Geology topics

Rodney J. Richards

Publications and source records attributed to Rodney J. Richards.

12 recordsLinked to original sources

USGS2023

Assessment of salinity retention or mobilization by sediment-retention ponds near Delta, Colorado, 2019

Salinity control efforts in the Colorado River Basin have focused on mobilization of salts from irrigated land, but nonirrigated rangelands are also a source of salinity. In particular, lands where soils have formed from the Late Cretaceous Mancos Shale under arid and semiarid climates contain considerable quantities of salt, mainly in the subsurface. Hundreds of thousands of contour furrows and check dams (gully plugs) were constructed by the Bureau of Land Management (BLM) and Bureau of Reclamation in the late 1950s and 1960s to reduce runoff, sedimentation, and salt mobilization from ephemeral stream channels on rangelands. Sediment-retention ponds associated with check dams are dry most of the year, except immediately following substantial rain events. Generally, no maintenance has been performed on these structures, some have degraded over time, and their current and past influence on salinity is poorly understood. To assess the influence of check dams and their associated ponds on salt retention and mobilization, the U.S. Geological Survey, in cooperation with the BLM, conducted a study of such ponds within the Gunnison Gorge National Conservation Area (GGNCA) near Delta, Colorado. This report includes conceptual models of how sediment-retention ponds function relative to salinity, and a collection of environmental data to evaluate the conceptual models. An inventory of 69 ponds indicated that 38 percent no longer had water holding capacity, and another 20 percent could hold 1 foot or less of water. Check-dam degradation was the main cause, but sediment infill of ponds contributed as well. Water content of soil profiles collected beneath ponds and immediately downstream from check dams indicated little penetration of water below 60 centimeters for most ponds and little evidence for lateral movement of water beneath check dams. Patterns of salt content in the soil profiles indicated no accumulation of salts at the pond surface from evaporating waters and little evidence for salt redistribution in the form of salt bulges or salt depletion curves at intermediate depths. Based on the conceptual models presented and interpretations of data collected by this study, it appears that the sediment-retention ponds in the GGNCA have neither mobilized nor retained substantial quantities of salt during their lifetimes.

Colorado↗

USGS2023

Preliminary analysis of a horizontal multifrequency hydroacoustic device designed for surrogate measurements of suspended sediment concentration: The Horizontal Acoustic Sediment Current Profiler

Single frequency active hydroacoustic measurements have been correlated with suspended sediment concentration. In river systems that include widely varying suspended sediment particle sizes, a multi-frequency hydroacoustic approach has increased predictive capabilities. However, the multi-frequency approach requires installation and operation of multiple sensors in a river channel and relies on technology previously designed for measuring water velocity. The Horizontal Acoustic Sediment Current Profiler (HASCP) is a single unit multi-frequency (500, 1,500, and 2,000 mHz) hydroacoustic sensor that was designed to target suspended sediment concentrations. The HASCP was briefly deployed in the Rio Grande at Albuquerque, NM, USGS gage in 2021 and is currently (2022) in operation at the Colorado River near Cameo, CO gage. Results of preliminary testing of the HASCP are presented in this paper.

Conference Paper↗

USGS2022

Implementing a rapid deployment bridge scour monitoring system in Colorado, 2019

The U.S. Geological Survey, in cooperation with the Colorado Department of Transportation, installed and operated real-time scour monitoring instrumentation at two bridges in Colorado in 2016 and 2017 to measure streambed elevations in real-time. The instrumentation included acoustic echosounder depth sensors mounted to the bridge substructure units with rigid conduit and fittings. Although functional, the rigid mounting configuration took several days to install at each site, which limits the instrumentation to long-term deployments at previously determined sites. To address this limitation and allow for greater flexibility in bridge selection, a rapid deployment bridge scour monitoring system (RDBSMS) was developed by the U.S. Geological Survey in cooperation with the Colorado Department of Transportation. The RDBSMSs were installed at two other bridges in Colorado in 2019, which were selected by using specific scoring criteria to rank candidate bridges and the potential for high streamflow based on accumulated snowpack. A matrix was developed to rank candidate bridges based on factors including depth, foundation type, average daily traffic, detour route, and scour critical condition. Colorado Department of Transportation bridges F-05-R and P-01-G were selected as the final candidate bridges for installation and testing of the rapid deploy scour monitoring system. Bridge F-05-R carries Colorado Highway 13 over the Colorado River near the town of Rifle, Colorado. Because of the misalignment of the pier wall with respect to the river, pier number 4 was instrumented on the left side (looking downstream) to monitor scour conditions. Bridge P-01-G carries U.S. Route 160 over the San Juan River near the Four Corners area in Colorado. Because of misalignment of the pier wall with respect to the river, pier number 4 was instrumented on the right side (looking downstream) to monitor scour conditions. The RDSMSs were installed in approximately 3 hours at each bridge. Scour conditions at both bridges were monitored during the snowmelt runoff period in 2019 using the installed RDBSMSs. No major scour events occurred at either structure, but minor scour and fill was measured at each. Sensor performance at F-05-R was excellent, with no missing or erroneous data. Sensor performance at P-01-G was good for most of the period, with some missing and erroneous data during periods of high turbidity. Both RDBSMSs were successfully deployed and produced reliable data, demonstrating that both the technology and the installation methods can work in two different riverine environments. Pre-installation of mounting plates would make the installation process faster at flood prone bridges. Having flood prone bridges preconfigured and several RDBSMSs ready to deploy could allow for rapid monitoring during floods such as those which occurred in 2013.

