Publications

The rural and unregulated Llano River watershed located in central Texas, USA, has a highly variable flow regime and a wide range of instantaneous peak flows. Abrupt transitions in surface lithology exist along the main-stem channel course. Both of these characteristics afford an opportunity to examine hydrologic, lithologic, and sedimentary controls on downstream changes in channel...

Baseline water-quality sampling was conducted for dissolved nutrients and for chemical and isotopic tracers at Kaloko-Honokōhau National Historical Park on the Island of Hawai'i. Existing and future urbanization in the surrounding areas have the potential to affect water quality in the Park, and so the National Park Service and the U.S. Geological Survey designed a water-sampling...

This study employs a hydrogeologic simulation approach to investigate subsurface fluid pressures for a landslide-prone section of the central California, USA, coast known as Devil's Slide. Understanding the relative changes in subsurface fluid pressures is important for systems, such as Devil's Slide, where slope creep can be interrupted by episodic slip events. Surface mapping...

This report is a user guide for the streamflow-hydrograph analysis methods provided with version 1.0 of the U.S. Geological Survey (USGS) Groundwater Toolbox computer program. These include six hydrograph-separation methods to determine the groundwater-discharge (base-flow) and surface-runoff components of streamflow—the Base-Flow Index (BFI; Standard and Modified), HYSEP (Fixed Interval...

The term organic matter refers to the remnants of all living material. This can include fallen leaves, yard waste, animal waste, downed timber, or the remains of any other plant and animal life. Organic matter is abundant both on land and in water. Investigating organic matter is necessary for understanding the fate and transport of carbon (a major constituent of organic matter). Organic...

Groundwater with elevated dissolved-solids concentrations—containing large concentrations of chloride, sodium, sulfate, and calcium—is present in the Mud Lake area of Eastern Idaho. The source of these solutes is unknown; however, an understanding of the geochemical sources and processes controlling their presence in groundwater in the Mud Lake area is needed to better understand the...

During May–June, 2013, the U.S. Geological Survey, in cooperation with Park County, Colorado, drilled and installed four groundwater monitoring wells in areas identified as needing new wells to provide adequate spatial coverage for monitoring water quality in the South Park basin. Lithologic logs and well-construction reports were prepared for each well, and wells were developed after...

Digital flood-inundation maps for a 39.7-mile reach of the Blue River and selected tributaries (Brush Creek, Indian Creek, and Dyke Branch) at Kansas City, Missouri, and vicinity, were created by the U.S. Geological Survey (USGS) in cooperation with the City of Kansas City, Missouri. The flood-inundation maps, accessed through the USGS Flood-Inundation Mapping Science Web site at http:/...

Answers for many critical water-related issues require solid-phase water-quality data that are representative, accurate, and consistent. Collection of suspended sediment samples for subsequent analyses of solid-phase constituents that represent water-column sediment concentrations requires use of appropriate isokinetic samplers and sampling techniques (Davis, 2005a). Recent review of...

In our directionally and continuously changing world, history still matters, and it does so in increasingly novel and important ways. Human adaptation to global change will rely heavily on robust baselines of historic environmental variability and detailed understanding of how both past and modern ecosystems have responded to both individual and multiple stressors. The question of global...

Atmospheric rivers are important mechanisms for transporting water vapor through the atmosphere outside the tropics. These long, narrow, transient corridors occur at low altitudes just ahead of the cold front in midlatitude cyclone systems. These rivers in the sky stitch together the components of the extratropical water cycle by providing large-scale horizontal water vapor transport.

A three-dimensional finite-difference model for part of the Mississippi River Valley alluvial aquifer in the Cache Critical Groundwater Area of eastern Arkansas was constructed to simulate potential future conditions of groundwater flow. The objectives of this study were to test different pilot point distributions to find reasonable estimates of aquifer properties for the alluvial...