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Daniel T. Chafin

Publications and source records attributed to Daniel T. Chafin.

11 recordsLinked to original sources
USGS2007

Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

During 2002, Colorado experienced the State's worst drought since 1977. In 2003, the U.S. Geological Survey entered into cooperative agreement with the Colorado Department of Public Health and Environment to evaluate the general effects of drought on the water quality of streams in Colorado during summer 2002 by analyzing a water-quality data set obtained during summer 2002 in cooperation with a variety of State and local governments. Water samples were collected at 148 stream sites in Colorado and were measured or analyzed for field properties, major ions, nutrients, organic carbon, bacteria, and dissolved and total recoverable metals. Mean annual streamflow was analyzed at 134 sites in Colorado, and mean summer (July-September) streamflow for 2002 was determined for 146 sites for water years 1978-2002. Mean annual streamflow for 2002 had an average percentile of 29.4 and mean summer streamflow for 2002 had an average percentile of 7.6 relative to 1978-2002. These results indicate that streamflow in Colorado was substantially less than median streamflow for the period and that the effect of drought on streamflow was greater during summer 2002 than during water year 2002 (October 1, 2001, through September 30, 2002). Few measured constituent concentrations or values were elevated or depressed on a widespread basis during summer 2002. Specific conductance was elevated (in the upper quartile relative to historical data) in five of the seven basins that had sufficient data for characterization, indicating that specific conductance likely was affected by drought in those basins. Chloride concentrations were elevated in three of five basins with sufficient data and indicate that chloride concentration generally was affected by drought in those basins. Sulfate concentration was elevated in four of six basins with sufficient data. The widespread elevation of specific conductance and concentrations of chloride and sulfate indicates that salinity generally was affected by drought in Colorado streams during July-September 2002, likely because streamflow at most sites was dominated by base flow of ground water, which usually has substantially greater salinity compared to runoff from precipitation. Total-recoverable iron and manganese concentrations were depressed (in the lower quartile of historical data) in the Arkansas River Basin, which likely was due to reduced land-surface washoff of sediment containing oxyhydroxides of these metals. Of the 246 water samples collected at 148 sites during the summer of 2002, constituents in 115 exceeded Colorado water-quality standards. Constituents that exceeded water-quality standards were pH (all 9.0 standard unit exceedances; 9 samples), chloride (1 sample), sulfate (9 samples), dissolved ammonia (10 samples), dissolved nitrite nitrogen (3 samples), E. coli (Escherichia coli) bacteria (34 samples, 20 in Arkansas River Basin), fecal-coliform bacteria (18 samples, all in Arkansas River Basin), dissolved copper (1 sample), dissolved iron (3 samples), total-recoverable iron (3 samples), dissolved manganese (13 samples), dissolved selenium (10 samples), and dissolved zinc (1 sample). Of these 115 exceedances, historical data were sufficient to conclude that 21 probably were affected by drought, that 39 probably were not affected by drought, and that 55 were of indeterminate nature. Specific conductance indicates that the San Juan River Basin (average percentile 95.2) experienced the greatest effects of drought on water quality during summer 2002 compared to other basins in Colorado, followed by the Upper Colorado (90.0) and Dolores River (85.7) Basins. The South Platte River Basin (70.9) experienced the least effect of drought, and the Yampa and White River Basin group (73.7) had the second smallest effect. The Gunnison River (82.1) and Arkansas River (81.2) Basins had intermediate drought effects. The Rio Grande had insufficient data to rank the relative effect of drought on salinity.

