2014-11-21_PERMIT FILE - C1996084 (23)

Home Browse Search

• Rule 2: Permi~r This would compaze favorably to the experience of field personnel with bailing some of the wells. A number of the wells at the site do not produce this volume of water during bailing. This transmissiviry indicates a fair to poor potential for domestic supply. Overburden The overburden in the Lorencito Canyon Permit area is located in higher elevations, above the Ciruela coal seam. The total estimated thiclrness of the overburden is up to 500 feet. The top of this unit consists of the Poison Canyon Formation, which outcrops in the southern portions of the site. The Poison Canyon Formation was investigated by Howard (1982), and is described as a medium grain sandstone, conglomerate and occasional interbedded mudstone. Within the Raton Basin, the Poison Canyon may have unconfined aquifer conditions within the sandstones. This is explained by the good porosity of the sandstone and the atmospheric contact of the formation (Howard, 1982). Within the permit area no water was encountered in the Poison Canyon and very little water in the Raton Formation overburden. Recharge to the overburden is via precipitation, since this unit forms the highest topographic unit in the permit area. Much of the water from precipitation events is lost to evapotranspiration or to runoff. Some of the water does infiltrate through the sandstones of the Poison Canyon, into the overburden. • Examination of a flow net of the system indicates that some of the recharge into the Poison Canyon Formation is discharged via evapotranspiration from the formation itself. Particular to the permit area, several of the principal springs are thought to emanate from the Poison Canyon/Raton Formation contacts. Springs in the Bonita Canyon azea of the project emanate from underneath massive sandstones that are indicative of the Poison Canyon, and may provide a mechanism for dischazge from this formation. Dischazge from springs would reduce the amount of water entering as recharge to the underlying units. Groundwater in the overburden is characterized as being under confined conditions. Water was not appazent in any of the borings into the overburden; therefore, wells were set into the sandstone overlying the Ciruela. The wells at location MW-2 have been dry and two of the three planned wells were not set at the location for MW-3 due to dry conditions. Water was present in only one well installed in the overburden (MW-lA). Groundwater in the overburden appears to be intermittent throughout the zone; therefore the potentiometric surface could not be determined. The physical characteristics of an overburden water-bearing zone could not be determined. A slug test was attempted in well MW-10, and no recovery from the initial "slug in" was recorded in eight hours of data collection. This indicates an extremely low hydraulic conductivity for the sandstone immediately overlying the Ciruela. Although not quantifiable, estimated hydraulic conductivity would be in range of 10-' to 10~ ft/day. Accordingly, the water-bearing zone is C~ PERMR.O]5\Deamb~r 30, 19% 2.04-13