Laserfiche WebLink
ESTIMATED POLLUTANT LOAD REDUCTION MODEL USED : <br /> For estimating watershed loading, exclusive of the RO Concentrate addition, the Spreadsheet Tool for Estimating Pollutant <br /> Loads (STEPL) was initially applied, with the land use breakdown as previously noted. In developing these loads, <br /> grass <br /> swales and dry detention were noted as the existing BMP elements . Event Mean Concentrations used were those applied to <br /> Florida conditionS2 shown in Table 1 of the Pollutant Load Calculations Attachment, which are similar to the default values <br /> within the STEPL model . Load projections for the entire watershed are noted in Table 2 of the Pollutant Load Calculations <br /> Attachment. <br /> There is available long term USGS flow data for the PC- South Relief Canal which represents the composite influence of the <br /> runoff and base flow associated with the majority of the watershed. Data from 1956 to 19824 reveals an annual average flow <br /> of 37 . 7 cfs or 24 .4 MGD, with a standard deviation of 13 . 7 cfs (8 . 9 MGD); a minimum annual average of 15 .2 <br /> cfs (9 . 8 <br /> MGD) and a maximum annual average of 61 .6 cfs (39 . 8 MGD) . Using the average flow rates and the STEPL <br /> post BMP <br /> loading values, the average annual concentrations within the canal can be estimated, as noted in Table 3 of the Pollutant Load <br /> Calculations Attachment. Included in this table is the actual concentrations as monitored in the South Canal, using data from <br /> USGS from 19724977, from Indian River Farms Water Control District from 2000, and from the ongoing PC-South ATSTM <br /> Pilot System. <br /> BMPs Installed TSS TP TN <br /> BMP #1 ATS lbs/yr lbs/yr lbs/yr <br /> y Pre-Project 33,851 79400 369834 <br /> b <br /> C° Post- <br /> Project 169925 49998 279229 <br /> Load 169926 21402 99607 <br /> Reduction <br /> pw % <br /> Reduction 50% 32.5% 26. 1 % <br /> BMP #2 TSS TP TN <br /> (wetlandpond) lbs/yr lbs/yr lbs/yr <br /> y Pre-Project 169925 49998 279229 <br /> "a Project 89463 49953 279004 <br /> Load <br /> Reduction 89463 45 225 <br /> a' % 50% 0.9% 0.8% <br /> Reduction <br /> TOTAL TSS TP TN <br /> lbstyr lbs/yr lbs/yr <br /> y Pre-Project 339851 79400 369834 <br /> v <br /> Post-Project 89462 49953 279004 <br /> ° Load <br /> 259389 21447 99830 <br /> Reduction <br /> a' % 75.0% 33. 1 % 26.7% <br /> Reduction <br /> 2 CDM, "Little Wekiva Basin Watershed Management Plan" 2005 Orange County , Florida . <br /> 3 USGS Station 02253500 Lat 27° 36 ' 11 " ; Long 80° 23 ' 24" <br /> 4 In 1982 RO Concentrate discharge to the canal was initiated and flows reflect this addition after 1982 . <br /> DEP Agreement No. 60353 , Attachment A, Page 4 of 12 <br />