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At least 379 records · Page 21Linked to original sources

USGS1997

Can the global carbon budget be balanced?

The Mississippi Basin Carbon Project of the U.S. Geological Survey (USGS) is an effort to examine interactions between the global carbon cycle and human-induced changes to the land surface, such as farming and urbanization. Investigations in the Mississippi River basin will provide the data needed for calculating the global significance of land-use changes on land-based carbon cycling. These data are essential for predicting and mitigating the effects of global environmental change. The Mississippi Basin Carbon Project is focused on the third largest river system in the world. The Mississippi River and its tributaries drain more than 40% of the conterminous United States. The basin includes areas that typify vast regions of the Earth's surface that have undergone human development.

Fact Sheet↗

USGS2022

Estimating stream temperature in the Willamette River Basin, northwestern Oregon—A regression-based approach

The alteration of thermal regimes, including increased temperatures and shifts in seasonality, is a key challenge to the health and survival of federally protected cold-water salmonids in streams of the Willamette River basin in northwestern Oregon. To better support threatened fish species, the U.S. Army Corps of Engineers (USACE) and other water managers seek to improve the thermal regime in the Willamette River and key tributaries downstream of USACE dams by utilizing strategically timed flow releases from USACE dams. To inform flow management decisions, regression relations were developed for 12 Willamette River basin locations below USACE dams relating stream temperature with streamflow and air temperature utilizing publicly available datasets spanning 2000–18. The resulting relations provide simple tools to investigate stream temperature responses to changes in streamflow and climatic conditions in the Willamette River system. Regression relations on the Willamette River and key tributaries show that, at locations sufficiently distant from the direct temperature influence of upstream dam releases, air temperature and streamflow are reasonable proxies to predict the 7-day average of the daily mean (7dADMean) and 7-day average of the daily maximum (7dADMax) water temperature with errors generally ≤1 degrees Celsius (°C). To account for seasonal variations in the relation between air temperature, streamflow, and stream temperature, a transition-smoothed, seasonal regression approach was used. Stream temperature is inversely correlated with streamflow in all seasons except “winter” (January–March), when it is relatively independent. Stream temperature is positively correlated with air temperature in all seasons, but the slope decreases at very low or very high air temperatures. Generally, fit is best for seasonal models “winter” (January–March), “spring” (April–May), “summer” (June–August), and “early autumn” (September–October). Error in “autumn” (November–December) is larger, probably due to variation in the onset timing of winter storms. Simulated results from a climatological analysis of predicted stream temperature suggest that, excluding extremes and accounting for some seasonal variability, the 7dADMean and 7dADMax stream temperature sensitivity to air temperature and streamflow varies by location on the river. To investigate the potential range of stream temperature variability based on historical air temperature and streamflow conditions, stream temperature predictions were calculated using synthetic time series comprised of daily temperature values representing the 0.10, 0.33, 0.50, 0.67, and 0.90 quantile of air temperature and streamflow from 1954 (the year meaningful streamflow augmentation began) to 2018. Results show that from a “very hot” (0.90 quantile) and “very dry” (0.10 quantile) year to a “very cool” (0.10 quantile) and “very wet” (0.90; all quantiles from 1954 to 2018) year, the stream temperature sensitivity to air temperature and streamflow is about 3 °C at Harrisburg (river mile 161.0) and increases to about 5 °C at Keizer (river mile 82.2). While the number of days exceeding regulatory criteria are fewer in cooler, wetter years than in warmer, dryer years, the models suggest that the Willamette River will likely continue to exceed the State of Oregon maximum water-temperature criterion of 18 °C for sustained periods from late spring to early autumn and that the flow management practices evaluated in this study, while effective at influencing stream temperature, likely cannot prevent many or all such exceedances. As modeled for 2018, a representative very hot year with normal to below-normal streamflow, stream temperature sensitivity to changes in streamflow of ±100 to ±1000 cubic feet per second produced mean monthly temperature changes from 0.0 to 1.4 °C at Keizer, Albany, and Harrisburg during summer. For a specified change in flow, temperature sensitivity is greater at upstream locations where streamflow is less than that at downstream locations because the change in streamflow is a greater percentage of total streamflow at upstream locations. Similarly, temperature response to a set change in flow is greater in the summer and early autumn low-flow season than in spring when flows are higher. The regression models developed in this study thus indicate that flow management is likely to have a greater effect on stream temperature at upstream locations (such as Harrisburg or Albany) and during the low-flow season than at downstream locations (such as Keizer) or during periods of higher streamflow.

