Stormwater Master Plan Update - Arlingtonva
Stormwater Master Plan Update Community Meeting
October 13, 2011
Agenda
Introduction
Storm Sewer Capacity Study
Watershed Retrofit Studies
Stream Assessment
Q&A
View Maps and Displays
Arlington’s watersheds
Chesapeake Bay watershed
Most of Arlington’s stormwater flows through storm sewer pipes directly to local streams, then flows down the Potomac River to the Chesapeake Bay
Water in storm drains does not go to a treatment plant!
Water Quality Impacts from Stormwater Runoff Potomac River is our source of drinking water.
• Stormwater runoff erodes local streams, carries sediment, nutrients, 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.
Regulatory Requirements
Virginia Stormwater Permit requires us to significantly reduce stormwater pollution from existing and new development.
Chesapeake Bay Total Maximum Daily Load (TMDL), issued by EPA in 2010, establishes a pollution budget for the Bay.
Master Transportation Plan includes recommendations for street trees and reduction of stormwater runoff.
Several of Arlington’s local ordinances address stormwater management (e.g., Chesapeake Bay, Stormwater Detention, Erosion & Sediment Control)
Current Stormwater Challenges
Existing Development
More stringent regulations
More than half of the storm sewer network is over 50 years old.
System Capacity
Required to reduce water pollution and protect Chesapeake Bay.
Aging Infrastructure
Most of Arlington was developed before stormwater regulations existed, so County streams are heavily impacted by stormwater runoff.
Needs to be sufficient to reduce flood risks to an acceptable level.
Climate change
Climate models predict frequency of heavy rainfall events could increase.
Current Stormwater Strategy
Maintain & replace stormwater infrastructure
Improve existing stormwater treatment facilities and add new ones where feasible
Require stormwater controls for new development
Reduce risks from flooding
Restore stream corridors
Implement urban housekeeping best practices (such as street sweeping)
Outreach, education, and monitoring
Ballston Pond Improvements Redesign of existing stormwater pond underway to enhance nutrient and sediment removal and improve water quality. Pond will treat ~ 400 acres of impervious area that drain to Four Mile Run.
Watershed Retrofit Plans
New Stormwater Facilities
Stream Restoration
Before
After
Urban Housekeeping
Outreach and Education
Stormwater Master Plan Update
Stormwater Master Plan (1996) and Watershed Management Plan (2001) are being updated and combined into a comprehensive Master Plan.
Storm Sewer Capacity Analysis to study the County's current storm sewer pipes. County-wide stream inventory to assess stream conditions and prioritize stream restoration projects. Watershed retrofit plans to identify locations where stormwater treatment facilities can be added to help slow down and filter stormwater runoff.
Master Plan Update Process
Technical Studies – currently underway
Draft Plan completed – Summer 2012
Circulate Draft Plan for Comment – Fall 2012
Adopt Master Plan – December 2012
October 13, 2011
Agenda
Introduction
Storm Sewer Capacity Study
Watershed Retrofit Studies
Stream Assessment
Q&A
View Maps and Displays
Arlington’s watersheds
Chesapeake Bay watershed
Most of Arlington’s stormwater flows through storm sewer pipes directly to local streams, then flows down the Potomac River to the Chesapeake Bay
Water in storm drains does not go to a treatment plant!
Water Quality Impacts from Stormwater Runoff Potomac River is our source of drinking water.
• Stormwater runoff erodes local streams, carries sediment, nutrients, 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.
Regulatory Requirements
Virginia Stormwater Permit requires us to significantly reduce stormwater pollution from existing and new development.
Chesapeake Bay Total Maximum Daily Load (TMDL), issued by EPA in 2010, establishes a pollution budget for the Bay.
Master Transportation Plan includes recommendations for street trees and reduction of stormwater runoff.
Several of Arlington’s local ordinances address stormwater management (e.g., Chesapeake Bay, Stormwater Detention, Erosion & Sediment Control)
Current Stormwater Challenges
Existing Development
More stringent regulations
More than half of the storm sewer network is over 50 years old.
System Capacity
Required to reduce water pollution and protect Chesapeake Bay.
Aging Infrastructure
Most of Arlington was developed before stormwater regulations existed, so County streams are heavily impacted by stormwater runoff.
Needs to be sufficient to reduce flood risks to an acceptable level.
Climate change
Climate models predict frequency of heavy rainfall events could increase.
Current Stormwater Strategy
Maintain & replace stormwater infrastructure
Improve existing stormwater treatment facilities and add new ones where feasible
Require stormwater controls for new development
Reduce risks from flooding
Restore stream corridors
Implement urban housekeeping best practices (such as street sweeping)
Outreach, education, and monitoring
Ballston Pond Improvements Redesign of existing stormwater pond underway to enhance nutrient and sediment removal and improve water quality. Pond will treat ~ 400 acres of impervious area that drain to Four Mile Run.
Watershed Retrofit Plans
New Stormwater Facilities
Stream Restoration
Before
After
Urban Housekeeping
Outreach and Education
Stormwater Master Plan Update
Stormwater Master Plan (1996) and Watershed Management Plan (2001) are being updated and combined into a comprehensive Master Plan.
Storm Sewer Capacity Analysis to study the County's current storm sewer pipes. County-wide stream inventory to assess stream conditions and prioritize stream restoration projects. Watershed retrofit plans to identify locations where stormwater treatment facilities can be added to help slow down and filter stormwater runoff.
Master Plan Update Process
Technical Studies – currently underway
Draft Plan completed – Summer 2012
Circulate Draft Plan for Comment – Fall 2012
Adopt Master Plan – December 2012
