dead run segment one stream restoration project

A Fairfax County, VA, publication

Department of Public Works and Environmental Services

Working for You!

Dead Run Segment One Stream Restoration ProjectPublic MeetingDominican Retreat House

June, 2015

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Meeting Outline

• Fairfax County Stormwater Management• Countywide Watershed Plan Implementation• Project Scope, Status, and Next Steps• Concept Plan Overview

– Basis for design– Tree save options– Floodplain analysis and review of more frequent storm impacts– Buffer restoration measures– Examples

• Q&A• Walk to site

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

DPWES Organization

Department of Public Works and Environmental Services

Land Development

Services

CapitalFacilities

Solid Waste Stormwater

Stormwater Planning Division

Maintenance and Stormwater

Management Division

Wastewater

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Stormwater Infrastructure

• Conveyance System– 1,600 miles pipe and

paved channel– 43,000 structures– 6,800 outfalls

• Management Facilities– 1,540 County Maintained – 3,720 Privately Maintained

• State Regulated Dams

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Service Drivers

In response to The Clean Water Act of 1972…

• National Pollutant Discharge Elimination System (NPDES)• Virginia Stormwater Management Program (VSMP) Regulations• Municipal Separate Storm Sewer Permit (MS4)• Total Maximum Daily Loads (TMDLs)

– Chesapeake Bay– Local Streams

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Dead Run– Stream Conditions

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Dead Run Segment 1 Stream Restoration Project

Countywide Watershed Planning

“Healthy Watersheds, Healthy Communities”

• 30 Designated Watersheds• All 15 watershed plans have

been adopted by Fairfax County

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

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Middle Potomac Watershed Plan

• Watershed Characterization– Water Quality Monitoring– Land Use Change– Pollutant Loading

• Structural Project– 25 year plan

• Non-Structural Practices– Policy and Regulations

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

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Dead Run Watershed Plan

• 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

Improvementshttp://www.fairfaxcounty.gov/dpwes/stormwater/projects/project_list.htm

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Partnership LID Stormwater Enhancements - Dolley Madison Library

Approximately 1/3 of the roof is covered in vegetation. The benefits of a “living roof” include:

• Reduces the amount of stormwater runoff• Absorbs air pollution and carbon dioxide• Reduces the energy needed to cool the building in summer

Vegetated Roof- Delosperma and Allium plants in bloom

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Partnership LID Stormwater Enhancements - Dolley Madison Library

Sustainable Site Design

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Stream Monitoring Program

Study Objectives

1. Generate long-term monitoring data.

2. Evaluate relations between observed conditions/trends and BMP implementation.

3. Transfer the understanding gained to other less-intensively monitored watersheds.

http://va.water.usgs.gov/projects/ffx_co_monitoring.htm

13Stormwater Planning Division

Dead Run Segment 1 Stream Restoration Project

Stream Restoration Pictures

Government Center Stream Restoration - Before & After

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Stream Restoration

Dead Run In Mclean Central Park – Before & After

Drainage Area(acres)

Phosphorous Removal(lbs/yr)

Nitrogen Removal(lbs/yr)

Sediment Removal(tons/yr)

415 15 283 3

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Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Dead Run – Stream Restoration

Dead Run Segment 1 Stream Restoration Project

Stormwater Planning Division

Dead Run –Stream Restoration

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August 2014January 2010

17Stormwater Planning Division

Dead Run Segment 1 Stream Restoration Project

Project Limits

Segment 1– Dominican Retreat• 2,000 Linear Feet

• Extends to Old Dominion Drive

• Residential lots along Merrimac Drive and Van Ness Court

18Stormwater Planning Divison

Dead Run Segment 1 Stream Restoration Project

Project timeline• Project initiated: Fall, 2013.

