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Larersciro Canvort Mine -Surface Wmer Technical Report • Conclusions In accordance with Rule2.04.7, baseline data has been collected for the Lorencito Canyon Mine to determine the surface water flow rates and surface water quality. The Lorencito Canyon Mine is located in the Purgatoire River drainage. The watershed for the Lorencito Creek encompasses 69.9 mi'- azea. All surface water in the site azea drains into the Purgatoire River. Generally, the study has determined that the amount of surface water at the site is relatively low. Perennial stream conditions were determined for only the LC-l, LC-4, PRGTY-1, and PRGTY-2 monitoring stations. All other stations were intermittent. High flows for the stations were measured during the wetter months of August and September, and low flows were noted during the months of January and February. Springs were also found within the permit area. A total of eleven springs were noted. Many of the springs were intermittent. Spring flows ranged from zero to a maximum of 12.25 gpm. The majority of the springs were found on the east side of the property. In addition to these springs, 19 ponds are located on the site. These ponds aze used as stock wildlife water sources. No other surface bodies of water were located onsite. The quality of the surface water at the site is principally acalcium-sodium bicarbonate type. The • water is typically neutral to partially alkaline, with low hazdness, and low to moderate salinity. pH ranges from 6.15 to 8.79, and hardness ranges from 1 I 1 mg/L to 213 mg/L. Total dissolved solids in the samples ranged from 50 to 650 mg/L (filterable residue). Several exceedances in the water quality were noted. These exceedances were mainly with the standards for iron, manganese, ammonia, nitrite, nitrate, and total lead. The water from the springs was slightly to moderately alkaline, slightly hard, calcium-sodium bicarbonate water. Total dissolved solids ranged from 300 mg/L to 710 mg/L. Total alkalinity of the samples ranged from 223 mg/L to 409 mg/L and hazdness ranged from 214 mg/L to 409 mg/L. pH ranged from 6.70 to 9.15. Generally, less exceedances from the standazds occurred at the spring stations. The exceedances were generally with ammonia, nitrate, nitrite, and dissolved lead. The Lorencito Canyon Mine permit area can be generally described as a semi-arid site with small amounts of surface water. Surface water availability increases in the monsoonal months of August and September, and decreases during the winter months. Water quality is moderate, with some exceedances noted. SECTION 4 -REFERENCES CITED Colorado Department of Health and the Environment, Water Quality Control Commission. April 1996. The Basic Standards for Groundwater 3.11.0. Denver, CO. • swA75\December 9. 1996 24