Colorado↗

USGS2021

Assessment of diel cycling in nutrients and trace elements in the Eagle River Basin, 2017–18

Diel cycles are known to occur in all types of waters, and increasing studies indicate routine water samples may not provide an accurate snapshot in concentrations of trace elements and nutrients. Diel behavior in neutral to alkaline pH ranges is independent of streamflow variability and concentration. Extensive historical U.S. Geological Survey (USGS) water-quality data have been collected in the Eagle River Basin during daylight hours, which is defined as the period of time between one-half hour prior to sunrise and one-half hour after sunset. However, no USGS data have been collected throughout the nighttime, defined as the time between one-half hour after sunset and one-half hour prior to sunrise, making the evaluation of diel cycles impossible. To assess the importance of diel cycling within the Eagle River Basin, the USGS, in cooperation with Eagle River Watershed Council, developed a study to assess the mechanisms, patterns, and magnitude of change during the diel cycle for selected constituents. Water-quality monitors at five USGS streamgage sites (09065500, Gore Creek at Upper Station, near Minturn, Colorado, 09063000, Eagle River at Red Cliff, Colorado, 09064600, Eagle River near Minturn, Colorado, 09066325, Gore Creek above Red Sandstone Creek at Vail, Colorado, and 394220106431500, Eagle River below Milk Creek near Wolcott, Colorado) were deployed in 2017 to evaluate the water-quality field parameters and to determine if water conditions were favorable for the diel cycling of nutrients and trace elements. Based on the evaluation of water-quality parameters, three of the five sites were sampled for nutrient and trace-element concentrations in 2018 to confirm the presence and magnitude of diel cycling. Historical data were also analyzed to assess the effect of time of day on measured nutrient and trace-element concentrations. An assessment of the effect of land use on diel cycling was also investigated. Measurable nutrients displayed a diel cycle at all three sites with the largest percentage change at the most downstream site (394220106431500), located on the Eagle River. More notable diel cycles at this site include filtered nitrate plus nitrite, which varied 179 percent, with concentrations from 0.24 to 0.67 milligrams per liter (mg/L) and filtered orthophosphate, which varied 71 percent, with concentrations from 0.07 to 0.12 mg/L. Filtered nitrate plus nitrite at site 09066325 varied 57 percent, ranging from 0.14 to 0.22 mg/L. Maximum concentrations occurred prior to noon, decreased through the afternoon (between noon and sunset), and increased during the night (between sunset and sunrise). That pattern is consistent with nutrient uptake in response to daytime (between sunrise and sunset) photosynthesis along with biologically driven denitrification and nitrification cycles. Nutrient concentrations at sites 09064600 and 09066325 were generally low and below laboratory reporting limits, which is the smallest measured concentration that nutrients could be measured by a given analytical method. Trace-element concentrations were detectable at all sites with the largest percentage change at the most downstream site (394220106431500) and exhibited diel concentration variation from 11.6 to 284 percent. Appreciable diel cycles included filtered copper (0.98–1.40 micrograms per liter [µg/L], 42.9 percent), filtered zinc (less than [<] 4.00–5.50 µg/L, greater than [>] 37.5 percent), total manganese (9.70–19.5 µg/L, 101 percent), and total arsenic (0.30–0.40 µg/L, 33.3 percent). The largest percentage change in concentration was filtered manganese (2.84–10.9 µg/L, 284 percent). Diel cycles at site 09064600 ranged from 9.1 to 64.5 percent across the trace elements measured. Dissolved trace elements with appreciable diel cycles during the sampling period include filtered cadmium (0.09–0.12 µg/L, 33.3 percent), filtered copper (0.99–1.40 µg/L, 41.4 percent), and total arsenic (0.20–0.30 µg/L, 50 percent). The largest percentage change was filtered zinc (38.3–63.0 µg/L, 65 percent). Trace-element concentrations at site 09066325 were below laboratory reporting limits for many parameters, and no diel cycle could be assessed for these parameters. However, total recoverable iron, filtered barium, filtered manganese, and filtered selenium exhibited changes in concentrations of <10.0–19.4 µg/L (>94 percent), 115–121 µg/L (5 percent), 1.44–1.72 µg/L (19.4 percent), and 0.25–0.28 µg/L (12 percent), respectively. At sites 09064600 and 394220106431500, maximum trace-element concentrations occurred during nighttime with some variation regarding the timing of the peak. The exceptions to this were filtered copper, total arsenic, and filtered selenium, which had maximum concentrations around noon or as the sun disappeared below the horizon. The timing of minimum concentrations occurred in the afternoon for many trace elements, with filtered copper, total arsenic, and filtered selenium having minimum concentrations in the morning or just prior to the appearance of the sun. Analysis of historical data also showed evidence of diel cycling. Historical samples collected from July through October were used to identify diel cycling in base-flow conditions. The resulting diel pattern in the median concentration for filtered manganese, filtered zinc at water-quality site 09064600, and filtered manganese and filtered nitrate plus nitrite at water-quality site 39422016431500 were consistent with the diel pattern in the September 2018 samples, and indicate time of day can bias sampling results even during daylight hours. Diel cycling in the Eagle River Basin appears to be driven primarily by instream, biological processes. However, land use, particularly human effects downstream from urban areas, mining, and agriculture, may affect these processes. At some locations, diel variations in nutrient and trace-element concentrations are small enough to be of low concern. At other locations, however, variations in concentrations up to 284 percent in the data collected for this study and 214 percent in base-flow historical data, indicate daytime-only sampling, particularly in late afternoon, can underestimate daily average nutrient and trace-element concentrations. When feasible, the potential of diel cycling warrants consideration in sample design to account for the potential of diel cycles, or at a minimum, be recognized as a component of the river dynamic and the potential consequences that diel cycles may have in data interpretation and river management decisions.

