Monday, April 20, 2009: 3:30 p.m.
Agave Ballroom (Hilton Tucson El Conquistador Golf & Tennis Resort )
The City of Cape Coral in coastal Southwest Florida has experienced meteoric growth from its founding in 1957 to a current population of 160,000. Limited fresh drinking water supplies forced the City to develop brackish sources from the Lower Hawthorn aquifer of the Upper Floridan aquifer (UFA), using RO treatment as early as 1976. The build-out population, estimated at 388,000, will require raw water supply in excess of 50 MGD.
The City currently supplies 70% of the population from one 18 MGD treatment plant, with the remaining 30% dependent upon domestic self supply wells. A second plant under construction will have a build-out capacity of 36 MGD, constructed in 12 MGD increments. A major water supply investigation and flow and solute modeling effort was conducted to determine if the Lower Hawthorn aquifer and deeper aquifers within the UFA can supply raw water through build-out, without causing salt water intrusion, or drawdown impacts to adjacent users.
Multiple withdrawal scenarios were run simulating projected demands through build-out, with production wells tapping the Lower Hawthorn and Suwannee Limestone permeable units of the UFA at different locations within the City. Model results indicate that the Lower Hawthorn aquifer in southern Cape Coral will experience significant drawdown and a salinity increase of 62% to 5,700 mg/L TDS, while the Lower Hawthorn aquifer in north cape Coral will experience moderate drawdown and a very moderate salinity increase of 6% to 1,800 mg/L TDS. Model results also indicate the Suwannee Limestone permeable unit layer, in northern Cape Coral will experience a salinity increase of 17% to 3,452 mg/L TDS, at build-out. The model results provide a basis for regulatory and wellfield operational approaches going forward with wellfield development that will not exceed the current treatment limits of the existing and planned treatment plants (approximately 4,000 mg/L).
The City currently supplies 70% of the population from one 18 MGD treatment plant, with the remaining 30% dependent upon domestic self supply wells. A second plant under construction will have a build-out capacity of 36 MGD, constructed in 12 MGD increments. A major water supply investigation and flow and solute modeling effort was conducted to determine if the Lower Hawthorn aquifer and deeper aquifers within the UFA can supply raw water through build-out, without causing salt water intrusion, or drawdown impacts to adjacent users.
Multiple withdrawal scenarios were run simulating projected demands through build-out, with production wells tapping the Lower Hawthorn and Suwannee Limestone permeable units of the UFA at different locations within the City. Model results indicate that the Lower Hawthorn aquifer in southern Cape Coral will experience significant drawdown and a salinity increase of 62% to 5,700 mg/L TDS, while the Lower Hawthorn aquifer in north cape Coral will experience moderate drawdown and a very moderate salinity increase of 6% to 1,800 mg/L TDS. Model results also indicate the Suwannee Limestone permeable unit layer, in northern Cape Coral will experience a salinity increase of 17% to 3,452 mg/L TDS, at build-out. The model results provide a basis for regulatory and wellfield operational approaches going forward with wellfield development that will not exceed the current treatment limits of the existing and planned treatment plants (approximately 4,000 mg/L).
See more of: Salinity Assessment and Management In Ground Water Basins II
See more of: Topical Sessions
See more of: Topical Sessions