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SUMMARY AND RECOMMENDATIONS The Phase 1 Study's goal was to test only basic parameters at strategic locations to quickly identify nutrient hot, spots in the canal, with a specific focus on the WRWWTF wetland/deep settling pond. Initial data indicates that canal NOx values begin increasing at Sample Point C and ramp up significantly between Sample Points D and E. Canal TKN values spike at Sample Point B and the highest TP occurs between Sample Points B and C. Most likely, discrete point sources are introducing NOx into the canal east of Sample Point C, although some NOx may be present due to conversion of ammonia nitrogen to NOx as part of the nitrogen cycle. Regarding TKN, it is necessary to determine what nitrogen forms are present that are contributing to the TKN totals. TKN is the sum of ammonia nitrogen and organic nitrogen. Ammonia nitrogen is biologically active and readily utilized by plants, while organic nitrogen is not. Therefore, it is useful to identify sources contributing ammonia nitrogen to the canal. Similarly, only the ortho-phosphorus (inorganic phosphorus) component of TP is readily available for uptake by plants. Therefore, average ortho-phosphorus concentrations must be determined to identify likely contributing sources. While the Phase 1 Study collected significant data, staff realized that a more detailed breakdown of canal water nitrogen and phosphorus elements is necessary in order to draw defensible conclusions regarding nutrient sources. Therefore, to provide a better snapshot of canal nutrients that are easily assimilated by plants, two supplementary sample sets were taken that included testing for ammonia nitrogen and ortho- phosphorus. Also, two new sample locations were added: a pipe discharge into the canal a little east of Sample Point A; and the northeast corner of the WRWWTF's deep settling pond. These additional samples indicate that neither the pipe discharge or the deep settling pond appear to contribute NOx. The pipe discharge contributes minimal ammonia nitrogen and the deep settling pond contains minimal amounts of ammonia nitrogen due to the upstream wastewater treatment process. Ortho -phosphate contributions, if any, by the pipe appear negligible, while levels of ortho-phosphate in the deep settling pond are minimal. If the County Commission determines to proceed with a Phase 2 study to try to identify specific potential nutrient contributors east of Sample Point B, staff recommends the following: (1) locate and identify all pipes discharging into the 8th Street Canal east of Sample Point B; and (2) at each pipe discharge, collect water samples and test them for NOx, TKN, ammonia nitrogen, TP, and ortho-phosphorus. All pipe connections may not discharge until a rain event, which will make sampling more difficult due to timing of rainfall runoff into the pipes. Staff recommends three post -rain grab sampling events. 17 FAPublic Works\KeithM\Stormwater Projects\IRFWCD 8th Street Canal Water Study\Memo 2 - 8th Street Canal.doc 48