Colorado↗

USGS2018

Streamflow and selenium loads during synoptic sampling of the Gunnison River and its tributaries near Delta, Colorado, November 2015

In response to the need for more information about selenium (Se) sources and transport, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, completed a study that characterized Se loads in a reach of the Gunnison River between Delta and Grand Junction, Colo. This report identifies where possible dissolved Se loading is occurring in a study reach in the Lower Gunnison River Basin between Delta and Grand Junction on November 19, 2015. The combined Se loads from the Gunnison River at Delta (site 3) and the Uncompahgre River at Delta (site 4) were about 95 percent of the load at the furthest downstream main-stem sample location at the Gunnison River below Roubideau Creek near Delta (site 20) (31.6 and 33.4 pounds per day, respectively), indicating that about 5 percent of the total load (1.8 pounds) was potentially contributed from diffuse groundwater inflow. Main-stem streamflow accounting during November 2015 in a downstream direction was not supportive of substantial net gains or losses in the main-stem water balance. The cumulative load from measured tributary inflows downstream from the Uncompahgre River confluence only amounted to 1.2 pounds of the main-stem loads (1.8 pounds gain) from site 4 to the end of the synoptic reach at site 20. The remaining 33 percent (about 0.6 pounds) of Se load increase was not accounted for by known tributary inflow. Yet, the small changes in the streamflow mass balance in the same reach does not strongly support a net inflow explanation for the apparent gain in load. Based on the results of the loading and streamflow analysis, when errors in the loading estimates are considered, there is no conclusive evidence of an appreciable amount of Se load that is unaccounted for in the study reach of the Gunnison River as was originally hypothesized. Differences determined from comparisons of cumulative tributary loads and Gunnison River main-stem loads for this study are within error estimates of the main-stem loads.

