Working Group Meeting #2 July 14, 2016 Parks Operations Bldg. - PowerPoint PPT Presentation

Working Group Meeting #2 July 14, 2016 Parks Operations Bldg.

Meeting Agenda 7:05 pm Opening Comments 7:10 pm Follow-up from Previous Meeting 7:15 pm Presentation: Environmental Background 8:15 pm Presentation: Planning & Zoning Background 9:00 pm Presentation: Planning History 9:30 pm Public Comment 10:00 pm Adjournment 2

Follow-up Items • Working Group Meeting Dates • Agenda for 7/27 Working Group Meeting • Updates on ongoing projects • Introduction of Consultant Team • Team members • Relevant work experience • Review Scope of Work • Updates to the 4MRV web page: • Comment/Question Matrix • Trade Center Master Plan • Park maps • Ownership / current uses • Anticipated Phase I park redevelopment 3

Park Ownership Map 4

Phase 1 Park Redevelopment 5

Upcoming Meeting Wednesday, July 27, 2016 Parks Operations Building 2700 South Taylor Street For more information: http://projects.arlingtonva.us/plans-studies/four- mile-run-valley/ 6

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Environmental Background Stormwater and Streams July 14, 2016 Parks Operations Bldg

Outline • Stormwater program overview • Resource Protection Areas • Floodplain Management Ordinance • Stormwater Management Ordinance • ‘Illicit discharges’ and pollution ‘hot spots’ • Four Mile Run Restoration Master Plan 9

Arlington Stormwater Facts • 220,400 people • 26.5 square miles • ~8,300 persons/square mile • 42% impervious cover • 370 miles of storm sewers • 32 miles of perennial streams • 44% tree canopy cover

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Watershed boundaries ADD SW MAP Underground storm drain pipes Storm drain system 12

Water quality impacts from stormwater • Stormwater runoff erodes local streams, carries sediment, nutrients, bacteria, petroleum, and litter downstream, kills trees, affects habitat for aquatic organisms, and damages sewer lines • Sediment and nutrients are major pollutants of concern for Chesapeake Bay 13

Stormwater program goals • Protect public health, safety, and property • Reduce development impacts on water quality in local streams, the Potomac River, and the Chesapeake Bay • Comply with state and federal regulations • Municipal Separate Storm Sewer System (MS4) permit • Chesapeake Bay cleanup requirements • Floodplain management 14

Basic program elements • Stormwater infrastructure • Flood risk reduction • Adding stormwater management for existing development • Regulation of new development • Stream restoration • Pollution prevention for public and private activities • Outreach, education, and monitoring 15

Stormwater Master Plan • Adopted by County Board September 2014 • Evaluates current state of stormwater management and condition of storm sewers, streams, and watersheds • Provides comprehensive framework for managing stormwater, streams, and watersheds for next 20 years. • Incorporates 3 technical needs assessment studies that identified priorities and led to current CIP project proposals: • Stream inventory • Watershed retrofit plans • Storm sewer capacity analysis 16

MS4 permit and Chesapeake Bay cleanup requirements • Major program driver with quantitative nutrient and sediment reduction requirements and regulatory deadlines • Stormwater Master Plan and CIP provide strategy and funding • MS4 permit also requires a broad range of programmatic and operational requirements to reduce stormwater pollution 17

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Resource Protection Areas (RPAs) 19

Overview • Established under Chesapeake Bay Preservation Ordinance • 100’ buffer from the banks of a stream (wider where steep slopes exist) • Additional controls on development activity • Goal is net stream buffer improvement in terms of vegetation and habitat • Compatibility with streamside passive recreation and aesthetic and habitat improvements 20

Exceptions Process • Exception required for projects that increase RPA encroachment or impervious area, or move structures closer to stream • Chesapeake Bay Ordinance Review Committee reviews most exception requests associated with redevelopment in RPA • Types of mitigation: • Tree replacement or protection • Overall vegetative enhancement • Invasive plant removal/control • Additional stormwater management measures • Enhanced erosion control measures during construction 21

