The Importance of Water-Supply Reports for Rural Subdivision Development: a 2006 study done on Rogers Mesa, Delta County, Colorado
In 2008 Kenneth R. Watts released Scientific Investigations Report 2008-5020 entitled “Availability, Sustainability, and Suitability of Ground Water, Rogers Mesa, Delta County, Colorado – Types of Analyses and Data for Use in Subdivision Water-Supply Reports.” In his report, Watts detailed the creation of the water-supply report guidelines that was determined by Delta County and the U.S. Geological Survey in the wake of future rural subdivision development.
As many are aware, Colorado, like other western states in the U.S., has the ability and is projected to see substantial population growth in the upcoming decades. A particular county of interest is that of Delta County in Colorado which is home to towns/cities including: Cedar Ridge, Crawford, Delta, Hotchkiss, and Paonia.
It is predicted that most of the development in Delta County will occur in rural areas – with the creation of rural subdivisions that rely most heavily on residential wells for their domestic water. In order to establish these residential wells, subdivision developers will be required to submit their water-supply plan through the county to the Colorado Division of Water Resources in order to obtain their water rights. If contractors plan to supply the subdivision water with the use of wells, they must include a water-supply report which will “demonstrate the availability, sustainability, and suitability of the water supply for the proposed subdivision.” In 2006, Delta County teamed up the U.S. Geological Survey to determine a list of criteria that the Delta County Land Use Department would be able to use when evaluating the water-supply reports that the contractors would submit.
To determine the criteria for a water-supply plan, Delta County and the U.S. Geological Survey prepared an analysis of Rogers Mesa in Delta County based on a hypothetical subdivision. They developed a table of all of the analyses that would need to be included in a water-supply report’s water-supply plan based upon this hypothetical subdivision.
Rogers Mesa is located along the north side of the North Fork Gunnison River, 15 miles east of Delta, Colorado. Rogers Mesa is 12-square miles and is used primarily for irrigated agriculture. 5,651 acres of Rogers Mesa is irrigated cropland, orchards, and grass pasture. Surface water from the North Fork Gunnison River and Leroux Creek serve as the primary sources of irrigation water for the upland mesa.
The Colorado Division of Water Resources provided files that enabled Delta County and the Geological Survey the ability to map out the primary aquifer, an alluvial fan on Rogers Mesa. With the help of those files, they were able to determine the source of recharging the aquifer: water diverted from irrigation. They were also able to estimate the capacity of the wells, thus confirming the availability of water on Rogers Mesa.
The data they collected and researched was also very valuable in determining the water recharge and discharge estimates for each year. Although it currently has sufficient ground water, converting the irrigated land into residential land would hinder in the process of recharging the water in the aquifer, ultimately making it more difficult to sustain.
When tackling the question of suitability, Rogers Mesa meets the standard of having a low concentration of nitrogen for drinking water, but fails to meet the standard for dissolved sulfates and solids.
Kenneth R. Watts Report gives deeper insight to this water-supply plan standard created by Delta County in his Scientific Investigations Report 2008-5020 entitled “Availability, Sustainability, and Suitability of Ground Water, Rogers Mesa, Delta County, Colorado – Types of Analyses and Data for Use in Subdivision Water-Supply Reports.” It is available online at http://pubs.usgs.gov/sir/2008/5020/