This document summarizes a community meeting held to discuss plans for restoring a section of stream in the Hollin Hills area of Fairfax County, VA. The project aims to stabilize 1,600 feet of eroding stream banks, reduce sediment and nutrient runoff, improve floodplain connectivity and aesthetics. The design team presented their assessment of existing issues like flooding and erosion. They outlined restoration goals and showed example structures to address issues. Alignment options were presented for the lower segment, seeking community input. Next steps include further design and obtaining easements to access private property.

1. A Fairfax County, VA, publication
Department of Public Works and Environmental Services
Working for You!
June 12, 2018
Community Meeting
Sherwood Regional Library
Paul Spring Branch Segment 1 @ Hollin Hills
Stream Restoration Project
Little Hunting Creek Watershed Plan Implementation

2. DPWES Stormwater Planning Division
Design Team
• Design Team includes:
– Members of the Hollin Hills Civic Association
– Members of the Hollin Hills community
– County staff: Project Manager, Construction Manager, Wastewater,
Urban Forester, Stormwater Ecologist
– Design Engineers: Stantec
– History Commission
– Northern Virginia Soil and Water Conservation District
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Hollin Hills Stream Restoration

3. DPWES Stormwater Planning Division
Meeting Outline
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• Status and General Schedule
• Site Location and Project Limits
• Existing Conditions
• Design Goals
• Proposed Alignment and Access
• Example Projects
• Q&A
Hollin Hills Stream Restoration

4. DPWES Stormwater Planning Division
Status and General Schedule
• Data Collection (Completed)
• Stream Restoration Design Process (In progress)
– Pre-Concept Plan Development (Completed)
– Concept (35%) Design Plan Development (Completed)
– Field Walk (Completed)
– Obtaining Easements (In progress)
– Preliminary (65%) Design Plan Development (After easement)
– Final Design Plan Development (After 65%)
– Construction Documents (After final design and permits)
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Hollin Hills Stream Restoration

5. DPWES Stormwater Planning Division
Status and General Schedule (continued)
• Construction (± 12 months)
– Construction date dependent on future funding
– Bidding and Contract Award
– Community Meeting
– Construction Begins
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Hollin Hills Stream Restoration

6. DPWES Stormwater Planning Division
Project Limits
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Storm Drainage and
Floodplain Easement,
pending
Hollin Hills Stream Restoration

7. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Existing Conditions Storm Sewer Outfall
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8. DPWES Stormwater Planning Division
Existing Conditions Eroding Banks
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Hollin Hills Stream Restoration

9. DPWES Stormwater Planning Division
Existing Conditions Eroding Banks
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Hollin Hills Stream Restoration

10. DPWES Stormwater Planning Division
Existing Conditions Path Flooding
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Hollin Hills Stream Restoration

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Existing Conditions Undermined Trees
DPWES Stormwater Planning Division
Hollin Hills Stream Restoration
Erosion undermines tree.
Tree becomes unstable and pulls out
bank.

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Existing Infrastructure
DPWES Stormwater Planning Division
Hollin Hills Stream Restoration
Road downstream Sanitary sewer

13. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design Goals
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What are the design goals?
• Stabilize 1600 LF of stream and storm sewer outfall
• Reduce excess sediment from being transported downstream
• Reduce excess nutrients from entering the waterway
• This concept estimates saving at least 103 lb/yr TP and 223.6 lb/yr
TN from waterway
• Improve aesthetics
• Reduce hazards (steep, eroding banks)
• Reconnect stream to floodplain
• Improve riparian buffers
• Protect valuable infrastructure

14. DPWES Stormwater Planning Division
Hollin Hills Stream Restoration
Example In-Stream Structures
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Reinforced Bed
Rock Steps
Boulder Riffle

15. DPWES Stormwater Planning Division
Hollin Hills Stream Restoration
Stream Bank Reinforcement
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Native Vegetation
In-Stream Log SillToe-Slope Protection

16. DPWES Stormwater Planning Division
Hollin Hills Stream Restoration
Stormwater Pipe
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Drop Structure Flared End Section

17. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design
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Upper
Middle
Lower

18. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design – Proposed Alignment (Upper)
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• Hand-work
• Minimum
disturbance
• Minimizing tree
removal

19. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design – Proposed Alignment (Middle)
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• Follow the existing alignment, grading the banks to remove
instability
• Add storm sewer pipe and drop structures to connect storm
sewer to main channel
• Add stabilization structures above and below confluence

20. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design – Proposed Alignment (Lower, private property)
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• Lower alignment includes work on private property
• Several alignment options, dependent on easements
• All will have positive drainage

21. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design – Proposed Alignment (Lower, HHCA)
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• Lower portion to shift alignment
• Construction staging area/access
• Abandoned Well

22. DPWES Stormwater Planning Division
Hoolin Hills Stream Restoration
Pre-Restoration
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23. DPWES Stormwater Planning Division
Hollin Hills Stream Restoration
Post-restoration
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24. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design – Tree Preservation
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• Surveyed 293 Trees
• This plan would remove 42 trees 12” or greater
• Up to 30 of these trees could be reused on site
Brush Habitat
Large Log Habitat

25. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design – Proposed Alignment (Lower)
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• Option 1: Stop project
upstream
• Does not address path
flooding
• Does not address
bank erosion

26. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Design – Proposed Alignment (Lower)
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• Option 2: Re-align stream
(example only, not yet
designed)
• Adds to construction
timeline
• Large disturbance
footprint

27. Hollin Hills Stream Restoration
DPWES Stormwater Planning Division 27
Construction Example
Pre-Construction 6 months post-Construction

28. 28DPWES Stormwater Planning Division
Hollin Hills Stream Restoration
Examples – Quander Road Outfall
Pre-Construction
6 months post-Construction

29. Pre-Construction Construction
Post Construction After plant establishmentPost-Construction
Hollin Hills Stream Restoration
DPWES Stormwater Planning Division
Examples – Big Rocky Run Tributary
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30. DPWES Stormwater Planning Division
Highlights & Next Steps
• Stream project requested by the community as storm
sewer erosion is degrading
• Evaluation and design will improve the stream condition
and prevent further degradation
• Civic Association will provide easements to access property
• Extensive replanting and non-native invasive control will be
incorporated in later design phases
• Ecological monitoring to take place in June (informs
replanting & management goals)
• Further design on lower segment of stream in coordination
with property owners
• Abandoned well determination
• Expecting design completion early in 2019
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Hollin Hills Stream Restoration

31. DPWES Stormwater Planning Division
Communication
– Comments for this plan version due June 15th
• Provide them directly to Project Manager (Meghan)
• Provide them to community representatives (Gus, et al.)
– Refinements of plan sets as we move forward will refine this
concept, do not expect major changes except in the lower portion
of the stream
– All refinements will be continued to be reviewed by Project Team
and regulatory organizations (e.g. History Commission, Army Corps
of Engineers)
– All refinements will be posted in Sharefile for review
– Continue to provide comments and suggestions
– Planned Next Community Meeting – just before construction
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Hollin Hills Stream Restoration

32. DPWES Stormwater Planning Division
Contact Information
Design
Meghan Fellows – Project Manager
703-324-5807
Meghan.Fellows@fairfaxcounty.gov
Fairfax County Stormwater Planning Division
12000 Government Center Parkway
Suite 449
Fairfax, Virginia 22035
www.fairfaxcounty.gov/publicworks/stormwater
To request this information in an alternate format call 703-324-5500, TTY 711
Presentation Website
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Hollin Hills Stream Restoration