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Sandra S. Embrey

Publications and source records attributed to Sandra S. Embrey.

9 recordsLinked to original sources
USGS2007

Nutrient and Suspended-Sediment Transport and Trends in the Columbia River and Puget Sound Basins, 1993-2003

This study focused on three areas that might be of interest to water-quality managers in the Pacific Northwest: (1) annual loads of total nitrogen (TN), total phosphorus (TP) and suspended sediment (SS) transported through the Columbia River and Puget Sound Basins, (2) annual yields of TN, TP, and SS relative to differences in landscape and climatic conditions between subbasin catchments (drainage basins), and (3) trends in TN, TP, and SS concentrations and loads in comparison to changes in landscape and climatic conditions in the catchments. During water year 2000, an average streamflow year in the Pacific Northwest, the Columbia River discharged about 570,000 pounds per day of TN, about 55,000 pounds per day of TP, and about 14,000 tons per day of SS to the Pacific Ocean. The Snake, Yakima, Deschutes, and Willamette Rivers contributed most of the load discharged to the Columbia River. Point-source nutrient loads to the catchments (almost exclusively from municipal wastewater treatment plants) generally were a small percentage of the total in-stream nutrient loads; however, in some reaches of the Spokane, Boise, Walla Walla, and Willamette River Basins, point sources were responsible for much of the annual in-stream nutrient load. Point-source nutrient loads generally were a small percentage of the total catchment nutrient loads compared to nonpoint sources, except for a few catchments where point-source loads comprised as much as 30 percent of the TN load and as much as 80 percent of the TP load. The annual TN and TP loads from point sources discharging directly to the Puget Sound were about equal to the annual loads from eight major tributaries. Yields of TN, TP, and SS generally were greater in catchments west of the Cascade Range. A multiple linear regression analysis showed that TN yields were significantly (p < 0.05) and positively related to precipitation, atmospheric nitrogen load, fertilizer and manure load, and point-source load, and were negatively related to average slope. TP yields were significantly related positively to precipitation, and point-source load and SS yields were significantly related positively to precipitation. Forty-eight percent of the available monitoring sites for TN had significant trends in concentration (2 increasing, 19 decreasing), 32 percent of the available sites for TP had significant trends in concentration (7 increasing, 9 decreasing), and 40 percent of the available sites for SS had significant trends in concentration (4 increasing, 15 decreasing). The trends in load followed a similar pattern, but with fewer sites showing significant trends. The results from this study indicate that inputs from nonpoint sources of nutrients probably have decreased over time in many of the catchments. Despite the generally small contribution of point-source nutrient loads, they still may have been partially responsible for the significant decreasing trends for nutrients at sites where the total point-source nutrient loads to the catchments equaled a substantial proportion of the in-stream load.

