Incorporating LID Stormwater Management Practices and Ecological Restoration on Redevelopment Properties Presented to LID Conference Philadelphia, Sept 2011
Presented by Dani Wise Johnson Vanasse Hangen Brustlin, Inc. LID and Ecological Restoration in Redevelopment
Considerations for Stormwater Management on Redevelopment Properties
Site-specific issues and treatment options • Design not “one size fits all” • Extensive site investigations required to properly address site characteristics (drainage patterns, soils, contaminants, ground water, etc)
Challenges related to stormwater treatment • Limited infiltration opportunities (soils) • Land cost high • Physical lack of space • Existing soil/groundwater contamination LID and Ecological Restoration in Redevelopment
Considerations for Ecological Restoration on Redevelopment Properties
Site-specific issues and restoration options • Design not “one size fits all” • Extensive site investigations required to properly address site characteristics (drainage patterns, soils, contaminants, ground water, etc) Challenges related to restoring streams, wetlands, and other habitats • Land cost high • Physical lack of space • Existing soil/groundwater contamination • Funding for such projects LID and Ecological Restoration in Redevelopment
Approach: Integrated Stormwater Management Practices – Master Planning
Look for opportunities to implement run-off capture/treatment and re-use in planning stages
Utilize a Tiered Approach if necessary/possible • Utilizing more than one practice for additional treatment, particularly when infiltration into groundwater limited Landscaping as Infrastructure • Carried over into the restoration/creation of ecologically sensitive areas: stream corridors, wetlands, riparian buffers, etc ….”Green Fingers” Requires Planners, Engineers, and Environmental Scientists to work TOGETHER LID and Ecological Restoration in Redevelopment
Supports Ecological Restoration Efforts
Considers Site Meets Regulatory Low Impact Constraints – Requirements – Development Utilities, Roads, Current and Future Stormwater Management Practices Buildings
Improves Site Aesthetics – Consider End User and Marketability LID and Ecological Restoration in Redevelopment
University of Delaware: Science and Technology Campus (STC)
• Previously a Chrysler Plant (~1950- 2008) • Over 80% Impervious • Adjacent University properties include College of Agriculture & Natural Resources • Christina River Watershed, Newark, DE • Piped perennial stream across property • Brownfields site • 50 Year Master Plan LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment
STC Stormwater Considerations
Existing Condition: Site predominately impervious
Little known about existing infrastructure (underground utilities)
Very low “time of concentration” during storm events
Need to address existing and upcoming stormwater regulations as site Master Plan is developed
Stream daylighting options need to incorporate stormwater practices
Results of Brownfields investigation will influence location and design of practices LID and Ecological Restoration in Redevelopment
Silver Brook today….. LID and Ecological Restoration in Redevelopment
Status of Evaluation of the Daylighting of Silver Brook
Analyzed historical conditions and available data • Appreciation for previous condition of Silver Brook and its significance in the landscape
Conducted site visit to assess current conditions of stream on the STC; also visited the upstream and downstream portions of the drainage
Met with Water Resources Agency/Stakeholders to discuss their knowledge of the watershed, relevant data they have available, and potential for funding sources for restoration
Evaluate the pro & cons of daylighting or not daylighting the channel
Coordinate efforts with the Brownfields investigation to aid in conceptual plans for stream and floodplain placement LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment
Considerations for Daylighting Silver Brook
Provide green-space within the STC
Create visual barrier between E & W
Create aquatic and terrestrial habitat
Create floodplain – providing various storm water treatment options
Create area for recreation and greenway
Improve water quality
Provide location for various research opportunities for UD Faculty and students ------
Cost of restoration, particularly with risk of contaminated soil treatment/removal
Cost related to stream crossings (auto and pedestrian)
100yr floodplain - regulated LID and Ecological Restoration in Redevelopment
Considerations of not daylighting Silver Brook
•Stream would remain in culvert on property •No constraints related to 100 yr floodplain boundary •Property more accessible ------
•No greenspace on- site/connection to off-site parks
•Disappointment of local citizens
•Require all storm water treatment occur in other areas on property
•Potential issues with integrity of existing culvert LID and Ecological Restoration in Redevelopment
Expanding on Ecological Aspects
Re-opening the piped channel restores a once free-flowing stream and vastly improves the ecological condition of the stream itself as well as the adjacent landscape
Provides a “sink” for sediment, nutrients and other pollutants entering the drainage upstream of the STC.
