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Flood Forecasting


AHPS - Advanced Hydrologic Prediction Service

Advanced Hydrologic Prediction Service (AHPS) are a new and essential component of our Climate, Water, and Weather Services. AHPS is a web-based suite of accurate and information-rich forecast products. They display the magnitude and uncertainty of occurrence of floods or droughts, from hours to days and months, in advance. These graphical products are useful information and planning tools for many economic and emergency managers. These new products will enable government agencies, private institutions, and individuals to make more informed decisions about risk based policies and actions to mitigate the dangers posed by floods and droughts.

Understanding The River Flood Forecasting Process

Understanding the Uncertainties in the River Flood Forecast Process

National Weather Service: Severe weather forecasts, flood forecasts, rainfall amounts, and flash flood guidance information are received from the NWS. The FWS obtains this information through the Steuben and Chemung county EMOs, by phone, or by fax. Near real-time rain and river gauge data are available through NWS web pages on the Internet.

Flood Warning Service automated rain and stream gauges: The FWS owns and maintains a network of automated rain and stream gauges located throughout Chemung, Schuyler and Steuben Counties. At this time, there are 4 automated river gauges and 17 precipitation gauges. Data from these automated gauges are fed by telemetry to the FWS. The data are collected, tabulated, and plotted by two computer data base program systems (ALERT and GAGER). These data are also relayed by telemetry to the NWS office in Binghamton for use in preparing NWS flood forecasts.

Telemark river gauges: River level data are currently available from six Telemark gauges, four of which are located at the same points as the FWS river gauges. This data are accessed by telephone. Near real- time data from some of these gauges are posted on the Internet.

Corps of Engineers Baltimore computer database: Current and historical reservoir data for the Hammond, Tioga, Cowanesque, Almond, and Arkport dams are available from the COE computer database and by telephone. The database also includes data from precipitation and river gauges in the COE and Susquehanna River Basin systems. The COE computer database can be accessed by a direct log-on procedure or through the internet.

United States Geological Survey internet database: River stage and discharge data from river gauges in the Chemung River Basin in New York and Pennsylvania are posted on the internet and accessed through the USGS web page. This data is updated daily.

Volunteers and emergency personnel: Additional precipitation and river/stream data are available from volunteer rain and river staff gauge readers. An answering machine at the FWS forecast center is set up to receive this information and can be accessed remotely by telephone. Staff gauges are monitored by DEC-operations-staff and local emergency personnel during a flood. Water levels are reported to the DEC flood control office, the county EMO, and/or FWS.

The redundancy of data sources and methods for accessing this data is a key to the reliability of the overall system for flood warning.