This document provides information on Fairfax County's Stormwater Program, including an overview of stormwater management drivers and history of funding. It discusses regulatory programs, conveyance systems, dam safety, emergency response, streams and water quality improvements, and completed projects. Maps and photos of completed stream restoration, outfall restoration, pond retrofit, and dredging projects are shown. Ongoing and planned projects in Braddock District are outlined, including details on the Long Branch Central Watershed Management Area project and Lake Accotink dredging project.

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. 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. 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. 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. 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. 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. 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. 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. Stormwater Management 9
Fairfax County's Stormwater Program
Inventory of Stormwater Management Facilities
October 16, 2019

10. Fairfax County's Stormwater Program
Stormwater Management
Dam Safety and Facility Rehabilitation
10October 16, 2019
Stormwater Facility Challenges
Before
After

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. 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. 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. 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. 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. 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. Fairfax County's Stormwater Program
Stormwater Management
Progress Towards Chesapeake Bay TMDL
17October 16, 2019

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. 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. 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. Fairfax County's Stormwater Program
Stormwater Management
Lake Dredging
21October 16, 2019
Lake Barton Dredging
Pohick Creek WS
AfterBefore

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. 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. 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. 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. Fairfax County's Stormwater Program
Stormwater Management
Outfall Restorations
26October 16, 2019
Toll House Road
Accotink Creek WS
AfterBefore

27. Fairfax County's Stormwater Program
Stormwater Management
Stormwater Retrofit
27October 16, 2019
Kings Park West
Accotink Creek WS
AfterBefore

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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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