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EXHIBIT A CCNA-2018 WO NO. 5 AMENDMENT 1 FOR INDIAN RIVER COUNTY UTILITIES ADDITIONAL GROUNDWATER MODELING SIMULATIONS AND PREPARATION OF REVISED GROUNDWATER MODELING PLAN OF MODIFICATION OF WATER USE PERMIT NUMBER 10524 This Amendment, when executed, shall be incorporated in and become part of the Agreement for Professional Services (Contract #2018008) between Indian River County (OWNER), and CDM Smith Inc. (CONSULTANT), dated April 17, 2018, hereafter referred to as the Agreement. PROJECT BACKGROUND The OWNER owns and operates two Water Treatment Plants [WTPs], the South County WTP and North County WTP. The South County WTP withdraws groundwater from seven existing Upper Floridan Aquifer (UFA) production wells, while the North County WTP relies on groundwater from nine existing UFA production wells. OWNERS's existing Consumptive Use Permit (CUP) (10524) currently allows for a total combined groundwater withdrawal allocation of 12.838 million gallons per day [mgd], with 6.438 mgd from the North County wellfield and 6.40 mgd from the South County wellfield. The current CUP expires on October 11, 2031. OWNER has experienced an increase in demand due to population growth and domestic self -supply users switching over to OWNER's water supply. OWNER began a draft application requesting modification of the existing CUP to the St. Johns River Water Management District (SJRWMD) in 2016. Groundwater modeling was performed to determine if there would be impacts on the water resources, environment, or other permitted users due to the anticipated increases in OWNER withdrawals from the UFA. CONSULTANT used a modified version of the South Florida Water Management District (SFWMD) East Coast Floridan Aquifer Model (ECFM) to perform the impact analysis for the UFA. Since the ECFM did not include the Surficial Aquifer System (SAS), the SJRWMD Coupled Aquifer [COUAQ] model was used to determine the drawdown in the Surficial Aquifer System (SAS) due to increased pumping and groundwater level drawdown in the UFA. The groundwater modeling results and analysis were summarized in a report that along with the model input and output files were submitted to the SJRWMD in support of the draft CUP application. SJRWMD staff previously approved the model as the best tool available for UFA uses in the area and the results of the modeling and impact evaluations. Due to the resurgence of development, the OWNER must now modify the permit to account for the new and future demand projections. Based on actual groundwater withdrawals and an approximate 2 percent increase in demands over time (including an expanded service area), the 2050 demand was calculated to be 23.18 mgd. This is an increase from the existing EOP withdrawal of 12.838 mgd, which was used in the draft 2016 CUP application and the associated groundwater modeling and impact analysis. Additional modeling simulations are therefore necessary to determine whether the new CDM Smith Page 1 of 4 ii2688_ExhibltA.ao.x