THE USE OF SPREADSHEET PROGRAMS AS A TOOL IN RESERVOIRDESIGN AND OPTIMIZATION

摘要

The rapid increase in population in the central and southern regions of Florida has forced water supply utilities to identify increased water storage capacity. Florida does not typically come to mind when dams and reservoirs are discussed, and historically there has been only limited construction of new storage reservoirs in the peninsula of Florida due to the little topographic relief of the area. Consequently there are few obvious sites for construction of an impoundment across a drainage channel, particularly in the near-coast areas. A feasibility study involving detailed evaluations of reservoirs with four different net storage capacities (ranging from 6,000 acre-feet to 18,000 acre-feet) was recently performed to identify an optimal off-stream, above-ground reservoir in southwestern Florida to address the increasing water requirements of the region. Considering the site conditions (e.g. topography, embankment construction material, seepage, and evaporation), a multitude of embankment geometry alternatives were initially postulated to provide the required storage volume. However, an efficient and logical storage reservoir geometry satisfying the site conditions and requirements was not obvious. Therefore, a series of detailed spreadsheets with associated plots was developed and calibrated for each storage size to optimize the design of the embankment cross-section and footprint. Evaluation of each of the alternatives considered a number of factors including embankment dimensions such as crest width, freeboard, slopes, and internal zoning; spoil and borrow quantities; seepage and evaporative losses; and reservoir footprint alternatives as well as estimates of unit prices of the primary construction features. Based on an evaluation of the alternatives, investigation and final design were performed for the resulting optimized configuration. Final design is underway with construction slated to begin in 2007. The optimized reservoir design is an 18,000 acre-foot balanced cut and fill earth embankment approximately 40 feet high with a geomembrane core, a slurry cutoff wall, and chimney and finger drains.