Nonprofits Plan ‘Green Infrastructure’ to Help Fight Algae Blooms in NJ Lakes

Rain gardens will filter phosphorus from runoff, preventing it from entering the water in rainstorms and feeding harmful blooms
Credit: Tuchodi from Flickr (CC BY-SA 2.0)
The hope is that “green infrastructure” will help filter out the contaminants that contribute to the formation of harmful algae blooms.

As concern mounts that New Jersey’s lakes will be clogged by harmful algae blooms again this summer, local nonprofits are planning to install “green infrastructure” such as rain gardens to absorb contaminant-laden runoff that feeds the blooms.

While such measures aren’t expected to offer a quick fix to a problem that has been decades in the making, advocates say the creation of gardens that allow stormwater to soak naturally into the ground rather than running off immediately into lakes will prevent significant quantities of phosphorus — an important contributor to the formation of the  blooms (also called HABs, for harmful algae blooms) — from entering the water.

Instead, about 90% of the chemical, which is used in farm fertilizer, will be removed by the slow filtering action of layers of soil, largely depriving the blooms of one of the substances that allows them to grow.

Among the lakes where activists plan to install the green infrastructure are Lake Hopatcong, New Jersey’s largest, straddling Morris and Sussex counties, and Deal Lake near Asbury Park in Monmouth County.

Their efforts complement those of the Department of Environmental Protection which has a new system for warning the public whether lakes are safe for bathing, and which is offering grants to local groups to build rain gardens. Earlier this summer, officials unveiled a color-coded warning system containing five rising stages of hazard from the blooms. Even at the lowest level, when harmful blooms are suspected, people, pets and livestock are advised not to ingest the water in that lake; at the highest level, which has not applied so far this summer, people are instructed to avoid “primary contact” such as swimming.

According to the DEP’s new interactive map on the blooms, seven lakes had algae levels at the “Advisory” level — at which swimming beaches are closed — as of July 6. Another 12 lakes had received the “Alert” designation, under which beaches remain open but harmful blooms are confirmed.

Credit: NJDEP
Warnings like this were posted at dozens of New Jersey lakes in summer 2019.

In 2019, more than 30 lakes were closed at different times because of an outbreak of harmful blooms that formed in response to warm water temperatures resulting from climate change, polluted runoff from impervious surfaces in the watersheds, and leaking septic systems in some places.

Runoff from a parking lot

This year, the nonprofit Deal Lake Watershed Alliance is hoping to expand basins in a creek bed, and install rock cages to hold back runoff from a shopping mall parking lot, giving the water time to soak into the ground rather than spilling into the lake during rainstorms.

Laura McBride, the group’s president, said the project would remove a significant quantity of phosphorus and other pollutants that currently flow directly into the lake from the lot and nearby highways.

“Our goal is to enlarge the basins in a way that allows us to put in rock cages, so that when we have heavy rains and sediment flows off those parking areas, it will collect behind the cages instead of flowing into the lake,” she said.

The Deal Lake group is also working with the Rutgers University Cooperative Extension, a statewide leader in building green infrastructure for the last 17 years. The partnership expected to start building 20 rain gardens in the Deal Lake watershed earlier this year, but plans were delayed by the COVID-19 shutdown.

Now that the Rutgers team, led by Chris Obropta, an extension specialist in water resources, is back at work, McBride said she’s hoping that the project will start soon with construction of 20 rain gardens. That won’t immediately reduce the pollution draining into the lake by much, she said, but will represent a start from which more will be built later.

She’s also hoping to build a rain garden demonstration center, which will show people how they can prevent rain from their roof from running off straight into the lake. “The message is just to keep the rain from the drain,” she said.

Growing public support for green infrastructure is a result of increasing environmental awareness and people’s need to make a contribution, Obropta said.

“People want to do something that makes a difference,” he said. “They hear about climate change and the environment and they just don’t know what to do. While not using plastic straws is a great thing, a lot of people really don’t see how that is going to help. Building a rain garden reduces flooding and helps stop the lake turning green.”

Stabilizing the shoreline at Lake Hopatcong

Donna Macalle-Holly, grant program director for the Lake Hopatcong Foundation, said the group received a DEP grant for preventing the harmful algae blooms and it is now seeking funding for shoreline stabilization and wetland basin construction at that lake.

Stephen Souza, owner of Clean Waters Consulting, and an expert on the algae blooms, said groups like those at Deal Lake and Lake Hopatcong are well-placed to contribute to the work of preventing the conditions that lead to the formation such blooms.

Credit: Hope Abrams/Flickr
Lake Hopatcong was closed last summer due to an algae bloom. Local nonprofit groups are hoping to mitigate the conditions that led to that closure.

“The lake communities have a built-in desire to do that type of work,” he said. “They can see the benefits, and they understand how phosphorus drives HABs, and whatever they can do to reduce phosphorus loading is beneficial for their water quality.”

But people can build their own rain gardens without waiting for action by nonprofits or local government to act, Souza said. He cited his own Hunterdon County property which has four rain gardens and aims to prevent all rainfall from running off into waterways. “You don’t have to sit back and wait for Big Brother to act; you can help yourself,” he said.

Despite the efforts of nonprofits or individuals, the algae blooms won’t disappear anytime soon, predicted Jennifer Coffey, executive director of the Association of New Jersey Environmental Commissions, but they can be reduced.

“The good news is that we can control HABs by decreasing phosphorus pollution with improved stormwater management, eliminating lawn fertilizer, and fixing septic system leaks,” she said. “It took decades to create the conditions that support HABs and close our waterways, so it’s going to take some time to correct the problem.”