Upper Greenwood Lake Downstream Face Maintenance and Improvement Scheme 2015


Andrew Quirk

The Regular Dam Inspection approved by the NJDEP Bureau of Dam Safety and Flood Control on Dec 14th 2014 made several recommendations that were addressed in the fall of 2015. The Upper Greenwood Lake (UGL) Board of Trustees voted to accept the recommendations of the UGL Dam Safety Committee’s proposed Downstream Face Maintenance and Improvement Scheme.

The Regular Report called for additional rip rap to be placed on the Upstream Face for a distance of 250 feet from the spillway and at a depth of 1 foot and extending 8 feet out from the overtopping wall. The new slope was required to be at a 2: 1 ratio. Jerry Cross, Engineer, provided advice and a sketch for the Contractor. He also met with the Contractor before the project began in October 2015 and was able to monitor the progress by way of receiving site photographs as the work proceeded and by phone conversations. A permit was obtained for a Lake Draw Down.

The Dec. 2014 report also noted the poor ability for the Dam Owner to assess animal burrows and potential sink holes on the downstream face, as the slope was made up of loose rocks in the form of rip rap. Similarly it was difficult and potentially dangerous for Dam Personnel to walk on the slope to clear weeds and vegetation and to access the Valve House. It was therefore decided to remove the Downstream Face rip rap and after cleaning and sorting the rocks, to relocate them to become the new required Upstream Face riprap. The Downstream face was then prepared in a similar and required 2:1 slope with dirt and topsoil. In order to allow for minimal and easy maintenance of this new slope, and to allow for greatly improved visual inspection of animal burrows, as called for in the Dec. 2014 report, it was decided to plant low growing (less than six inches) grass and wildflowers.

In addition, the Report called for the sinkhole at the toe of the downstream face of the Dam at the low level outlet to be repaired. This was addressed by the Contractor by creating a new pathway of stones and a rock border in the area of the low level outlet. The rocks chosen were large and heavy to deter vandals from throwing them into and blocking the outflow pipe which had occurred in previous years. Graffiti had also become a problem with very unsightly paint applied by vandals on the spillway walls. Therefore the area was cleaned, re-cemented, and new video cameras were installed. The cameras are able to zoom, tilt and pan and can be remotely accessed. This will be extremely useful in the event of major storms as the spillway flow can now be observed by iPhone or PC from the safety of indoors thereby giving greater ability to monitor the situation with reduced requirement for Dam Safety Committee personnel to be on the roads in the midst of a storm or when a State of Emergency has been declared. Additionally, two new floodlights were installed during the Improvement scheme to light up the Dam Complex, particularly the Spillway Walls. This required running new electrical power to the Valve House and Spillway walls from the Pavilion. During the trench digging for the conduit the top of the dam core cement wall was partially exposed, inspected and found to be in excellent condition. The new electrical power, inspected and passed by the West Milford Electrical Inspector, is important and extremely significant in many ways. For the first time it provides for illumination in the area when the valve is being opened or closed. Moreover, going forward it allows the Association the option of an electrical winch when the time comes to modernize or replace the 1930s original operator.
While the maintenance work was underway, two divers inspected the inflow pipe and measurements were taken for future reference. Previous reports had noted that the trash rack needed to be replaced so this process was commenced.

In conclusion, the work done at UGL Dam in the Fall of 2015 was performed to address and correct points raised in the Dec. 2014 Regular Inspection Report and consisted of maintenance and improvements which will greatly improve the safety of the volunteer Dam Personnel and allow for remote monitoring of the area to deter vandalism.

Andrew Quirk
Chairman of the UGL Dam Safety Committee.
May 2016.