[en] An experiment is described wherein fluorescein dye was introduced into the James River Estuary and its subsequent dispersion and dissolution-was measured. Results of this experiment are discussed in relation to the oceanography of the estuary and are compared with the dispersion predicted using various techniques described in literature. (author)

[en] Emissions of greenhouse gases and aerosols from human activities continue to alter the climate and likely will have significant impacts on the terrestrial hydrological cycle and water quality, especially in arid and semiarid regions. We applied an improved Soil and Water Assessment Tool (SWAT) to evaluate impacts of increased atmospheric CO₂ concentration and potential climate change on the water cycle and nitrogen loads in the semiarid James River Basin (JRB) in the Midwestern United States. We assessed responses of water yield, soil water content, groundwater recharge, and nitrate nitrogen (NO₃–N) load under hypothetical climate-sensitivity scenarios in terms of CO₂, precipitation, and air temperature. We extended our predictions of the dynamics of these hydrological variables into the mid-21st century with downscaled climate projections integrated across output from six General Circulation Models. Our simulation results compared against the baseline period 1980 to 2009 suggest the JRB hydrological system is highly responsive to rising levels of CO₂ concentration and potential climate change. Under our scenarios, substantial decrease in precipitation and increase in air temperature by the mid-21st century could result in significant reduction in water yield, soil water content, and groundwater recharge. Our model also estimated decreased NO₃–N load to streams, which could be beneficial, but a concomitant increase in NO₃–N concentration due to a decrease in streamflow likely would degrade stream water and threaten aquatic ecosystems. These results highlight possible risks of drought, water supply shortage, and water quality degradation in this basin. - Highlights: ► We used a modified version of SWAT to more accurately simulate the effects of CO₂. ► Our sensitivity analysis indicated this basin is very responsive to climate change. ► Downscaled GCM outputs showed decreased precipitation and increased temperature. ► There may be large reductions in water yield, soil moisture, and recharge. ► Substantial decreases in NO₃–N load, but increases in concentration, could occur.

No abstract available

No abstract available

[en] Thermal plume entrainment studies indicate little or no entrainment of fish or fish eggs by the plume. Number of individuals and number of species were highest in early summer and declined in late summer and fall. Many fish remain in this vicinity for extended periods because the area is a nursery ground

No abstract available

No abstract available

[en] ⁷Be is measured directly in surficial sediments in a low-level gamma-ray spectrometer. Nominal 200-gram samples are placed in a 550-cm³ Marinelli beaker on a Ge(Li) detector for 200-minute counting times. Using a detector with 22% relative photopeak efficiency and 1.8 Kev FWHM resolution yields one count per 630 disintegrations and a detection limit of approximately 60 pCi. Surficial sediments taken from the James and Susquehanna Rivers and from Chesapeake Bay were analyzed. Concentrations of ⁷Be found range from not detectable to 2.6 pCi/g corresponding to areal concentrations as high as 1.7 pCi/cm². ⁷Be is more frequently found in sediments taken from zones of high deposition rate than in low deposition areas. Highest concentrations are found in the high deposition rate area associated with the turbidity maximum in the James. Whether or not salinity directly affects ⁷Be concentrations is not apparent in the present data. ⁷Be is present in sediments taken from fresh and brackish areas with salinities as high as 15 to 20%. Higher salinity areas have not yet been sampled

[en] The Department of the Army is authorized to build and operate nuclear reactors for defense purposes under Paragraph 91b of the Atomic Energy Act of 1954 (1). As part of the Army Reactor Program, the United States Army Corps of Engineers (Corps) is responsible for nuclear reactor engineering and design, reactor construction, and decommissioning design and implementation (2). The Corps is currently focused on ensuring the safety and security of the Army's three deactivated power reactors and planning for their final decommissioning. To support decommissioning cost projections, the Corps is gathering information on the residual radiological and chemical hazards associated with each reactor, starting with the MH-1A reactor on the Sturgis Barge (3). Because the Sturgis Barge is moored in the James River Reserve Fleet, there were unique challenges that had to be overcome during the characterization survey and others that will become a concern when final decommissioning is to be per formed

No abstract available