Flood Experts Ask For Stronger Runoff Protections in NJ

Rain can't soak into paved surfaces the way it does in natural areas.
Credit: Source: EPA.

Devastating floods have struck Baton Rouge, Louisiana and Ellicott City, Maryland in recent weeks, destroying homes and claiming lives. But in addition to these high-profile disasters, moderate flooding continues to affect communities across the country on a regular basis.

Take New Jersey, one of many places that’s experienced flooding this summer. Areas of the state were inundated by floodwater during the same storm that ravaged Ellicott City in late July. Those floods left people stranded, knocked out power, and destroyed community assets like a church and nursery school.

NRDC has written about the role of climate change in the intense precipitation events that are causing these floods. (So has the Washington Post editorial board.) But climate change isn’t the only factor at play. Urban development also contributes to flooding, as the Baltimore Sun pointed out after the Ellicott City tragedy.

Paving over natural areas to create buildings, roads, and parking lots dramatically increases the amount of water running off the land during storms. As a result, development worsens communities’ vulnerability to flooding.

The good news is that we know how to build better to reduce our flood risks. One strategy is to require developers to reduce the volume of storm runoff their sites generate. They can do this by using water-absorbent green infrastructure technologies, like rain gardens and green roofs, to capture rain where it falls.

The bad news is that many states still don’t impose such requirements, thanks to political pressure from developers. New Jersey is one of these states.

No one understands the importance of reducing runoff better than floodplain managers. They’re the experts—from government agencies, citizen groups, private consulting firms, academia, and the insurance industry—who work to reduce communities’ risk of flooding. So when they speak up about the need for stronger protections, we should all listen.

Earlier this summer, the New Jersey Association for Floodplain Management sent a letter to the New Jersey Department of Environmental Protection (NJDEP) asking the state to strengthen the requirements in municipal stormwater permits.

In New Jersey, as in other states, runoff that flows through municipal sewer systems into nearby water bodies is regulated by permit under the federal Clean Water Act. These permits require local governments to take steps to control their runoff so it doesn’t pollute local waterways or cause floods. In New Jersey, the permits require municipalities to enforce the state’s rules for runoff controls on private development sites.

Green infrastructure practices like rain gardens effectively capture runoff, but they're not required in many places, including New Jersey.
Credit: Source: EPA.

The floodplain managers wrote to NJDEP because New Jersey’s permits will be renewed this year. The current permits have proven woefully inadequate to prevent flooding and curb water pollution, which is why NRDC petitioned the state to incorporate stronger requirements two years ago. But the state's only action in response has been to put forward a weak proposal that doesn't address our key concerns.

In their letter, the floodplain managers asked NJDEP to strengthen the runoff design standards for development and require builders to reduce stormwater volumes on their sites. They also supported a proposed new requirement for proper maintenance of controls like stormwater ponds and green infrastructure practices. And they asked for better training of the municipal officials and engineers who are charged with enforcing the standards.

The experts know that these reforms are needed to reduce urban flooding in New Jersey, as well as to clean up local rivers and streams. NJDEP should heed their advice as it prepares drafts of the new permits, which will be released for public review this fall.

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