The LRWP and SEWA volunteers went out to the litter trap in the Green Brook on Saturday, June 28th, 2025, to conduct a litter tally. The water was low, with minimal trash flows. Huge thanks to our SEWA International Central Jersey youth partners! Thanks to their efforts, we’ll have much better data on how the litter trap keeps our watershed clean. Learn more about the litter trap initiative here. And learn more about the LRWP’s litter tally project with SEWA here. Below, you’ll find Sewa’s Aasmi Bora describing the litter we picked up, as well as her initial thoughts on why so much litter gets buried in sediment before it reaches the trap.
Guest post by Aasmi Bora
The litter trap is a device that is designed to collect trash and debris before it can end up in larger bodies of water, like the Raritan River. Its main structure is a chute-like mechanism, shown in the picture below, supported by two buoyant pipes (or booms) which keep it afloat.
How effective is our litter trap? To evaluate the effectiveness of the Litter Trap, we conducted an analysis of the waste found both inside and outside the device.
Here’s what we found inside the Litter Trap:
4 small liquor bottles
2 markers
1 small plastic ball
1 basketball
1 fishing bobber
8 plastic bottles
1 plastic eye dropper
3 aluminum cans
1 unopened cigar packet
1 piece of plastic
A large amount of styrofoam (mostly too small to
pick out individually)
In comparison, this is what we found outside of the Litter Trap:
1 toy train
1 teddy bear
7 aluminum cans
2 plastic bottles
2 plastic wrappers
1 shoe sole
3 pieces of glass
1 piece of fabric
1 shoe sole
1 plastic utensil
1 base of gumball dispenser
2 plastic bags
2 tires
Many more pieces of plastic
More styrofoam
Seat cushion
Why might the Litter Trap be capturing less trash than what is found outside of it?
We began to explore further up the stream to identify possible causes. We noticed how most of the debris was getting caught on tree branches as well as being embedded in the stream bed. Based on these findings, we hypothesized that the shallowness of the stream could be the main culprit.
During our exploration of the Green Brook, we found a section of the stream with a stronger current than where our litter trap currently rests. We predict that if the litter trap were repositioned in faster current then we would see a better accumulation of debris in the litter trap. As we continue to explore the functions of Litter Trap we aim to find solutions to enhance the design and effectiveness of the device.
This summer, the Lower Raritan Watershed Partnership will partner with the Central Jersey chapter of Sewa International to train the next generation of citizen scientists! The collaboration will focus on the Green Brook litter trap, a project funded through the ‘damages’ assessment of the Cornell Dubilier Electronics site in Plainfield. Together with a handful of science-minded high school students, we will be assessing our toolkit for counting the litter trap’s collections, imagining new ways of protecting our streams, and investigating the point-source of various pollutants in the Green Brook. In a few days, our Sewa volunteers will begin posting their findings.
Ashwin, Nilesh, and Aasmi (L to R) explore the Green Brook for the first time.
This project is part of the Cornell-Dubilier Electronics Natural Resource Damage Assessment and Restoration Plan (NRDAR Plan), and our partners include Dunellen, Green Brook, and the Cornell Dubilier Trustees (New Jersey Department of Environmental Protection, US Fish and Wildlife Service, and National Oceanic Atmospheric Administration).
The LRWP and SEWA volunteers went out to the litter trap in the Green Brook on Saturday, June 12th, 2025, to conduct a litter tally. Huge thanks to our SEWA International Central Jersey youth partners! Thanks to their efforts, we’ll have much better data on how the litter trap keeps our watershed clean. Learn more about the litter trap initiative here. And learn more about the LRWP’s litter tally project with SEWA here. Below, you’ll find Sewa’s Ashwin Pemmaraju describing the litter we picked up and conditions surrounding the litter trap.
Blog post by Ashwin Pemmaraju
We here at Sewa International Central Jersey Chapter have strived to clean up the site around the Green Brook litter trap, and to develop a better understanding of how plastic pollution and rainfall interact with the trap. We’ve noticed new items slipping past the trap and polluting the river, and some interesting challenges to floating litter traps that rely on capturing debris suspended in fast moving water.
Trash found outside the trap:
7 plastic bottles, 2 juice boxes, 2 masks, 1 spoon, 1 metal piece, 1 calculator, 20 wrappers, 5 aluminum cans, 1 possible car part, 1 shovel, 99 glass pieces, 1 small plastic liquor bottle, 1 bubble wand, 26 plastic bags, 1 plastic food container, 1 pill sheet, 2 plastic cups, 1 piece of roof slate, 1 piece of clay pot, 1 piece of brick, 1 glove, 6 pieces of fabric, 1 latex glove, 1 cigarette butt, 1 piece of plastic.
Perhaps the oil canister we found today explains the presence of oil slicks we noticed last week.
Trash found inside the trap:
Plastic bottle (1), aluminum cans (2), pieces of styrofoam (6), nails (1), cigarette butt (1).
We also noticed an interesting aspect of the litter trap’s design: The current rebounds off the trap, slowing down incoming trash – the trash then falls from suspension, descends into the current, and passes under the booms. Thus, the heavier trash easily slides under the booms and escapes the trap. Perhaps this explains the immense abundance of garbage found on the river banks and the shallower isles down the stream.
We found a small leech hiding among the debris in the litter trap.
