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
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