Achievements in our first 2years

Written by; Gail Shaffer
Engineering Safety Standard Maximized for Dam Structure
DCC was adamant that New York City be required to ensure the highest possible safety standard in the renovation of Gilboa Dam. There is an engineering formula known as the Factor Of Safety (FOS) which, with the persistent urging of DCC, has been set at 1.5 / 2.0. Simply put, this safety standard --- higher than originally proposed by the City --- will ensure that the completed project will be 50% stronger than the forces created by the heaviest flood anticipated, and 100% stronger than forces created by a normal full pool of water reaching the breaking point.

Siphons
DCC advocated the installation of siphons at the dam, to proactively drain more water downstream to alleviate pressure on the dam and avoid flooding in high water episodes. After initial resistance, NYC agreed to this proposal and installed four large siphons, which, along with the notch carved into the dam face, have proven to be valuable components in alleviating high water problems.

Notch and Siphons for Flood Control to Remain for Duration of Project
The city’s original plan was to remove the siphons and replace the notch once the anchors had been fully installed. DCC requested that both the notch and the siphons remain in place until the long-term renovation project has been completed, to be used as needed to release water proactively within safety levels during high level episodes. The City has agreed to keep them operational for the duration of the project.

Anchors’ Integrity Ensured; Additional Anchor Installed
A major feature of the Interim Repairs done to the Gilboa Dam in 2007 was the installation of 80 post tensioned anchors, each consisting of a bundle of 58 braided steel cables. Then 8 cable strands broke from a bundle in one of the post tensioned anchors, DCC asked that an additional anchor (230’ long) be installed adjacent to the compromised anchor. The 79 anchors originally installed increased the Factor Of Safety significantly, this 80th anchor further reinforces the dam’s strength.

Greater Accountability by Government Agencies and Dam Owners
DCC has testified at public hearings for greater dam safety measures, and for strengthening the state Department of Environmental Conservation (DEC) division relating to oversight of dam safety. We were pleased that the state budget for FY 2007 added 12 additional positions to the dam inspection team, to ensure better oversight and avoid further dam catastrophes in New York State.

Flood Mitigation; Present
In the winter of 2006-2007, residents of Schoharie, Montgomery and Schenectady Counties faced flooding scares and problems due to NYC not responding to a plea for the engaging of the 4 siphons as a tool for flood mitigation. The icing of the siphons delayed the release of snow melt water due to problems in de-icing of the siphons.

In October of 2007 DCC requested, through the Board of Supervisors, NYCDEP use some means of preventing the siphons from icing such that the siphons could be used in mitigating floods due to snow melts. In December, NYCDEP engaged the siphons with a built in deicing mechanism and have run the siphons continuously. In conduction with the notch, these two methods of preemptively drawing down the Schoharie Reservoir have served as flood mitigation, this winter / spring and have worked.

Flood Mitigation; Future Design
Traditionally New York City had maintained that its sole responsibility was ensuring its water supply. The city have conceded responsibility for flood mitigation. DCC has persistently urged, through public hearing testimony and other advocacy, that the City be required to incorporate flood mitigation in the renovation. NYC, in a historic precedent, eventually committed publicly to incorporate flood mitigation mechanisms in the design for the long-term renovation project. This will provide future ability to drain down 90% of the reservoir in 10 days if necessary.

Low Level Water Releases
It is important that, in addition to the capacity to release water when the reservoir is at critical flood level, there also be in place mechanisms for low level releases to be made proactively and gradually, before a critical flood level is reached. The Federal Government has mandated that NYCDEP incorporate low-level release capability in the Future Design of the Gilboa Dam. This will provide future ability to drain down 90% of the reservoir in 10 days if necessary.

Critical Resource to County Emergency Efforts
DCC has been a resource in helping ensure public participation in emergency plans, including flood evacuation routes and signage, and distribution of critical information to the public. Most significantly, DCC pressed for and ultimately ensured the commitment by NYC to fully reimburse Schoharie County for the cost of emergency sirens in the valley, as well as for other emergency expenses.

Schoharie County Chamber of Commerce Community Leadership Award
DCC was honored in 2007 by the Chamber with its annual Leadership Award for its activities on behalf of the community.

Remaining challenges: Future Challenges that DCC --- with Your Help --- Must Aggressively Pursue