Colorado↗

USGS2015

Characterization of streamflow, salinity, and selenium loading and land-use change in Montrose Arroyo, western Colorado, from 1992 to 2013

Salinity and dissolved selenium are known water-quality impairments in the lower Gunnison River watershed of western Colorado. Salinity is a concern because of its adverse effects on agricultural land and equipment, and on municipal and industrial users. The Montrose Arroyo watershed in Montrose, Colorado, contains agricultural and residential areas as well as undeveloped land and has undergone substantial land-use change since the early 1990s. Previous sampling efforts indicated salinity concentrations and loads have remained constant since land-use change began in the early 1990s; however, recent sampling also indicated that dissolved-selenium concentrations and loads have begun to increase. In response to the potential increasing dissolved-selenium concentrations and loads, the U.S. Geological Survey—in cooperation with the Bureau of Reclamation; Colorado River Basin Salinity Control Forum; and Colorado River Water Conservation District—continued to monitor salinity and dissolved-selenium concentrations and loads in the Montrose Arroyo watershed. This report characterizes salinity and dissolved-selenium loads in Montrose Arroyo from 1992 to 2013 at three sites: Montrose Arroyo at East Niagara Street (MA2, U.S. Geological Survey site identification number 382802107513301), Montrose Arroyo at 6700 Road (MA3, U.S. Geological Survey site identification number 382711107500501), and Montrose Arroyo at 6750 and Ogden Roads (MA4, U.S. Geological Survey site identification number 382702107493701). A detailed land-use change analysis was also characterized in the MA3 subwatershed. The three sites were used to monitor salinity and dissolved-selenium concentrations and loads in Montrose Arroyo. Over a period from December 2011 through September 2013, 46 water-quality samples and streamflow measurements were collected at sites MA2, MA3, and MA4. Streamflow, salinity concentrations and loads, and selenium concentrations and loads were characterized and compared between the pre-lateral (before April 1999) and post-growth periods (March 2008 through September 2013) and between post-lateral (April 1999 through October 2000) and post-growth periods. Results from a previous USGS study on the characterization of salinity and selenium loading and land-use change in Montrose Arroyo from 1992 to 2010 indicated that there was no change in salinity load at site MA2 and a significant increase in dissolved-selenium load from the pre-lateral period to the post-growth period. Data associated with this report indicate the selenium loads at site MA2 show no significant change from the pre-lateral period to the post-growth period. In addition, both salinity load and dissolved-selenium load at site MA3 show significant decreases in salinity and dissolved-selenium load for both periods that are potentially associated with land-use change. Land use was characterized for 1992, 2002, and 2009 for site MA3. The common land-use change in the MA3 subwatershed was a conversion from previously irrigated agricultural land to urban land use. The MA3 subwatershed had 124 acres of irrigated land use converted to urban land use and 27.1 acres of unirrigated desert converted to urban land use from 1992 to 2009. Consistent with findings in previous land-use change reports, salinity and dissolved-selenium loading at site MA3 showed significant decreases as irrigated land was converted to urban land use.

Colorado↗

USGS2015

Hydraulic, geomorphic, and trout habitat conditions of the Lake Fork of the Gunnison River in Hinsdale County, Lake City, Colorado, Water Years 2010-2011