Oregon↗

USGS2009

Ground-Water Budgets for the Wood River Valley Aquifer System, South-Central Idaho, 1995-2004

The Wood River Valley contains most of the population of Blaine County and the cities of Sun Valley, Ketchum, Haley, and Bellevue. This mountain valley is underlain by the alluvial Wood River Valley aquifer system which consists of a single unconfined aquifer that underlies the entire valley, an underlying confined aquifer that is present only in the southernmost valley, and the confining unit that separates them. The entire population of the area depends on ground water for domestic supply, either from domestic or municipal-supply wells, and rapid population growth since the 1970s has caused concern about the long-term sustainability of the ground-water resource. To help address these concerns this report describes a ground-water budget developed for the Wood River Valley aquifer system for three selected time periods: average conditions for the 10-year period 1995-2004, and the single years of 1995 and 2001. The 10-year period 1995-2004 represents a range of conditions in the recent past for which measured data exist. Water years 1995 and 2001 represent the wettest and driest years, respectively, within the 10-year period based on precipitation at the Ketchum Ranger Station. Recharge or inflow to the Wood River Valley aquifer system occurs through seven main sources (from largest to smallest): infiltration from tributary canyons, streamflow loss from the Big Wood River, areal recharge from precipitation and applied irrigation water, seepage from canals and recharge pits, leakage from municipal pipes, percolation from septic systems, and subsurface inflow beneath the Big Wood River in the northern end of the valley. Total estimated mean annual inflow or recharge to the aquifer system for 1995-2004 is 270,000 acre-ft/yr (370 ft3/s). Total recharge for the wet year 1995 and the dry year 2001 is estimated to be 270,000 acre-ft/yr (370 ft3/s) and 220,000 acre-ft/yr (300 ft3/s), respectively. Discharge or outflow from the Wood River Valley aquifer system occurs through five main sources (from largest to smallest): Silver Creek streamflow gain, ground-water pumpage, Big Wood River streamflow gain, direct evapotranspiration from riparian vegetation, and subsurface outflow (treated separately). Total estimated mean 1995-2004 annual outflow or discharge from the aquifer system is 250,000 acre-ft/yr (350 ft3/s). Estimated total discharge is 240,000 acre-ft/yr (330 ft3/s) for both the wet year 1995 and the dry year 2001. The budget residual is the difference between estimated ground-water inflow and outflow and encompasses subsurface outflow, ground-water storage change, and budget error. For 1995-2004, mean annual inflow exceeded outflow by 20,000 acre-ft/yr (28 ft3/s); for the wet year 1995, mean annual inflow exceeded outflow by 30,000 acre-ft/yr (41 ft3/s); for the dry year 2001, mean annual outflow exceeded inflow by 20,000 acre-ft/yr (28 ft3/s). These values represent 8, 13, and 8 percent, respectively, of total outflows for the same periods. It is difficult to differentiate the relative contributions of the three residual components, although the estimated fluctuations between the wet and dry year budgets likely are primarily caused by changes in ground-water storage. The individual components in the wet and dry year ground-water budgets responded in a consistent manner to changes in precipitation and temperature. Although the ground-water budgets for the three periods indicated that ground-water storage is replenished in wet years, statistical analyses by Skinner and others (2007) suggest that such replenishment is not complete and over the long term more water is removed from storage than is replaced. In other words, despite restoration of water to ground-water storage in wet years, changes have occurred in either recharge and (or) discharge to cause ground-water storage to decline over time. Such changes may include, but are not limited to: lining or abandoning canals and ditches, conversion of surface-water irriga

Scientific Investigations Report↗

USGS2017

Movements of Atlantic Sturgeon of the Gulf of Maine inside and outside the geographically defined Distinct Population Segment

