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geer > 2000 > poster > synthesis on the impact of 20th century water-management and land-use practices on the coastal hydrology of southeastern florida > temporal changes in the ground-water flow system
Synthesis On The Impact of 20th Century Water-Management And Land-Use Practices On The Coastal Hydrology Of Southeastern Florida
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Water-table contour maps shown here illustrate five-year 'average' conditions that existed during the months of October 1940-44 and October 1990-94. Accordingly, the reader should be careful not to confuse these maps with synoptic potentiometric surface maps. In southeastern Florida, water levels are highest in September or October and lowest during April or May. A five-year interval of time was used to dampen or smooth the effect of unusually wet or dry months.
Maps showing average conditions were prepared to examine temporal and spatial changes in the flow system resulting from development of the present-day surface water conveyance system. The October 1940-44 map shows conditions prior to development of that conveyance system. In the early 1940's, the levee system, most canals, water conservations areas, and gated salinity control structures had not been constructed. By 1990-94, the water management system evolved to include hydraulic control structures, and a system of levees, impoundments, and conveyance canals affecting both the altitude and configuration of the water table. Such features were designed to control flooding in urban and agricultural areas during the rainy season, impound water and provide recharge to the underlying aquifer, retard the inland advance of the saltwater within the aquifer, and provide adequate municipal and agricultural water supplies.
Note: The information in this legend relates to the four maps below
A well hydrograph can illustrates only the temporal change in ground-water levels at only a single site. Maps shown here illustrate both temporal and spatial water level changes that occurred during the last 60 years of the 20th century. These maps illustrate the temporal change in 'five-year average' water levels that occurred between 1990-94 and 1940-44, 1990-94 and illustrate the temporal change in 'five-year average' water levels that occurred between 1990-94 and 1940-44, 1990-94 and October 1990-94 appear to have declined in large inland areas when compared to the average conditions that existed during the months of April 1940-44 or October 1940-44. This is assumed to be the result of water management efforts to control urban and agricultural flooding. Water levels along the coast seem to be, on average, higher during the 1990-94. This is assumed to be the result of water management efforts to control saltwater intrusion. Conversely, a comparison of water level maps for October 1970-74 and October 1990-94 suggests that, on average, similar hydrologic conditions existed in Broward and Miami-Dade Counties. Conditions appear to be more variable in Palm Beach County on the basis of this same comparison.
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U.S. Department of the Interior, U.S. Geological Survey
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Last updated: 04 September, 2013 @ 02:07 PM (KP)
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