Channel rehabilitation, or reconfiguration, to mitigate a variety of riverine problems has become a common practice in the western United States. However, additional work to monitor and assess the channel response to, and the effectiveness of, these modifications over longer periods of time (decadal or longer) is still needed. The Lake Fork of the Gunnison River has been an area of active channel modification to accommodate the needs of the Lake City community since the 1950s. The Lake Fork Valley Conservancy District began a planning process to assess restoration options for a reach of the Lake Fork in Lake City to enhance hydraulic and ecologic characteristics of the reach. Geomorphic channel form is affected by land-use changes within the basin and geologic controls within the reach. The historic channel was defined as a dynamic, braided channel with an active flood plain. This can result in a natural tendency for the channel to braid. A braided channel can affect channel stability of reconfigured reaches when a single-thread meandering channel is imposed on the stream. The U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board and Colorado River Water Conservation District, began a study in 2010 to quantify existing hydraulic and habitat conditions for a reach of the Lake Fork of the Gunnison River in Lake City, Colorado. The purpose of this report is to quantify existing Lake Fork hydraulic and habitat conditions and establish a baseline against which post-reconfiguration conditions can be compared. This report (1) quantifies the existing hydraulic and geomorphic conditions in a 1.1-kilometer section of the Lake Fork at Lake City that has been proposed as a location for future channel-rehabilitation efforts, (2) characterizes the habitat suitability of the reach for two trout species based on physical conditions within the stream, and (3) characterizes the current riparian canopy density. The FaSTMECH computational flow-model within MD_SWMS was selected to characterize the effects of streamflow on hydraulic and habitat-suitability conditions for a study reach of the Lake Fork. Habitat suitability was evaluated for cutthroat ( Oncorhynchus clarkii ) and brown trout ( Salmo trutta morpha fario ) fry, juveniles, and adults. Microscale (point locations) and mesoscale (reach features) habitats were assessed using the combination of field observations, measurements, and hydraulic simulations within the study reach of the Lake Fork. Microscale trout habitat, presented as weighted usable area, generally increased as streamflow increased for both trout species and all life stages. Areas of suitable microscale habitat occur along the banks for flows of 900 cubic feet per second (ft 3 /s) and less. Out-of-bank areas became more substantial contributors to overall habitat availability for flows of 1,300 ft 3 /s or more when compared to other features. Adult habitat, for both trout species, was the most abundant habitat type for nearly all streamflows. In general, the upper reach provided 2–3 times more available habitat than the lower reach for both trout species. Mesoscale trout habitat of the Lake Fork was assessed based on the conditions present in the 150 ft 3 /s flow simulation as well as field observation. Both the upper and lower reach is primarily characterized as riffle/run habitat. The presence of pool habitat was limited throughout both reaches and occurred along the channel margins. For both reaches, the pool habitat was less than 5 percent of the total wetted area, a percentage that is substantially lower than the recommendations for sustainable populations of 40–70 percent. Areas of cover were adjacent to potential drift feeding areas in the lower reach, and often occurred within the same pool habitat. This may favor energy expenditure ratios of both fish species, wherein little energy is needed to acquire adequate food sources. Sediment mobility is an important process for flushing fine sediments from within the gravel frameworks. Evaluations of channel and flow characteristics at cross-section locations 2–8 show a range of streambed mobility. In general, boundary shear stress and streambed mobility increase with increases in streamflow. Within the cross sections, the greatest boundary shear stress occurs towards the center of the channel. Reach-scale assessment of sediment mobility in the lower reach shows increased streambed mobility. This is due in part to smaller grain sizes in the lower reach, but may also reflect the greater extent of channel alterations, specifically the temporary berms constructed by CDOT in the late 1980s and 1990s, present in this reach.

Colorado↗

USGS2015

Suspended-sediment transport and storage: A demonstration of acoustic methods in the evaluation of reservoir management strategies for a small water-supply reservoir in western Colorado

The U.S. Bureau of Reclamation (USBR) and local stakeholder groups are evaluating reservoir-management strategies within Paonia Reservoir. This small reservoir fills to capacity each spring and requires approximately half of the snowmelt-runoff volume from its sediment-laden source waters, Muddy Creek. The U.S. Geological Survey is currently conducting high-resolution (15-minute data-recording interval) sediment monitoring to characterize incoming and outgoing sediment flux during reservoir operations at two sites on Muddy Creek. The high-resolution monitoring is being used to establish current rates of reservoir sedimentation, support USBR sediment transport and storage models, and assess the viability of water-storage recovery in Paonia Reservoir. These sites are equipped with in situ, single-frequency, side-looking acoustic Doppler current meters in conjunction with turbidity sensors to monitor sediment flux. This project serves as a demonstration of the capability of using surrogate techniques to predict suspended-sediment concentrations in small streams (less than 20 meters in width and 2 meters in depth). These two sites provide the ability to report near real-time suspended-sediment concentrations through the U.S. Geological Survey National Water Information System (NWIS) web interface and National Real-Time Water Quality websites (NRTWQ) to aid in reservoir operations and assessments.

Colorado↗

USGS2014

Characterization of salinity loads and selenium loads in the Smith Fork Creek region of the Lower Gunnison River Basin, western Colorado, 2008-2009

