A private corporation has proposed to export up to 54,000 acre-feet per year of groundwater from the San Agustin basin of central New Mexico for use within the Rio Grande basin. This water would be used for eleven stated purposes. Concerns have been expressed regarding the hydrologic, economic, environmental, and legal consequences. Sustainability of the water supply is an issue, as are effects on the neighboring Rio Grande and Gila River watersheds. A system dynamics model of groundwater and its relationship to the local economy in the basin was developed to explore some of these issues. Subsurface flow between six subbasins was modeled as well as flow to two neighboring groundwater basins. Simulation runs occur on an annual time-step over a 40-year period. Two simulations are presented: 1) no-development based on historic precipitation and evapotranspiration, and 2) development, which includes a 54,000 acre-foot per year appropriation. Model results indicate that effects are measurable. Pumping is sustainable over 40 years. Basin-wide groundwater resources decline 1.76%. Water levels decline 11 feet. Twenty-eight active wells are projected to become dry. Water volume decreases 4.78% or 46 feet in the subbasin where the proposed wells would be located. Water table decreases are averaged for each of six subbasins; wells closer to the pumping center are impacted more than distant wells. Subsurface discharge to the Gila River and Alamosa Creek watersheds decreases 2.93% and 30.2%, respectively. Sensitivity analyses were conducted using hydrologic values suggested in other studies, viz. recharge, hydraulic conductivity, volume, climate change, and water price figures. Basin-wide groundwater volume decreases 1.56-3.87%. Water levels decline 10.6-24.7 feet. Water volume decreases 4.02-10.35%, or 38.8-100 feet in the subbasin where the wells would be located. Subsurface discharge to the Alamosa and Gila River watersheds decreases 21.7-73.7% and 1.67-7.86%, respectively. Examples of costs include drilling 37 wells and constructing associated pipeline, deepening existing wells, and impacts on endangered species. Net costs over 40 years to basin residents and endangered species are projected to be $587,156 and $12.4 million, respectively, the latter assuming water decreases are not offset or replaced. Economic benefits would come primarily through marketing water outside of the basin. Net earnings from water sales range from $1.43 billion to $1.88 billion before taxes. Legal analysis utilizes groundwater and economic results. As New Mexico Office of the State Engineer Application No. RG-89943 is currently being appealed, any future application may need greater specificity, as well as firmly show proof of demand, contractual arrangements, and an absence of harm to basin residents.
Water resources development--New Mexico., Water transfer--New Mexico., Water diversion--New Mexico., Groundwater--New Mexico--Catron County., Groundwater--New Mexico--Soccoro County.
Reese, David J.. "Groundwater, economic, and legal analysis of a proposed diversion from the San Agustin Basin of New Mexico." (2013). https://digitalrepository.unm.edu/wr_sp/40