Joint 118th Annual Cordilleran/72nd Annual Rocky Mountain Section Meeting - 2022

Paper No. 14-2
Presentation Time: 8:25 AM

CHANGES IN GROUNDWATER CONTRIBUTION TO MOUNTAIN RIVERS UNDER VARYING TECTONIC AND CLIMATE CONDITIONS: OBSERVED INTERACTIONS BETWEEN BASEFLOW AND FORCINGS


HAN, Kyungdoe and WILSON, John L., Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, 801 Leroy Pl., Socorro, NM 87801

Tectonic and climatic variations affect the amount and location of groundwater upwelling. In headwater streams that reside in arid to semi-arid regions, the long-term history of changes in groundwater flow regime is of utmost importance for aquatic and riparian species since hydrologic connections established by groundwater provide dispersal pathways and nutrients. To better understand how upwelling has been changing, it is necessary to track changes associated with the long-term coevolution of landscape and groundwater under varying tectonic and climatic conditions within the area of interest.

This study demonstrates the degree of correlation between groundwater discharge to the surface and tectonic and climatic forcings. A landscape evolution model coupled with deep, 3D groundwater simulation is thus constructed to accommodate the variabilities. We examined changes in groundwater upwelling characteristics in several hypothetical topographic settings for dozens of million years. In addition, we present several metrics that represent the overall “connectedness” of surface flow (i.e., mountain rivers) supported by baseflow.

The constructed history of groundwater contribution to mountain rivers and resulting stream connections through time can indicate the importance of baseflow on characteristics of fluvial geomorphic processes and species evolution. This work supports our currently ongoing project aimed at developing an integrated understanding of geology, ecology, and hydrology.