Groundwater flow

The problem of solute transport through saturated porous media is considered in this thesis. The end application of this study is to evaluate the option of spray irrigation as a means of disposing reverse osmosis effluent. Reverse osmosis effluent was sprayed on an experimental field composed of typical area soil. The changes in groundwater quality were monitored at intervals of ten to twenty days. Applying the experimentally obtained data to a basic numerical model, which uses the convection-diffusion equation, the key parameter of the soil, D* the diffusion coefficient, is obtained for the Myakka sand. While the numerical model can predict the qualitative behavior of hardness and conductivity, hysteresis is observed for the response of the total organic carbon (TOC) content. Further studies are needed to understand and model the inherent capacitance of the soil for hardness and the observed hysteresis in TOC response.

This thesis presents a preliminary study on geochemical conditions within the Snapper Creek well field in Miami-Dade County, Florida. The study investigates the background groundwater chemistry within the Biscayne aquifer in order to provide information on the geochemical processes and water-rock interactions within the study site. In conjunction with hydraulic gradient information, major ion chemistry and deuterium and oxygen-18 data were used as environmental tracers to help describe the groundwater-surface water interactions between the well field and the Snapper Creek canal. Hydrologic data show there is potential for natural groundwater recharge from the canal within the shallow flow zone of the Biscayne aquifer and chemical data show evidence of canal-groundwater mixing within this zone. The limitations for the v environmental tracers employed within the study are addressed, as well as recommendations for further research involving natural geochemical tracers and groundwater-surface water interactions near municipal well fields. This study was part of a larger effort being conducted by the U.S. Geological Survey in order to assess municipal well field pumping effects on the Snapper Creek (C-2) canal.

Deep injection wells (DIW) in Florida are regulated by the U.S. Environmental Protection Agency (USEPA) and the state of Florida through the Underground Injection Control regulations contained within the Safe Drinking Water Act. Underground injection is defined as the injection of hazardous waste, nonhazardous waste, or municipal waste below the lowermost formation containing an underground source of drinking water within one-quarter mile of the wellbore. Municipalities in Florida have been using underground injection as an alternative to surface disposal of treated domestic wastewater for nearly 40 years. The research involved collecting data as of September, 2007 on all the Class I DIWs in the state of Florida and evaluating the differences between them. The analysis found regional differences in deep well practice and canonical correlation analyses concluded that depth below the USDW is the most significant factor to prevent upward migration of the injected fluid.