Scientific Investigations Report↗
USGS2003

Effect of the Paradox Valley Unit on the dissolved-solids load of the Dolores River near Bedrock, Colorado, 1988-2001

Discharge of brine with an average dissolved-solids concentration of about 256,000 milligrams per liter from alluvium in Paradox Valley, a collapsed salt anticline, substantially increases the dissolved-solids load of the Dolores River. In 1996, the Bureau of Reclamation began operation of the Paradox Valley Unit, a series of brine-withdrawal wells completed in alluvium along the Dolores River and a deep-injection well for the brine, to decrease flow of brine into the river. This report presents the findings of a study to determine the effectiveness of the Paradox Valley Unit from 1988 through September 2001. Differences in dissolved-solids load of the Dolores River between two gaging stations, one upstream and one downstream from the Paradox Valley Unit, indicate that an average dissolved-solids load of about 313 tons per day (an annual average of about 115,000 tons) was contributed by brine inflow to the Dolores River before operation of the Paradox Valley Unit began in July 1996. By September 30, 2001, the dissolved-solids load contributed by brine had declined to an average of about 29 tons per day? a decrease of about 90 percent. This decrease might have been facilitated by a decrease in precipitation and streamflow into the Paradox Valley during the last few years of the assessed period.

Colorado↗
USGS2002

Evaluation of trends in pH in the Yampa River, northwestern Colorado, 1950-2000

In 1999, the U.S. Geological Survey began a study of pH trends in the Yampa River from near its headwaters to its mouth. The study was prompted by an apparent historical increase in measured pH at the Yampa River near Maybell, from an average of about 7.6 in the 1950's and 1960's to about 8.3 in the 1980's and 1990's. If real, further increase could cause more frequent exceedances of the Colorado water-quality standard of 9.0 and adversely affect aquatic life in the Yampa River Basin, including Dinosaur National Monument. The principal conclusion of this study is that this apparent historical increase in measured pH was caused mostly by changes in measurement protocol. Synoptic sampling during August 16­19, 1999, a period of relatively warm weather and base flow, showed that late afternoon pH of the Yampa River ranged from 8.46 to 9.20. The largest pH (9.20) exceeded the Colorado water-quality standard and was measured at Yampa River above Elk River, about 1.8 miles downstream from the Steamboat Springs Regional Waste Water Treatment Plant outfall, where nutrient enrichment caused photosynthesis by algae to dominate. Here, the dissolved oxygen concentration was 161 percent of saturation and carbon dioxide (CO 2 was at 26 percent of saturation. At Yampa River downstream from a diversion near Hayden, 16.3 miles downstream, the effects of photosynthesis were still dominant, though attenuated by reaeration and dilution with freshwater from the Elk River. About 37.2 miles farther downstream, at Yampa River below Craig, which is about 6.2 miles downstream from the Craig Waste Water Treatment Plant, the effects of photosynthesis increased slightly, and pH rose to 8.80. Respiration plus oxidation of organic matter became dominant at Yampa River at Deerlodge Park in Dinosaur National Monument, where pH was 8.51, dissolved oxygen concentration was at 109 percent of saturation, and CO 2 was at 189 percent of saturation. Respiration plus oxidation of organic matter, though diminished, apparently extended to the mouth of the Yampa River. Diurnal measurements on the Yampa River during August 23­26, 1999, show that the effects of photosynthesis and respiration plus oxidation of organic matter decreased downstream with distance from the developed urban area in the eastern part of the basin. Larger night-time values of pH in Dinosaur National Monument at Deerlodge Park and at the mouth of the Yampa River indicate that source waters varied with respect to capacity for respiration plus oxidation and photo-synthesis, that photosynthesis was minor, and that pH was largely controlled by