Scientific Investigations Report↗
USGS2006

Microbial Quality of the Nation's Ground-Water Resources, 1993-2004

As part of the National Water-Quality Assessment (NAWQA) program, microbiological data were collected from wells in 22 NAWQA study units during 1993-2004. The wells constituted the sampling networks for three major NAWQA efforts--the major aquifer study, the land-use study, and source-water quality assessments of ground water used for public supplies. Sixteen principal aquifers were represented by these well networks. Samples of untreated ground water were analyzed for concentrations of fecal-indicator bacteria, which included the total-coliform bacteria, fecal-coliform bacteria, and Escherichia coli, and for the presence of somatic and male-specific coliphage viruses. Analyses of the samples showed that coliform bacteria occur relatively frequently-nearly 30 percent of all wells tested positive-and that domestic wells commonly are contaminated by total coliform bacteria, with 33 percent of these wells testing positive. Coliphage viruses were present in 10 percent or fewer of the wells sampled in the Central Columbia Plateau-Yakima, Georgia-Florida, San Joaquin, and Trinity study units, which represent the Columbia Plateau, Floridan, Central Valley, and Coastal Lowlands principal aquifers, respectively. The frequency of detections and concentrations of total coliform bacteria generally were higher in samples from domestic wells than in samples from public-supply wells; in fractured or porous rock materials (carbonate rocks) than in unconsolidated materials (mixtures of sand, gravel, clay); and in principal aquifers with median depths of sampled wells ranging from 100 to 200 feet than in principal aquifers with median depths of sampled wells less than 100 feet or greater than 200 feet. The waters most affected by the presence of coliform bacteria were those in the Valley and Ridge, the Floridan, and the Piedmont and Blue Ridge aquifers, where more than 50 percent of the study wells tested positive for these bacteria. The numbers of wells with detections of coliform bacteria were significantly lower for the Glacial Deposits, Stream and River Valley, Columbia Plateau, Basin and Range, High Plains, Southeastern Coastal Plain, and Coastal Lowlands aquifers. Of the 16 principal aquifers sampled, wells in the Valley and Ridge had the highest overall concentrations of total coliforms, with a median of 2 colony-forming units per 100 milliliters. Elevated concentrations of coliform bacteria (greater than 300 colony-forming units per 100 milliliters) also were reported for wells completed in the Mississippian-Pennsylvanian aquifer and the Ordovician aquifer in lower Tennessee. More than 50 percent of wells completed in carbonate or crystalline rocks tested positive for coliform bacteria. The Floridan, Piedmont and Blue Ridge, Ordovician (lower Tennessee), and Valley and Ridge aquifers are composed of these types of rocks. The lowest detection frequencies (less than 5 percent) were for wells in the Basin and Range and the Snake River aquifers. The materials that constitute these aquifers primarily are unconsolidated sand, gravel, and clay, or basalt with interbeds of sand, gravel, or clay. No strong correlations between concentrations of total coliforms and well depths were identified, nor were there any correlations between total coliform concentrations and selected chemical constituents in the waters. Other factors, such as geohydrologic characteristics, proximity of contaminating sources, interactions with surface water, or well-construction features (including the age of the well), likely control the presence and transport of coliform bacteria in the ground water.

Scientific Investigations Report↗
USGS2004

Water Quality in the Yakima River Basin, Washington, 1999-2000

This report contains the major findings of a 1999?2000 assessment of water quality in streams and drains in the Yakima River Basin. It is one of a series of reports by the NAWQA Program that present major findings on water resources in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is assessed at many scales?from large rivers that drain lands having many uses to small agricultural watersheds?and is discussed in terms of local, State, and regional issues. Conditions in the Yakima River Basin are compared to those found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, Tribal, State, or local agencies; universities; public interest groups; or the private sector. The information will be useful in addressing a number of current issues, such as source-water protection, pesticide registration, human health, drinking water, hypoxia and excessive growth of algae and plants, the effects of agricultural land use on water quality, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of water resources in areas near where they live, and how that water quality compares to the quality of water in other areas across the Nation. Other products describing water-quality conditions in the Yakima River Basin are available. Detailed technical information, data and analyses, methodology, and maps that support the findings presented in this report can be accessed from http://or.water.usgs.gov/yakima. Other reports in this series and data collected from other basins can be accessed from the national NAWQA Web site (http://water.usgs.gov/nawqa).

Circular↗
USGS2003

Concentrations and loads of suspended sediment and nutrients in surface water of the Yakima River basin, Washington, 1999-2000 [electronic resource] : with an analysis of trends in concentrations

