Publications

The temporal-gravity method was used to estimate ground-water storage change and specific -yield values at wells near Rillito Creek, Tucson, Arizona, between early December 1992 and early January 1994. The method applies Newton's Law of Gravitation to measure changes in the local gravitational field of the Earth that are caused by changes in the mass and volume of ground water. Gravity...

Quitobaquito Springs, in Organ Pipe Cactus National Monument near the south end of the northwestward-trending Quitobaquito Hills, are less than 0.25 mile north of the international boundary between the United States and Mexico. The National Park Service is concerned that the natural flow from Quitobaquito Springs might be reduced by ground-water withdrawals in the adjacent State of...

An accounting system for estimating and distributing consumptive use of water by vegetation to water users was developed for the Colorado River to meet the requirements of a U.S. Supreme Court decree and used with data from calendar year 1984. The system is based on a water-budget method to estimate total consumptive use by vegetation which is apportioned to agricultural users by using...

No abstract available.

No abstract available.

No abstract available.

Havasu Creek, the second largest tributary of the Colorado River in Grand Canyon National Park, attracts numerous visitors each year owing to its spectacular scenery. Perennial streamflow seldom exceeds 2 cubic meters per second (m3/s), but supports important stands of riparian vegetation, forms unique travertine pools, and spills over spectacular waterfalls. Havasu Canyon is home to the...

Methods for computing the volume of sand deposited in the Colorado River in Grand Canyon National Park by floods in major tributaries and for determining redistribution of that sand by main-channel flows are required for successful management of sand-dependent riparian resources. We have derived flow, sediment transport, and bed evolution models based on a gridded topography developed...

Many regions, cities, and towns in the Western United States need new or expanded water resources because of both population growth and increased development. Any tools or data that can help in the evaluation of an area's potential water resources must be considered for this increasingly critical need. Remotely sensed satellite images and subsequent digital image processing have been...

The chemistry and toxicity of urban stormwater, streamflow, and bed material in the Phoenix, Arizona, area were characterized to determine if urban stormwater could degrade the quality of streams. Toxic phases of stormwater (oil and grease, suspended solids, dissolved metals, and dissolved organics) were identified to aid water-quality managers minimize the sources of toxicants. Acute...

Rill erosion, slumping, and fissuring develop on seepage faces of many sandbars along the Colorado River in the Grand Canyon. These processes, observed at low river stage, are a response to residual head gradients in the sandbars caused by the river-stage fluctuation. Three sandbars were instrumented with sensors for continual monitoring of pore pressure and ground-water temperature...

Stormwater and streamflow in the Phoenix, Arizona, area were monitored to determine the physical, chemical, and microbial characteristics of storm- water from areas having different land uses; to describe the characteristics of streamflow in a river that receives urban stormwater; and to estimate constituent loads in stormwater from unmonitored areas in Maricopa County, Arizona. Land use...