AWWA SOURCES59190

Tampa Bay Water, Florida's largest wholesale public water supplier, has historically relied ongroundwater to meet approximately 70 percent of the region's public water supply needs of240 million gallons per day (mgd). The state has mandated a reduction in groundwater usebecause of environmental effects observed near the wellfields. The 2000 through 2001 droughtmagnified the importance of a reliable water supply in the Tampa Bay, Florida, region to meetcurrent and future municipal water supply needs. To meet current and future demands and todiversify their water supply, Tampa Bay Water has developed new surface water supplies as analternative source. Tampa Bay Water has also developed other sources from desalinization ofseawater and through system interconnections.New surface water sources were made operational beginning in 2002 to replace traditionalgroundwater. Unlike groundwater supplies, the natural variability in surface water flows hascaused new challenges in developing long-term plans. Tampa Bay Water's Enhanced SurfaceWater System (ESWS) is composed of withdrawals from two rivers and a 15-billion-gallon offlinestorage reservoir. The surface withdrawals are operational and the reservoir is currentlyunder construction.This paper describes a combination of statistical methods that were applied for evaluating futurewater supply availability. These statistical methods included long-term trend analysis, seasonalanalysis using Fast Fourier Transforms (FFT), time series analysis using Box-Jenkinsautoregressive, integrated, moving-average (ARIMA) modeling, and Monte Carlo simulations.Mathematical models of the 25-year forecast for the ESWS were developed, including errorbounds. The availability or non-availability of the large reservoir was also analyzed to determineits impact on reducing variability. The reservoir dramatically altered the expected supply timeseries characteristics; however, these statistical approaches were still applicable in this situation.This work was used by Tampa Bay Water to help plan for near-term and long-range capitalimprovements. Collectively, these models provide a thorough approach to analyze and representa highly variable and complex water supply system. Includes reference, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

01/11/2004

Number of Pages:

20

File Size:

1 file , 810 KB