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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)
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)
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)
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)
Nutrient Yields Related to Watershed Settings in Central and Eastern North Carolina –USGS, in cooperation with the North Carolina Department of Environment and Natural Resources, Division of Water Quality, assessed nutrient yields in watersheds in central and eastern North Carolina, 1997-2008. Based on monitoring at 48 stream sites, the study establishes relations among watershed variables that affect nutrient export. Findings can be used to support the development and prioritization of management strategies for restoring nutrient-impaired streams. (Report)
Continuous Water Quality Available for Mattawoman Creek, Maryland –USGS, in cooperation with the Charles County Department of Planning and Growth Management, Maryland Department of the Environment, and Maryland Geological Survey, assessed discrete and continuous water-quality monitoring data for Mattawoman Creek in Charles County, Maryland, 2000–11. Mattawoman Creek is a fourth-order Maryland tributary to the tidal freshwater Potomac River; the creek’s watershed is experiencing development pressure due to its proximity to Washington, D.C. Data were analyzed for the purpose of describing ambient water quality, identifying potential contaminant sources, and quantifying nutrient and sediment loads to the tidal freshwater Mattawoman estuary. (Report)
Water Quality Assessed in 10 Major Iowa Tributaries to the Mississippi and Missouri Rivers –USGS, cooperation with the Iowa Department of Natural Resources, characterized water quality (concentrations and stream loads) near the mouths of 10 major Iowa tributaries to the Mississippi and Missouri Rivers from March 2004 through September 2008. Constituent concentrations in Iowa streams exhibit streamflow, seasonal, and spatial patterns related to the landform and climate gradients across the studied basins. For example, nitrogen concentrations (total nitrogen and nitrate plus nitrite) increased with low and moderate streamflows, but decreased with high streamflows. Total phosphorus, suspended sediment, and turbidity were greatest from the steep, loess-dominated southwestern Iowa basins. Nutrient concentrations, though not regulated for drinking water at the study sites, were high compared to drinking-water limits and criteria for protection of aquatic life proposed for other Midwestern states. Loads and yields also differed among sites and years. (Full report)
Increased Sediment and Nutrient Delivery to Chesapeake Bay as Susquehanna Reservoirs New Sediment Capacity –USGS compared storm-delivery of sediments and nutrients from the Susquehanna River over the past 34 years. Findings showed that the Susquehanna River delivered more sediment and phosphorus to the Chesapeake Bay in 2011 than in any year since 1978, when monitoring of this delivery began. The large sediment and phosphorus inputs resulted largely from Tropical Storm Lee in September 2011, in combination with accumulations of sediment over time in three large Susquehanna reservoirs: Safe Harbor Dam and Holtwood Dam in Pennsylvania and Conowingo Dam in Maryland. Sediment accumulations in the reservoirs have increased the potential for sediment delivery during any given storm event, which can help to counteract some of the extensive basin-wide efforts—such as through agricultural best management practices, wastewater-treatment plant upgrades, stormwater management, and other actions—to reduce inputs of sediments and nutrients reaching the Bay from its many tributaries. (Full report; Virginia Water Central News article)
High Concentrations of Nitrate and Perchlorate in Some Inland Empire Groundwater in southern California –USGS in cooperation with California State Water Resources Control Board, showed elevated nitrate in one quarter of the aquifer system used for Inland Empire public water supply. Additionally, high concentrations of perchlorate were detected in 11 percent of the aquifer system and in moderate concentrations in about 50 percent. This aquifer system, located in Riverside and San Bernardino Counties, includes the Upper Santa Ana Valley, San Jacinto, and Elsinore groundwater basins, although, high nitrate and perchlorate concentrations were not found in the Elsinore groundwater basin. Sources of nitrate include agriculture, effluent from wastewater treatment plants, and septic systems. Perchlorate sources include rocket fuel, fireworks, safety flares, and fertilizers. Elevated concentrations of both nitrate and perchlorate in drinking water have been associated with adverse health effects and are monitored by the California Department of Public Health. (Full report; Fact Sheet; Press release) This study is part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program that is characterizing groundwater quality in 120 basins that supply about 95 percent of public groundwater supplies.
Real-time monitoring of nitrate in streams across Iowa –USGS, in cooperation/partnership with the Iowa Department of Natural Resources (Geological and Water Survey), The Nature Conservancy, U.S. Fish and Wildlife Service, municipal water supply and waste-water utilities, watershed groups, and agriculture industry groups, are operating a real-time data network that includes nitrate monitoring at 13 sites. Clickable maps link to the USGS NWIS data and show a plot of real-time nitrate concentrations in context of the previous 7 days. The nitrate data are valuable for diverse uses, including managing drinking water supplies and stream ecological health and tracking watershed improvement. (Contact: Jessica Garrett, firstname.lastname@example.org, (319) 358-3625). Learn about similar nitrate monitoring in Minnesota by contacting Chris Ellison, email@example.com, (763) 783-3121)
Water quality improvements and best-management practices in agricultural watersheds in Wisconsin –USGS, in cooperation with the Wisconsin Department of Natural Resources, assessed the effectiveness of watershed-management practices, including fencing, streambank protection, barnyard-runoff control, and other practices-for controlling nonpoint-source contamination for the largely agricultural and wooded Eagle Creek and Joos Valley Creek Watersheds. Water quality improvements are attributed to the implemented management practices and to a reduction in the number of cattle in the watersheds.
Water-quality trends and increasing urban land use near Oklahoma City, Oklahoma –USGS, in cooperation with the City of Oklahoma City, tracked increasing urban land use and water-quality trends in nitrogen, phosphorus and some pesticides from 1999-2009 in parts of the North Canadian River watershed, downstream of Oklahoma City, Oklahoma (Press release; Fact Sheet; USGS report). Increases in concentrations in nitrogen, phosphorus, and some pesticides may have been caused by changes in point-source wastewater discharges, urban development, population growth, streamflow, and/or agricultural activities.
Nitrate and wastewater compounds in the Barton Springs Zone, South-Central Texas –USGS, in cooperation with the City of Austin, the City of Dripping Springs, the Barton Springs/Edwards Aquifer Conservation District, the Lower Colorado River Authority, Hays County, and Travis County, released a report characterizing concentrations and isotopic compositions of nitrate and concentrations of wastewater compounds in the Barton Springs zone, and their potential relation to urban development. (Fact sheet, Full report)
Applications of treated municipal wastewater and other sources of nitrate in groundwater beneath Leon and Wakulla Counties, Florida –USGS, in cooperation with the City of Tallahassee, studied the sources and transport of nitrate-nitrogen in groundwater associated with agricultural sprayfields (related to disposal of treated municipal wastewater), along with other sources of nitrate (including atmospheric deposition, onsite sewage disposal systems, disposal of biosolids by land spreading, creeks discharging into sinks, domestic fertilizer application, and livestock wastes).(Full report)