Hydrosphere Resource Consultants

Projects by Discipline / Water Resources Engineering

Pecos River Basin Groundwater Modeling

The New Mexico Interstate Stream Commission (NM-ISC) retained Hydrosphere to assist in the development and application of two groundwater models in the Pecos River basin: the Roswell Artesian Basin Groundwater Model and the Carlsbad Area Groundwater Model, and linking these models to the Pecos River RiverWare™ water operations model.

Analyses with these models have been performed in support of:

  • Pecos Consensus Plan
  • Lower Pecos Adjudication Settlement
  • Carlsbad Project Water Operations and Water Supply Conservation EIS
  • Carlsbad Project Miscellaneous Purposes Contract Re-operation EIS
  • Pecos River Compact issues

The Roswell Artesian Basin Groundwater Model is a 3-layer MODFLOW model that simulates the impacts of well pumping and irrigation return flows in the Roswell artesian basin, with the spatial domain basically encompassing the approximate hydrologic boundaries of the basin. The aquifer system underlying this region is comprised of a shallow unconfined aquifer and a deep artesian aquifer, separated by a confining layer. The aquifer system contributes a significant amount of water to the Pecos River in the form of subsurface base inflows, and provides the primary water supply for all agricultural, municipal, domestic, and industrial water uses in the basin. Groundwater extraction for beneficial uses directly impacts aquifer storage levels and these base inflows. As such, the model is a key component in the NM-ISC's ability to quantify and assess groundwater development as part of NEPA and Compact evaluations.

The Carlsbad Area Groundwater Model is a 2-layer MODFLOW model that simulates impacts of surface irrigation and well pumping in the Carlsbad area on return flows to the Pecos below Avalon Dam. Return flows from the Carlsbad Irrigation District and base inflows from the underlying aquifer contribute significantly to Pecos River flows below Lake Avalon. Groundwater is used to supplement CID's surface water supply in dry years. This "supplemental" pumping causes additional depletions to the return flows from surface water irrigation, as well as depletions to the native groundwater that would otherwise seep into the Pecos, thereby significantly affecting New Mexico's ability to meet Compact obligations to Texas. The model captures these relationships, allowing the NM-ISC to quantify and assess the impacts of CID operations.