Identification of potential critical habitat, seasonal distributions, and movements within and between river systems is important for protecting the Gulf of Maine (GOM) Distinct Population Segment of Atlantic Sturgeon. To accomplish these objectives, we captured Atlantic Sturgeon in four GOM rivers (Penobscot, Kennebec system, Saco, and Merrimack), and tagged 144 (83.3–217.4 cm TL) internally with uniquely coded acoustic transmitters. Tagged fish were detected between 2006 to 2014 by primary receiver arrays deployed in the four GOM rivers or opportunistically on a secondary group of receivers deployed within the GOM and along the continental shelf. Atlantic Sturgeon tagged in the four rivers were documented at three spawning areas in the Kennebec system in June and July, including one that became accessible in 1999 when the Edwards Dam was removed. After being tagged, the majority (74%) of Atlantic sturgeon were detected in the estuaries of the four GOM rivers, primarily from May through October. Tagged fish spent most of their time in saline water in the Saco River and Merrimack River, moved into brackish water in the Penobscot River, and were found in saline, brackish, and fresh water in the Kennebec system. Approximately 70% of the tagged fish were detected in GOM coastal waters, and aggregated in the Bay of Fundy (May–January), offshore of the Penobscot River (September-February and May), offshore of the Kennebec River (September–February), in Saco Bay and the Scarborough River (July–November), and along the eastern Massachusetts coast between Cape Ann and Cape Cod (April–February). Nine tagged Atlantic sturgeon (7%) left the GOM, three of which moved as far north as Halifax in Canada and six moved as far south as the James River in Virginia. Information from this study will be used to make recommendations to avoid, reduce or mitigate the impacts of in-water projects and on Atlantic sturgeon.

Maine, Massachusetts, New Hampshire↗

USGS2000

Concentrations and characteristics of organic carbon in surface water in Arizona: Influence of urbanization

Dissolved (DOC) and total (TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants (p < 0.05). Reservoir outflows and wastewater-treatment plant effluent were higher in DOC concentration (p < 0.05) and exhibited less variability in concentration than inflows to the reservoirs. Specific ultraviolet absorbance values at 254 nm were typically less than 2 m-1(milligram DOC per liter)-1 and lower than values found in most temperate-region rivers, but specific ultraviolet absorbance values increased during runoff events. Fluorescence measurements indicated that DOC in desert streams typically exhibit characteristics of autochthonous sources; however, DOC in unregulated upland rivers and desert streams experienced sudden shifts from autochthonous to allochthonous sources during runoff events. The urban water system (reservoir systems and wastewater-treatment plants) was found to affect temporal variability in DOC concentration and composition. (C) 2000 Elsevier Science B.V.Dissolved (DOC) and total (TOC) organic carbon concentrations and compositions were studied for several river systems in Arizona, USA. DOC composition was characterized by ultraviolet and visible absorption and fluorescence emission (excitation wavelength of 370 nm) spectra characteristics. Ephemeral sites had the highest DOC concentrations, and unregulated perennial sites had lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater-treatment plants (p<0.05). Reservoir outflows and wastewater-treatment plant effluent were higher in DOC concentration (p<0.05) and exhibited less variability in concentration than inflows to the reservoirs. Specific ultraviolet absorbance values at 254 nm were typically less than 2 m-1(milligram DOC per liter)-1 and lower than values found in most temperate-region rivers, but specific ultraviolet absorbance values increased during runoff events. Fluorescence measurements indicated that DOC in desert streams typically exhibit characteristics of autochthonous sources; however, DOC in unregulated upland rivers and desert streams experienced sudden shifts from autochthonous to allochthonous sources during runoff events. The urban water system (reservoir systems and wastewater-treatment plants) was found to affect temporal variability in DOC concentration and composition.The influence of urbanization, becoming increasingly common in arid regions, on dissolved organic carbon (DOC) concentrations in surface water resources was studied. DOC concentration and composition, seasonal watershed runoff events, streamflow variations, water management practices, and urban infrastructure in several Arizona watersheds were monitored. Ephemeral sites had the highest DOC levels, and unregulated perennial sites and lower concentrations than unregulated intermittent sites, regulated sites, and sites downstream from wastewater treatment plants. Reservoir outflows and wastewater treatment plant effluent had higher and less variable DOC concentrations than inflows to reservoirs. UV absorbance values, fluorescence measurements, and other indicators suggest that urban water systems (reservoirs and wastewater treatment plants) affect temporal variability in DOC concentration and composition.

