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Harris County Flood Warning System

The Harris County Flood Control District in Texas was created in 1937 as a response to the devastating floods that struck the region between 1929 and 1935. The District's boundaries protect 3.7 million people and include the city of Houston. Twenty-two different watersheds are included in the district's boundaries, each with a unique set of monitoring challenges.

The District is using the "Flood Warning System" (FWS) to measure rainfall and water level amounts in real-time, to provide up-to-date flood information to the public. The installation of the FWS gauge system began in 1982, initially with 13 stations. Since then, the number of stations has grown to 139 stations, many of which use the OTT RLS and CBS water level sensors.

Non-contact bubbler in water level sensor for surface water monitoring

OTT CBS - Compact Bubbler Sensor

Non-contact, bubbler sensor for longterm surface water level monitoring

The OTT CBS is a compact, accurate, and low power bubbler sensor for surface or groundwater level monitoring.

  • Surface water Groundwater
  • Bubbler-in
  • Drift-free water level measurement - no pressure sensor or electronics in the water
  • 0 to 15 m or 0 to 30 m
  • ± 3 mm (high accuracy version); ± 5 mm (standard and 30 meter versions)
  • No
  • SDI-12, RS-485 (using SDI-12), or 4 ...20 mA
water level radar sensor for surface water applications

OTT RLS - Radar Level Sensor

Non-contact water level sensor for long term surface water measurements

The OTT RLS is a non-contact radar level sensor with pulse radar technology that is ideal for monitoring in remote or hard to reach locations.

  • Surface water
  • Water level / distance to water
  • Non-contact pulse radar
  • Measures water level or depth to water from a bridge, pier or mounting arm
  • 0.4 … 35 m
  • 0.8 … 2 m: ± 10 mm; 2 … 30 m: ± 3 mm; 30 … 35 m: ± 10 mm
  • No
  • SDI-12, RS-485 (using SDI-12), or 4 ...20 mA
  • 139 monitoring stations use a variety of water level measurement technologies, including OTT Radar Level Sensors (OTT RLS), OTT Compact Bubbler Sensors (CBS), and pressure transducers
  • The OTT RLS and CBS provide excellent non-contact water level measurement and are unaffected by rising flood waters
  • Data is transmitted in real-time and can be viewed on the Harris County Flood Warning System website here:
  • The flood warning information is also available to the public via a mobile app
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