APRIL PEARL RIVER FLOOD OF 1979
"EASTER FLOOD OF 1979"

Service Improvements since 1979 Flood

  • Coordination Conference Call is initiated by the National Weather Service in Jackson, MS when inflows or discharges out of Ross Barnett Reservoir are expected to exceed 30,000 cubic feet per second. The conference call brings together the United States Army Corps of Engineers (Vicksburg District), Lower Mississippi River Forecast Center (Slidell, LA), PRVWSD, United States eological Survey (Mississippi District) and the National Weather Service Forecast Office (Jackson, MS). This conference call is designed for each agency to share information relating to flood forecasts and to provide coordinated information for the Pearl River Valley Water Supply District to use in its regulation of the Ross Barnett Reservoir.

     

  • During the 1979 flood, there were very few real-time rain gages. Most rainfall reports were called into the National Weather Service once or twice daily by Cooperative Observers. Since 1979, the National Weather Service has increased the number of Cooperative Observers in the Pearl River Basin. Also, the National Weather Service, United States Geological Survey (Mississippi District) and the PRVWSD have added more automated tipping bucket and weighing rain gages. The Mississippi Forestry Commission and National Park Service, as a part of their RAWS programs (fire weather observation network), have, in recent years, added real-time automated tipping bucket rain gages in or near the Pearl Basin.

     

  • During the 1979 flood, some of the river gages did not have telemetry; therefore, real-time river gage reports were impossible to obtain. Cooperative Observers manually read a wire weight gage and phoned the report into the National Weather Service. Today, several new river gages have been added to the network. All gages in the Pearl Basin are automated and report every 4 hours by satellite telemetry. These gages are funded by the Mississippi District of the United States Geological Survey , Pearl River Basin Development District, and the Pearl River Valley Water Supply District. The river gages are maintained by the United States Geological Survey.

     

  • New reservoir inflow models have been developed by the United States Army Corps of Engineers for the PRWVSD. Operation of these models helps PRVWSD optimize reservoir discharges for flood control and to prevent bank caving below the river.

     

  • The National Weather Service spent millions of dollars in the 80s and early 90s developing the WSR-88D, Doppler Radar System. This system is a valuable source for detection of severe weather within Mississippi. For river forecast operations, the WSR-88D radar is also able to produce reliable rainfall estimates over the Pearl River Basin. These rainfall estimates can be input directly into the Lower Mississippi River Forecast Center's river forecasting models.

     

  • Also, the National Weather Service has spent millions of dollars upgrading computer systems and infusing new technologies into weather and hydrologic forecasts. The Advanced Hydrologic Prediction Service (AHPS) is the National Weather Service's frontline solution to provide improved river and flood forecasting and water information across Mississippi. Since 1979, the Lower Mississippi River Forecast Center has increased its staff and upgraded its river forecasting models to provide more timely and accurate flood forecasts for the Pearl River Basin. The National Weather Service in Jackson, MS, through the use of new technologies, is able to monitor rainfall and river gages in near real-time. The internet and increased power and coverage of NOAA weather radio in the Pearl River Basin has allowed the dissemination of flood information more effectively to the public and to local Emergency Managers.

     

  • The Fortification Street ramp onto I-55 was built up to keep flood waters from entering downtown Jackson. In 1979, water flowed over the Fortification Street ramp, which is part of the downtown levee system.

     

  • Since 1979, counties and cities along the river have increased their participation in the Federal Flood Insurance Program.

     

  • A new river gage was added in the 1980s on the Pearl River at Rockport, MS. This gage was activated as a result of the 1979 and the 1983 floods. This gage was used by the Lower Mississippi River Forecast Center to produce more timely and accurate forecasts along the Lower Pearl River. The automated Rockport gage lost funding and was closed a few years ago. There is a staff gage read by an observer currently in Rockport, but not having a automated Rockport gage limits accurate river height measurements and forecasting downstream.

     


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