Refinement of Statewide Water Assessment Underway

By Jesslyn Ratliff, Program Specialist

A Dynamic Statewide Water Budget for New Mexico (Jesse Roach, Tetra Tech Inc.; Ken Peterson, Tetra Tech Inc.; Joshua Randall, NM WRRI; Bruce Thomson, UNM; Vince Tidwell, Sandia National Laboratories)

DSWB allows visualization of historical mass balance terms at the river basin, water planning region, county, and state level for any month or series of consecutive months from 1975 through 2013 including a range of uncertainty associated with each mass balance term. Specific objectives for the third year of DSWB development include: incorporation of new data, development of dynamic future scenario analysis, and continued development of graphic user interface.

Estimation of Total Available Water (TAW) as Input for the Evapotranspiration Recharge Model (ETRM) for Statewide Evapotranspiration Assessment (Jan Hendrickx, NM Tech; Dan Cadol, NM Tech)

The overall study goal is to develop a procedure for cost-effective assessment of evapotranspiration (ET) at spatial and temporal scales needed by New Mexico’s water resources managers. Because accurate estimates of TAW will greatly improve the accuracy of ET estimates with ETRM, specific objectives for the third year are:

  1. Further develop procedure [ Hendrickx et al., 2016b ] for estimation of TAW at a spatial resolution adequate for assessment of potential recharge in mountainous regions.
  2. Test and validate the improved procedure for TAW estimation in two mountain regions of New Mexico.
  3. Map TAW over the entire state of New Mexico at the spatial resolution of 250 m that is used by the EvapoTranspiration and groundwater Recharge Model (ETRM).

Regional Equations for Estimating Mean Annual Streamflow at Ungaged Stream Locations in New Mexico (Anne Tillery, USGS; Kyle Douglas-Mankin, USGS)

The proposed work will provide a statewide set of regional equations that can be used to calculate mean annual streamflow at ungaged locations on perennial streams. These equations will be incorporated into the NM StreamStats application in 2018 if funding is available. The regional equations will allow water-resource managers to calculate the mean annual streamflow for a watershed, at a county boundary, or other user-defined areas and will provide commonly needed, scientifically defensible hydrologic information in a uniform and non-biased manner.

Using Remote Sensing to Develop Evapotranspiration (ET) Fluxes for the Mesilla Valley Aquifer (Zohrab Samani and Salim Bawazir, NMSU)

The work proposed here will include: measurement of ET fluxes for a crop (to be selected; alfalfa or pecan) in the Mesilla Valley; compare ET estimates using satellite-remotely based models identified as Simplified Surface Energy Balance (SSEB) and Regional Evapotranspiration Estimation Model (REEM) with ground measurements that reflect local climatic and geographic landscape conditions; calibrate model parameters; validate modified models; and generate spatial and temporal ET fluxes (i.e., ET maps) for the Mesilla Valley. The expected benefit from this project will be a more accurate estimate of ET fluxes for the Mesilla Valley using remote sensing technology at higher resolution (Landsat8 satellite data). The ultimate goal of this project is to develop a satellite-based ET model that could estimate regional ET for the assessment of water in New Mexico without the need for a more expensive ground-level ET flux measurement. The regional ET fluxes can be used for the following purposes: groundwater modeling for groundwater management; use by farmers in irrigation scheduling, conservation measures, and other agronomic practices; optimizing water release from reservoirs; and other applications.

Groundwater Level and Storage Change in the Southern High Plains Aquifer and in Two Variable Confined Aquifers (Alex Rinehart, NM Bureau of Geology and Mineral Resources; Geoff Rawling, NM Bureau of Geology and Mineral Resources; Nathan Myers, USGS; Mike Johnson, OSE)

The fundamental results of this study are (1) a consistent method to estimate changes in groundwater levels and storage in variably-confined aquifers, such as those in the Roswell Artesian District and the San Juan Basin; and (2) maps and estimates of groundwater storage change and depth-to-water changes in the Southern High Plains aquifer in Curry and Roosevelt Counties using the methodology developed in previous years. The proposed work is a continuation of work that estimated the amount of water level and storage changes in basin-fill aquifers. In addition, work will be done to continue to populate the New Mexico Water Level Database housed at the NMBGMR and NM WRRI with the latest water levels provided by the USGS, NM OSE and other local entities.

Continued Development of the Evapotranspiration and Recharge Model (ETRM): Focused Recharge through Ephemeral Streams (Talon Newton, NM Bureau of Geology and Mineral Resources; Fred Phillips, NM Tech)

This project will work to improve recharge estimates from ETRM by including a representation of focused recharge. In this process, runoff from hillslope areas flows to ephemeral channel networks, where some fraction of the water seeps into the channel bed. This bed seepage may supply riparian vegetation or continue downward as deep drainage recharge to the water table. In closed basins, channel flow that does not infiltrate into the streambed will eventually reach a playa or other depression where it will then infiltrate or evaporate. Because ETRM already estimates runoff from each cell, the next step is routing this runoff to channels and estimating bed seepage. This work focuses on ephemeral channels, because perennial channels are typically connected to the groundwater in a stable way, and either gain flow from the groundwater, or lose water in equilibrium with the evaporative demand of the surrounding riparian community that has developed. Additionally, perennial streams constitute a small fraction of total channel length in New Mexico. This work will be done by a master’s degree student in hydrology at NM Tech.

Isotopic and Geochemical Characterization of Deep and Shallow Groundwater Residence Time, Connectivity, and Mixing in the Mesilla Basin, New Mexico (Kenneth Carroll, NMSU; Andrew Robertson, USGS)

This project will use geochemical and isotopic signatures to characterize the age (and residence time) and sources (and mixing) of groundwater at various depths within the Mesilla Aquifer system. This will include the development and use isotopes of noble gases for the first time in this region of the world, which will fill a critical time gap in methods commonly used for groundwater age dating. This project will provide the stakeholders in the region with quantified estimates of the deep groundwater contributions to the shallow groundwater and surface-water systems of the Mesilla Basin. The study provides water resource managers with information on groundwater movement and salinity to aid in effectively managing the water resources of the Mesilla Basin, by protecting the sources of recharge and fresh groundwater reserves and managing use to reduce salt loading. Age dating and residence time evaluation versus depth within the groundwater system will support evaluation of recharge, upwelling flow sources, flow dynamics, and resiliency of the groundwater system, which is critical for sustainable management of our groundwater as a water supply resource.

Project reports, posters, and fact sheets from the past two years of the Statewide Water Assessment can be found here: https://nmwrri.nmsu.edu/category-blocks-swa/#DSWB