The local meteoric water line (LMWL), the functional relationship between locally measured values of δ18O and δ2H in precipitation, represents the isotopic composition of water entering hydrologic systems. The degree to which the LMWL departs from the global meteoric water line (GMWL), moreover, can reveal important information about meteoric sources of water (e.g. oceanic or terrestrial) and atmospheric conditions during transport. Here we characterize the isotopic composition of precipitation within an experimental watershed in the Western US that is subject to large topographic and seasonal gradients in precipitation. Interpreting the hydrometeorologic and spatial controls on precipitation, we constructed a seasonally weighted LMWL for southwestern Idaho that is expressed by the equation δ2H = 7.40 × δ18O − 2.17. A seasonally weighted LMWL that is based on weighting isotopic concentrations by climatic precipitation volumes is novel, and we argue better represents the significant seasonality of precipitation in the region. The developed LMWL is considerably influenced by the semiarid climate experienced in southwest Idaho, yielding a slope and y‐intercept lower than the GMWL (δ2H = 8 × δ18O + 10). Moderate to strong correlations exist between the isotopic composition of precipitation from individual events and surface meteorologic variables, specifically surface air temperature, relative humidity, and precipitation amount. A strong negative correlation exists between the annual average isotopic composition of precipitation and elevation at individual collection sites, with a lapse rate of −0.22‰/100 m. Copyright © 2016 John Wiley & Sons, Ltd.

This fact sheet describes baseline water quality of the Equus Beds aquifer and Little Arkansas River and water-quality effects of artificial recharge by the city of Wichita associated with Phase I (2007-present) of the Aquifer Storage and Recovery project. During 1995 through 2012, more than 8,800 surface water and groundwater water-quality samples were collected and analyzed for more than 400 compounds, including most of the compounds on the U.S. Environmental Protection Agency's primary drinking-water standards maximum contaminant level list and secondary drinkingwater regulations secondary maximum contaminant level list. Water-quality constituents of concern discussed in detail in this fact sheet are chloride, arsenic, total coliform bacteria, and atrazine. Sulfate, nitrate, iron, manganese, oxidation-reduction potential, and specific conductance also are constituents of concern and are discussed to a lesser extent.

received from Equus Beds Groundwater Management District Number 2 (GMD2) managers Mike Dealy and Tim Boese. Gratitude is also expressed to Terryl Pajor, Vernon Strasser, and laboratory staff at the city of Wichita Municipal Water and Wastewater Laboratory for laboratory analyses. Technical colleague reviews by Scott Prinos (U.S. Geological Survey [USGS]) and Mandy Stone (USGS) contributed to improved technical and editorial clarity of the report. Trudy Bennett, Carlen Collins, and Barb Dague of the USGS Kansas Water Science Center collected water samples, measured water levels, and maintained automated equipment at monitoring sites. Deneise Schneider (USGS) completed data entry, database maintenance, and quality assurance.