respiration plus oxidation of organic matter. Synoptic sampling was repeated during March 13-16, 2000, when discharge was larger in response to late-winter melting of snow and ice at lower altitudes in the basin. Concentrations of nitrite plus nitrate were about 9 times greater in the Yampa River during March 2000 than during August 1999, and the largest increase (greater than 1,200 percent) was at Yampa River below Craig. At and downstream from Steamboat Springs, Colorado, pH at Yampa River sites averaged 8.85 during synoptic sampling in March 2000 compared to 8.70 in August 1999, with the partial pressure of carbon dioxide gas (PCO2) averaging 67 percent of saturation (compared to 99 percent during August 1999). The apparently larger effects of photosynthesis on pH and dissolved oxygen concentrations during March 2000 compared to August 1999 probably were caused by (1) slower rates of exchange of CO 2 into and dissolved oxygen out of the river because of colder and deeper water and (2) slower rates of CO 2 production and oxygen consumption resulting from slower rates of respiration by organisms and from slower rates of aerobic decomposition of organic matter in the colder river water and streambed sediment. Hypothetical thermodynamic simulations were done for samples collected in the lower Yampa River Basin to simulate the same amount of photosynthesis that existed at Yampa River above Elk River. These simulations indicate that maximum potential late-afternoon pH would equal about 9.1 to 9.2 (exceeding the Colorado water-quality standard of 9.0) during late-winter lowland runoff and during late-summer base flow. Additional simulations indicate that late-summer drought conditions could further raise maximum potential late-afternoon pH by about 0.1 unit, potentially causing late-afternoon pH to remain above the water-quality standard. Flow-adjusted, two-tailed Wilcoxon-Mann-Whitney rank-sum tests were used to compare onsite measurements, constituent concentrations, and thermodynamic properties of water samples collected from Yampa River near Maybell between 1950­74 and 1975­99. These two periods were defined to represent the general periods of time before and after onsite measurements of pH were begun and to separate the earlier period of minor coal-mining activity from the period of more extensive coal mining that began in the late 1970's. Specific conductance, concentration of dissolved solids, dissolved-solids load, measured pH, and dissolved concentrations of calcium, magnesium, sodium, and sulfate were significantly greater during 1975­99. Dissolved concentrations of chloride, fluoride, and silica were significantly greater during 1950­74. Alkalinity and dissolved potassium concentration were not significantly greater during either period. The CO 2 saturation factor was significantly greater during 1950­74 (median 10.2) than during 1975­99 (median 2.5). However, hypothetical equilibration of all samples with ambient atmospheric pressure of CO 2 resulted in no significant difference in pH for the two periods. Therefore, the significantly greater measured pH values during 1975­99 cannot be attributed to the significant increase in concentrations of dissolved solids, calcium, magnesium, sodium, and sulfate, leaving decrease in the partial pressure of CO 2 as the most likely cause. Greater dominance of rates of respiration plus oxidation of organic matter (relative to rates of photosynthesis) during 1950­74 and (or) greater dominance of rates of photosynthesis (relative to rates of respiration plus oxidation of organic matter) during 1975­99 possibly contributed to the significantly smaller measured pH values at Yampa River near Maybell during 1950­74, although these causes were not the primary cause. Most of the significant difference in measured pH between the two periods can be attributed to oxidation of organic matter in sample containers during shipping and holding prior to laboratory measurement, especially in composited samples analyzed before 1970. Laboratory measurements and underestimated onsite measurements before September 6, 1983, probably are less reliable than onsite measurements made after that date.

