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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #421270
Research Project: Improving Water Productivity and Quality in Irrigated Landscapes of the Northwestern United States

Location: Northwest Irrigation and Soils Research

Title: Using Sr and U isotopic tracers to identify water flow paths and solute sources in agricultural areas in Idaho: understanding agrohydrology processes of Dryland Critical Zone

Author
item HERRERA, JENNIFER - University Of Texas - El Paso
item MA, LIN - University Of Texas - El Paso
item PIERCE, JENNIFER - Boise State University
item Bjorneberg, David - Dave
item Huber, David

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Irrigation in agricultural systems changes hydrological cycles by redistributing surface water and groundwater, modifies Critical Zone elemental cycles, and impacts water quantity and quality due to land use changes and climate variability. Here we focus on understanding the agrohydrologic processes in Dryland Critical Zone at an extensively irrigated agricultural area in south central Idaho. The Snake River and the underlying Snake River Plain Aquifer are principal water sources for over 900,000 acres of farmland and 200,000 people in southern Idaho. The Snake River originates in Wyoming and runs across southern Idaho, providing water for irrigation in Kimberly, Idaho, our focus study area, and known for its agricultural activity. With the increase in crop production for future population growth, monitoring water quantity and quality is a top priority, and it is still not fully understood that how the subsurface flows in the fractured basalt aquifer systems return excess water, and nutrients from the agricultural fields back into the Snake River. For this study, different types of agricultural water samples were collected in July 2024 at the end of the irrigation season from multiple locations along the Snake River, agricultural irrigation canals, regional groundwater wells, and underground tunnels that were created in the 1920s and used to divert irrigation water and prevent floods. Water chemistry parameters (major, trace elements, and alkalinity) and isotope ratios of 87Sr/86Sr and 234U/238U systems will be measured to determine the agrohydrologic signatures for the Kimberly study area. We will use U and Sr isotope ratios as tracers, to improve our understanding of the infiltration depth, flow paths and directions, and residence time of the water source and to allow for a clear picture of the irrigation practices and its effects on flow of natural river systems. Furthermore, we will understand better the distribution of dissolved inorganic carbon, trace elements and nutrients along the irrigation water pathways that eventually merge into the Colombia River and drain into the Pacific Ocean.