Spatial and temporal variations in concentrations and loads of suspended sediment and nutrients in surface water of the Yakima River Basin were assessed using data collected during 1999?2000 as part of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program. Samples were collected at 34 sites located throughout the Basin in August 1999 using a Lagrangian sampling design, and also were collected weekly and monthly from May 1999 through January 2000 at three of the sites. Nutrient and sediment data collected at various time intervals from 1973 through 2001 by the USGS, Bureau of Reclamation, Washington State Department of Ecology, and Roza-Sunnyside Board of Joint Control were used to assess trends in concentrations. During irrigation season (mid-March to mid-October), concentrations of suspended sediment and nutrients in the Yakima River increase as relatively pristine water from the forested headwaters moves downstream and mixes with discharges from streams, agricultural drains, and wastewater treatment plants. Concentrations of nutrients also depend partly on the proportions of mixing between river water and discharges: in years of ample water supply in headwater reservoirs, more water is released during irrigation season and there is more dilution of nutrients discharged to the river downstream. For example, streamflow from river mile (RM) 103.7 to RM 72 in August 1999 exceeded streamflow in July 1988 by a factor of almost 2.5, but loads of total nitrogen and phosphorus discharged to the reach from streams, drains, and wastewater treatment plants were only 1.2 and 1.1 times larger. In years of ample water supply, canal water, which is diverted from either the Yakima or Naches River, makes up more of the flow in drains and streams carrying agricultural return flows. The canal water dilutes nutrients (especially nitrate) transported to the drains and streams in runoff from fields and in discharges from subsurface field drains and the shallow ground-water system. The average concentration of total nitrogen in drains and streams discharging to the Yakima River from RM 103.7 to RM 72 in August 1999 was 2.63 mg/L, and in July 1988 was 3.16 mg/L; average concentrations of total phosphorus were 0.20 and 0.26 mg/L. After irrigation season, streamflow in agricultural drains decreases because irrigation water is no longer diverted from the Yakima and Naches Rivers. As a result, concentrations of total nitrogen in drains increase because nitrate, which constitutes much of total nitrogen, continues to enter the drains from subsurface drains and shallow ground water. Concentrations of total phosphorus and suspended sediment often decrease, because they are transported to the drains in runoff of irrigation water from fields. In Granger Drain, concentrations of total nitrogen ranged from 2-4 mg/L during irrigation season and increased to about 6 mg/L after irrigation season, and concentrations of total phosphorus, as high as 1 mg/L, decreased to about 0.2 mg/L. In calendar year 1999, Moxee Drain transported an average of 28,000 lb/d (pounds per day) of suspended sediment, 380 lb/d of total nitrogen, and 46 lb/d of total phosphorus to the Yakima River. These loads were about half the average loads transported by Granger Drain during the same period. Average streamflows were similar for the two drains, so the difference in loads was due to differences in constituent concentrations: those in Moxee Drain were about 40-60 percent less than those in Granger Drain. Loads of suspended sediment and total phosphorus in Moxee and Granger Drains were nearly four times higher during irrigation season than during the non-irrigation season because with increased flow during irrigation season, concentrations of suspended sediment and total phosphorus are usually higher. Loads of nitrate in the drains were about the same in both seasons because nitrate concentrations are higher during the non-irrigation season.

Water-Resources Investigations Report↗
USGS2002

Pesticides in surface water of the Yakima River basin, Washington, 1999–2000 — Their occurrence and an assessment of factors affecting concentrations and loads

