We will immediately pilot various BMPs to monitor and assess their performance in New York City neighborhoods
The Task Force will begin by piloting the following three BMPs, selected for their feasibility and proven effectiveness in other programs across the United States:

• Create a mollusk habitat pilot program
• Plant trees with improved pit design
• Create vegetated ditches (swales) along highways

Within the next two years, the City will also pilot other BMPs, including developing storm water BMPs for ballfields along the Bronx River, using vacant public property to create urban storm water systems that offer greater infiltration and protect wildlife habitat. We will also study the treatment and capture of storm water from large parking lots using vegetation and infiltration through pilots in the Jamaica Bay Watershed.

We will introduce 20 cubic meters of ribbed mussel beds
When Henry Hudson first sailed through New York's Harbor, half the world's oysters were alive beneath him. Approximately 350 square miles of oyster beds lined the surrounding harbor estuary, removing impurities from our water free of charge. At one time, oyster trade supported the city's early mercantile economy. But over-harvesting and raw sewage led to the loss of the oyster population by the early 20th century. While scattered populations of oysters and other mollusks, including mussels, can be found in the city's harbor estuary, there are no longer enough to significantly improve the city's water quality. The loss of mollusks has resulted in the loss of one of nature's finest filtration systems.

To once again reap the benefits of these natural bio-filters, the City will create a habitat and reintroduce 20 cubic meters of ribbed mussel beds. Ribbed mussels present little safety risk because they are not eaten. Through this pilot, we will test the capability of mollusks to improve the water quality of our tributaries around combined sewer overflow outlets. Our first location will be Hendrix Creek, a tributary to Jamaica Bay, which is located next to the 26th Ward Wastewater Treatment Plant, at a cost of $600,000. (See photo on facing page: Long-Line Mussel Farm)

According to the Gaia Institute, 20 cubic meters of ribbed mussels should be able to filter all the effluent, 65 mgd, from the 26th Ward Wastewater Treatment Plant. But because this premise has not been tested recently in New York City, we can't confirm that this level of performance is possible. Therefore, we will test the solution in order to determine whether or not it should be expanded.

The study will evaluate to what extent mollusks can grow in our waterways, the mollusks densities necessary to address urban pollution and nutrient problems, and the costs associated with achieving various levels of water quality improvement. The demonstration habitat will be monitored, documented, and replicated as appropriate.

Progress (as of 4/22/08):
DEP released an RFP on February 27 to procure a consultant to design the ribbed mussel pilot and the necessary monitoring process. The City expects the consultant to be selected and begin work in Fall 2008.

We will plant trees with improved pit designs
New York City street trees are often planted in small confined pits-commonly four feet by four feet square and 20 feet apart-with densely packed soil. These characteristics restrict roots, blocking their ability to absorb oxygen, nutrients, and water. In addition, these confined pits limit the amount of storm water that can be captured. (See illustration above: Improved Tree Pit Design).

Trees planted in cramped pits can either die or damage the sidewalk as they grow. Improving the design and size of the tree pit will confer the dual benefits of improving the chances for the tree's survival and retaining storm water.

Installing underground storage areas and using structured soils will expand the volume of storm water captured by these redesigned pits. Structured soils have more air space and can be used in trenches between trees, under sidewalks or under porous pavement.

DEP, in partnership with the Gaia Institute and DPR, will pilot in the Jamaica Bay watershed five enhanced tree pits with below-grade water catchments to increase storm water infiltration. The pilot program will include three years of monitoring and data collection with annual reports and a final project summary of findings. If successful, this technology will be recommended for widespread application during future sidewalk and road reconstruction.

Progress (as of 4/22/08):
DEP released an RFP on February 27 to design the tree pit pilot and the necessary monitoring process. DEP expects the consultant to begin work by June 2008.

We will create vegetated ditches (swales) along parkways
Vegetated ditches (called swales) are linear, dry ditches designed to receive runoff and slowly move rain to an outfall point along our waterways, absorbing water along the way. They are especially effective when located adjacent to parking lots, streets, parkways or highways or when used as a median. In addition to storing direct rainfall and reducing storm water volumes entering the combined sewer system, swales provide natural cleansing of runoff through the soil and vegetation. (See illustration on previous page: Vegetated Swale)

But there are challenges associated with swale construction, including finding enough space given the city's density. Nevertheless, incorporating swales into the redesign of roadways may prove less expensive than constructing traditional piped drainage systems. For example, Seattle's pilot Street Edge Alternatives Project (SEA Streets) is designed to provide drainage that more closely mimics the natural landscape instead of traditional piped systems. Two years of monitoring show that SEA Streets has reduced the total volume of storm water from the street by 99%.

Progress (as of 4/10/08):
DEP released an RFP on February 27 design the swale pilot and the necessary monitoring process. DEP expects the consultant to begin work by June 2008.