GENERAL46267 - Laserfiche WebLink

Home Browse Search

snow melt and rainfall at outcrops along the anticline. All aquifers exhibit water table conditions near the outcrop. However, observation wells installed downdip indicate the aquifers are all under artesian conditions with increased pressure related to increased depth. Quality m all aquifers is poor and undesirable for use as either a drinking or irrigation supply. The Seneca II-W Mine permit area lies on the western flank of the Sage Creek Anticline, a local structure located within the more regional Sand Wash Basin. The Sage Creek Anticline is thought to control local ground water flow, as artesian head increases with distance from the anticlinal axis. Ground water occurs in the alluvium associated with Hubberson Gulch within and adjacent to the permit boundary. Quality of this water prohibits its use for drinking and severely limits its use for irrigation. Drinking water and irrigation standards were exceeded for TDS, Conductivity and Manganese. Surface Water The mine permit boundary encompasses two surface watersheds. Most of the mine site and the major portion of the disturbed area will drain into Hubberson Gulch and an unnamed tributary to Dry Creek. A small area on the eastern edge of the permit boundary drains to Sage Creek. Flows on Sage Creek range from intermittent to perennial, depending on location and precipitation patterns. At the Seneca II-W monitoring sites, Sage Creek can be classified as perennial during years at or above average precipitation, and intermittent in years below average. The numerous small drainages which are tributary to Dry Creek are ephemeral in nature. Hubberson Gulch, downstream of the mine site to its confluence with Dry Creek, is intermittent. Dry Creek, like Sage Creek, can be classified as perennial most years, and intermittent during years with below average precipitation. Both Sage Creek and Dry Creek are confluent with the Yampa River near Hayden, Colorado. Water in Hubberson Gulch is a MgCa-SO, type. Surface water total dissolved solids (TDS) averages 820 mg/l. The water is hard, and is characterized as slightly alkaline (average pH 8.10). It is suitable for livestock watering and irrigation of salt-tolerant crops grown in well drained soils. Water quality in Sage Creek is a CaMg-HC03 type. Samples from baseline monitoring points indicate the water is slightly alkaline with a pH ranging between 7.0 and 8.0. The water has a TDS level of less than 500 mgl1, but is characterized as very hard. It is suitable for livestock and irrigation, however, flow is generally inadequate for irrigation. Dry Creek water quality is categorized as brackish, since TDS averages greater than 1000 mg/1 (1048 mg/1} near the confluence with Hubberson Gulch. Water quality degrades further Seneca II-W Findings Document 9 Tune 15, 2001 Permit Renewal No. 3 May 2, 2003