Phase III Stream Assessment Study: Potential Stream Restoration - - PowerPoint PPT Presentation

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Phase III Stream Assessment Study: Potential Stream Restoration - - PowerPoint PPT Presentation

Sep 14, 2023 292 likes •744 views

Phase III Stream Assessment Study: Potential Stream Restoration Projects Strawberry Run and Taylor Run December 5, 2018 Tonights Agenda Introduce the project team Why stream restoration? Healthy stream characteristics

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Phase III Stream Assessment Study: Potential Stream Restoration Projects Strawberry Run and Taylor Run

December 5, 2018

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Tonight’s Agenda

  • Introduce the project team
  • Why stream restoration?
  • Healthy stream characteristics
  • City’s Stream Assessment Program
  • Project selection
  • Finished project examples
  • Next steps

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Project Team

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Transportation and Environmental Services (T&ES) Recreation, Parks and Cultural Activities (RPCA) Department of Project Implementation (DPI)

City Departments

Wood Environment & Infrastructure Solutions

Consultant

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Project Drivers

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1. Water quality and improving local streams is a City priority 2. Local benefits: enhanced water quality, improved habitat, protection of property 3. State and EPA require development of Total Maximum Daily Loads (TMDLs) for impaired streams

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Chesapeake Bay TMDL

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Chesapeake Bay TMDL Cleanup Mandates

  • Enforced through the City’s stormwater permit
  • Requires ~1/4 of the City to be retrofit for water quality

treatment before 2028

  • Dense urban nature of the City limits potential solutions
  • Stream restoration is one of the more cost-efficient

approaches 6 MS4 Permit Cycle % Total

  • Approx. Acres

Phase I (2013 - 2018) 5% 120 - 130 Phase II (2018 - 2023) 35% 660 Phase III (2023 - 2028) 60% 1,450 Total All Phases 100% 2,140

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What Makes a Stream Healthy?

  • 1. Bed stability and diversity
  • 2. Sediment transport balance
  • 3. In-stream habitat & flow diversity
  • 4. Bank stability (native plant roots)
  • 5. Riparian buffer (streamside forest)
  • 6. Active floodplain
  • 7. Healthy watershed

“Multiple Benefits” or “Co-Benefits”

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Physical Chemical Biological

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Stream Pyramid

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Courtesy of Stream Mechanics

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Scour

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Scour – Field Examples

10 Outfall to Holmes Run Strawberry Run Taylor Run

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Stream Assessment Program

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Phase I

Stream Categorization

Mapping of streams, defining limits, and stream categorization

Phase II

Assessment of Streams

Stream habitat, infrastructure impacts, problem areas, characteristics

Phase III

Project Identification

Potential project sites evaluated and ranked. Conceptual designs for top projects.

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Locations

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Potential Projects – Stream Segments

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Unnamed Tributary near Walleston Ct. Strawberry Run near Taft Avenue Taylor Run near Chinquapin Park Holmes Run north of N. Beauregard St. Timber Branch near Ivy Hill Cemetery

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Unnamed Tributary near Walleston Ct.

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Strawberry Run near Taft Avenue

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Taylor Run near Chinquapin Park

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Holmes Run north of N. Beauregard St.

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Timber Branch near Ivy Hill Cemetery

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Phase III Stream Assessment

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Evaluation of Potential Projects

  • Field Assessment
  • Recommendations
  • Decision Matrix and Priority Ranking
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Strawberry Run

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Strawberry Run

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Strawberry Run

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Strawberry Run

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Strawberry Run

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Taylor Run

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Taylor Run

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Taylor Run

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Taylor Run

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Phase III Stream Assessment

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Conceptual Designs and Cost Estimates

  • Conceptual Designs
  • Using Natural Channel Design (NCD) which emulates

natural river systems

  • Planning Level Cost Estimates

~900 ft ~1900 ft

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Natural Channel Design

30 Riffle Cascade Step-Pools Log Vane

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Conceptual Designs

31 Strawberry Run Taylor Run

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Feasibility

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Potential Construction Access

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Benefits

Habitat Aesthetics Water Quality Native Vegetation

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Strawberry Run – Downstream Project

Before After

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35 Before

Strawberry Run – Downstream Project

After

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Joint Base Andrews

36 Before After

Courtesy of Wood Environment & Infrastructure Solutions

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Cullers Run

37 Before After

Courtesy of Wood Environment & Infrastructure Solutions

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Cullers Run

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Courtesy of Wood Environment & Infrastructure Solutions

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North Mill Creek

39 Before After

Courtesy of Wood Environment & Infrastructure Solutions

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Big Rocky Run

40 Before After

Courtesy of Wood Environment & Infrastructure Solutions

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Habitat…

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Next Steps & What To Expect

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Outreach

  • Public and Stakeholder Outreach
  • Consider feedback in designs
  • More outreach…

Finalize Phase III Stream Assessment

  • Outfall Conceptual Designs – Dec. 2018
  • Report – January 2019

Funding

  • Applied for matching 50/50 state grants
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Next Steps & What To Expect

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Continue with Design (may depend on grant funding)

  • 30%, 60%, 90%, Final
  • Topographic survey
  • Tree survey
  • Refine designs
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Joni Calmbacher, PE

Stormwater Management Division Transportation & Environmental Services City of Alexandria, VA 703.746.4174 Joni.Calmbacher@alexandriava.gov

Brian Meli, PE

Department of Project Implementation City of Alexandria, VA 703.746.4110 Brian.Meli@alexandriava.gov

City Contact Information