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bed load fraction of the Elk River's sediment load. Monitoring data collected during the study 11, <br /> found a net export of total suspended solids out of Lake Orono. <br /> Total suspended solids loadings calculated during the Elk River study can be compared to <br /> suspended sediment yields calculated by the USGS. The USGS conducted suspended sediment <br /> sampling at ERCR 15 from 1975 - 1981. The USGS data was analyzed and documented in <br /> USGS Suspended Sediment in Minnesota Streams Water Resources Investigations Report <br /> 85-4312, 1986. The USGS study involved collection of 178 suspended sediment samples and <br /> sediment yields were calculated based on a 14-year stream flow record. <br /> The USGS report documents two sediment load values. The average annual sediment yield was <br /> calculated to be 3.7 tons/day and the median sediment discharge was calculated to be <br /> 11.1 tons/day. The total suspended solids discharge calculated in the Elk River study was <br /> 9.2 tons/day. <br /> • <br /> B. WATER QUALITY ASSESSMENT <br /> 1. Suspended Solids and Phosphorus <br /> Flow- and time-weighted averages were calculated for total phosphorus, ortho-phosphorus, TSS, <br /> VSS and TSS-VSS at monitoring stations: ERCR 15, TBCR 35, and the Lake Orono Dam (see <br /> Appendix D). Average total phosphorus and TSS concentrations were 0.12 milligrams per liter <br /> (mg/I) and 9 mg/I at ERCR 15, 0.15 mg/1 and 9 mg/1 at TBCR 35, and 0.11 mg/1 and 11 mg/1 at <br /> the Lake Orono Darn. The MPCA has developed a water quality database from monitoring <br /> minimally impacted streams from various ecoregions across Minnesota. (Selected Water Quality <br /> Characteristics of Minimally Impacted Streams from Minnesota's Seven Ecoregions, February <br /> 1993.) The Elk River watershed is within the North Central Hardwood Forest (NCHF) <br /> ecoregion. "Typical" values for total phosphorus and TSS, within the NCHF ecoregion, range • <br /> N.W 59E W I\ELK RI VERRPT-NCW 13 <br />