GEOCHEMICAL AND AGE TRACER DATA FROM NORTHERN GREAT BASIN SPRINGS: PRELIMINARY FINDINGS FROM HART MOUNTAIN AND SHELDON NATIONAL WILDLIFE REFUGES

The Northern Great Basin has limited perennial surface water, resulting in a high reliance on springs and seeps for seasonal and permanent water sources and riparian habitat. Water users have developed many springs in this region to provide water for livestock, wildlife, recreational use, and to support wildland fire management. Despite their importance, the basic hydrology of most springs in the Northern Great Basin is not well understood. The U.S. Fish and Wildlife Service (USFWS) manages two national wildlife refuges within this region – Hart Mountain National Antelope Refuge, in Oregon (Hart), and Sheldon National Wildlife Refuge, in Nevada (Sheldon). In partnership with USFWS, the U.S. Geological Survey is investigating the occurrence and persistence of springs within these refuges. The study is being conducted in two parts: 1) field assessments and sample collection to assess the source, depth, and relative “age” of water produced by selected springs and seeps, and 2) statistical and geospatial analysis using field observations and sample data to understand the hydrology of the spring systems. The results of the study will inform USFWS management and conservation objectives for these springs. Preliminary findings from the Hart and Sheldon field efforts will be discussed in this talk.