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Elevated Nitrate Levels Associated with Septic Tanks in Carson Valley Groundwater, Nevada –USGS, in cooperation with Nevada's Douglas County and Carson Water Subconservancy District, investigated sources and transport of nitrates in the alluvial aquifer underlying the Carson Valley in Douglas County, Nevada. The study confirms that septic tanks are contaminating groundwater in the region with concentrations of nitrates, posing human health risks from contaminated drinking water. Conducted on a larger scale than previous investigations, the study showed that the amount of nitrate contamination is two times greater in suburban areas dominated by single-family homes with septic tanks, compared to areas that are more rural, with fewer homes on the land. (Press Release)
Nowcasting Bacteria on Beaches throughout the Great Lakes –The Great Lakes Restoration initiative (GLRI) (Beach Recreation Water Quality), in cooperation with 23 local and state agencies, expanded the use of predictive modeling at 45 beaches throughout the Great Lakes. (Report; Press Release) Local agencies measure fecal-indicator bacteria such as Escherichia coli (E. coli.) along with easily obtained environmental variables used as surrogates to estimate concentrations of fecal-indicator bacteria through a predictive modeling approach. Each beach model is based on a combination of explanatory variables, most commonly, turbidity, day-of-year, change in lake level over 24 hours, rainfall, wave height, and wind direction and speed.
Nowcast websites provide near real-time information on water-quality conditions at recreational swimming areas. The USGS has cooperated with local agencies on the Ohio Nowcast project since 2006. A pilot is under development in New York. The USGS will continue to collaborate with local agencies to expand Nowcasting to more beaches around the Great Lakes. Nowcast websites estimate the probability of exceeding the EPA bathing-water standard of 235 colony forming units per 100 milliliters (CFU/100 mL) based on the value of explanatory variables, which are entered into the Nowcast website by 9 AM each-and-every morning during the summer-swimming season. Using the result of the predictive models and the probability of exceeding the bathing-water standard, beach managers can make informed decisions on whether or not to close a beach.
Brine-Contaminated Groundwater in Northeastern Montana –USGS, in cooperation with the Fort Peck Tribe, reports on the extent and movement of contamination in the East Poplar oil field area in northeastern Montana. The contamination in shallow groundwater and the Poplar River is brine, which is saltier than seawater and is a byproduct as part of the process of extracting crude oil in the East Poplar oil field. Findings show that brine contaminated groundwater is generally moving towards the southwest, eventually discharging into the Missouri River. For more than half a century, millions of gallons of brine have been produced along with oil from the East Poplar oil field on the Fort Peck Indian Reservation. Until recently, the waste brine was placed in pits and ponds or injected into the ground through deep disposal wells and has made its way to the shallow groundwater and the Poplar River. Currently, the only approved method of brine disposal is to inject it deep into the ground. When the brine mixes with the groundwater in the area, it often makes the water unsuitable for domestic purposes. Currently, treated water from the Missouri River about 20 miles upstream of the city of Poplar is piped to the city and nearby residents. This information is used by the Fort Peck Tribes to direct future natural resource conservation efforts. (Report; Press Release)
Real-time Monitoring Pays Off for Tracking Nitrate Pulse in Mississippi River Basin to the Gulf of Mexico –Cutting edge optical sensor technology is being used in the Mississippi River basin to more accurately track the nitrate pulse from small streams, large tributaries and ultimately to the Gulf of Mexico. Excessive springtime nitrate runoff from agricultural land and other sources in the Mississippi drainage eventually flows into the Mississippi River. Downstream, this excess nitrate contributes to the Gulf of Mexico hypoxic zone, an area with low oxygen known commonly as the "dead zone." These optical sensors measure and transmit nitrate data every 15 minutes to 3 hours and are located at the mouth of the Mississippi River near Baton Rouge, LA, and at several large tributaries to the Mississippi River—including the Missouri River at Hermann, MO; Ohio River at Olmsted, IL; Ohio, Illinois River at Florence, IL; and Iowa River at Wapello, IA – to track how nitrate concentrations from different areas of the watershed pulse in response to rainfall and seasons. Nitrate sensors in Iowa, Illinois, Indiana, Nebraska, Kansas, Wisconsin, Missouri, and Arkansas provide new insights for researchers into the storage and transport of nitrate from headwaters to the Gulf of Mexico.
