Published by the American Geophysical Union as part of the Water Science and Application Series, Volume 9. Groundwater recharge, the flux of water across the water table, is arguably the most difficult component of the hydrologic cycle to measure. In arid and semiarid regions the problem is exacerbated by extremely small recharge fluxes that are highly variable in space and time. --from the Preface Groundwater Recharge in a Desert Environment: The Southwestern United States speaks to these issues by presenting new interpretations and research after more than two decades of discipline-wide study. Discussions ondeveloping environmental tracers to fingerprint sources and amounts of groundwater at the basin scalethe critical role of vegetation in hydroecological processesnew geophysical methods in quantifying channel rechargeapplying Geographical Information System (GIS) models to land surface processescoupling process-based vadose zone to groundwater modeling, and more make this book a significant resource for hydmlogists, biogeoscientists, and geochemists concerned with water and water-related issues in arid and semiarid regions.

This 116-page report presents the results of an investigation by the Utah Geological Survey of land subsidence and earth fissures in Cedar Valley, Iron County, Utah. Basin-fill sediments of the Cedar Valley Aquifer contain a high percentage of fine-grained material susceptible to compaction upon dewatering. Groundwater discharge in excess of recharge (groundwater mining) has lowered the potentiometric surface in Cedar Valley as much as 114 feet since 1939. Groundwater mining has caused permanent compaction of fine-grained sediments of the Cedar Valley aquifer, which has caused the land surface to subside, and a minimum of 8.3 miles of earth fissures to form. Recently acquired interferometric synthetic aperture radar imagery shows that land subsidence has affected approximately 100 mi² in Cedar Valley, but a lack of accurate historical benchmark elevation data over much of the valley prevents its detailed quantification. Continued groundwater mining and resultant subsidence will likely cause existing fissures to lengthen and new fissures to form which may eventually impact developed areas in Cedar Valley. This report also includes possible aquifer management options to help mitigate subsidence and fissure formation, and recommended guidelines for conducting subsidence-related hazard investigations prior to development.