Colorado Plateaus Aqifers


http://www.stgeorgeutahrentals.com/zion-national-park.html

by

Erin Allen


Table of Contents


Introduction

The Colorado Plateaus Aquifer is made up of four smaller aquifers, the Uinta-Animas, the Mesa Verde, the Dakota-Glen, and the Coconino-De Chelly. They are located in western Colorado, eatern Utah, northeastern New Mexico, and northwestern Arizona. They cover an area of approximately 110,00 square miles. The general composition of the aquifers are moderately to well-consolidated sedimentary rocks of an age ranging form Permian to Tertiary (Robson and Banta, 1995). Each aquifer is separated from the others by an impermeable confining unit. Two of the confining units are completely impermeable and cover the entire area of the aquifers. The other two confining units are less extensive and are thinner. These units allow water to flow between the principal aquifers. The aquifers are very important to the people of this region because on average the Colorado Plateau receives less than 10 inches of rain a year (Grahame and Sisk, 2002). There are countless streams, rivers, and lakes that overlay the Colorado Plateaus Aquifers. The surface water bodies in this region provide a place for the aquifers to discharge. Some of the high altitude rivers and lakes may also provide recharge.


http://capp.water.usgs.gov/gwa/ch_c/jpeg/C107.jpeg

Return to table of contents.


Uinta-Animas Aquifer

Hydrologic and Geologic Setting

The Uinta-Animas aquifer is located in northwestern Colorado, eastern Utah, and northwestern New Mexico. There are three basins that make up this particular aquifer. The Uinta basin in Utah, the Piceance basin in Colorado, and the San Juan basin in New Mexico. It is composed of Lower Tertiary sandstones, conglomerates, and siltstones (Robson and Banta, 1995). The thickness of the aquifer ranges in each basin and generally increases from the margins in. The average thicknesses in the basins ranges from 500 feet in the Uinta basin to 3,500 feet in the San Juan basin.

Recharge

Recharge for the San Juan Basin aquifer occurs in the area of Durango, Colorado and flows toward the San Juan River to discharge (SAIC, 2003). The Piceance Basin recharges in the valleys of the White and Colorado Rivers. The Uinta Basin recharges at the southern margin and discharges near the White and Green Rivers (Robson and Banta, 1995).

Water Quality

Dissolved-solids concentrations are common near the areas of recharge where the water is calcium or magnesium bicarbonate and at areas of discharge the waters are of sodium bicarbonate or sulfate type (Robson and Banta, 1995).


http://capp.water.usgs.gov/gwa/ch_c/jpeg/C108.jpeg

Return to table of contents.


Mesa Verde Aquifer

Hydrologic and Geologic Setting

The Mesa Verde Aquifer is located in northeastern Colorado, central Utah, northeastern New Mexico, and northwestern Arizona. This aquifer is split into eight basins: Piceance, Uinta, Kaiparowits, Black Mesa, San Juan, Wasatch Plateau and High Plateaus. The sediments that make up this aquifer are conglomerates, sandstones, siltstones, mudstones, claystones, carbonaceous shales, limestones, and coal of the Upper Cretaceous Mesa Verde Group. The Coal beds that are present are being mined and are causing some concern for water contamination (Robson and Banta, 1995).

Recharge

The water in the Piceance Basin is recharging from snowmelt in high altitudes of the West Elk Mountains and then flows northwest towards the Colorado River where it discharges (Topper et al, 6.2). The Uinta Basin recharges at the margins of the basin and has no preferred direction of flow. The San Juan Basin is recharging near the Zuni Uplift in the Chuska Mountains and flows toward the Chaco and San Juan Rivers to discharge (Robson and Banta, 1995).

Water Quality

The Mesa Verde Aquifer is high in chloride concentrations (BLM, 25). The other water quality issue is the coal mining that is occurring in some basins. The mines can leak acid and seep into the ground and surface waters near by if they are not properly cleaned up.


http://capp.water.usgs.gov/gwa/ch_c/jpeg/C116.jpeg

Return to table of contents.


