Possible sources of nitrate to the springs of southern Gooding County, eastern Snake River Plain, Idaho

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The purpose of this report is to identify potential contamination sources that may be impacting springs discharging to the Snake River Farms aquaculture facility. Baldwin et al. (2006) identified a statistically significant increasing nitrate trend in springs supplying water to the Snake River Farms facility in southern Gooding County, Idaho. Continued observations at this facility show that nitrate concentrations and flow rates increase during the later portion of each year (October to December), likely caused by upstream irrigation recharge. Recharge that occurs via percolation can transport nitrogen to the regional aquifer, which, in turn, migrates laterally to the discharge sites at these springs. The chemical variability among springs observed at the Snake River Farms facility suggests that the complex geology underlying the Snake River Plain has created zones of high transmissivity that potentially channelize water with high nitrate concentrations toward spring discharge outlets north of the Snake River and, subsequently, into the Snake River Farms facility. These channels of high transmissivity are considered to be directly related to the emplacement of the Snake River Group, where paleo-river channels were buried by advancing basalt flows. An estimate of nitrogen loading from human, animal, and fertilizer sources was calculated to evaluate potential sources up-gradient of the Snake River Farm springs. These estimated amounts of nitrogen, along with isotope and personal care product and pharmaceutical (PCPP) data, indicate animal and human sources and commercial fertilizer are the most likely sources of nitrogen to springs near Snake River Farms. The land use and nitrate loading within a delineated ground water capture zone that is hydraulically up-gradient from Snake River Farms is the suspected source of elevated nitrate concentrations in these springs.

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ELECTRONIC FILE - Zoology: Multiple Species

SWAP (2/19/2016) citation:
Schorzman K, Baldwin J, Bokor J. 2009. Possible sources of nitrate to the springs of southern Gooding County, eastern Snake River Plain, Idaho. Boise (ID): Idaho Department of Environmental Quality, Technical Services and Twin Falls Regional Office. 41 p. Ground Water Quality Technical Report No.: 38. [accessed 2015 Jun 1]. https://www.deq.idaho.gov/media/471155-_water_data_reports_ground_water_...