Colorado↗
USGS2000

Effect of Georgetown Lake on the water quality of Clear Creek, Georgetown, Colorado, 1997-98

Georgetown Lake is a recreational reservoir located in the upper Clear Creek Basin, a designated Superfund site because of extensive metal mining in the past. Metals concentrations in Clear Creek increase as the stream receives runoff from mining-affected areas. In 1997, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, began a study to determine the effect of the reservoir on the transport of metals in Clear Creek. A bathymetric survey determined the capacity of the reservoir to be about 440 acre-feet of water, which remained constant during the study. Average water residence time in the reservoir is about 1-3 days during high flow. During low flow (10 cubic feet per second), average residence is about 22 days without ice cover and about 15 days with a 3-foot-thick ice cover. Sediment samples collected from the bottom of Georgetown Lake contained substantial concentrations of iron (average 25,500 milligrams per kilogram), aluminum (average 12,300 milligrams per kilogram), zinc (2,830 milligrams per kilogram), lead (618 milligrams per kilogram), manganese (548 milligrams per kilogram), and sulfide minerals (average 602 milligrams per kilogram as S). Sediment also contained abundant sulfate-reducing bacteria, indicating anoxic conditions. Algae and diatoms common to cold-water lakes were identified in sediment samples; one genus of algae is known to adapt to low-light conditions such as exist beneath ice cover. Vertical profiles of temperature, specific conductance, pH, and dissolved-oxygen concentrations were measured in the reservoir on July 28, 1997, when inflow to the reservoir was about 170 cubic feet per second and average residence time of water was about 1.3 days, and on February 13, 1998, when the reservoir was covered with about 3 feet of ice, inflow was about 15 cubic feet per second, and average residence time was about 12 days. The measurements on July 28, 1997, showed that the reservoir water was well mixed, although pH and dissolved-oxygen concentrations were increased by photosynthesis near the bottom of the reservoir. Measurements on February 13, 1998, indicated thermal and chemical stratification with warmer water (about 4 degrees Celsius) beneath colder water and increases in pH and dissolved-oxygen concentrations generally occurring near the top of the warmer layer. Concentrations of dissolved oxygen were saturated to over-saturated throughout the water column on both dates, although the concentrations were greater on February 13, 1998, because of colder temperature and photosynthesis. Median pH was about 0.5 unit higher on February 13, 1998, than on July 28, 1997, largely because the longer residence time on February 13, 1998, allowed greater cumulative effects of photosynthesis. Samples of inflow and outflow water were collected from August 1997 to August 1998. Dissolved cadmium and dissolved lead in inflow and outflow samples exceeded acute and chronic water-quality standards during some of the sampling period, whereas dissolved zinc exceeded both standards in inflow and outflow samples during the entire sampling period. Chromium, nickel, and silver were detected in a few samples at small concentrations. Arsenic, selenium, and thallium were not reported in any water samples. Georgetown Lake removes some metals from inflow water and releases others to outflow water. From August 1997 to August 1998, Georgetown Lake estimated outflow loads were about 21 percent less than the inflow load of cadmium and about 11 percent less than the inflow load of zinc. Estimated inflow loads were about 18 percent less than the outflow load of copper, about 13 percent less than the outflow load of iron, and about 27 percent less than the outflow load of manganese. Inflow and outflow loads of lead were essentially balanced. The outflow load of nitrite plus nitrate was about 14 percent less than the inflow load, probably because of plant uptake.

Colorado↗
USGS1996

Hydrogeology of the alluvial aquifers at the Pueblo Depot Activity near Pueblo, Colorado

In 1992, the U.S. Army Corps of Engineers and the U.S. Army Pueblo Depot Activity requested that the U.S. Geological Survey study the hydrogeology of the Pueblo Depot Activity, a 36-square-mile facility that has been operated by the U.S. Army since 1942. The purpose of the study was to provide an updated hydrogcological framework to facilitate the investigation of specific sites on the facility that might require remediation. This report describes the hydrogeology of the alluvial aquifers beneath the facility and the distribution of specific conductance of ground water in those aquifers. The Pueblo Depot Activity is underlain by two alluvial aquifers: (1) The terrace alluvial aquifer, which is a southernmost, downgradicnt part of an erosional remnant of an extensive terrace deposit; and (2) the Chico Creek alluvial aquifer, a smaller alluvial system along Chico Creek. These aquifers primarily consist of sand separated by clay layers and are underlain by the almost impermeable Pierre Shale of Upper Cretaceous age. The bedrock surface, which has an average slope of 28 feet per mile to the south-southeast, is relatively regular beneath the northern two-thirds of the terrace deposits at the Pueblo Depot Activity, but forms an irregular surface of troughs, hills, and ridges in the southwestern part of the terrace alluvium. Saturated thickness of the terrace aquifer ranges from 0 to about 45 feet. The bedrock surface beneath the Chico Creek aquifer slopes about 31 feet per mile to the south. Saturated thickness of the Chico Creek alluvium ranges from 0 to about 30 ft, but generally is less than 15 ft. Total thickness of the Chico Creek alluvium in the saturated area ranges from 16 to 41 ft. Water in the terrace alluvial aquifer generally flows southward, except in the southwestern part where directions of flow are complex. Measured hydraulic conductivity ranges from 0.4 to 400 feet per day (median 26 feet per day). Estimates for vertically averaged ground-water-flow velocity range from 0.02 to 3 feet per day (median 0.9 foot per day). Water in the Chico Creek alluvial aquifer generally flows southward to the Arkansas River alluvium. Measured hydraulic conductivity ranges from 14 to 310 feet per day (median 42 feet per day). Estimates for vertically averaged ground water-flow velocity range from 0.5 to 4 feet per day (median 0.7 foot per day). Specific conductance of ground water in the terrace alluvial aquifer generally is less than 800 microsiemens per centimeter; the smallest values were observed in the north-central part of the Pueblo Depot Activity. In the southwestern part of the terrace alluvial aquifer, values varied in an irregular pattern, and values as large as 3,300 microsiemens per centimeter were measured locally. Water in the terrace alluvial aquifer was dominated by the sodium cation and usually by the bicarbonate anion, and sulfate usually was present in substantial (and locally predominant) concentrations. Measured specific conductance of water in the Chico Creek alluvial aquifer ranged from 683 to 1,460 microsiemens per centimeter. This water was dominated by the sodium cation and by the bicarbonate and sulfate anions; sulfate was more predominant to the south.

