A flood assessment study commissioned in 2012 after Hurricane Irene has finally been published, and the findings offer no easy solutions for West Windosr residents living in flood prone areas. The study’s overall conclusion is that the major flooding in the Little Bear Brook watershed between Washington Road and Alexander Road is primarily caused by an overflowing Millstone River, and the more frequent chronic flooding is due to inadequate roadway storm sewer capacity.
A concurrent study analyzed stormwater management for the 350-acre redevelopment area, which overlaps with Little Bear Brook, though findings of the storm sewer system and “the potential use of stormwater management facilities” will be presented in a future Phase II report.
The township will hold a public meeting to discuss both reports. A date for the meeting has not yet been determined.
As part of a 2.39-square-mile watershed, Little Bear Brook flows under Alexander Road, the Dinky rail line, and Washington Road before discharging into the Millstone River.
The Little Bear Brook flood study addressed two flooding problems: chronic flooding where the brook crossed roadways and major floods affecting the watershed area during large storms.
“Contrary to original expectations, these sources did not include the brook itself but rather the Millstone River and inadequate roadway storm sewer systems,” the study stated.
Chronic flooding is due to the “inadequate capacity” of the storm sewer systems draining the roadways. Major flooding effecting the entire area, for example during Hurricane Irene in 2011, is “caused by excessive flows and water levels on the Millstone River at the mouth of the Brook.” Upstream flows from other towns contribute to the river’s high water levels.
The flood study outlined “flood mitigation strategies” that “warrant further investigation” and those “that do not have a realistic potential.”
To address the overflow of the Millstone River at the mouth of Little Bear Brook, the report recommended raising Washington and Alexander roads, as well as large-scale levee and flood systems. However, Mayor Shing-Fu Hsueh and township engineer Francis Guzik indicated that major engineering projects are unlikely as they would require the involvement of state or federal authorities.
A smaller scale recommendation is the installation of a gage system to monitor the river’s water level, which would alert township authorities of flood risks. The report also recommended floodproofing for individual flood-prone structures.
Hydraulic modification of the Carnegie Lake Dam, the D&R Canal Aqueduct, and the Route 1 bridge would not significantly reduce the river’s water levels at Little Bear Brook, according to the report, and a large upstream detention basin was also deemed unfeasible due to regulatory and property rights constraints.
Michael Stevens lives on Fieldston Road, and his neighborhood turned into a lake after Hurricane Irene. The rescue squad had to send a boat to Stevens’ house to extract him, his daughter, and their two dogs. Before Irene, the last major flood occurred in 1999, when Hurricane Floyd landed.
With heavy rainfall, the stormwater that usually flows into Millstone River instead flows out of the drains. Stevens knows at least four neighbors whose basements were submerged after Irene, and Stevens was a main proponent of having the flood study done after Irene.
“It floods the green space we have here, and it starts coming up our street,” Stevens says. “It’s rather remarkable when it does. The manholes that cover our streets start bubbling like geysers. The water pressure in what should be downstream becomes upstream.”
The single-family homes in Penns Neck are not the only properties affected. The area between Washington Road and Alexander Road, as well as the roadways, were flooded. This affects emergency services, says Stevens, who volunteers for West Windsor Volunteer Fire Company No. 1.
In response to the damage done in 2011, nearly 20 families in the Penns Neck area formed Citizens For a Safer Township and called for infrastructure and inter-municipal cooperation to prevent repeat flooding whenever the next big storm hits.
Another concern is the impact future development would have for the floodplain.
“With the proposal to build additional housing, if you start getting rid of the natural ground and start putting in asphalt, that water has nowhere to go,” Stevens says. “How is that going to affect the water flow during large scale meteorological events?”
While the township is not positioned to implement solutions to mitigate overflow at the Millstone River, it can upgrade and improve the stormwater sewer system. The system’s inadequate capacity was found to the cause of the chronic flooding. The phase II report will focus on the area’s existing stormwater collection system.
The second report on the redevelopment area’s stormwater management, as well as the flood study, will serve as a technical basis for the future, Hsueh says. The report analyzed the current and proposed conditions of the redevelopment area and stormwater management options.
Recommendations include the construction of a wet pond and infiltration basin combination, though significant obstacles include state regulations and the presence of private landowners.
“All we can do is we’re hoping all the developers in the area will use this as a reference to reduce the impact,” Hsueh says. “It will provide information for future developers so they will not add additional problems to the flooding.”
There are currently no plans to change the municipal stormwater collection ordinances. Stricter ordinances would increase construction costs, as future developers would be required to retain more water runoff and in turn have to build bigger water detention systems.
“Based on the finding, that the flooding is going to happen no matter what we do, we would still weigh whether it makes sense to implement more stringent ordinances,” Guzik says. “We probably wouldn’t get return on investment. Developers would spend more money, and we wouldn’t see a bigger benefit.”
#b#Council News.#/b# Bike lanes and sidewalk improvements were the highlight of the Council meeting May 26. Council approved an agreement with Roberts Engineering Group for $31,800 to conduct survey and engineering services for the North Post Road Widening Project. The roadway improvement is occurring at the sharp bend on North Post Road near the library, and a utility pole will be removed as part of the project.
Council also approved the reappointment of Victor Stein and the appointment of Zain Sultan to the Human Relations Council, and a summer recreation busing agreement with Irvin Raphael, Inc. for $19,000.
#b#Coffee with a Cop.#/b# Residents can chat with members of the West Windsor Police Department Sunday, May 31, at 3 p.m. at PJ’s Pancake House in Windsor Plaza. The Coffee with a Cop event is part of the department’s community policing initiative aimed at improving relationships between police officers and residents. Community members can meet officers and discuss local issues in an informal setting.