Floodplain Management Ordinance 23

Overview • Residential development in or adjacent to FEMA designated 100-year floodplain must meet these requirements: • Lowest level elevation must be one foot above 100-year flood elevation • Footprint of structure must be at least 15 feet horizontally from floodplain • Non-residential – Meet above OR flood-proof structures. • No encroachment in 100-year floodplain without analysis demonstrating no significant impact • New flood data will be used to update map in study area – ~5 years 24

Stormwater Management Ordinance 28

Overview • Required by State in response to Chesapeake Bay cleanup requirements • Arlington Stormwater Management Ordinance adopted by County Board effective July 1, 2014 • Regulatory threshold is 2,500 SF of land disturbance • Stormwater management compliance level of effort is driven by the increase in impervious cover for the project 29

Performance standard summary • 10% to 20% net pollutant load reduction. • Protect downstream properties from increases in runoff volume • Control construction impacts • Typical compliance techniques include: • Stormwater planters • Bioretention Pervious pavements • • Underground filter systems Infiltration • 30

‘Illicit discharges’ and pollution ‘hot spots’ 31

Overview • MS4 permit requires programs to address pollution incidents and potential pollution sources • Combination of techniques, including inspections, monitoring, and technical assistance and outreach 32

‘Hot spot’ inspections • Industrial and commercial facilities with high pollution potential • Auto-related businesses and restaurant strips most common in Arlington • Coordinate with multiple agencies to resolve issues and conduct enforcement  Health Department, Fire Marshal Office, Code Enforcement, Solid Waste 33

Storm drain screening • Includes S. Four Mile Run Drive area • Collection of stormwater and ‘dry weather’ samples • Concentrated auto-related services contribute to petroleum pollution seen in stormwater runoff • Larger road network also a major source 34

Challenges • Existing, older development and site constraints • Lack of awareness • Incidents often occur after hours • Turnover of property managers and/or tenants • Limited enforcement authority Redevelopment of sites will provide much stronger opportunity and authority to address pollutant impacts. 35

Pollution Prevention https://environment.arlingtonva.us/streams/prevent-pollution/ • Targeted outreach to business community • Educational materials and technical guidance • Community meetings • Collaboration between business community, civic associations, and County • Outreach to public • How to report illicit discharges and prevent pollution 36

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Four Mile Run Restoration Master Plan Adopted in 2006 38

Four Mile Run 39

Overview • Provides planning framework and vision for ecological restoration, aesthetic and recreational enhancements along lower Four Mile Run, extending upstream to the lower part of the study area. • The principles of the plan can be applied throughout the study area. 40

Stream restoration principles • Streambank naturalization and buffer enhancement • Streamside pathways and overlooks • In-stream habitat enhancements • Educational interpretation • Maintenance of flood capacity 41

Four Mile Run Design Guidelines Adopted in 2009 42

Infrastructure Re-Use / Modern Rustic 43

Infrastructure Re-Use / Modern Rustic 44

Green infrastructure emphasis • Bioretention (rain gardens) • Pervious paving • Green roofs 45

4MR Stream Restoration • Bank naturalization: remove rip rap, terracing, living shorelines, invasive plant removal, native plantings • Improved access: Viewing platform, re-build bike trail 46

4MR Stream Restoration • Construction begins August/September 2016 • Duration of 1 year • Bike trail will be closed with detour through Alexandria 47

4MR Stream Restoration 48

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 Public Spaces Master Plan Update (POPS) o Planning Context o 2005 PSMP o POPS Schedule o Public Engagement  Survey Results 51

PLANNING CONTEXT Supporting Documents: Arlington County  CIP Comprehensive  Sector Plans Plan UPDATE  Area Plans  Park Master Plans  Neighborhood Conservation Plans, etc. Natural Urban Forest Public Art Resources REFERENCE Master Plan Master Plan Management Plan 52