County Installs Rain Garden to Treat Water Before it Flows into Lakes, Streams

JAMESBURG – A grassy island in a parking lot at Middlesex County’s Thompson Park was transformed today into a Rain Garden—complete with coneflowers, black eyed susans, joe pye weed, and other assorted native plants designed to treat polluted stormwater runoff before it flows into the park’s Manalapan Lake.

Middlesex County Freeholders Carol Barrett, Stephen J. “Pete” Dalina and Ronald Rios welcomed a group of more than 35 volunteers from a Rutgers Cooperative Extension Rain Garden Certification Workshop, who installed the approximately 1300-square-foot rain garden.


“It is critical that we do everything possible to address pollution that affects our lakes and streams,” said Barrett, chair of the County’s Engineering and Planning Committee. “Treating parking lot runoff with a rain garden before it enters the lake is an effective and low-cost approach.”

A rain garden is a planted, shallow depression that is designed to capture rainwater runoff — also called stormwater — from impervious surfaces like driveways, rooftops, walkways and compacted lawn areas. This runoff can carry salt, sand, pet waste, pesticides, fertilizers, leaves and grass clippings, oil, litter and other pollutants into nearby waterways.

Once in the garden, the polluted water is taken up by the plants, infiltrates into the ground or evaporates as water vapor back into the atmosphere. Through these processes, the volume of stormwater reaching storm drains and surface waterways is reduced and is less polluted. The rain garden at Thompson Park will intercept polluted runoff from the adjacent parking lot before it reaches Manalapan Lake.

“Thompson Park is the perfect location for this demonstration project,” said Freeholder Dalina, chair of the County’s Parks and Recreation Committee. “We are making this incredible park even more beautiful by planting such colorful blooms while at the same time improving the water quality of our lake and stream system.”

The rain garden demonstration project is the first component of the Manalapan Brook Watershed Restoration and Protection Plan, scheduled to be completed later this year.

The Middlesex County Department of Planning has led this effort, which is funded through a federal Clean Water Act section 319(h) grant from the New Jersey Department of Environmental Protection. Other partners in the effort include the New Jersey Water Supply Authority, Middlesex County Department of Parks and Recreation, nine municipalities in Middlesex and Monmouth Counties, Freehold Soil Conservation District, and many others.

The plan focuses on rehabilitating the watershed, which stretches from Millstone Township in Monmouth County to DeVoe Lake in Spotswood, where the Manalapan Brook meets up with the Matchaponix Brook and forms the South River.

The plan was developed to recommend measures necessary to address high concentrations of total suspended solids (TSS) that affect water quality in the Manalapan Brook and its tributaries, and eventually end up deposited in Manalapan Lake, which is in Thompson Park. The suspended solids are made up of small particles that are washed into the stream with storm water runoff, and soil that is flushed from stream banks during storm events.

The demonstration rain garden project, which also includes a shoreline buffer planting with geese deterrent structures along the southern shore of Manalapan Lake, will provide stakeholders with a tangible example of what can be done to improve water quality.

This rain garden, designed by Princeton Hydro, LLC of Ringoes, was installed as part of a Rain Garden Certification Workshop, coordinated by the Rutgers Water Resource Program, which teaches individuals about non-point source pollution and provides hands-on experience in rain garden installation.

“This is an impressive gathering of volunteers who want to help us improve the quality of life here in Middlesex County,’ said Freeholder Ronald Rios, who is liaison to the Rutgers Cooperative Extension. “I thank them for their commitment to the environment and for helping to make the environment cleaner for all of us.”

Rain Garden Specialists can use this knowledge to install their own rain garden and teach others about the benefits of these landscape features.  Rain gardens can easily be planned and installed on any size property. Visit for more information on Rutgers’ Rain Garden Program.

Middlesex County Freeholders Carol Barrett (center) and Ronald Rios (kneeling at right) join Dr. Clay Emerson from Princeton Hydro and volunteers from the Rutgers Cooperative Extension Rain Garden Certification Workshop, as they install an approximately 1,300-square-foot rain garden in the County’s Thompson Park in Jamesburg.  The Rain Garden was planted with Coneflowers, Black Eyed Susans, Joe Pye Weed, and other assorted native plants designed to treat polluted stormwater runoff before it flows into the Park’s Manalapan Lake.

Connect with NJTODAY.NET

Join NJTODAY.NET's free Email List to receive occasional updates delivered right to your email address!
Email for advertising information Send stuff to NJTODAY.NET Like Us On Facebook Follow Us On Twitter Download this week's issue of NJTODAY.NET
Print Friendly, PDF & Email