The lower Gunnison River Basin of the Colorado River Basin has elevated salinity and selenium levels. The Colorado River Basin Salinity Control Act of June 24, 1974 (Public Law 93–320, amended by Public Law 98–569), authorized investigation of the Lower Gunnison Basin Unit Salinity Control Project by the U.S. Department of the Interior. The Bureau of Reclamation (Reclamation) and the Natural Resources Conservation Service are responsible for assessing and implementing measures to reduce salinity and selenium loading in the Colorado River Basin. Cost-sharing programs help farmers, ranchers, and canal companies improve the efficiency of water delivery systems and irrigation practices. The delivery systems (irrigation canals) have been identified as potential sources of seepage, which can contribute to salinity loading. Reclamation wants to identify seepage from irrigation systems in order to maximize the effectiveness of the various salinity-control methods, such as polyacrylamide lining and piping of irrigation canals programs. The U.S. Geological Survey, in cooperation with Reclamation, developed a study to characterize the salinity and selenium loading of seven subbasins in the Smith Fork Creek region and identify where control efforts can be maximized to reduce salinity and selenium loading. Total salinity loads ranged from 27.9±19.1 tons per year (t/yr) to 87,500±80,500 t/yr. The four natural subbasins—BkKm, RCG1, RCG2, and SF1—had total salinity loads of 27.9±19.1 t/yr, 371±248 t/yr, 2,180±1,590 t/yr, and 4,200±2,720 t/yr, respectively. The agriculturally influenced sites had salinity loads that ranged from 7,580±6,900 t/yr to 87,500±80,500 t/yr. Salinity loads for the subbasins AL1, B1, CK1, SF2, and SF3 were 7,580±6,900 t/yr; 28,300±26,700 t/yr; 48,700±36,100 t/yr; 87,500±80,900 t/yr; and 52,200±31,800 t/yr, respectively. The agricultural salinity load was separated into three components: tail water, deep percolation, and canal seepage. Annual tail-water salinity loads ranged from 48.0 to 2,750 tons in the Smith Fork Creek region. The largest tail-water salinity load was in subbasin SF3, and the lowest salinity load from tail water was in subbasin R1. The remaining four agricultural subbasins—AL1, B1, CK1, and SF2—had tail-water loads of 285 t/yr, 180 t/yr, 333 t/yr, and 1,700 t/yr, respectively. The deep percolation component of the agricultural salinity load ranged from 3,300 t/yr in subbasin AL1 to 51,800 t/yr in subbasin SF2. Subbasins R1, B1, CK1, and SF3 had deep percolation salinity loads of 4,940 t/yr, 15,200 t/yr, 21,200 t/yr, and 23,600 t/yr, respectively. The canal seepage component of the agricultural salinity load ranged from 1,100 t/yr in subbasin AL1 to 15,300 t/yr in subbasin CK1. Subbasins B1, R1, SF2, and SF3 had canal seepage salinity loads of 6,610 t/yr, 3,890 t/yr, 9,430 t/yr, and 12,100 t/yr, respectively. Four natural subbasins—RCG1, RCG2, SF1, and BkKm—were used to calculate natural salinity yields for the remaining subbasins. The appropriate salinity yield was applied to the corresponding number of acres and resulted in a natural salinity load for each subbasin. The annual salinity yields for the Dakota Sandstone and Burro Canyon Formation, Mancos Shale, and crystalline geologies are 0.217 tons per acre (t/acre), 0.113 t/acre, and 0.151 t/acre, respectively. Three of the four natural subbasins had little to no selenium load based on the measured data and calculated selenium loads. Subbasins RCG1 and RCG2 had surface-water selenium loads of 0.106±0.024 pounds (lb) and 0.00 lb, respectively. Subbasin BkKm did not have an estimated surface-water selenium load because of the lack of any water-quality samples during the study period. The subbasin designated by site CK1 had the highest selenium load with 135±38.7 lb, and the next highest subbasins in decreasing order are B1, SF3, AL1, SF1, and R1 with selenium loads of 69.6±28.4 lb, 56.5±23.8 lb, 30.5±16.6 lb, 26.8±6.95 lb, and 15.6±27.7 lb, respectively.

Colorado↗

USGS2013

Application of sediment characteristics and transport conditions to resource management in selected main-stem reaches of the Upper Colorado River, Colorado and Utah, 1965-2007

