Tampa Bay Regional Drought Index (September 10, 2007)

CLEARWATER (September 10, 2007)—Sporadic summer rainfall patterns to-date have not yielded expected river flows, which continues to negatively affect surface water availability and regional storage conditions. Long-term below normal rainfall from October 2005 through August 2007 in the Hillsborough River and Alafia River watersheds have produced long-term below normal streamflows through August.  Due to these deficits, the Southwest Florida Water Management District issued two Executive Orders to Tampa Bay Water which increased surface water yields beginning on July 28 and continuing through August. This has allowed surface water storage optimization to occur. Even with additional withdrawals, long-term below normal surface water conditions continue to affect surface water supply storage.

Regional water facts for August:

• Flows in the Hillsborough and Alafia River’s were both slightly greater than 50 percent below normal.  
• Regional water demand in August was over 251 million gallons per day (mgd) due to inconsistent rainfall, but declined on individual days (ex: 219 mgd on August 2) due to rainfall and reduced irrigation.
• The C.W. Bill Young Regional Reservoir has supplied nearly 11 billion gallons of water for treatment and distribution to the region to date in Water Year 2007. As of August 31, 2007, about 6.31 billion gallons of water was stored in the Regional Reservoir.
• To store at least 9 billion gallons in Reservoir for use next year, daily influent rates into the reservoir need to exceed 100 million gallons for 27 days.
• Early September reservoir influent rates have dropped to less than 70 million gallons per day on September 5.  Long-term withdrawal rates average over 182 million gallons per day in September.

Above normal river flows will be needed for the next five or six months to totally bring reservoir and river supplies back to pre-drought conditions. Tampa Bay Water issued a Level III Water Supply Crisis in June, requesting the cities of Tampa, St. Petersburg, New Port Richey and counties of Hillsborough, Pinellas and Pasco to reduce demand and increase enforcement of water restrictions.  The Southwest Florida Water Management District area remains in a Level II Water Shortage.

For more information contact Dave Bracciano or Alison Adams at 727.796.2355.