New Mexico Geological Society Annual Spring Meeting — Abstracts

The frequent flash flood events experienced in the arid watersheds of central New Mexico during the monsoon season commonly result in damage to property, infrastructure, and human life. The creation of reasonably accurate hydrologic models of such watersheds allows for preemptive identification of high-risk regions within and surrounding the watershed. In the Arroyo de los Pinos watershed, the variable topography, soil depths, and soil types result in complex rainfall-runoff relationships. Efforts to create reasonable numerical rainfall-runoff models of the Pinos are therefore equally complicated. Precise field measurements of soil hydraulic parameters throughout the watershed would be a crucial component in the creation and correction of such models. While spatial datasets of hydrologic soil group classifications are publicly available courtesy of the Natural Resources Conservation Service (NRCS), these data are heavily based on historical and remote observations, and are highly generalized over large areas. Many of the classified areas encompass multiple topographic highs. The flats and crests, slopes, and slope toes of these hills can have variable soil properties, possibly to a degree that would justify an updated hydrologic classification. Using a double-ring infiltrometer and mini-disc tension infiltrometer, infiltration measurements will be conducted at 36 sites across 12 hillslopes within the Arroyo de los Pinos watershed to quantify hydraulic conductivity and sorptivity. Infiltration measurements will commence in the Arroyo de los Pinos watershed in mid-May of 2025. Preliminary field work will begin in April 2025 along the Quebradas Backcountry Byway to fine tune water requirement estimates and best-use practices for infiltrometers on different types of slopes and soils. The data collected will be analyzed in conjunction with geologic and topographic spatial datasets to refine hydrologic soil classifications. The results of this field work will enhance future predictive models of infiltration and runoff, which will improve estimates of transmission losses and flood response within the watershed. By refining hydrologic soil group classifications, this research will contribute to more accurate 1-D, 2-D, and 3-D rainfall-runoff models, ultimately aiding in the mitigation of flood hazards and sediment transport impacts in the region.