The Colorado River Basin provides habitat for 14 native fish, including 4 endangered species protected under the Federal Endangered Species Act of 1973. These endangered fish species once thrived in the Colorado River system, but water-resource development, including the building of numerous diversion dams and several large reservoirs, and the introduction of non-native fish, resulted in large reductions in the numbers and range of the four species through loss of habitat and stream function. Understanding how stream conditions and habitat change in response to alterations in streamflow is important for water administrators and wildlife managers and can be determined from an understanding of sediment transport. Characterization of the processes that are controlling sediment transport is an important first step in identifying flow regimes needed for restored channel morphology and the sustained recovery of endangered fishes within these river systems. The U.S. Geological Survey, in cooperation with the Upper Colorado River Endangered Fish Recovery Program, Bureau of Reclamation, U.S. Fish and Wildlife Service, Argonne National Laboratory, Western Area Power Administration, and Wyoming State Engineer’s Office, began a study in 2004 to characterize sediment transport at selected locations on the Colorado, Gunnison, and Green Rivers to begin addressing gaps in existing datasets and conceptual models of the river systems. This report identifies and characterizes the relation between streamflow (magnitude and timing) and sediment transport and presents the findings through discussions of (1) suspended-sediment transport, (2) incipient motion of streambed material, and (3) a case study of sediment-transport conditions for a reach of the Green River identified as a razorback sucker spawning habitat (See report for full abstract).

Colorado;Utah↗

USGS2011

Characterization of hydrology and salinity in the Dolores project area, McElmo Creek region, southwest Colorado, water years 1978-2006

Increasing salinity loading in the Colorado River has become a major concern for agricultural and municipal water supplies. The Colorado Salinity Control Act was implemented in 1974 to protect and enhance the quality of water in the Colorado River Basin. The U.S. Geological Survey, in cooperation with the Bureau of Reclamation and the Colorado River Salinity Control Forum, summarized salinity reductions in the McElmo Creek basin in southwest Colorado as a result of salinity-control modifications and flow-regime changes that result from the Dolores Project, which consists of the construction of McPhee reservoir on the Dolores River and salinity control modifications along the irrigation water delivery system. Flow-adjusted salinity trends using S-LOADEST estimations for a streamgage on McElmo Creek (site 1), that represents outflow from the basin, indicates a decrease in salinity load by 39,800 tons from water year 1978 through water year 2006, which is an average decrease of 1,370 tons per year for the 29-year period. Annual-load calculations for a streamgage on Mud Creek (site 6), that represents outflow from a tributary basin, indicate a decrease of 7,300 tons from water year 1982 through water year 2006, which is an average decrease of 292 tons per year for the 25-year period. The streamgage Dolores River at Dolores, CO (site 17) was chosen to represent a background site that is not affected by the Dolores Project. Annual load calculations for site 17 estimated a decrease of about 8,600 tons from water year 1978 through water year 2006, which is an average decrease of 297 tons per year for the 29-year period. The trend in salinity load at site 17 was considered to be representative of a natural trend in the region. Typically, salinity concentrations at outflow sites decreased from the pre-Dolores Project period (water years 1978—1984) to the post-Dolores Project period (water years 2000—2006). The median salinity concentration for site 1 (main basin outflow) decreased from 2,210 milligrams per liter per day in the preperiod to 2,110 milligrams per liter per day in the postperiod. The median salinity concentration for site 6 (tributary outflow) increased from 3,370 milligrams per liter per day in the preperiod to 3,710 milligrams per liter per day in the postperiod. Salinity concentrations typically increased at inflow sites from the preperiod to the postperiod. Salinity concentrations increased from 178 milligrams per liter per day during the preperiod at Main Canal #1 (site 16) to 227 milligrams per liter per day during the postperiod at the Dolores Tunnel Outlet near Dolores, CO (site 15). Calculation of the historical flow regime in McElmo Creek was done using a water-budget analysis of the basin. During water years 2000—2006, an estimated 845,000 acre-feet of water was consumed by crops and did not return to the creek as streamflow. The remaining 76,000 acre-feet, or 10,900 acre-feet per year for the 7-year postperiod, was assumed to represent a historical flow condition. The historical flow of 10,900 acre-feet per year is equivalent to 15.1 cubic feet per second. Average total dissolved solids concentrations for water in each type of sedimentary rock were used to estimate natural salinity loads. Most surface-water sites used to fit the criteria needed to achieve a natural TDS concentration were springs. An average spring TDS value for sandstones geology in the basin was 350 milligrams per liter, and the average value for Mancos Shale geology was 4,000 milligrams per liter. The natural salinity loads in McElmo Creek were estimated to be 29,100 tons per year, which is 43 percent of the salinity load that was calculated for the postperiod.

