Groundwater Supply Evaluation and Management Projects
City of Gallipolis, Ohio: This project included a groundwater resource exploration program to find a well-field site with the potential to produce at least 3.3 MGD for the City of Gallipolis. The exploration phase involved a review of available information to identify potentially suitable areas in the alluvial aquifer adjacent to the Ohio River. Five potential well-field sites were selected and option/access agreements were negotiated with the land owners. Test borings were drilled at each site and the results were used to rank the sites in order of preference based on hydrogeologic considerations. The most promising site was selected, a test well and observation wells were installed, and a 72-hour aquifer test was performed. The test data were analyzed to determine the hydraulic characteristics of the aquifer and to assess the recharge potentially available. The site was considered acceptable and construction specifications were prepared for a well field consisting of five 18 x 36-inch gravel pack wells. The wells were installed using reverse rotary drilling methods and construction supervision was provided. Supervision also was provided for well development and acceptance tests, and a program for operation, management, and maintenance of the well field was prepared.
Indiana American Water – Noblesville System: Eagon & Associates has been involved with the INAW Noblesville water supply system for many years. We assisted in exploratory drilling and aquifer testing and evaluation that led to the development of the White River North Well Field. Two wells were initially installed, and we have been involved with the siting, design, construction, and testing of three additional wells since the initial development of the well field. More recently, we have assisted INAW with additional exploratory drilling that has led to the development of the Riverwood Well Field and the identification of at least one other potential location for future expansion of the water-supply capacity. The groundwater flow model used for the initial well-field capacity evaluation has been continually revised and recalibrated to new hydrogeologic data from test drilling and aquifer testing. The model has been used for the wellhead protection area delineation for the White River North and Riverwood Well Fields. Eagon & Associates also performed a potential contaminant source inventory for the White River North and Riverwood Well Fields and performed a residential well survey for the Riverwood Well Field. We maintain pressure transducers and data loggers at the White River North Well Field and the Riverwood Well Field. The water-level database is used to aid in well-field management, along with the residential survey data and ongoing water-level monitoring at residential wells, will be used to assess any potential problems at the residential wells that could result from pumping at the INAW well fields.
Indiana American Water – Babb/Shaw Well Field, Jeffersonville, Indiana: Eagon & Associates completed a groundwater flow model analysis to evaluate the feasibility and property acquisition requirements to expand the existing Babb Well Field to over 25 MGD. The hydrogeologic setting is the Ohio River Valley Aquifer. We completed a model analysis based on available information and defined a conceptual layout for the expansion. We submitted a Wellhead Protection Area delineation for a well field with a total of 17 wells to IDEM in order to get new well-site approval for 12 new wells. Additional test holes were drilled to verify geologic information and a 36 x 54-inch well was installed. A 72-hour pumping test was performed to determine the rate of induced river infiltration, and refine well design and spacing for the new wells. We designed and provided oversight for the construction and testing of eight new 36 x 54-inch wells with sustainable capacities ranging from 1,400 to 1,750 gpm. We provided design criteria for an additional well at the well field and performed an updated evaluation of well performance and well-field capacity.
City of Springfield, Ohio: This project involved preparation of technical specifications for installation of pilot wells and supervision of test drilling. Data generated by test drilling was analyzed along with data from previous investigations and performance data for existing wells in order to determine the optimum location for two new production wells. Based on this analysis, Eagon & Associates prepared technical specifications for construction of the new production wells. The wells were 30 x 42-inch gravel pack construction, 110 feet deep, and equipped with 45 feet of stainless steel screen. Eagon & Associates provided oversight of well construction, approved final selection of screen slot size and gravel pack, supervised the well development, and collected water-level data during the acceptance pumping tests. Reports were prepared detailing well performance characteristics to be used as a baseline for the evaluation of future performance and well efficiency.
Indiana American Water – Warsaw System: This well field will provide expanded capacity to meet projected future demands in the Warsaw area and will allow INAW to remove two obsolete well fields from service. Investigations for the new well field began with the completion of 11 test borings and a 20-inch diameter test/production well. A 72-hour pumping test was completed and the results of the pumping test and the test-boring data were used in conjunction with other available hydrogeologic data to construct and calibrate a groundwater flow model. The model was used to evaluate well-field capacity and to aid in the determination of optimal well locations and spacing to achieve the desired capacity. The new well-field property includes an area of high quality forested wetlands, and permits were required from the US Army Corp of Engineers (USACE) (Clean Water Act (CWA) Section 404) and IDEM (CWA Section 401). Eagon & Associates performed investigations of soil conditions in the wetlands, analyzed river-flow data and aquifer recharge, and performed additional groundwater flow modeling to evaluate the potential impact that production from the new well field could have on river flow and the wetlands. The groundwater flow model also was used to evaluate potential alternative well-field locations in support of the wetland permits. These investigations and efforts were significant in demonstrating that operation of the well field would have a minimal impact on the wetlands and river flow, and INAW was able to obtain authorization for the project from USACE under a regional general permit without the need for mitigation or monitoring. This allowed INAW to meet their commitments relative to completion of the new water supply facility. Work continues with well construction supervision and well performance testing of three additional wells at the new well field.
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