The occurrence, distribution, and transport of pesticides in surface water of the Yakima River Basin were assessed using data collected during 1999&shy;2000 as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Samples were collected at 34 sites located throughout the basin in August 1999 using a Lagrangian sampling design. Samples also were collected weekly and monthly from May 1999 through January 2000 at three of the sites. This report includes data for 47 pesticide compounds from the analysis of filtered water using ocadecyl (C-18) solid-phase extraction and gas chromatography/mass spectrometry. Twenty-five pesticide compounds were detected in samples collected during the study. Detection frequencies ranged from about 1 percent for ethalfluralin, ethoprophos, and lindane to 82 percent for atrazine. Maximum concentrations of azinphos-methyl, carbaryl, diazinon, para,para'-dichlorodiphenyldichloroethylene (p,p'-DDE), and lindane exceeded chronic-toxicity guidelines for the protection of freshwater aquatic life. Twenty pesticide compounds were detected during sampling in August 1999. Atrazine was the most widely detected herbicide, and azinphos-methyl was the most widely detected insecticide. The median number of sites at which a particular pesticide compound was detected was six. Pesticide compounds detected at more than six sites include atrazine, simazine, terbacil, trifluralin, deethylatrazine, azinphos-methyl, carbaryl, diazinon, malathion, and p,p'-DDE. Because many factors affect the transport of pesticides from areas of application to surface water, there was not a simple correspondence between pesticide occurrence and use in the Yakima River Basin. For example, the high detection rates of atrazine, simazine, deethylatrazine, and p,p'-DDE are probably related more to their mobility and wide distribution in the hydrologic system than to their usage. Likewise, higher detection frequencies of the insecticides azinphos-methyl and carbaryl compared with chlorpyrifos appear to be related more to differences in their physical and chemical properties than to usage. The highest detection frequencies and concentrations of pesticides generally occurred during irrigation season, which is from mid-March to mid-October. Pesticides are applied during irrigation season, and runoff of excess irrigation water from fields transports them to surface water. Ground-water discharges also transport some pesticides to surface water. Atrazine, deethylatrazine, and simazine were frequently detected in samples collected after the irrigation season when there was little or no surface runoff and most of the flow in irrigation drains was derived from ground water. Daily loads of atrazine, terbacil, azinphos-methyl, and carbaryl discharged to the Yakima River from inflows between river mile 103.7 and river mile 72 varied widely between sites. For example, East Toppenish Drain discharged over 50 percent of the total load of terbacil to this reach of the Yakima River, but none of the total load of carbaryl and only about 4 percent of the total load of atrazine. Pesticide loads from the wastewater treatment plants were relatively small compared with loads from other inflows because their discharges were small. Pesticide losses, defined as the ratio of the amount discharged from a basin from May 1999 through January 2000 divided by the amount applied during 1999, were estimated for Moxee and Granger Drains and the Yakima River at Kiona. Losses ranged from less than 0.01 to 1.5 percent of pesticides applied and are comparable to those observed (0.01 to 2.2 percent) in irrigated agricultural basins in the Central Columbia Plateau of Washington State.

Washington↗
USGS2000

Water quality in the Puget Sound basin, Washington and British Columbia, 1996-98

Puget Sound basin streams during 1995-98 met most guidelines and criteria. Seventy-four manmade compounds were detected and different mixtures linked to land use. Urban expansion into forested areas is changing stream habitats--urban and agricultural streams are warmer and support less diverse insect populations than streams in forested areas. Elevated nitrate concentrations and the presence of manmade organic compounds indicated shallow ground water in urban and agricultural settings is vulnerable to contamination.

Circular↗
USGS1999

Surface-water-quality assessment of the Yakima River basin, Washington: Overview of major findings, 1987-91

