Dead Run Stream Restoration Project Segments 2/3 – Final Concept Plan

A Fairfax County, VA, publication
Department of Public Works and Environmental Services
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Dead Run Stream Restoration Project
Segments 2/3 – Final Concept Plan
Community Meeting
Dolley Madison Library
May 4, 2016

Dead Run Segment 2/3 Stream Restoration Project
Stormwater Planning Division
Meeting Outline
2
• Project Scope
• Project Timeline
• Background
• Existing Conditions
• Task Force and Community Involvement
• Revised Final Concept Changes – Summary
• Proposed Condition Renderings
• Revised Final Concept Design Approach
• Buffer and Riparian Corridor Restoration Plan
• Next Steps
• Q&A

Dead Run Stream Restoration
Project Limits – Two Projects
3
Segment 2:
McLean Central Park
• 750 linear feet of main
channel and 560 feet of
tributary channels
Segment 3:
Dead Run Stream Valley
Park
• 1,460 linear feet of main
tributary channels
Segment 1:
Dominican Retreat
• 1,500 linear feet of main
tributary channels

4
Segment 2 – McLean Central Park
• 750 linear feet main
tributary channels
• Completely in Park
• Starts below previously
restored section near
library

5
Segment 3 – Dead Run Stream Valley Park
• 1,460 linear feet of main channel
and 350 feet of tributary
channels
• Extends to Churchill Road
• Residential lots along Elizabeth
Drive and Carol Raye Street

Stormwater Planning Divison
Project timeline
6
• Fall, 2013: Project initiated
• Winter, 2013: Surveys and assessment completed
• April, 2014: Pre-concepts submitted
• April 23, 2014: First public meeting
• August 15, 2014: Field walk with FCPA, MTF, Urban Forestry
• February, 2015: Pre-concept revisions to minimize tree loss completed
• February 18, 2015: Second public meeting
• May 12, 2015: Revised concept plan with alternative access options for
Segment 3 completed
• May 19, 2015: Third public meeting and first field walk with community
• June 9, 2015: Fourth public meeting and second field walk with
community

Project timeline
7
• Community Stream Team – Task Force
• Held 4 meetings between August and December 2015
• Visited completed stream restoration sites
• Met with residents adjacent to project in March, 2016
• Revised final concept design completed in April, 2016.
Next Steps:
• Site visit with Community (May 19, 2016)
• Final design phase
• Coordination with task force and community
• Final construction documents and bidding
• Pardon our dust community meeting and construction
• Post-construction monitoring and maintenance

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
8
http://www.fairfaxcounty.gov/dpwes/watersheds/

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
9
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)
– Discharge from approximately 7,000 storm drain outfalls
– 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
10

Dead Run– Stream Conditions
11
http://www.deq.virginia.gov/Programs/Water.aspx

Existing Conditions - Biological Monitoring Data
12

Dead Run– Stream Conditions
13
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 Resources Monitoring
• http://va.water.usgs.gov/fairfax/

14

Dead Run Stream Valley – A historical perspective
15
1937

Dead Run Stream Valley – A historical perspective
16
1954

Dead Run Stream Valley – Today
17
2015

Segment 2 Existing Conditions
18

19
Stream Bank Erosion and at Risk Trees

20
February 2012
July 2015
Trees along stream bank
continue to fall and/or die

21

22

23

24
February 2012
July 2015

25

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Bridge at Churchill Road

On-line: Story Map of Existing Conditions
28
Existing conditions: http://arcg.is/1Y55MNj

Summary of Task Force Comments and Concerns
29
• Project Benefits
• Design Approach
• Tree Loss
• Frequent Yard Flooding
• Flooding at Churchill Road
• Construction Equipment and Footprint
• Trail Closures
• Invasive Plant Management
• Others
– Site restoration and maintenance
– Stream conditions and erosion below Churchill Road

Project Benefits
• Estimated annual erosion rates for Segment 2/3 based
on field data is between 783 to 1,500 tons/year
30
Stream Bank Erosion Field Data• Chesapeake Bay Expert Panel
protocols used for estimating
stream restoration nutrient
and sediment credits.
• Estimated reduction in Total
Phosphorus loading is
between 190 and 788
lbs/year

Churchill Road Flooding
• VDOT staff attended last Stream
Team meeting (December, 2015)
• VDOT inspection reports
indicate no deficiencies with the
bridge
• No current or future project
planned for the bridge at this
time
31
• Proposed stream restoration project includes removing
sediment and debris upstream of the bridge and aligning
channel with bridge abutments.

Churchill Road Bridge Backwater area
32

Summary of Plan Revisions – Tree Loss
33
Tree Loss Summary
Date 6” to 12” 12” and Larger Total Trees at Risk
February 2014
Not Surveyed
137 137
February 2015 110 110
May 2015
Alt 1 133 88 221
Alt 2 153 98 251
December 2015
Alt 1 76 72 148 48
Alt 2 81 72 153 45
Alt 1 and Alt 2 refer to access alternatives 1 and 2:
Alt 1: Access road is closer to the stream for Segment 3
Alt 2: Access road follows trail and utilizes cut-throughs for access to stream for Segment 3.

