2002-03-13_REVISION - M1979089 (2)

Home Browse Search

Grand Junction Pipe Surficial Geology Investigation, 23 Road Proposed Grave! Pit, Grand Junction, Colorado February 26, 2002 Page 4 confined aquifers. Some of these confined water are potable. Information available to Lincoln DeVore, the U.S. Geological Survey Professional Paper # 451, Geology and Artesian Water Supply, Grand Junction area, Colorado, S. W. Lohman, 1965, provides a dri[[ers tog ofseveral walls penetrating some ofthe confined aquifers. Making corrections For topography and the structural dip of the beds, a salty ground water in the Dakota Formation could be anticipated approximately 100 feet below the ground surface, a thin potable aquifer in the Somerville Formation approximately 700 feet below the ground surface and potable water in the Entrada Sandstone approximately 1000 feet below the ground surface. As can be seen from these depths, the confined water strata would be found az significant depths and would probably be separated from the proposed mineral extraction. SURFACE WATER Surface water generated on this tract, resulting from storm runoff is expected to be quite small. The principle source of storm water on dils site will probably be by flooding of the Colorado River, The Persigo Wash Drninage is located about 1-1l2 mile northwest of this tract. A number of small ponds are located on surrounding the site. These ponds developed after excavation in past pits ceased and were no longer drained. This site is within the designated 100 Year Flood Plain, shown on the National Flood Insurance Program Maps for Mesa County, Colorado. ECONOMIC GEOLOGIC DEPOSITS The economic deposit of consequence on this site is the sand and gravel of the Present Colorado River Terrace The perched ground water on this site, which may be encountered between 5 to 8 feet below the present ground surface, contains soluble sulfate salts and other minerals in sufficient quantity that the water is not considered potable. These waters may, in some instances be utilized for imgation but, are nomrally considered to have excessive minerals. The wnfined waters in the Dakota, Summerville and Entrada Formations are generally considered of minor consequence in this area It is not believed this proposed gravel extraction operation would affect, either positively or adversely, these deeper, confined ground waters. Some petroleum and significant amounts ofnatural gas have been prospected for and extracted from the Dakota, Burro Canyon and Morrison Formarons. The established producing gas fields are located north and northwest of this tract. These established producing gas fields are located in the desert area north of the Government Highline Canal and within the Bookcliffs, approximately IS miles north of this site. To our knowledge, exploration for natural gas or petroleum has not been accomplished in this portion of the Grand Valley. It is possible that natural gas deposits are present beueati this site but, development of these resources is prohibitive az this time and has not been considered an issue within this portion of the Grand Valley. Radioactive ores have been mined from the lower Burro Canyon and Morrison Formations, in the Uncompahgre UpliR to the south. In general, the producing mines and significant deposits are located more than 20 miles south of this site.