TOWNSHIP OF WASHINGTON—The township engineer said the unnamed tributary that runs behind Meisten Street homes — and behind a proposed 17,100-square-foot retail plaza near the Pascack Road–Washington Avenue nexus — is not a regulated waterway by the state Department of Environmental Protection (DEP) because it drains an area “definitively less” than 50 acres.
Township Engineer Kevin Boswell told the council and residents on April 17 that the tributary to the Musquapsink Brook was not a Category One — or a state-regulated — waterway, because it did not drain an area of 50 acres or more.
He said two calculations done by Boswell using data available on the state Department of Environmental Protection website showed the drainage area less than 50 acres. One showed a basin of 48.83 acres; another showed a basin of 48.832 acres.
Boswell said he did not produce a report for council because generally reports are produced when trying to change a waterway from protected to non-protected status. He appeared to provide a copy of written results to the mayor and council and to a concerned resident.
Meanwhile, other nearby segments of the Musquapsink Brook, which the tributary flows into, are considered “C1” regulated waters, according to NJDEP, which provides a list of statewide “C1” waters on its website.
The issue of whether the unnamed tributary is a regulated Category One water was important to Meisten Street resident Michael Agnello, whose backyard it bisects 24/7. He has repeatedly said when he bought his home 40-plus years ago, he was shown an easement on his property deed and told the tributary was a protected “C1” waterway.
Township Council also recently directed its attorney, Ken Poller, to conduct a title search in mid-March on Agnello’s property to see if an easement could be found. Poller has yet to report on that, at least in open session.
Following Boswell Engineering’s review of data used to determine the unnamed tributary’s drainage area, Township Engineer Kevin Boswell said that the LIDAR data used by Najarian Associates, Eatontown, was based on U.S. Geologic Service (USGS) LIDAR data available on the state Department of Environmental Protection website.
He said Najarian did not create its own LIDAR data
Agnello had pointed out — after consulting with a local engineer — that he believed the LIDAR data was developed by Najarian and not a government agency as the DEP Flood Hazard Area Act Technical Manual states is required. Boswell said that the LIDAR data used by Najarian Associates was publicly available on the DEP site.
LIDAR (Light Detection and Ranging) data is gathered from aerial sources (drones, planes, and helicopters) that works on the principle of radar, but uses light from a laser. The laser bounces back off ground elevations to provide an accurate measure of ground contours and elevations, helping to outline the areas draining into a waterway or waterway segment.
Based on the LIDAR data submitted by Najarian in 2019 to NJDEP that showed a 48.2-acre drainage area, the DEP ruled in January 2020 that the tributary behind Agnello’s home was not regulated and did not have a riparian area associated with it.
In 2011, using topographical maps that are less precise than LIDAR mapping, said Boswell, a prior township engineer submitted maps showing the waterway’s drainage area to be greater than 50 acres. At that point, NJDEP used that data to determine the waterway was a protected “C1” waterway.
Boswell said the two calculations run by Boswell engineers, using USGS LIDAR data available on the DEP website, showed a drainage basin of either 48.830 or 48.832 acres. Both were less than the 50 acres required to make the stream segment a regulated waterway, he said.
Boswell said that his firm reviewed mapping data, including LIDAR data, available on the DEP website. He said 2019 LIDAR data shows 1-foot contours (elevations) on the ground, which means the contours are “accurate plus or minus 6 inches” and LIDAR data is more accurate than that, he added.
He said the difference in Boswell’s two data modeling results, 48.83 acres and 48.832 acres, was due to identifying all breaks and ridges, which added approximately 60% of an acre to initial calculations. He told the council that both results “showed definitively less than 50 acres.”
Council/Public Questions
Agnello wondered why Boswell did not use the USGS StreamStats data, which showed the drainage basin at 58.8 acres in size, as recommended in the DEP technical manual.
Boswell said the DEP manual noted that applicants could obtain “more specific data” from other data sources, such as LIDAR data.
Boswell said he agreed that the USGS StreamStats data showed a larger drainage basin, which used 10-foot elevation contours. However, he said the LIDAR data used 1-foot elevation contours and was “most precise” showing a 48.832-acre drainage basin.
Councilwoman Stacey Feeney wondered if there were “other factors” besides a 50-acre drainage basin that go into determining whether a waterway is a C1 waterway. She asked Boswell what about a waterway that was close to 50 acres.
Boswell noted DEP has regulated and non-regulated areas, including wetlands, riparian areas, open waters, floodplains, floodways, and threatened and endangered species.
However, Boswell said, referring to the unnamed tributary, that the “threshold question of (regulated) applicability or not” is a minimum 50-acre drainage basin. He noted that on one side of a road where a waterway runs could be a regulated waterway, and on the other side where it runs, it may not be a regulated waterway.
He said in January 2020, the NJDEP determined that — based on LIDAR data — the unnamed tributary behind the proposed Four Seasons Marketplace strip mall was not a regulated waterway
Councilman Tom Sears noted that three sets of data were used by engineers to make determinations whether the waterway was regulated or not regulated over the years. “Kind of confusing, don’t you think?” he said to Boswell.
He said that “it seems kind of odd” that three engineers’ calculations went from 58 acres to 48 acres, adding that when a resident asks if he can fill in the same unregulated waterway, officials say that cannot be done. He wondered if the township should hire another engineer to look at the various data used to calculate the drainage basin.
Boswell said he was “very confident” that the unnamed tributary was not a regulated waterway based on Boswell’s LIDAR data review and calculations.However, he said, ”Please don’t say that I’m saying they’re not protected,” then added,“It may not be a regulated waterway by the DEP.”
Burke Street resident James Walsh told Boswell that local officials had agreed that some areas of Northgate Condominium complex that drained to the unnamed tributary were not included on the drainage maps.
Boswell said he reviewed the areas and said that they were excluded because the storm drain system was not designed for a “100-year” storm, noting most street storm drains are designed for so-called “10-year” and “25-year” storms. These are storms identified as occurring only once in a 10-year or once in a 25-year period. He said the 100-year storm threshold was in the NJDEP Technical Manual on Flood Hazard Area Act Determination criteria.