Tuesday, August 16, 2011

North Hudson Sewerage Authority Publishes Memo on Hoboken Flooding

The North Hudson Sewer Authority (website: http://www.nhudsonsa.com/) has published this memo on August 15th in response to the flooding that occurred in Hoboken last week with near record rains being accumulated in the area....

August Flooding in Hoboken

From August 8th to 15th, the Authority’s service area was hit very hard by torrential rain storms, resulting in severe flooding in certain sections of Hoboken and, to a lesser extent, in “The Shades” area of Weehawken. In Hoboken, the intersections around Harrison and First Street, Jackson and 4th Street, and Madison and 9th Street experienced the worst of the street flooding, especially on August 14th when an incredible 5.81 inches of rain fell in a 19 hour period, beginning at 1:50 AM.
Flooding from 8-14-2011 by the Hoboken Shoprite. High tides plus a large downpour equals bad results for Hoboken.
Street flooding occurs in Hoboken, much of which is below sea level, when there are unusually heavy rains that fall when the Hudson River is at high tide. The rain water flows into the sewer system through outfalls into the River, but at high tide the water cannot empty into the Hudson. Consequently, the rain water backs up the sewer system until the system is completely filled with water, forcing it out into the lowest lying streets.

On August 14th, in the midst of the heavy rains, the tides were high not once, but twice: at 9:39 AM and again at 9:50 PM. Exacerbating the situation was the fact that the tides were extremely high, running at 5.1 feet, almost two feet higher than average Hudson River high tides.

The Authority is in the midst of a major initiative to alleviate the worst of the flooding in Hoboken, flooding that has been a problem for over 100 years. The strategy includes the following:

  • The thorough overhaul and relining of almost the entire Hoboken collection system. This first step was initiated several years ago and is substantially complete as of today. The last of the Civil War era wooden sewers is currently being replaced, with the work expected to be completed in the Spring of 2012. The total amount invested by the Authority in the rehabilitation of the Hoboken system has, to date, been approximately $40 million.
  • The construction of an $18 million wet weather pump station that is scheduled to be on line by the 4th Quarter of 2011. The pump station will be capable of forcing 100 million gallons of water per day into the Hudson River during rain events. To accelerate this project, the Authority authorized in July the doubling of the manpower needed to clean the outfall to the Hudson River. This difficult cleaning cannot be done by machines, but requires hand cleaning due to the conditions of the pipelines.
  • The analysis of the impact of the pump station on other areas in Hoboken. Once the pump station is on line, the low lying areas in the southwest sections of Hoboken should see major alleviation of flooding. Because the collection system in Hoboken is interconnected, the Authority’s engineers believe that other areas of Hoboken should also see mitigation of flooding. By the 1st Quarter of 2012, the Authority will begin to examine the extent to which storm water from other areas of Hoboken can be conveyed to the new pump station. If necessary, the Authority will take subsequent remedial construction and engineering steps to accomplish this.
The Authority, which services the populations of four communities, has made major investments in Hoboken’s long neglected wastewater infrastructure. It recognizes the severity of the flooding in the City. Its engineers have carefully studied the problem, and the Authority has initiated a comprehensive approach to solve the problem. We are acutely aware of the tremendous difficulties and inconveniences of the current flooding, and we are moving as rapidly as possible to implement our program.

Link to memo: http://www.nhudsonsa.com/images_subpages/August%20Flooding%20in%20Hoboken.pdf