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Kimley»>Horn February 24, 2022 Mr. Terry Southard Operations Manager Indian River County, Department of Utility Services 4350 4151 Street Vero Beach, Florida 32960 RE: Wellfield Feasibility Expansion - Change Order No. 1 All Webbs Enterprises Dear Mr. Southard: In July 2021, All Webbs Enterprises, Inc. (AWE) was contracted to assist with a Wellfield Feasibility Expansion Study that included deepening two of the County's existing production wells from the Upper Floridan Aquifer (UFA) to the Avon Park Production Zone (APPZ)/Lower Floridan Aquifer (LFA). The goal of the project was to deepen production wells S1 (south wellfield) and N7 (north wellfield) to obtain representative water quality and production data from the lower aquifer, to facilitate long-term water supply planning efforts. AWE began the process of deepening S1 in October 2021; however, it was quickly discovered that the well was producing high volumes of sand during the drilling process and the well was determined to be unsuitable for further use. Given the condition of the well during drilling activities and the overall age of the well (constructed in 1982), the decision was made to halt the deepening activities and to plug and abandon the well. Well S1 has now been plugged and the County is making arrangements to drill a replacement well (S1 R) under a separate contract. As a result, the work completed to date, through restoration for the abandoned well site, totals $273,900 less than the originally budgeted amount. Plans were made in December 2021 to mobilize to Well N7 to complete the scope of work associated with deepening the well. It was discovered that three gopher tortoise burrows were located within 25 feet of the planned work area limits, and therefore required relocation of the tortoises. The permitting and relocation activities were performed by others under separate authorization; however, AWE agreed to set the silt fence required to exclude the tortoises from returning to the work area. The additional work associated with the silt fence installation is $4,000. In the course of permitting the discharge for the N7 deepening, the Indian River Farms Water Control District indicated that the permit would be contingent upon meeting two strict water quality parameters. Total dissolved solids (TDS) would not be permitted to exceed 1,250 ppm, and turbidity of the discharge would not be permitted to exceed the background turbidity of the receiving canal at the end of pipe (0 NTU above background). Complying with these conditions will require that discharge water be blended with raw water from the surrounding wells (via the raw water main) and require the installation of additional turbidity measures that were not accounted for in the original kimley horn.com 445 24111 Street, Suite 200, Vero Beach, Florida 32960 772 794 4100