Surface-water-quality conditions were assessed in the Yakima River Basin, which drains 6,155 square miles of mostly forested, range, and agricultural land in Washington. The Yakima River Basin is one of the most intensively farmed and irrigated areas in the United States, and is often referred to as the &ldquo;Nation&rsquo;s Fruitbowl.&rdquo; Natural and anthropogenic sources of contaminants and flow regulation control water-quality conditions throughout the basin. This report summarizes the spatial and temporal distribution, sources, and implications of the dissolved oxygen, water temperature, pH, suspended sediment, nutrient, organic compound (pesticide), trace element, fecal indicator bacteria, radionuclide, and aquatic ecology data collected during the 1987&ndash;91 water years. The Yakima River descends from a water surface altitude of 2,449 feet at the foot of Keechelus Dam to 340 feet at its mouth downstream from Horn Rapids Dam near Richland. The basin can be divided into three distinct river reaches on the basis of its physical characteristics. The upper reach, which drains the Kittitas Valley, has a high gradient, with an average streambed slope of 14 feet per mile (ft/mi) over the 74 miles from the foot of Keechelus Dam (river mile [RM] 214.5) to just upstream from Umtanum. The middle reach, which drains the Mid Valley, extends a distance of 33 miles from Umtanum (RM 140.4) to just upstream from Union Gap and also has a high gradient, with an average streambed slope of 11 ft/mi. The lower reach of the Yakima River drains the Lower Valley and has an average streambed slope of 7 ft/mi over the 107 miles from Union Gap (RM 107.2) to the mouth of the Yakima River. These reaches exhibited differences in water-quality conditions related to the differences in geologic sources of contaminants and land use. Compared with the rest of the basin, the Kittitas Valley and headwaters of the Naches River Subbasin had relatively low concentrations and loads of suspended sediment, nutrients, organic compounds, and fecal indicator bacteria. There were very few failures to meet the Washington State dissolved oxygen standard or exceedances of the water temperature and pH standards in this reach. In general, these areas are considered to be areas of lessdegraded water quality in the basin. The preTertiary metamorphic and intrusive rocks of the Cle Elum and Teanaway River Subbasins, however, were found to be significant geologic sources of antimony, arsenic, chromium, copper, mercury, nickel, selenium, and zinc. As a result, the arsenic, chromium, and nickel concentrations measured in the streambed sediment of the Kittitas Valley were 13 to 74 times higher than those measured in the Lower Valley. The Mid and Lower Valleys had similar water-quality conditions, governed by the intensive agricultural and irrigation activities, highly erosive landscapes, and flow regulation. Most of the failures to meet the Washington State standards for dissolved oxygen and exceedances of the standards for water temperature and pH occurred in the Mid and Lower Valleys. Agricultural drains in the Mid and Lower Valleys were found to be significant sources of nutrients, suspended sediment, pesticides, and fecal indicator bacteria. Downstream from the irrigation diversions near Union Gap, summertime streamflow in the Yakima River was drastically reduced to only a few hundred cubic feet per second. In the lower Yakima River, agricultural return flow typically accounts for as much as 80 percent of the main stem summertime flow near the downstream terminus of the basin. Therefore, the water-quality characteristics of the lower Yakima River resemble those of the agricultural drains. The highest fecal bacteria concentrations (35,000 colonies of Escherichia coli per 100 milliliters of water) were measured in the Granger/Sunnyside area, the location of most of the livestock in the basin. The east side area of the Lower Valley (area east of the Yakima River) was the predominant source area for suspended sediment and pesticides in the basin. This area had the largest acreage of irrigated land and generally received the largest application of pesticides. Owing to the highly erosive soils of the area, the suspended sediment load from the east side in June 1989 (320 kilograms per day) was five or more times larger than from any other area, and the loads of several of the more hydrophobic organic compounds were four or more times larger. An ecological assessment of the Yakima River Basin ranked physical, chemical, and biological conditions at impaired (degraded) sites against reference sites in an effort to understand how land use changes physical and chemical site characteristics and how biota respond to these changes. For this assessment, the basin was divided into four natural ecological categories: (1) Cascades ecoregion, (2) Eastern Cascades Slopes and Foothills ecoregion, (3) Columbia Basin ecoregion, and (4) large rivers. Each of these categories has a unique combination of climate and landscape features that produces a distinctive terrestrial vegetation assemblage. In the combined Cascades and Eastern Cascades site group, which had the fewest impaired sites, the metals index was the only physical and chemical index that indicated any impairment. The moderate levels of impairment noted in the invertebrate and algal communities were not, however, associated with metals, and may have been related to the effects of logging, although the intensity of logging was not directly quantified in this study. Sites in the Columbia Basin site group were all moderately or severely impaired with the exception of the two reference sites (Umtanum Creek and Satus Creek below Dry Creek), which showed no physical, chemical, or biological impairment. Three sites were heavily affected by agriculture (Granger Drain, Moxee Drain, and Spring Creek) and were listed as severely impaired by most of the physical, chemical, and biological condition indices. Agriculture was the primary cause of the impairment of biological communities in this site group. The primary physical and chemical indicators of agricultural effects were nutrients, pesticides, dissolved solids, and substrate embeddedness, which all tended to increase with agricultural intensity. The biological effects of agriculture were manifested by a decrease in the abundance and number of native species of fish and invertebrates, a shift in algal communities to species indicative of eutrophic conditions, and higher abundances. There was also an increase in the abundance and number of nonnative fish species due to the prevalence of fish that are largely tolerant of nutrient-rich conditions. Main stem (large river) sites downstream from the city of Yakima exhibited severe impairment of fish communities associated with high levels of pesticides in fish tissues and the presence of external anomalies on fish.

Washington↗