• Surveys and assessment completed: Winter, 2013

• Pre-concepts submitted: April, 2014

• First public meeting – April 23, 2014

• Acquired floodplain and storm drainage easement on the Dominican Retreat property – Ongoing

• Public meeting with residents of surrounding properties – June 10, 2015

19Stormwater Planning Division

Dead Run Segment 1 Stream Restoration Project

Next steps with target dates

• Receive concept design comments from residents

• Inform residents of locations where project abuts their property and where work will take place within existing easements on their property

• Develop 95% design plans by September, 2015

• Final design phase public meeting, late September, 2015

• Final plan authorization and bidding phase – TBD based on funding and approved budget

• Target is early, 2016

• Pardon Our Dust meeting with residents and contractor before issuing construction notice to proceed.

Agenda

1 Basis for Design

2 Trees

3 Design Plan

4 Critical Erosion Areas

5 Pedestrian Bridge Replacement

1 Basis for Design

• Stable Channel• Understanding of

Floodplain• Address Erosion

1 Basis for Design • Natural Channel Design (NCD) Approach – Reference Reach, Analytical,

Regional Relationships and hydraulic analysis

• Stream Pattern, Profile and Section

• Range of Values for Stable Stream Pattern

• Tree Loss is Unavoidable but Provides Opportunity to Improve Riparian Diversity

1 Basis for Design • Establish Goals:

• 1. Improve Flow Conditions in the Channel through Adjustments to Plan/Profile/Section

• 2. Create a Stable Channel by Reducing Bed/Bank Erosion that has Benefit of Reducing Contributions of Nitrogen and Phosphorus (i.e. Water Quality Improvement)

• 3. Improve Channel Geomorphology and Opportunities for Species Diversity (i.e. Use Structures to Stabilize Channel and Create Pool Habitats)

• 4. No-Rise / No-Impact of the Floodplain

2 Trees

12” and Larger Trees:• ~190 trees 12” and larger assessed within the project area• ~19 trees 12” and larger are “at risk”

• ~11 of the “at risk” trees may be removed

• Low Diversity of Species: ~45% tuliptree, ~24% red maple• ~39 Trees proposed to be removed

• A few additional trees maybe removed for new storm pipe to address drainage issues.

3 Design Plan - Overall

Map of the entire project limits with property lines and easements shown

3 Design Plan - Overall

Map of the entire project limits with property lines and easements shown

3 Design Plan - Overall

3 Design Plan - Overall

3 Design PlanExhibits where the limits of disturbance enters individual property owners’ lots

3 Design PlanExhibits where the limits of disturbance enters individual property owners’ lots

3 Design PlanExhibits where the limits of disturbance enters individual property owners’ lots

3 Design PlanExhibits where the limits of disturbance enters individual property owners’ lots

3 Design PlanExhibits where the limits of disturbance enters individual property owners’ lots

3 Design PlanExhibits where the limits of disturbance enters individual property owners’ lots

4 Critical Erosion Areas

4 Critical Erosion Areas

Left Bank

Left Bank

Right Bank

Driveway

5 Pedestrian Bridge – Wood Bridge

Two new bridges and one fair weather crossing.

5 Pedestrian Bridge – Wood Bridge

Two new bridges locations

Bridge #1Bridge #2

5 Pedestrian Bridge – Fair Weather Crossing

Two new bridges and one fair weather crossing.

5 Pedestrian Bridge – Wood Bridge

Fairweather Crossing

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Joe Riley-Ryan, Joseph.Riley-Ryan@fairfaxcounty.gov

Dipmani Kumar, Dipmani.Kumar@fairfaxcounty.gov

Matt Meyers, Matthew.Meyers@fairfaxcounty.gov

Stormwater Planning DivisionDepartment of Public Works and Environmental ServicesFairfax County12000 Government Center Parkway, Suite 449Fairfax, Virginia 22035

www.fairfaxcounty.gov/dpwes/stormwater

• Contact Information

A Fairfax County Publication, April 2014ADA Statement: To request this information in an alternate format call 703-324-5500, TTY 711