Water Resources Research Act Program

Details for Project ID 2006FL147B

Development and documentation of upconing and drawdown models for regulatory use

Institute: Florida
Year Established: 2006 Start Date: 2006-03-01 End Date: 2007-02-28
Total Federal Funds: $6,000 Total Non-Federal Funds: $15,000

Principal Investigators: Louis Motz

Project Summary: In groundwater permit applications to water management districts in Florida, applicants may be required to address pumping impacts in terms of saltwater upconing and aquifer drawdowns. Extensive hydrogeological investigations that include numerical modeling may be required in some cases to address these issues. However, in other cases, analyses utilizing analytical modeling techniques may be sufficient to assess impacts. Also, analytical modeling techniques may be useful in screening for impacts and/or conducting preliminary investigations that may indicate the need for more detailed investigations. Currently, there is a lack of consistency in the analytical techniques used to make assessments of pumping impacts, and some of the techniques used may lack adequate documentation. An investigation has been proposed to the St. Johns River Water Management District (District) in which the objective will be to develop software and a users manual that will provide District personnel and permit applicants a means to quantify the impacts of saltwater upconing and wellfield pumping using consistent techniques that are based on documented analytical solutions. Four tasks are proposed to meet the project objectives. In the first two tasks, software that can be used to calculate saltwater upconing and drawdowns due to pumping from a two-layer aquifer system will be developed. Saltwater upconing will be simulated using steady-state, leaky-aquifer solutions for single and multiple wells (Motz 1992 and 1994). Drawdowns due to pumping from a two-layer aquifer system will be simulated using a transient two-layer coupled aquifer solution (Denis and Motz 1998). In both the first and second tasks, FORTRAN source codes and executable files will be written for single- and multiple-well applications, and beta versions will be provided to the District for review. Based on review of the beta versions by the District and benchmark testing by the University of Florida, final versions of the FORTRAN source codes and accompanying executable files for the saltwater upconing solution and the two-layer drawdown model will be developed. In the third task, a users manual will be prepared and submitted as a draft final report. In the fourth task, a final report that incorporates the review comments and suggested revisions resulting from the Districts review of the draft report will be prepared and submitted to the District. The users manual will include description of the saltwater upconing and drawdown problems, the solutions and equations used, a listing of the source codes, the results of the benchmark testing, and example problems to illustrate how to use the software. Electronic copies of the source codes, executable files, and input files for the benchmark and examples problems will be provided to the District.