Background and Issue Summary

Background and Issue Summary

The City of New York operates the Schoharie Reservoir, impounded by the Gilboa Dam on the Schoharie Creek. Reservoir capacity is about 20 billion gallons.^A The dam is 2,000 feet long and 182 feet high. The reservoir is 5.8 miles long and has a maximum depth of 150 feet. The dam was completed in 1926.^B The river floods periodically due to weather conditions.^C Floods were regular and severe for hundreds of years before construction of dams.^D

In 1997 the city DEP made renovation of this dam a No. 1 priority and planned to start the work in the 2002-2004 period.^E In 2001, the New York City Department of Environmental Protection analyzed the possibility of a major dam failure and had "dam break analysis" maps prepared showing the projected extent of flooding.^F In 2003 a city engineer co-authored a paper titled "Stability Analysis and Interim Safety Improvements Gilboa Dam Spillway, Schoharie Reservoir, New York," presented at the U.S. Society of Dams conference in South Carolina.^G  Years later, on 25 October 2005, the city issued a Public Advisory stating "recent investigations reveal that safety factors associated with modern engineering practices are not met by the Dam in its present state." City officials met with local officials and said they would make emergency repairs in the spring of 2006.^H

The New York Power Authority operates the Blenheim-Gilboa Reservoir with a smaller dam 5.3 miles downstream from the city's Schoharie Reservoir. Failure of the Gilboa Dam is projected to impact the Blenheim Gilboa Reservoir in 15 minutes.^M NYC DEP engineers say their dam-break flood projections assume their flood will wipe out the B-G dam and the B-G water will add to the NYC water.

Thousands of people^N live in the Schoharie Valley downstream of the dam. Many fear dam failure. In recent history, many American dams have broken including in 1963, 1972^O and 2005.^P Rumors circulated concerning the dam's condition and stability, and the degree of danger and severity of flooding likely in event of a major dam failure. Emergency response preparations commenced.^Q

Public meetings were held on the issue.^R Residents^I and federal^J state^K and local officials^L howled in protest and many demanded work begin sooner. This Web site was established to publish as much reliable information as we can obtain. We will also publish responsible public comment and questions. Residents demanded immediate drawdown and suggested using siphons. The city balked but eventually agreed and installed siphons.

Preliminary repair work began December 15, 2005, and the emergency repairs began on December 19 when D.A. Collins Co. commenced installation of a floating debris boom to keep flotsam from the work area. On January 7, 2006, Collins started installation of the siphons. Work has been interrupted by high water. In December, 2006, the city completed the installation of 80 massive cables to anchor the dam into the bedrock. Additional repairs are to be made over the next several years.

End of Background & Summary

NOTES TO BACKGROUND AND SUMMARY

Note A.  25 October 2005 Public Advisory states capacity is 19.5 billion gallons. See other calculations and comment.

Note B. Catskill Center for Conservation and Development article

Note C. National Weather Service Advance Hydrologic Prediction which states the greatest flood occurred 19 January 1996 [a federal disaster was declared downstream from the dam]. The second- and third-ranked floods occurred on 16 October 1955 and 4 April 1987 respectively. The 3 April 2005 flood was the fourth greatest.

Note D. Article from fall 1996 Schoharie County Historical Review.

Note E. My research.

Note F. 2001 map.

Note G. New York City engineer Paul Costa was a co-author of a paper titled "Stability Analysis and Interim Safety Improvements Gilboa Dam Spillway, Schoharie Reservoir, New York" given at the 23rd annual United States Society on Dams conference at Charleston, South Carolina, on April 14-18, 2003. The conference theme was "Reducing Risk from Extreme Events" Costa was then an Executive Project Manager for NYC DEP. Paul attended several of the recent public meetings on the Gilboa Dam issue including Middleburgh on November 15 2005. He said he's in charge of the project design.

Note H. Comment in city's October 25 2005 N.Y.C. Advisory.

Note I. November blog.

Note J. Sens. Charles Schumer, Hillary Clinton and Rep. Michael McNulty.

Note K. Sen. James Seward. Gov. Pataki has been silent on the New York State issue while campaigning in New Hampshire.

Note L. Too many to list here. County government, which underfunded the Emergency Management Office for years and placed EMO in charge of operating duplicating machines, was caught with outdated, inadequate and/or non-existent emergency plans.

Note M. Tables on 2001 Dam Break Analysis maps

Note N. The 2000 census for the towns of Blenheim, Fulton, Middleburgh and Schoharie totals 8,639 people.

Note O. History Channel documentary. Ordering information in Historical Facts table below.

Note P. NYS DEC report

Note Q. Schoharie County Emergency Management is arranging new evacuation shelters on higher ground and the Red Cross has moved a supply trailer to a nearby site. A variety of other measures were taken.

Note R. Middleburgh Nov. 15 2005, County Board Nov. 18 2005, Fultonham Nov. 22 2005, others

Schoharie Valley Flood History