Improvements for the way waterfront redevelopment of brownfields can be approached falls into three general categories. These include:
- Low Impact Development (LID) to keep contaminants out of the waterway
- Eco-System Analysis & Integrated Monitoring
- Holistic View of Remediation and Redevelopment
Click on a recommendation heading for details!
A photo of the river would work nicely here
1. Low Impact Development. {this will be a new page linked from the first page of the “future” waterfront section}
The use of LID technologies, advocated for in CRMC’s Urban Coastal Greenways program {link to “present” waterfront section entitled “Coastal Regulations Governing Urban Waterfront Redevelopment And Their Meaning For Brownfields In The Jewelry District”}, will have a positive effect on water quality. This will occur for two reasons. First, LID technologies {in-text link to http://www.epa.gov/nps/lid} that manage stormwater can reduce contaminants that enter the river via urban runoff, such as is associated with car traffic and road surfaces. Second, some LID methods may be used as part of brownfields cleanup strategy to prevent the movement of industrial contaminants into the water. It is this second effect that is of particular interest to brownfields remediation, and potentially to the redevelopment of the Jewelry District waterfront.
Examples of LID technologies for managing storm-water include: green roofs, storm-water collection systems, alternative permeable surfacing, vegetative swales and bio-retention basins or “rain gardens.”
BIO-RETENTION CAN PREVENT SEEPAGE TO GROUNDWATER
Bio-retention methods can feature underlying impermeable layers to prevent the seepage of industrial onsite contaminants into groundwater. The geology of the Jewelry District waterfront sends groundwater flow into the Providence River, meaning that contaminants that can travel via water are likely to enter the waterway {link to “present” page entitled Environmental Implications of Known & Suspected Contamination} Studies have shown success in using mulch, vegetation or straw to prevent the movement of metals, PAH, toluene and other contaminants associated with urban run-off and power plant land use history from passing through the site , , . A study by Hong et al. has found that a mulch layer contaminant trap can remove 80 to 95 percent of dissolved or particulate naphthalene and dissolved toluene and motor oil hydrocarbons, all of which have either been detected or suspected at the Dynamo House location. Lead, which is common across all Jewelry District soils, had a removal rate of close to 100 percent in lab simulations of vegetation-based storage and infiltration used in parking lots and similar areas, and field investigations have supported these simulations .
Some LID strategies may be more effective than others. A study out of the University of New Hampshire found that petroleum is most effectively treated using wet or dry retention ponds rather than swales, although all three methods are considered bio-retention strategies. Meanwhile, a CICEET-affiliated study (Cooperative Institute for Coastal and Estuarine Environmental Technology) has shown that the use of wood or straw byproducts as underground filtration can remove 90 percent of dissolved contaminants including PAHs, which have been found at Dynamo House, and which pose a threat to aquatic life, as well as to human beings .
The placement and interplay of these technologies on the landscape is crucial to their success. The placement of bio-retention basins near the source of contamination has been proven to maximize interception.
Because of the variability of quantity and quality of water passing through the system depending on a number of factors (placement, types of contaminants, volume of water), it would make sense to conduct periodic monitoring of onsite and coastal water.
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