Publications

Kaloko-Honokōhau National Historical Park (KAHO) on western Hawaiʻi was established in 1978 to preserve, interpret, and perpetuate traditional Native Hawaiian culture and activities, including the preservation of a variety of culturally and ecologically significant water resources that are vital to this mission. KAHO water bodies provide habitat for 1 threatened, 11 endangered, and 3...

Recent studies have documented the presence of trace elements, organic compounds including polycyclic aromatic hydrocarbons, and radionuclides in sediment from the Colorado River delta and from sediment in some side canyons in Lake Powell, Utah and Arizona. The fate of many of these contaminants is of significant concern to the resource managers of the National Park Service Glen Canyon...

The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating over 4.5 million acres of farmland, and annually generating about 12 billion kilowatt hours of hydroelectric power. The Upper Colorado River Basin, part of the Colorado River Basin, encompasses more than 110,000 mi2 and is the source of much...

Tavasci Marsh is a large freshwater marsh within the Tuzigoot National Monument in central Arizona. It is the largest freshwater marsh in Arizona that is unconnected to the Colorado River and is designated as an Important Bird Area by the Audubon Society. The marsh has been altered significantly by previous land use and the monument’s managers are evaluating the restoration of the marsh...

Recent studies have shown that excessive dissolved-solids concentrations in water can have adverse effects on the environment and on agricultural, domestic, municipal, and industrial water users. Such effects motivated the U.S. Geological Survey’s National Water Quality Assessment Program to develop a SPAtially-Referenced Regression on Watershed Attributes (SPARROW) model that has...

We have developed a screening method for simplifying groundwater models by delineating areas within the domain that can be represented using steady-state groundwater recharge. The screening method is based on an analytical solution for the damping of sinusoidal infiltration variations in homogeneous soils in the vadose zone. The damping depth is defined as the depth at which the flux...

As groundwater becomes an increasingly important water resource worldwide, it is essential to understand how local geology affects groundwater quality, flowpaths and residence times. This study utilized multiple tracers to improve conceptual and numerical models of groundwater flow in the Middle San Pedro Basin in southeastern Arizona (USA) by determining recharge areas...

The National Park Service is responsible for monitoring the effects of visitor use on the quality of water, lakebed material (bottom sediments), and biota, in Lake Powell, Utah and Arizona. A sampling program was begun in 2010 to assess the presence, distribution, and concentrations of organic and inorganic compounds in the water column and bottom sediment. In response to an...

Time-lapse gravity data provide a direct, non-destructive method to monitor mass changes at scales from cm to km. But, the effectively infinite spatial sensitivity of gravity measurements can make it difficult to isolate the signal of interest. The variable-baseline gravity gradient method, based on the difference of measurements between two gravimeters, is an alternative to the...

Flooding is among the costliest natural disasters in terms of loss of life and property in Arizona, which is why the accurate estimation of flood frequency and magnitude is crucial for proper structural design and accurate floodplain mapping. Current guidelines for flood frequency analysis in the United States are described in Bulletin 17B (B17B), yet since B17B’s publication in 1982...

A continuous active sampling method was compared to continuous passive and discrete sampling methods for the sampling of trace organic compounds (TOCs) in water. Results from each method are compared and contrasted in order to provide information for future investigators to use while selecting appropriate sampling methods for their research. The continuous low-level aquatic monitoring...

The Field Manual for the Collection of Navajo Nation Streamflow-Gage Data (Navajo Field Manual) is based on established (standard) U.S. Geological Survey streamflow-gaging methods and provides guidelines specifically designed for the Navajo Department of Water Resources personnel who establish and maintain streamflow gages. The Navajo Field Manual addresses field visits, including...