Colorado↗
USGS1996

Effects of land use on water quality of the Fountain Creek alluvial aquifer, east-central Colorado

Water-quality data were collected from the Fountain Creek alluvial aquifer in 1988 and 1989 as part of the Toxic-Waste Ground-Water Contamination Program. These data indicate that dissolved solids, most major ions, fluoride, ammonium, boron, lithium, selenium, and strontium were more concentrated in the agricultural land-use area than in the upgradient urban land-use area. Nitrate and phosphate had significantly larger concentrations, and volatile organic compounds had significantly greater detection frequencies in the urban land-use area.

Water Supply Paper↗
USGS1994

Sources and migration pathways of natural gas in near-surface ground water beneath the Animas River valley, Colorado and New Mexico

In July 1990, the U.S. Geological Survey began a study of the occurrence of natural gas in near-surface ground water in the Animas River valley in the San Juan Basin between Durango, Colorado, and Aztec, New Mexico. The general purpose of the study was to identify the sources and migration pathways of natural gas in nearsurface ground water in the study area. The purpose of this report is to present interpretive conclusions for the study, primarily based on data collected by the U.S. Geological Survey from August 1990 to May 1991. Seventy of the 205 (34 percent) groundwater samples collected during August-November 1990 had methane concentrations that exceeded the reporting limit of 0.005 milligram per liter. The maximum concentration was 39 milligrams per liter, and the mean concentration was 1.3 milligrams per liter. Samples from wells completed in bedrock have greater mean concentrations of methane than samples from wells completed in alluvium. Correlations indicate weak or nonexistent associations between dissolved-methane concentrations and concentrations of dissolved solids, major ions, bromide, silica, iron, manganese, and carbon dioxide. Dissolved methane was associated with hydrogen sulfide. Soil-gas-methane concentrations were measurable at few of 192 ground-water sites, even at sites at which ground water contained large concentrations of dissolved methane, which indicates that soil-gas surveys are not useful to delineate areas of gas-affected ground water. The reporting limit of 0.005 milligram per liter of gas was equaled or exceeded by 40 percent of soil-gas measurements adjacent to 352 gas-well casings. Concentrations of at least 100 milligrams per liter of gas were measured at 25 (7 percent) of the sites. Potential sources of gases in water, soil, gas-well surface casings, and cathodic-protection wells were determined on the basis of their isotopic and molecular compositions and available information about gas-well construction or leaks. Biogenic and thermogenic sources of gas exist in the near-surface environment of the study area. Biogenic gas is present locally in the near-surface Animas and Nacimiento formations, and biogenic gas has been detected in water wells completed in those rocks. Most gas probably is thermogenic gas from deep reservoirs, including the Dakota Sandstone, Mesaverde Group, Lewis Shale, Pictured Cliffs Sandstone, and coals in the Fruitland Formation. Less important sources include sandstones in the upper Fruitland Formation and the Kirtland Shale. Although migration of gas by diffusion or through natural fractures is possible, manmade conduits probably account for most of the upward migration of gas to the near-surface environment of the study area. Primary migration pathways largely consist of 1) leaking, conventional gas wells and 2) uncemented annuli of conventional gas wells along coals in the Fruitland Formation. Secondary migration pathways are gas-well annuli, cathodic-protection wells, seismic-test holes, and bedrock water wells.

Colorado, New Mexico↗