A modeling assessment of agricultural land groundwater recharge in the Kaweah River watershed, California.

Authors: AJAMI, HOORI - University Of California, Riverside; ACERO TRIANA, JUAN - University Of California, Riverside; YUAN, YUSEN - University Of California, Riverside; ARMENGOL, SANDRA - University Of California, Riverside; WINETEER, ERIC - University Of California, Riverside; Anderson, Raymond - Ray; Kelley, Jason; Wang, Dong

Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: 8/6/2023
Publication Date: 8/8/2023
Citation: Ajami, H., Acero Triana, J.S., Yuan, Y., Armengol, S., Wineteer, E., Anderson, R.G., Kelley, J.R., Wang, D. 2023. A modeling assessment of agricultural land groundwater recharge in the Kaweah River watershed, California.. Soil and Water Conservation Society. N/A.

Interpretive Summary:

Technical Abstract: Sustainable management of agricultural ecosystems is a great challenge in the 21st century because of increasing demand for food production and decreases in fresh water availability. Groundwater accounts for 40% of water withdrawals in irrigated agriculture, and groundwater depletion in major aquifers impacts sustainability of agricultural production. Therefore, quantifying groundwater recharge and plant water use is of great importance for sustainable water management in agroecosystems and maximizing irrigation efficiency. In the mountain-valley aquifers such as the Kaweah River watershed in the southern Central Valley California, mountain system recharge is a major component of recharge. Our recent study using geochemical data revealed that mountain block recharge is the primary natural recharge pathway in the watershed. This result contradicts results of an integrated groundwater-land surface model of the watershed that showed higher mountain front recharge (streamflow infiltration at the mountain front). In this study, we updated our conceptual geological model of the Kaweah River watershed to characterize major hydrologic pathways using ParFlow.CLM. Preliminary results showed that for this watershed mountain front recharge is the primary and mountain aquifer recharge the secondary pathways of groundwater recharge. Furthermore, we conducted three major field campaigns in two citrus orchards in the watershed to partition evapotranspiration (ET) fluxes between soil evaporation and plant transpiration using flux variance similarity approach and isotope- based ET artitioning methods. Field results showed that plant ranspiration was higher during mid day and equal or less than 50% of ET in early morning and late afternoon or evening. These data help to constrain vegetation parameters in the ParFlow.CLM model of the watershed. Our results are expected to greatly improve the characterization of ecohydrologic processes of the mountain-valley aquifer system. The findings are valuable for growers and roundwater sustainability agencies to formulate sustainable and effective groundwater management practices in highly managed agroecosystems.