incorporating lid stormwater management practices and ... · practices and ecological restoration...

Incorporating LID Stormwater Management Practices and Ecological Restoration on Redevelopment Properties

Presented toLID ConferencePhiladelphia, Sept 2011

Presented byDani Wise JohnsonVanasse 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


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


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


Low Impact Development Stormwater

Management Practices

Supports Ecological Restoration Efforts

Considers Site Constraints –Utilities, Roads,

Buildings

Improves Site Aesthetics –

Consider End User and Marketability

Meets Regulatory Requirements –

Current and Future


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


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


Silver Brook today…..


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


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


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


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


University of DelawareSchool of Agriculture

Science and Technology Campus

University of Delaware Athletics





Rittenhouse Park

Devon Park

Christina Creek

Phillips Park

West Park Place Elementary

Dickey Park

Robscott Manor

White Chapel Park

Lewis Park





Rittenhouse Park

Devon Park

Christina Creek

Phillips Park

West Park Place Elementary

Dickey Park

Robscott Manor

White Chapel Park

Lewis Park

100’ Floodplain


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


PRECEDENTS: STORMWATER STREETSCAPES


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


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.


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

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