REP47405 - Laserfiche WebLink

Home Browse Search

HYDROLOGY IMPACTS 1987 CWI initiated the present hydrology monitoring program in 1982, and added sever- al more resources in 1983, and 1984. Presently, a few more than 100 hydrologic resources are monitored at least monthly. An abundance of data has been accu- mulated and interpreted over the years. Based on this data, CWI has ascertained and projected impacts which may have been due, at least in part, to mining and established patterns of natural fluctuations which may occur. Flow and quality may be affected by the lack of or excess precipitation, dilution by runoff, livestock activity, geologic conditions, vegetative growth or decay, or other causes. CWI plans to submit a technical revision during the Sumner of 1988, to reduce the number of resources that are presently monitored and concentrate monitoring efforts on adjudicated water rights and those resources which may be undermined during the next five year mine plan term. The following discussions are divided into four sections. These are: Precipi- tation, Surface Water - Existing Monitoring and Impacts, Groundwater - Existing Monitoring and Impacts, and Orchard Valley Mine Site - Existing Monitoring and Impacts. Surface water discussions include streams and ponds. Groundwater dis- cussions include colluvial-alluvial and bedrock resources. PRECIPITATION Precipitation data is presently obtained from a rain gauge on the fan level of the Orchard Valley Mine site and an evaporation pan station at the Steven's Gulch well field site. Precipitation data from the Paonia 1-SW Federal climatic station is also obtained. • The rain gauge consists of a 12-inch dual traverse rain gauge and an 8-day strip chart recorder. The rain gauge was not operated in January, 1987, as it was defective. Due to the furlough in December, the rain gauge was not operated during that month and some of 1988. Less these two months of data, a total of 13.4 inches of rainfall was recorded in 1987. Utilizing the Federal station data, we could assume that 1.5 to two inches of precipitation was received dur- ing the months the gauge was not operated. The total rainfall would then be approximately 15.0 inches and compares to data recorded in the late 1970's. The evaporation pan is a round stainless steel container, ten inches deep and four feet in diameter. The pan was set up in May and drained in early October of 1987. During 1987 the average monthly evaporation loss for the four full months monitored was 5.60 inches. This is 0.75 inches more loss than the aver- age monthly loss recorded in 1986. The total loss recorded was 22.38 inches. The pan was monitored for a month or more longer in 1987, than in 1986. CWI will continue to monitor the evaporation pan in 1988.