Reports

We present geochronologic and geochemical data for Mesozoic rocks in the Black Mountain area northeast of Victorville, California, to supplement previous geologic mapping. These data, together with previously published results, limit the depositional age of the sedimentary Fairview Valley Formation to Early Jurassic, refine the ages and chemical compositions of selected units in the...

A Presidential Disaster Declaration was issued for Massachusetts, with a focus on the northwestern counties, following flooding from tropical storm Irene on August 28–29, 2011. Three to 10 inches of rain fell during the storm on soils that were susceptible to flash flooding because of wet antecedent conditions. The gage height at one U.S. Geological Survey (USGS) streamgage rose nearly...

In July (19 - 26) and November (17 - 18) of 1999, the USGS, in cooperation with the Florida Geological Survey (FGS), conducted two geophysical surveys in: (1) the Atlantic Ocean offshore of Florida's east coast from Orchid to Jupiter, FL, and (2) the Gulf of Mexico offshore of Venice, FL. This report serves as an archive of unprocessed digital boomer subbottom data, trackline maps...

From June 3 to 13, 2011, the U.S. Geological Survey conducted a geophysical survey to investigate the geologic controls on barrier island framework and long-term sediment transport along the oil spill mitigation sand berm constructed at the north end and just offshore of the Chandeleur Islands, LA. This effort is part of a broader USGS study, which seeks to better understand barrier...

Flow and water-quality models are being used to support the development of Total Maximum Daily Load (TMDL) plans for the Klamath River downstream of Upper Klamath Lake (UKL) in south-central Oregon. For riverine reaches, the RMA-2 and RMA-11 models were used, whereas the CE-QUAL-W2 model was used to simulate pooled reaches. The U.S. Geological Survey (USGS) was asked to review the most...

From April through July 2011, the U.S. Geological Survey collected surface-water samples from 69 water-quality stations and 3 flood-control structures in 4 major subbasins of the Mississippi River Basin to characterize the water quality during the 2011 Mississippi River flood. Most stations were sampled at least monthly for field parameters suspended sediment, nutrients, and selected...

Arctic and boreal ecosystems provide important breeding habitat for more than half of North America’s migratory birds as well as many resident species. Northern landscapes are projected to experience more pronounced climate-related changes in habitat than most other regions. These changes include increases in shrub growth, conversion of tundra to forest, alteration of wetlands, shifts in...

Afghanistan is endowed with a vast amount of mineral resources, and it is believed that the current economic state of the country could be greatly improved through investment in the extraction and production of these resources. In 2007, the “Preliminary Non-Fuel Resource Assessment of Afghanistan 2007” was completed by members of the U.S. Geological Survey and Afghan Geological Survey...

The watershed model SPARROW (Spatially Referenced Regressions on Watershed attributes) was used to estimate mean annual surface-water nutrient conditions (total nitrogen and total phosphorus) and to identify important nutrient sources in catchments of the Pacific Northwest region of the United States for 2002. Model-estimated nutrient yields were generally higher in catchments on the...

This fact sheet highlights findings included in a comprehensive new report (see USGS Professional Paper 1800) which investigated land-use change, economic characteristics, and rural community well-being in the Prairie Pothole Region of the United States. Once one of the largest grassland-wetlands ecosystems on earth, the North American prairie has experienced extensive conversion to...

The quality of the Nation’s water resources are vital to the health and well-being of both our communities and the natural landscapes we value. The U.S. Geological Survey investigates the occurrence, quantity, quality, distribution, and movement of surface water and groundwater and provides this information to engineers, scientists, managers, educators, and the general public. This...

The Trinity aquifer is an important source of groundwater in central Texas, including Bexar County, where population growth has resulted in an increased demand for water (Ashworth, 1983; Mace and others, 2000). Numerous springs issue from rock outcrops within and surrounding the Trinity aquifer in northern Bexar County (fig. 1). The effects of increased groundwater withdrawals from the...