Army Corps study provides several options for local flood mitigation

Sections of downtown Springfield was under several feet of flood water due to Tropical Storm Irene.
Sections of downtown Springfield was under several feet of flood water due to Tropical Storm Irene.

UNION COUNTY — Last week mayors of towns impacted by Rahway River flooding heard the first positive news in decades: the U.S. Army Corps of Engineers is on their side and came up with multiple alternatives to reduce the severity of the devastating impacts of flooding.

For former Cranford Mayor Dan Aschenbach, who formed the Mayors Council on Rahway River Watershed Flood Control in late 2011 after Tropical Storm Irene hit, this was “huge” because, as one army corps manager said, “now we are in the game.”

The mayor’s council has been working since late 2011 to find a regional flooding solution for the communities impacted by Irene. They certainly had their work cut out for them, Aschenbach said, but pointed out that perseverance prevailed after 14 legislators, two congressmen, 9 mayors and governing boards requested the flooding problem be evaluated fully by the state New Jersey Department of Environmental Protection and the U.S. Army Corps of Engineers.

Despite this, residents along the Rahway River who have waited more than a decade to hear that their ongoing flooding woes might be on the way to being alleviated could find rising opposition to one of the more favored projects involving the South Mountain Reservation.

Although it will be quite awhile before the Army Corps makes a final determination as to which of the ten alternatives they proposed is the best for the Rahway River area, rumors already spread that an 800-foot by 70-foot “dam” will be built in the South Mountain Reservation. This spread like wildfire in just the last two weeks and since then a Facebook page called “Save the South Mountain Reservation” popped up claiming a “dam” will destroy the reservation.

A petition was also put online with more than 2,500 objectors already signing their name against such a project moving forward. Municipalities also are up in arms about a flood project that would change the reservation as they know it.
In fact, last week the Maplewood Township Committee passed a resolution opposing any “dam” proposal, as did the South Orange Board of Trustees in March, even though the Army Corps has not selected a project or set a timetable for a flood project. Aschenbach felt this was premature considering a flood project has not even been selected as of yet.

On March 31 local mayors met with the New York District Army Corps of Engineers to hear the plan they came up with to alleviate flooding along the Rahway River, and they walked away breathing a sigh of relief.

Not only did these army engineers confirm that towns along the Rahway River suffered over $100 million in damage to properties during Tropical Storm Irene alone in 2011, but also that extreme weather patterns suggested it is not if a storm like this will occur again, but when.

More importantly, while rumors have circulated of a proposal for a dam to be built in the South Mountain Reservation, the army engineers presented ten possible flood risk management plans they believed would put a dent in the flooding risk that continues to plague homeowners living along the river downstream.

The plans included projects that showed positive benefit cost ratios that, after making it through the evaluation process, could end up being recommended to congress for funding.

However, any major flood mitigation project will not come cheap and could end up costing anywhere from $91.1 million to $230.3 million. Despite this cost, local taxpayers would not be on the hook for the entire amount.

Data provided by the Army Corps noted the cost of a project would be divided, with 65 percent coming from federal aid, 25 percent from state aid and the balance funded locally through taxes. As of yet, towns have not addressed how they would fund their end of such a project, but it is expected in the coming months this will be discussed by the various towns involved.
Aschenbach felt this was more than just a move in the right direction.

“This was a make or break decision and an important milestone,” the former Cranford mayor said, explaining that after the Army Corps did their economic analysis several of the alternatives “have benefits that exceed the costs.”

For Aschenbach, who was mayor in 2011 after Tropical Storm Irene barrelled through his community leaving more than 2,220 homes and businesses under water – including town hall – news that the Army Corps of Engineers was stepping in was a major breakthrough. But Cranford was not the only community who felt this way.

Towns like Millburn, Union, Springfield and Rahway also desperately need significant flood control relief for the safety of their residents because the Rahway River continues to cause major flooding problems in these municipalities.

Although the Army Corps came up with ten flooding project alternatives, they felt there were two that stood out from the rest.
These two options included modification to the outlet structure at the Orange Reservoir at a cost of $68.8 million and a South Mountain Regional Detention Basin at a cost of $108.4 million.

According to the Army Corps, these options had the greatest positive ratio for working to reduce – not eliminate – flooding downstream. There was, though, no mention of a dam.

The Army Corps stressed that no flood management project can eliminate the risk of flooding, and “given a long enough period of time, most projects will experience an event that is larger than the event for which they were designed.”

“Flood Risk Management projects can only reduce the frequency and severity of flooding and provide additional time to respond,” said one Army Corps manager, noting that insurance, zoning and an emergency action plans are other important aspects of Flood Risk Management.
The Army Corps also mentioned that solving a flooding problem is never one dimensional.

“Flood safety is a shared responsibility and a collaborative approach is required to effectively manage the risk of flooding and to save lives,” the Army Corps pointed out, adding that this included the Army Corps, FEMA, state, county and local government, emergency personnel and residents.
The Rahway River basin has a drainage area of approximately 81.9 square miles that includes Union, Essex and Middlesex counties. The most recent damaging floods of record within this basin were Tropical Storm Floyd in September 1999, the April 2007 Nor’easter and Tropical Storm Irene in late August 2011.

Aschenbach, who attended the Army Corps presentation, explained the proposed detention basin would be built near the Campbell Mill pond in the South Mountain Reservation.

“It would detain water, not retain it,” he stressed, adding that while opponents are saying this is retention is a “dam,” this is not true at all and the purpose is to hold water when there is a severe storm with heavy rainfall.
The former mayor gave an example of how this basin would work.

“The calculation is that if this basin was in place the last 15 years, or 5,475 days, out of that it would have been full only 10 days,” Aschenbach explained, adding those ten days are the most important because during that time period is when all the damage occurs downstream.

“By detaining the water and storing it for a few days and then slowly releasing it, communities downstream benefit by not being inundated with flood waters,” he said, adding that the at the Route 78 underpass where Millburn, Union and Springfield come together, the river elevation would be as much as three-feet lower.

Aschenbach agreed the detention basin option does have the potential for environmental impacts but that this still has to be evaluated by the Army Corps. He did point out any basin built, though, would look much like Lenape Park in Cranford does now, with trails, trees and a park like atmosphere.

“Opponents are overstating the case that all trees in 100 acres would be taken down, adding that environmental concerns would not be taken lightly and the U.S. Army Corps of Engineers will be evaluating that aspect of any proposed project in that area next.
According to information obtained from the Army Corps by LocalSource, one of the five evaluations they will be looking into prior to approving a project is how various communities feel about the project, including community impacts, displacement, recreational, and business loss or gains.

Also considered is environmental impacts along with biological and habitat considerations.
In the meantime, the mayors council, which includes mayors and engineers from Cranford, Kenilworth, Springfield, Union, Garwood, Winfield Park, Rahway, Millburn, Maplewood and Orange, were tasked by the NNDEP to come back with “a few” recommendations for alternatives with the best cost ratios that later will be further refined.

Aschenbach said the mayors will be meeting by the end of the month to come to a consensus on this so they can move onto the next step, which is the environmental review and the design.

“Of course we will be starting a strong political outreach to the 14 legislators, two U.S. congressman and two U.S. Senators who have been supportive of the evaluation so far,” Aschenbach said.

He added that last year the state pledged $370,000 to complete a portion of the environmental review required by the NJDEP.