In support of UD Climate Action Plan and Sustainability goals
Connects the green-space to the north (Prichard Park) and to the Christina River riparian area (Rittenhouse Park) to the south
Improves the water quality of Silver Brook prior to its confluence with the Christina River ( trout fishery) - 303d listed river with TMDLs in place LID and Ecological Restoration in Redevelopment
University of Delaware School of Agriculture
Science and Technology Campus
University of Delaware Athletics Dickey Park LID and Ecological Restoration in Redevelopment
White Chapel Park West Park Place Lewis Park Elementary
Phillips Park
University of Delaware School of Agriculture
Science and Devon Park Technology Campus
University of Delaware Athletics
Christina Creek
Robscott Manor
Rittenhouse Park Dickey Park LID and Ecological Restoration in Redevelopment
White Chapel Park West Park Place Lewis Park Elementary
Phillips Park
University of Delaware School of Agriculture
Science and Devon Park Technology Campus
University of Delaware Athletics 100’ Floodplain Christina Creek
Robscott Manor
Rittenhouse Park LID and Ecological Restoration in Redevelopment
Master Plan – Stormwater Management/Ecological Restoration
Integration of innovative stormwater practices throughout the STC can offer multiple benefits • Incorporate BMPs into landscaping rather than set aside valuable real estate for large scale (regional) approaches • Naturally lends itself to creating these green corridors or “fingers” • If soil contamination is an issue in a particular area, stormwater facilities can be installed to prevent mixing with groundwater • Opportunity for incorporation of newly designed practices and monitoring for research and learning opportunities • Needs to allow for PHASED DEVELOPMENT but with whole site plan in mind
Sustainability Approach UD Path to Prominence LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment
PRECEDENTS: STORMWATER STREETSCAPES LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment LID and Ecological Restoration in Redevelopment
DNREC Stormwater Management Regulations
City of Newark is the Delegated Agency for most UD projects DNREC is Delegated Agency for S&TC because it is in the Brownfield Program
Current Regulations:
Quantity: post-development peak cannot exceed pre-development peak for 2, 10 and 100 year frequency storm events
Quality: 80% TSS removal as modeled by the Delaware Urban Runoff Management Model (DURMM)
Impact on Redevelopment: no quantity management required if reducing impervious, quality management required for all runoff LID and Ecological Restoration in Redevelopment
Proposed Regulations (Draft, implemented 2011?)
Quantity: Volume control for Resource Protection (1 yr), Conveyance (10 yr) and Flooding (100 yr) Events (promoting recharge and infiltration of 1 year storm)
Quality: 80% TSS removal and Nitrogen and Phosphorus reductions consistent with receiving watershed’s TMDL requirements (using updated DURMM model)
Impact on Redevelopment:
As currently drafted: .
5.6.3.2 Redeveloped areas shall employ runoff reduction practices to achieve a 20% reduction in the effective imperviousness based on the pre-developed condition. LID and Ecological Restoration in Redevelopment
Funding Considerations
Grant funding opportunities include local, state, and federal • Existing TMDL for Christina River – this can open up avenues for funding through EPA 319 program • City of Newark securing their NPDES permit (Phase II) and as a result will be required to create and implement a stormwater management plan; Potential for a “utility” (fee) in the future. • Possible funding through cooperation with Research at UD and Water Resources Agency • Willingness to utilize more progressive storm water BMPs and emphasize sustainability will aid in securing public funding • Brownfields Remediation funding