Flow-adjusted trends in dissolved selenium load and concentration in the Gunnison and Colorado Rivers near Grand Junction, Colorado, water years 1986--2008

Mayo, John W.; Leib, Kenneth J.

doi:10.3133/sir20125088

Cited by 10 publications

(42 citation statements)

References 7 publications

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“…It is important to remember that because the estimated loads and concentrations given for WY 1986 and WY 2016 were based on normalized streamflow, the results were only illustrative of the change in selenium loads and concentrations over the period of study. They were not the actual loads and concentrations that occurred in WY 1986and WY 2016(Mayo and Leib, 2012 …”

Section: Normalized Mean-daily Streamflowmentioning

confidence: 99%

“…Various transformations are commonly used to enhance estimation accuracy (logarithmic [log] transformation, quadratic terms, decimal time, centered time, and sinusoidal transformations of time). For this study, daily streamflow, decimal time, and various transformations were used in estimating trends in selenium load and concentration (Mayo and Leib, 2012). Calibration datasets included the current and previous water year's streamflow, specific conductance, and dissolved-selenium concentration for each discrete water-quality sample collected.…”

Section: General Approach Of the Analysismentioning

confidence: 99%

“…Only flow-adjusted trend analyses were carried out in this study because the effect of selenium-control efforts over the study period was of primary interest to the cooperator (Mayo and Leib, 2012).…”

Section: Flow-adjusted Trend Analysismentioning

confidence: 99%

“…R-LOADEST was derived from LOADEST (Runkel and others, 2004). R-LOADEST was used to calculate daily selenium loads and concentrations from measured selenium-concentration calibration data spanning WY 1986 through WY 2016 (Mayo and Leib, 2012).…”

Section: Regression Analysis Softwarementioning

confidence: 99%

“…A parallel goal is to continue implementation, monitoring, and evaluation of management practices that will maintain or continue to reduce dissolvedselenium concentration in the river. Mayo and Leib (2012) documented a downward trend in dissolved-selenium load from 1986 to 2008 at the Whitewater gage. The SMP's long-term objective is to improve water quality by reducing dissolvedselenium concentrations sufficiently to assist in the recovery of the Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus) (Bureau of Reclamation, 2011).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Assessment of dissolved-selenium concentrations and loads in the lower Gunnison River Basin, Colorado, as part of the Selenium Management Program, from 2011 to 2016

Henneberg¹

2018

Scientific Investigations Report

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Section: Normalized Mean-daily Streamflowmentioning

confidence: 99%

Section: General Approach Of the Analysismentioning

confidence: 99%

Section: Flow-adjusted Trend Analysismentioning

confidence: 99%

Section: Regression Analysis Softwarementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Assessment of dissolved-selenium concentrations and loads in the lower Gunnison River Basin, Colorado, as part of the Selenium Management Program, from 2011 to 2016

Henneberg¹

2018

Scientific Investigations Report

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Orthophosphate-P in the nutrient impacted River Taw and its catchment (SW England) between 1990 and 2013

Tappin

Comber

Worsfold

2016

Environ. Sci.: Processes Impacts

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Excess dissolved phosphorus (as orthophosphate-P) contributes to reduced river water quality within Europe and elsewhere. This study reports results from analysis of a 23 year (1990-2013) water quality dataset for orthophosphate-P in the rural Taw catchment (SW England). Orthophosphate-P and river flow relationships and temporal variations in orthophosphate-P concentrations indicate the significant contribution of sewage (across the catchment) and industrial effluent (upper R. Taw) to orthophosphate-P concentrations (up to 96%), particularly during the low flow summer months when maximum algal growth occurs. In contrast, concentrations of orthophosphate-P from diffuse sources within the catchment were more important (>80%) at highest river flows. The results from a 3 end-member mixing model incorporating effluent, groundwater and diffuse orthophosphate-P source terms suggested that sewage and/or industrial effluent contributes ≥50% of the orthophosphate-P load for 27-48% of the time across the catchment. The Water Framework Directive (WFD) Phase 2 standards for reactive phosphorus, introduced in 2015, showed the R. Taw to be generally classified as Poor to Moderate Ecological Status, with a Good Status occurring more frequently in the tributary rivers. Failure to achieve Good Ecological Status occurred even though, since the early-2000s, riverine orthophosphate-P concentrations have decreased (although the mechanism(s) responsible for this could not be identified). For the first time it has been demonstrated that sewage and industrial effluent sources of alkalinity to the river can give erroneous boundary concentrations of orthophosphate-P for WFD Ecological Status classification, the extent of which is dependent on the proportion of effluent alkalinity present. This is likely to be a European - wide issue which should be examined in more detail.

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Regression models for estimating salinity and selenium concentrations at selected sites in the Upper Colorado River Basin, Colorado, 2009-2012

Linard¹,

Schaffrath²

2014

Open-File Report

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Elevated concentrations of salinity and selenium in the tributaries and main-stem reaches of the Colorado River are a water-quality concern and have been the focus of remediation efforts for many years. Land-management practices with the objective of limiting the amount of salt and selenium that reaches the stream have focused on improving the methods by which irrigation water is conveyed and distributed. Federal land managers implement improvements in accordance with the Colorado River Basin Salinity Control Act of 1974, which directs Federal land managers to enhance and protect the quality of water available in the Colorado River. In an effort to assist in evaluating and mitigating the detrimental effects of salinity and selenium, the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, the Colorado River Water Conservation District, and the Bureau of Land Management, analyzed salinity and selenium data collected at sites to develop regression models. The study area and sites are on the Colorado River or in one of three small basins in Western Colorado: the White River Basin, the Lower Gunnison River Basin, and the Dolores River Basin. By using data collected from water years 2009 through 2011, regression models able to estimate concentrations were developed for salinity at six sites and selenium at six sites. At a minimum, data from discrete measurement of salinity or selenium concentration, streamflow, and specific conductance at each of the sites were needed for model development. Comparison of the Adjusted R 2 and standard error statistics of the two salinity models developed at each site indicated the models using specific conductance as the explanatory variable performed better than those using streamflow. The addition of multiple explanatory variables improved the ability to estimate selenium concentration at several sites compared with use of solely streamflow or specific conductance. The error associated with the log-transformed salinity and selenium estimates is consistent in log space; however, when the estimates are transformed into non-log values, the error increases as the estimates decrease. Continuous streamflow and specific conductance data collected at study sites provide the means to examine temporal variability in constituent concentration and load. The regression models can estimate continuous concentrations or loads on the basis of continuous specific conductance or streamflow data. Similar estimates are available for other sites at the USGS National Real-Time Water Quality Web page (http://nrtwq.usgs.gov) and provide water-resource managers with a means of improving their general understanding of how constituent concentration or load can change annually, seasonally, or in real time.

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Flow-adjusted trends in dissolved selenium load and concentration in the Gunnison and Colorado Rivers near Grand Junction, Colorado, water years 1986--2008

Cited by 10 publications

References 7 publications

Assessment of dissolved-selenium concentrations and loads in the lower Gunnison River Basin, Colorado, as part of the Selenium Management Program, from 2011 to 2016

Assessment of dissolved-selenium concentrations and loads in the lower Gunnison River Basin, Colorado, as part of the Selenium Management Program, from 2011 to 2016

Orthophosphate-P in the nutrient impacted River Taw and its catchment (SW England) between 1990 and 2013

Regression models for estimating salinity and selenium concentrations at selected sites in the Upper Colorado River Basin, Colorado, 2009-2012

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