New York is rich with water resources. Our celebrated streams, lakes, and coasts are fed by an average annual precipitation that ranges from 60 inches in the Catskills to 28 inches in the Lake Champlain Valley. But even here, in our "temperate moist" climate, normal fluctuations in regional weather
Cannonsville Reservoir. Lower photo
shows same view as upper except at
6.5% capacity (Dec 20, 2001)
patterns can lead to periods of dry weather. Occasional drought is a normal, recurrent feature of virtually every climate in the United States. The last severe droughts in New York occurred in the mid-1960s, and again in the early and mid-1980s.
What is Drought?
Meteorologists and hydrologists have their own precise definitions of drought. Meteorologists compare deficiencies in precipitation to normal levels when they speak of drought. Hydrologists consider stream flow and water levels in aquifers, lakes, and reservoirs along with precipitation. New York uses elements of both disciplines to determine when a drought is occurring.
The State Drought Index compares four parameters to historic or "normal" values to evaluate drought conditions: stream flows, precipitation, lake and reservoir storage levels, and groundwater levels. New York's Drought Management Task Force uses those factors as well as water use, duration of the dry period, and season to assess drought in different parts of the state.
New York also uses the Palmer Drought Index, a measure of soil moisture computed by the National Weather Service. The two indices reveal different aspects of drought. The Palmer Index, with its emphasis on soil moisture, is useful in exploring agricultural impacts. The State Index helps assess the impact on human welfare and the regional economy.
New York is divided into nine drought management regions based roughly on drainage basin (watershed) and county lines. DEC monitors precipitation, lake and reservoir levels, stream flow, and groundwater level at least monthly in each region and more frequently during periods of drought. DEC uses this data to assess the condition of each region, which can range from "normal" to "drought disaster."
Some areas of the state may make their own determinations of drought stage, using different criteria. For example, the New York City system relies largely on upstate reservoirs for its water supply. The City bases its assessment of drought conditions on the probability of the reservoirs being full by the following June.
Developed and implemented by the New York Drought Management Task Force, the State Drought Plan focuses on research, monitoring and possible legislative actions to help prevent and mitigate impacts from droughts. The Task Force coordinates actions prior to declaration of drought emergency, at which time the Disaster Preparedness Commission takes over.
The NYSDEC and USGS are partners in evaluating hydrologic conditions across New York State. Data evaluated includes stream discharge, water levels, precipitation, and components from water-quality monitors. This information and additional information from other Federal, State, and local agencies assist the NYSDEC and the State Drought Management Task Force in evaluating regional conditions for determination of drought classifications. The USGS maintains tables and reports of monthly hydrologic conditions (link leaves NYSDEC website). The map to the right shows the latest Hydrologic Conditions Network, which includes monitoring wells and stream gauging stations.
The Four Drought Stages and What They Mean
The Drought Plan describes the actions to be taken during each drought stage by water purveyors, towns and villages, water authorities, and other agencies with water supply responsibilities.
- Drought Watch - The least severe of the stages, a drought watch is declared when a drought is developing. Public water suppliers begin to conserve water and urge customers to reduce water use.
- Drought Warning - Voluntary water conservation is intensified. Public water suppliers and industries update and implement local drought contingency plans. Local agencies make plans in case of emergency declaration.
- Drought Emergency - The Governor may declare emergency. The Disaster Preparedness Commission coordinates response. Mandatory local/county water restrictions may be imposed. Communities may need to tap alternative water sources to avoid depleting water supplies, protect public health and provide for essential uses.
- Drought Disaster - Disaster plans are implemented. Water use is further restricted. The Governor may declare disaster and request federal disaster assistance. Emergency legislation may be enacted. The state provides equipment and technical assistance to communities.
More about Drought:
- Drought Conditions - Information updated during drought conditions.
- New York State Drought Management Regions - Map of New York State Drought Regions
- Hydrologic Conditions Network Map - This map shows the groundwater wells and stream gauging stations used by the USGS and DEC for analyzing drought conditions.