Drought Management Plan
The New York City Drought Management Plan has three phases - Drought Watch,
Drought Warning and Drought Emergency - that are invoked sequentially as conditions
dictate. The Drought Emergency phase is further subdivided into four stages
with increasingly severe mandated use restrictions. Guidelines have been established
to identify when a Drought Watch, Warning or Emergency should be declared
and when the appropriate responses should be implemented. These guidelines
are based on factors such as prevalent hydrological and meteorological conditions,
as well as certain operational considerations. In some cases, other circumstances
may influence the timing of drought declarations.
A Drought Watch is declared when there is less than a 50% probability that
either of the two largest reservoir systems, the Delaware (Cannonsville,
Neversink, Pepacton, and Rondout Reservoirs) or the Catskill (Ashokan, and
Schoharie Reservoirs), will fill by June 1 - the start of the water-year.
Drought Warning is declared when there is less than a 33% probability
that either the Catskill or Delaware Systems will fill by June 1.
A Drought Emergency is declared when there is a reasonable probability
that, without the implementation of stringent measures to reduce consumption,
a protracted dry period would cause the City's reservoirs to be drained.
This probability is estimated during dry periods in consultation with the
New York State Drought Management Task Force and the New York State Disaster
Preparedness Commission. The estimation is based on analyses of the historical
record, the pattern of the dry period months, water quality, subsystem storage
balances, delivery system status, system construction, maintenance operations,
snow cover, precipitation patterns, use forecasts, and other factors. Because
no two droughts have identical characteristics, no single probability profile
can be identified in advance that would generally apply to the declaration
of a drought emergency.
For a complete copy (22 pages) of the the Drought Management Plan and Rules,
download this PDF file:
Drought Plan (PDF)