Dakota-Glen Canyon Aquifer System

Hydrologic and Geologic Setting

The Dakota-Glen Aquifer covers most of the Colorado Plateau aquifers region. It covers large portions of Colorado, Utah, and New Mexico. The Dakota-Glen is also split into several basins with their own unique characteristics. The rocks that make up this aquifer are late Cretaceous to Triassic in age. There are four areas of permeable rock that are then referred to as the Dakota aquifer, the Morrison aquifer, the Entrada aquifer, and the Glen Canyon aquifer (Robson and Banta, 1995). These four aquifers are considered one unit however because they are confined from all of the other principal aquifers in the region.

Recharge

There are a few major regions of recharge and discharge for this aquifer. The areas of recharge are located around the southern end of the Uinta basin, western margins of the San Rafael Swell, and the northern portion of the Four Corners Platform (Robson and Banta, 1995). Discharge flows towards the major rivers of the region such as the Colorado, San Juan, White, Green, and Gunnison Rivers. Another source of discharge is located where the Wingate sandstone and the Chinle Formation meet in Mesa County, Colorado (CSU, 2002). The water in the Grand Valley is used for irrigation and has to be pumped through wells because of overuse of the artesian wells (CSU, 2002).

Water Quality

The water in this aquifer is highly mineralized. There is a substantial amount of dissolved halite most likely form an unplugged or poorly plugged oil test hole (Robson and Banta, 1995).


http://capp.water.usgs.gov/gwa/ch_c/jpeg/C120.jpeg

Return to table of contents.


Coconino-De Chelly Aquifer

Hydrologic and Geologic Setting

The Coconino-De Chelly Aquifer is much like the Dakota-Glen Aquifer in the it covers most of the Colorado Plateau region. Large portions of Arizona, New Mexico, and Utah are underline by this aquifer. The rocks are of an Early Permian age (CSU, 2002).

Recharge

The aquifer is recharged in the Uncompahgre Uplift, Paradox Basin, San Rafael Swell, Circle Cliffs Uplift, Defiance Uplift, Zuni Uplift, and Mogollon Slope (Robson and Banta, 1995) Discharge occurs along the Colorado and Green Rivers again.

Water Quality

The water in the Coconino-De Chelly Aquifer has a lot of dissolved minerals in it. Some regions are more concentrated than others though. There is also dissolved halite in the water much like that of the Dakota-Glen only less concentrated.


http://capp.water.usgs.gov/gwa/ch_c/jpeg/C129.jpeg

Return to table of contents.


Water Laws

Arizona
Arizona water laws are based upon prior appropration. The Arizona Department of Water Resources has established a framework for obtaining water rights. There are three levels of management within the water resource department (BLM, 2001). The first level is in charge of managing general water provisions statewide. The second level manages irrigation non-expansion areas. Finaly, the thrid level maages active management areas.
Colorado
Colorado's water laws are based upon a modified version of prior appropriation. Groundwater is governed by the Ground Water Management Act of 1965 (BLM, 2001). Colorado does not have one agency that is in charge of issuing water rights. There is a system of water courts where water rights may be obtained. There are seven differnt courts for the seven major river basins. The State Engineer, Colorado Ground Water Commission, and Colorado Water Conservation Board also have a hand in managing the rights and conservation of water use in the state.
New Mexico
New Mexico is also a prior appropriation water law state. The groundwater is governed by the New Mexico ground water code of 1931 and the State Engineer (BLM, 2001). New Mexico has also declared that all water in the state is public and subject to appropriation.
Utah
Utah is also governed by the prior appropriation docterine and the fact that all water is a public resource. The State Engineer and the Divison of Water Rights is responsible for administering groundwater rights in the state BLM, 2001).

Return to table of contents.


Conclusions

While the Colorado Plateaus Aquifers are four separate bodies of water with their own unique characteristics they do share some similarities. Their close proximity and sometimes interaction with each other makes them one large aquifer system. Their existence is not only very hydrologically interesting but also very important to the people who live in and around the Colorado physiographic region.

Return to table of contents.


References