Nutrient Enriched Groundwater Contributes to Excessive Algal Growth in Fish Creek, Wyoming –USGS, in cooperation with the Teton Conservation District, analyzed groundwater flow and streamflow, and collected water, aquatic insect, and algal samples from 2007 to 2011 to characterize the stream and to compare data to neighboring rivers and streams. The study found greater growth of algae and other aquatic plants in Fish Creek than in nearby rivers and streams. This excess algae is related to the influx of nutrients—orthophosphate and nitrate—to the stream from groundwater. Sources of nutrients to the groundwater include septic tanks, sewage treatment plants, animal confinement areas, and lawn fertilizer. Because groundwater discharge into Fish Creek is such a large percentage of flow in the stream, such nutrient inputs are ultimately affecting rapid growth of algae and large aquatic plants in the summer and fall in Fish Creek, which, in turn, results in declining species of aquatic insects such as the caddsifly and mayfly. (Press Release)
Saltwater Intrusion in the Biscayne Aquifer, Florida –USGS, in cooperation with Miami-Dade County, have depicted saltwater intrusion in the Biscayne aquifer, which will help water managers protect the primary drinking water source for the county’s roughly 2.5 million residents. The new study, which uses information gathered through 2011, found that saltwater had intruded about 460 square miles of the mainland part of the county. The new report provides an updated understanding of the extent of saltwater in the aquifer, describing where saltwater has further intruded since last being mapped in 1995, where it has been pushed back toward the ocean and where it’s leaking from canals. Saltwater intrusion began in the area early in the 20th century when canals were dredged to drain the Everglades. As water levels in the Biscayne aquifer declined, saltwater from the ocean flowed inland along its base. (Press Release)
Mercury in the Boise River, Idaho –USGS, in cooperation with the City of Boise, published a study that documents low concentrations of mercury in water samples and high concentrations in two fish species already under Idaho state consumption advisories. This is the first year of a six-year watershed-based mercury monitoring program required in wastewater discharge permits for the City of Boise and other municipalities. City and USGS scientists will collect water and fish-tissue samples from the Boise River near Middleton again this fall. Sampling will rotate between one site and all six sites each year through 2018. (Press Release; Report)
Groundwater Study Assesses Potential for Contamination of Drinking-Water Aquifers in Los Angeles, California –USGS, in cooperation with the Water Replenishment District of Southern California, reported that contaminated groundwater found at shallow depths in the northeastern portion of the Central Groundwater Basin in southern California could migrate to greater depths where many drinking water supply wells are located. Over two million residents get approximately 60 percent of their drinking water supply from these deeper aquifers. There are multiple sites in the northeast portion of the basin where shallow groundwater contamination is already being investigated and remediated under the oversight of several federal and state regulatory agencies. The results of this study will allow the Water Replenishment District to anticipate possible future contaminant migration and to plan accordingly to protect uncontaminated areas. Additionally, regulatory agencies can use the study results to inform future monitoring and cleanup actions for contaminated sites located in the Central Groundwater Basin. (Press Release; Report)
Artificial Recharge Affects Groundwater Levels and Water Quality in San Bernardino County, California –USGS, in cooperation with the Hi-Desert Water District, reported that the artificial replenishment of the groundwater aquifer system in the west hydrogeologic unit of the Warren groundwater basin in San Bernardino County’s Yucca Valley resulted in a decrease of nitrate concentrations in groundwater samples and a rise in water levels. The nitrate concentrations of the replenishment water were lower than the native groundwater. (Press Release; Report)
Tracking Wastewater Contaminants in Red Creek, New York –The USGS New York Water Science Center has begun a pilot program to locate sources of leaking sewage from imperfect infrastructure and misconnection within the sewer system at three locations Milwaukee Estuary, Clinton River and the Rochester Embayment. As wastewater collection infrastructure (sanitary sewers) ages in the Great Lakes region, leakage of wastewater into nearby streams poses a contamination threat from pathogens and toxic contaminants. Locating sources of these leakages is a constant challenge for local wastewater utilities, and in collaboration with Monroe County, USGS will systematically track sources in a small urban basin within the Genesee River basin called Red Creek basin. New optical sensor technology for tracing sanitary sewage leakage to the source is being developed – including for optical properties, dissolved organic matter, eight human viruses, nine bovine viruses, three protozoa, and three pathogens related to fecal contamination, among other constituents. The findings will help local wastewater utilities to plan and implement restoration, and monitor effectiveness of solutions starting at these small tributaries within these larger dynamic systems.
Assessment of Phosphorus on Retired Agricultural Lands in Minnesota –USGS cooperated with the Minnesota Board of Water and Soil Resources and worked collaboratively with the Hawk Creek Watershed Project to examine phosphorus trends in the West Fork Beaver Creek Basin in Renville County, which has the largest number of “Reinvest in Minnesota” (RIM) land retirement contracts in the State. Among all conservation easement programs, a total of 24,218 acres of agricultural land were retired throughout Renville County, and 2,718 acres were retired in the West Fork Beaver Creek Basin from 1987 through 2012. Findings showed a significant downward trend in flow-weighted mean total-phosphorus concentrations from 1999 through 2008, which most likely reflected annual land retirement. Flow-weighted total-phosphorus concentrations increased substantially in 2009, which may be due to a number of factors, including industrial discharges, increases in drain tile installation, changes in land use including decreases in agricultural land retirement after 2008, increases in erosion, or increases in phosphorus applications to fields. Inclusion of land-retirement effects in agency planning along with other factors adds perspective to the broader picture of interdependent systems and allows agencies to make informed decisions on the benefits of perpetual easements compared to limited duration easements. (Report)
Nutrients and Pesticides Assessed in a Citrus-Production Region of Florida –USGS and the Florida Department of Agriculture & Consumer Services and the Southwest Florida Water Management District described nutrients and pesticides in groundwater underlying an important citrus-production region from 1999-2010. The results of quarterly sampling span changes in agrichemical usage and the onset of citrus greening disease (in 2005), which continues to be a serious threat to Florida and national citrus crops. The network has provided early warning of chemicals prone to leaching into underlying aquifers, documented temporal changes in concentrations, and assisted state agencies in the protection of groundwater quality and drinking-water supplies. (Report 1; Report 2)