29 March 2005. A writes:
On the high hazard dams in NYC, Ridgewood Reservoir is empty, and has been
off line for years. Onassis Reservoir in Central Park is also no
longer a source. Silver Lake Reservoir is now just a lake, but there
is a reservoir underneath it (the largest underground water tanks in
the world, I think.)
25 September 2003. See related New York City Water Reservoirs:
Add Hillview Reservoir.
20 April 2003
Source of photos and maps: Mapquest.com
National Inventory of Dams Data Status
September 2002 - NID Web Site re-opened to all users.
October 2001 - NID Web Site restricted to government (.mil, .gov,
.fed.us domains) users.
National Inventory of Dams Inclusion Criteria
For defintions of hazard, please use data dictionary:
Downstream Hazard Potential
Code indicating the potential hazard to the downstream area resulting from
failure or misoperation of the dam or facilities:
L for Low;
S for Significant;
H for High.
Definitions, as accepted by the Interagency Committee on Dam Safety, are
1. LOW HAZARD POTENTIAL -- Dams assigned the low hazard potential classification
are those where failure or misoperation results in no probable loss of human
life and low economic and/or environmental losses. Losses are principally
limited to the owners property.
2. SIGNIFICANT HAZARD POTENTIAL -- Dams assigned the significant hazard potential
classification are those dams where failure or misoperation results in no
probable loss of human life but can cause economic loss, environment damage,
disruption of lifeline facilities, or impact other concerns. Significant
hazard potential classification dams are often located in predominantly rural
or agricultural areas but could be located in areas with population and
3. HIGH HAZARD POTENTIAL -- Dams assigned the high hazard potential
classification are those where failure or misoperation will probably cause
loss of human life.
High hazard dams shown are designated by the US Army Corps of Engineers on
the National Inventory of Dams database.
The relatively small number of high hazard dams in New York City is due to
most of the city's water coming from large upstate New York reservoirs through
large water tunnels. Tunnels 1 and 2 are built, Tunnel 3 is under construction.