Summary of Plan Revisions – Tree Loss
34
• Total number of trees to be removed for project (148-153)
• Total number of trees within the LOD that were either dead or at risk (45-48) –
approximately 1/3rd
• Reduction in tree loss impact as a result of design modification between May
2015 and December 2015:
• Alt 1 – 73 trees saved (33% reduction)
• Alt 2 – 98 trees saved (39% reduction)
• Existing trees have very little diversity with only 2 species making up the majority
of trees: red maples and tulip poplars.

Proposed Planting
35
• Proposed Planting Based on
Alternative 1
• Approx. 250 trees 1 inch to
1.5 inch caliper size
• Approx. 500 trees that are 6
to 8 feet tall
• Approx. 2,600 shrubs
• All vegetation is native
species and specifically
selected for the stream
corridor

Dead Run Stream Restoration Project
Existing Park Conditions
• Park Area = 33.25 acres
• Tree Canopy = 27.45 acres
36

Summary of Plan Revisions – Area disturbed
37
Total Acres* Woodland /
Open**
May 2015
Alt 1 ~5.05 Acres 3.65
Alt 2 ~5.15 Acres 3.75
December 2015
Alt 1 ~4.58 Acres 3.18
Alt 2 ~4.72 Acres 3.32
*Excludes trail area, ** Excludes stream channel area and trail area
Conclusion Alt 2 access has slightly more disturbance and would close the trails for a
longer period of time compared to Alt 1, and would likely necessitate the use of
woodchip trails which would have additional impacts.
The overall area of disturbance has been reduced by 10% from May 2015. If the
stream channel area (1.4 ac) is excluded (i.e only impacts to woodland/open areas
considered), the actual AOD has been reduced by 11-13%

Summary of Plan Revisions – Channel Size
38
Segment 2 Upper Segment 3 Lower Segment 3
Existing channel size(SF) 59-82 57-113 62-70
Proposed channel size (SF) 55-80 60-129 62-72
Proposed channel size is now comparable in size to the existing channel.
This channel was sized using natural channel design principles and represents a
balance to minimize impacts but still provide long-term channel stability and
water quality benefits.

Summary of Plan Revisions – Floodplain and Drainage
39
• No change in 100-year or
FEMA floodplain
• No rise certification
• Improve drainage from
existing storm drains
Fairfax County 100-Year Floodplain
FEMA Special Flood Hazard Area

Proposed Conditions Renderings – Segment 2
40
Existing Conditions

41
Rendering of Proposed Conditions

42
Existing Conditions

43

44
Existing Conditions

45

Proposed Conditions On-line Map Tour
46
http://arcg.is/1N4KSgq

Riparian Corridor Restoration Plan
47

Existing vegetation baseline characterization
48
Existing Vegetation classified into 5 major areas:
MCPP1: Gazebo area, Area near Martha Jane
Street
MCPP2: Areas adjacent to Segment 2 and
upstream of Segment 2.
MCPP3: Adjacent to Segment 3
MCPP4: Area to the right of trail along middle and
lower Segment 3 (looking towards Churchill Road
MCPP5: Area to the right when entering park from
Oak Ridge Avenue (near tennis courts)
Story Map: http://arcg.is/1TKK67P

49

Dolley Madison Library Outfall before Restoration
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Elements of Riparian Corridor Restoration Plan
• Invasive Plant Management
• Planting plan
– Inside and outside project limits
within park
• Residential lots adjacent to
stream
• Warranty requirements (2-years)
• Long-term monitoring and
maintenance
55

Chesapeake Bay Preservation Ordinance
Resource Protection Area (RPA)
56
http://www.fairfaxcounty.gov/dpwes/environmental/cbay/

Proposed Planting
57
• Proposed Planting Based on
Alternative 1
• Approx. 250 trees 1 inch to
1.5 inch caliper size
• Approx. 500 trees that are 6
to 8 feet tall
• Approx. 2,600 shrubs
• All vegetation is native
species and specifically
selected for the stream
corridor

Next Steps
58
• Continue to work with residents to develop buffer enhancements on
private lots adjoining Segment 3.
• Site visit (May 19, 2016) – trees to be flagged
• Final design phase and prepare construction documents
• Coordination with Task Force and community
• Bidding and contract award
• Pardon Our Dust Meeting
• Construction
• Post-construction monitoring and maintenance

Next Steps: Site Visit
Site Visit
• Date: Thursday, May 19, 2016
• Time: 6:30 – 8:00 pm
• Meeting Location: McLean
Central Park - Pedestrian bridge
crossing Dead Run near tennis
courts
59
Meeting Location

Additional Information
For additional information, please contact
www.fairfaxcounty.gov/dpwes
Stormwater Planning Division 60
Dipmani Kumar
Project Manager
703-324-5500
dkumar@fairfaxcounty.gov

Dead Run Stream Restoration Project Segments 2/3 – Final Concept Plan

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