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INDIAN RIVER COUNTY, FLORIDA <br />MEMORANDUM <br />TO: <br />Jason E. Brown, County Administrator <br />THROUGH: <br />Richard B. Szpyrka P.E., Public Works Director <br />Vincent Burke, P.E., Utilities Director <br />FROM: <br />W. Keith McCully, P.E., Stormwater Engineer <br />Eric Charest, Environmental Compliance Specialist <br />SUBJECT: <br />Results of Phase 1 Water Quality Study of Nutrients in the Indian River Farms <br />Water Control District's 8th Street Canal <br />DATE: <br />March 2, 2018 <br />DESCRIPTION AND CONDITIONS <br />The following summarizes staff's investigation of nutrients in Indian River Farms Water Control District's <br />(IRFWCD) 8th Street Canal between 90th Avenue and 74th Avenue, as requested by the County Commission. <br />The primary purpose of the study was to determine if suspected seepage from the County's West Regional <br />Wastewater Treatment Facility's (WRWWTF) wetland system/deep settling pond or nearby artesian wells <br />may be entering the canal and adding nutrients, contributing to reported excessive aquatic plantgrowth in <br />the canal. The secondary purpose was to identify the source of any excessive nutrient loading in the canal. <br />As discussed below, results are inconclusive. <br />Initially, six sample locations were identified and nine water quality samples were taken from each location <br />between September 13, 2016 and November 1, 2016. These samples (Sample Group 1) were tested for <br />Total Nitrogen (TN), Total Kjeldahl Nitrogen (TKN), Nitrite -Nitrate Nitrogen (NOx), and Total Phosphorus <br />(TP). Results are shown in Table 1. Because the results of the original sample sets did not allow concrete <br />conclusions as to the source of nutrients, two additional sample sets were taken on July 20, 2017 and <br />August 11, 2017. The second group of samples (Sample Group 2) were taken from the original sample <br />locations and two new locations: the WRWWTF's Deep Settling Pond and a pipe discharging from private <br />property into the canal. Figure 1 shows sample locations for both sample groups. Sample Group 2 was <br />analyzed for NOx, Ammonia Nitrogen (NHA and Ortho -Phosphate (OP) and results are presented in Tables <br />2, 3, and 4. These three parameters were investigated because they are nitrogen and phosphorus <br />components of TN and TP that are readily assimilated by plants. The analysis of Sample Group 2 is also <br />inconclusive with respect to nutrient source, but it does indicate that WRWWTF's Deep Settling Pond / <br />wetland system is not contributing significant quantities of nutrients to the 81h Street Canal. <br />A summary of the entire investigation is presented in Exhibit 1, a memotitled "Results ofthe Phase 1 Water <br />Quality Study of the IRFWCD 8th Street Canal Between 90th Avenue and 74th Avenue" <br />Project costs to date are $3,598 for laboratory analysis. <br />28 <br />C:\Users\legistar\AppData\L.ocal\Temp\BCL Technologies\easyPDF 8\@BCL@740DFDD9\@BCL@74ODFDD9.doc <br />