Colorado↗

USGS2011

Assessment of surface-water quantity and quality, Eagle River watershed, Colorado, 1947-2007

From the early mining days to the current tourism-based economy, the Eagle River watershed (ERW) in central Colorado has undergone a sequence of land-use changes that has affected the hydrology, habitat, and water quality of the area. In 2000, the USGS, in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, City of Colorado Springs, Colorado Springs Utilities, and Denver Water, initiated a retrospective analysis of surface-water quantity and quality in the ERW. Surface-water quantity data and surface-water quality data were obtained from local, State, and Federal agencies to assist in the analysis of surface-water conditions in the ERW 1947-2007. Surface-water-quality data from 293 sites and 12 different source agencies were compiled into 192 unique sites located on streams and rivers in the ERW. Approximately 39 percent of the unique sites had fewer than 5 samples; while 23 percent of the sites had more than 100 samples. Physical properties were the most abundant type of samples collected, with major ions, nutrients, and trace elements also commonly collected. For selected water-quality properties and constituents in the watershed, this report: (1) characterizes available water quantity and water-quality data, (2) identifies spatial and seasonal variability in water quantity and water quality, (3) provides comparisons to Federal and State water-quality standards or recommendations, (4) characterizes temporal changes in water quality, and (5) where possible, identifies potential causes of these changes. This report provides reconnaissance-level statistical summaries and comparisons of water-quality conditions and characteristics using available data within the ERW. The report also includes streamflow statistics such as: mean annual runoff totals, peak-flood-frequency recurrence intervals, and minimum 7-day mean streamflows for selected sites within the watershed. The spatial patterns for concentrations of trace metals (aluminum, cadmium, copper, iron, manganese, and zinc) indicate an increase in dissolved concentrations of these metals near historical mining areas in the Eagle River and several tributaries near Belden. In general, concentrations decrease downstream from mining areas. Concentrations typically are near or below reporting limits in Gore Creek and other tributaries within the watershed. Concentrations for trace elements (arsenic, selenium, and uranium) in the watershed usually are below the reporting limit, and no prevailing spatial patterns were observed in the data. Step-trend analysis and temporal-trend analysis provide evidence that remediation of historical mining areas in the upper Eagle River have led to observed decreases in metals concentrations in many surface-waters. Comparison of pre- and post-remediation concentrations for many metals indicates significant decreases in metals concentrations for cadmium, manganese, and zinc at sites downstream from the Eagle Mine Superfund Site. Some sites show order of magnitude reductions in median concentrations between these two periods. Evaluation of monotonic trends for dissolved metals concentrations show downward trends at numerous sites in, and downstream from, historic mining areas. The spatial pattern of nutrients shows lower concentrations on many tributaries and on the Eagle River upstream from Red Cliff with increases in nutrients downstream of major urban areas. Seasonal variations show that for many nutrient species, concentrations tend to be lowest May-June and highest January-March. The gradual changes in concentrations between seasons may be related to dilution effects from increases and decreases in streamflow. Upward trends in nutrients between the towns of Gypsum and Avon were detected for nitrate, orthophosphate, and total phosphorus. An upward trend in nitrite was detected in Gore Creek. No trends were detected in un-ionized ammonia within the ERW. Exceedances of State water-quality standards (nitrite, nitrate, and un-ionized ammonia) and levels higher than U.S. Environmental Protection Agency recommendations (total phosphorus) occur in several areas within the ERW. The majority of the exceedances are from comparisons to the U.S. Environmental Protection Agency total phosphorus recommendations. A positive correlation was observed between suspended sediment and total phosphorus. An upward trend in total dissolved solids in Gore Creek may be the result of increases in chloride salts. Highly significant trends were detected in sodium, potassium, and chloride with a significant upward trend in magnesium and a weakly significant upward trend in calcium. A quantitative analysis of the relative abundance of calcium, magnesium, sodium, and potassium to the available anions suggests that chloride salts likely are the source for the detected upward trends because chloride is the only commonly occurring anion with a trend in Gore Greek. A potential source for the observed chloride salts may be the chemical anti-icing and deicing products used during winter road maintenance in municipal areas and on Interstate-70. A downward trend in dissolved solids in the Eagle River between Gypsum and Avon may be contributing to the detected trend on the Eagle River at Gypsum. Significant downward trends were detected in specific ions such as calcium, magnesium, sulfate, and silica. Measures of total dissolved solids as well as comparisons to specific ions show that in water-quality samples within the ERW concentrations generally are lower in the headwaters, with increases downstream from Wolcott. Differences in concentrations likely result from increased abundance of salt-bearing geologic units downstream from Avon. Few sites had measured concentrations that exceeded the State standards for chloride.

Scientific Investigations Report↗