 2022 Commence Dredging March 1, 2025 Complete Dredging March 1, 2029 Complete Permit Compliance Monitoring Ongoing Maintain Sustained Dredging Program
  36. 36. DPWES Stormwater Planning Division Lake Accotink Financing Options 36 Long Branch Central Watershed Management Area Lake Accotink Dredging • Virginia Clean Water Revolving Loan Fund (“Fund”) • Department of Environmental Quality (DEQ) program administrator of the Fund; Virginia Resources Authority (VRA) is financial manager of the Fund • Base interest rate of 1% below municipal market rates • County’s dedicated source of stormwater revenue ($3.25 per $100 of Assessed Value) provides for an additional interest rate reduction of 1% below municipal market rates • Flexibility in debt service repayment through project completion • Loan would be subject to the approval of the State Water Control Board • Full year debt service for the entire $30.5m estimated at $1.5M/year per current market conditions • Anticipated debt service would begin in FY 2025/2026, and will be included in future STW service district budgets • On-Going Funding for Debt Repayment and Maintenance Dredging • Fairfax County Stormwater Service District - About $3.5M/year
  37. 37. DPWES Stormwater Planning Division Dredge Spoils Processing & Disposal 37 Long Branch Central Watershed Management Area Lake Accotink Dredging Spoils Processing Methods  Geotextile Fabric Dewatering System  Mechanical Separators Potential Regional Disposal Sites  Loudoun Quarry (Sterling)  Luck Stone Quary
  38. 38. DPWES Stormwater Planning Division Local Spoils Disposal 38 Long Branch Central Watershed Management Area Lake Accotink Dredging Wakefield – Dominion Right of Way  Recommended Location of Forebay  Proximity to dewatering area  Access through Braddock Road  Maximum capacity 75,000 CY Lake Accotink Park  High Wetland Impacts  Requires Access Upgrades  Close Proximity to Residential Community  Not Recommended
  39. 39. DPWES Stormwater Planning Division Potential Spoils Handling Locations 39 Long Branch Central Watershed Management Area Lake Accotink Dredging Potential Sites  Dominion Right of Way in Wakefield Park  Howrey Field Park  Forested Area Near Area 2 Maintenance Shop
  40. 40. Fairfax County Stormwater Program DPWES Stormwater Management Program Additional Information 40 For additional information please contact Charles Smith 703-324-2467, TTY 711 Charles.Smith@FairfaxCounty.gov www.FairfaxCounty.gov/publicworks/stormwater

×