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Carla Lenkey ` COLOWYO 3rd QUARTER 1998 DMR October 19, 1998 page 2 are related to surface runoff. The discharged water had been in the pond since mid June. The pond was warm and had algae growing in it. The pond is constructed on Campspass loam type soils with moderately alkaline subsoils in the range of pH 8.4 (see enclosed soil series description from the Moffat County SCS office). The combined effects of the algae bloom and the alkaline soils contributed to an elevated pH for the discharging waters. The sediment control pond contributing to Outfall 010 has been receiving a steady inflow since March, 1998. This pond also receives minimal inflows from clear, fresh water springs. Outfall OlOA discharged July 27, 1998 and met the total suspended solids daily maximum of 61 mg/1. The 30 day average also measured 61 mg/l. Pursuant to our conservation on October 6, 1998 the highest 30 day average within the quarter must be caculated fora "calendar" 30 days and not a rolling 30 day average. Since there was only one sample gathered during the month of July the 61 mg/1 measurement must be used as the average. Similar to pond 002A this pond also had a mid-summer algae growth which contributed to the elevated TSS measurement. TSS values are not attributed to surface runoff. The sediment control pond associated with Outfall OOSA is located on alkaline shale derived soils near the perimeter of Colowyo's mine permit boundary and discharges infrequently. The pond was + discharged to bring the storage capacity into agreement with the Colorado Division of Minerals and Geology requirement of maintaining a 10-year, 24-hour storm event capacity, and to facilitate dredging of the pond. Outfall OOSA discharged on August 19, 1998 and had a field pH of 10 (maximum), a laboratory pH of 9.6, and an additional field pH of 9.4 (minimum) on August 25, 1998. The prior discharge from this pond occurred September 22, 1997 and at that time the field pH was 8.1 and the laboratory pH was 7.8. Water in this pond is associated with the local ground water table in the tight, heavy, clay loams and clays associated with the area near the Unit Train Loadout and is typical of mid-summer conditions with a warm water algae bloom. Further, the pond is constructed in moderately alkaline (pH 8.4) shale derived subsoils (please refer to the attached soils series description for the Pinelli Loam). The combination of the alkaline derived soils and the mid-summer algae contributed to the elevated pH level. The sediment control pond associated with Outfall 008A receives a minor inflow from clear freshwater springs. This pond was discharged on August 11, 1998 to facilitate dredging the pond inlet of sediment during the month of August. This pond had amid-summer algae growth in it along with vegetative growth (primarily cattails). The debris attached to the cattails contributed to the elevated TSS levels by being dislodged when the pond was discharging. Elevated TSS values are not related to any surface runoff conditions.