Welcome to California Data Exchange Center

Overview of CDEC


The California Data Exchange Center (CDEC) installs, maintains, and operates an extensive hydrologic data collection network including automatic snow reporting gages for the Cooperative Snow Surveys Program and precipitation and river stage sensors for flood forecasting.

CDEC provides a centralized location to store and process real-time hydrologic information gathered by various cooperators throughout the State. CDEC then disseminates this information to the cooperators, public and private agencies, and news media.

CDEC Database System

The California Data Exchange Center (CDEC) collects, stores, disseminates, and exchanges hydrometeorological data and related information. The data collection began as a small system designed to obtain data urgently needed to provide river stage forecasts and flood warnings for the North Coastal area and for the Central Valley. In the beginning, data was obtained from less than 100 telemetered precipitation and stream gage stations.

Since then, real-time hydrometeorological data needs have continuously grown. Currently, numerous Federal, State, and local agencies collect data from hundreds of rain, snow, temperature, wind, atmospheric pressure, humidity, and stream stage sensors. The data enable forecasters to prepare flood forecasts and water supply forecasts; reservoir and hydroelectric operators to schedule reservoir releases; and water suppliers to anticipate water availability.

Currently, over one hundred and forty (140) agencies provide data to CDEC and also obtain data through CDEC's cooperative hydrologic database. The CDEC cooperative database contains information collected by:

  1. Eighty-nine (89) remote data stations that have six hundred and forty-nine (649) sensors transmitting over the State microwave system. Real-time data include river stages, precipitation amounts, snow water content, temperature, and water quality.
  2. Eight hundred and three (803) remote data stations that have 6,591 sensors transmitting via the GOES satellite.
  3. There are two hundred and eleven stations (211) that have 1,270 sensors which are transmitted via network from Federal, State, and other agencies via an automated data exchange program.

Data Exchange Program

CDEC operates a data exchange program with various Federal and State agencies and other public agencies. This data exchange program involves the automated transfer and receipt of data and information via network connections. Following are the major agencies involved in data exchange:
  • National Weather Service (NWS): weather forecasts, river bulletins, full weather data
  • U.S. Bureau of Reclamation (USBR): reservoir operations, reservoir summary reports
  • U.S. Army Corps of Engineers (USACE): precipitation, snow water content, reservoir operations, reservoir summary reports
  • Pacific Gas & Electric (PG&E): precipitation, snow water content
  • Sacramento Municipal Utility District (SMUD): precipitation, reservoir operations
  • U.S. Geological Survey (USGS): river gage data, river flow rating tables and shifts

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