Journal of Nevada Water Resources Association

 
 

The Economic Cost of Unanticipated Water Supply Reductions for Agricultural Producers in the Humboldt River Region

Michael H. Taylor, Jacob Kingsley, Kimberly Rollins, Lec Bowman

ABSTRACT
This article develops economic models for a cow-calf ranching operation and an alfalfa hay operation in the Humboldt River Region (HRR) that use surface water for irrigation. The models were built and parameterized through consultation with ranchers and farmers in the HRR in order to represent typical agricultural operations in the region. The models were used to calculate the economic value to an operation of an acre-foot of water not received due to an unanticipated supply reduction. This analysis was conducted to support the conjunctive management of surface and groundwater in the HRR by providing estimates of the economic value of the water that surface water users expect but do not receive due to interference from upstream groundwater pumping.
For the cow-calf ranch model, reduced water deliveries impact ranch profits by reducing the amount of low-cost feed grown on the ranch. The increase in average feed costs forces the ranch to reduce its herd size, which lowers the number of new calf births and, as a result, lowers future profits from livestock sales. The cow-calf ranching model predicts an economic value of an acre-foot of water for the cow-calf ranch in the range of $215 per acre-foot for unanticipated supply interruptions that occur in normal water years, and upwards of $290 per acre-foot for supply interruptions that occur during drought. Model results do not provide evidence that the economic value of an acre-foot of water increases with the length of the unanticipated supply reduction.
Keywords: Water economics, water policy, alfalfa hay, livestock ranching, agriculture, conjunctive management, Humboldt River
Authors: MICHAEL H. TAYLOR, Department of Economics, University of Nevada Reno, 1664 North Virginia Street, Mail Stop 204, Reno, NV, 89557 (taylor@unr.edu), JACOB KINGSLEY, KIMBERLY ROLLINS, ALEC BOWMAN.
Citation: Taylor, M., et al., 2021, The economic cost of unanticipated water supply reductions for agricultural producers in the Humboldt River Region. Journal of the Nevada Water Resources Association, Winter 2021, p. 5-41.
DOI: 10.22542/jnwra/2021/1/1. Copyright 2021 Nevada Water Resources Association























The Influence of Compost on Arsenic Removal from Contaminated Groundwater in Granitic Aquifers

Porraket Dechdacho, Ronald L. Hershey,Lazaro J. Perez, Rishi Parashar

ABSTRACT
Arsenic is classified as a group 1 human carcinogen according to the World Health Organization. Anthropogenic activities such as mining and wood preservation contribute to arsenic contamination of surface and sub-surface water. Most of the currently available remediation strategies to remove arsenic involve slow processes and produce residues that are difficult to treat or dispose. In this study, with an objective to develop alternative arsenic remediation strategies, we examined removal of arsenic using organic compost as a potential adsorbent. We ran saturated column experiments by injecting 10 mg/L arsenic spiked synthetic groundwater to compare the arsenic removal between the presence and absence of compost in granitic aquifers. The water analysis showed the compost removed 14 percent (%) of arsenic from the contaminated water within 16 min, while there was no change in arsenic concentration in the experiment without compost. The results illustrated that arsenic treatment using compost is feasible for contaminated groundwater remediation. Different pH evolution was also observed in both experiments. The column with only decomposed granite showed a small decrease in pH, which we believed was caused by a dissolution of silicate minerals in the granite. The column with compost exhibited a more fluctuating pH. An abrupt drop in pH was observed at an early time period and thought to be caused by release of H+ from organic anions after water interacted with the compost. After the initial period, the change in pH was primarily driven by mixing of the water used for column saturation and the injected contaminated groundwater. The major factors identified for arsenic removal are the presence of iron (Fe) and a lower starting pH condition in the compost experiment, which provides more available sorption sites leading to higher arsenic sorption.

Keywords: Arsenic remediation, laboratory experiments, reactive transport
Authors: PORRAKET DECHDACHO, Desert Research Institute, 2215 RaggioPkwy, Reno, NV, 89512 (Porra.Dechdacho@dri.edu) Second affiliation: University of Nevada Reno, 1664 North Virginia Street, Mail Stop 154, Reno, NV, 89557, RONALD L. HERSHEY, LAZARO J. PEREZ, RISHI PARASHAR.
Citation: Dechdacho, P., et al., 2021, The influence of compost on arsenic removal from contaminated groundwater in granitic aquifers. Journal of the Nevada Water Resources Association, Winter 2021,p. 42-54.
DOI: 10.22542/jnwra/2021/1/2. Copyright 2021 Nevada Water Resources Association