Journal of Hydrology↗

USGS2024

Beaver dam analogs did not improve beaver translocation outcomes in a desert river

Stream restoration programs employ beaver-related restoration techniques, including beaver translocations and installation of beaver dam analogs (BDA), to create complex in-stream habitat. We investigated whether BDA installations improved the probability of translocated beavers surviving and colonizing a section of a degraded desert river. We translocated beavers fitted with tracking devices to the Price River, Utah, United States, for 2 years before and after BDAs were installed. We monitored survival and site fidelity of beavers to estimate apparent survival ( φ ), using model selection to evaluate models with BDA, flow, and other factors hypothesized to relate to apparent survival. We found similar apparent survival 8 weeks post-release of pre-BDA ( φ = 0.50 ± 0.08 SE) and post-BDA beavers ( φ = 0.41 ± 0.06 SE). There were 15 predator-caused mortalities and 39 beavers emigrated out of the study site. Top models indicated apparent survival was negatively related to mean flow. Of the 70 BDAs constructed, beaver activity was detected on only two structures and the number of intact natural dams decreased due to monsoon floods. Our results suggest BDAs may not improve survival and site fidelity of translocated beavers in desert river systems. Instead, the dynamic flow of desert rivers and negative relationship between flow and apparent survival suggest the timing of release may be an important consideration for successful beaver translocation. Additional research is needed to understand how habitat, food availability, individual behavior, and resident conspecifics influence beaver translocation success.

Utah↗

USGS2020

Dye-tracing plan for verifying the Kansas River time-of-travel model

The Kansas River provides drinking water for multiple cities in northeastern Kansas and is used for recreational purposes. Thus, improving the scientific knowledge of streamflow velocities and traveltimes will greatly aid in water-treatment plans and response to critical events and threats to water supplies. Dye-tracer studies are usually done to enhance knowledge of transport characteristics, which include streamflow velocities, traveltimes, and dispersion rates, within a river system. To achieve this in the Kansas River, rhodamine water-tracing dye is planned to be injected into the Kansas River during three different flow ranges at three locations: Manhattan, Topeka, and Eudora. The primary purpose of doing a dye-tracer study in the Kansas River is to calibrate a time-of-travel model used for estimating streamflow velocities and traveltimes, which can be used by the public as well as drinking water suppliers to protect water resources and public-water supplies.

Kansas↗

USGS1988

User's guide for RIV2; a package for routing and accounting of river discharge for a modular, three-dimensional, finite-difference, ground- water flow model

RIV2 is a package for the U.S. Geological Survey 's modular, three-dimensional, finite-difference, groundwater flow model developed by M. G. McDonald and A. W. Harbaugh that simulates river-discharge routing. RIV2 replaces RIVI, the original river package used in the model. RIV2 preserves the basic logic of RIV1, but better represents river-discharge routing. The main features of RIV2 are (1) The river system is divided into reaches and simulated river discharge is routed from one node to the next. (2) Inflow (river discharge) entering the upstream end of a reach can be specified. (3) More than one river can be represented at one node and rivers can cross, as when representing a siphon. (4) The quantity of leakage to or from the aquifer at a given node is proportional to the hydraulic-head difference between that specified for the river and that calculated for the aquifer. Also, the quantity of leakage to the aquifer at any node can be limited by the user and, within this limit, the maximum leakage to the aquifer is the discharge available in the river. This feature allows for the simulation of intermittent rivers and drains that have no discharge routed to their upstream reaches. (5) An accounting of river discharge is maintained. Neither stage-discharge relations nor storage in the river or river banks is simulated. (USGS)

Open-File Report↗

USGS2020

2020 Four-band aerial imagery testing and acquisition for 2020 land cover/land use mission

The aerial camera testing project lays the groundwork for the collection of aerial imagery that will be used in the creation of the next iteration of systemic land cover/land use data for the Upper Mississippi River System. Prior to acquisition in the summer of 2020, the new 4-band aerial camera will be assessed for image quality at various resolutions and be compared to the camera used for the 2010/2011 collection. Systemic aerial imagery has been acquired, and vegetation datasets derived from that imagery, by the Upper Mississippi River Restoration Program’s Long Term Resource Monitoring element on a decadal basis beginning in 1989 and follow-up imagery missions in 2000 and 2010/2011. Remote sensing and geographic information system technology has changed dramatically during this time, transitioning from a workflow based on 9-inch by 9-inch aerial film-based cameras to today’s 80-megapixel four-band digital camera. In addition to the camera testing, this report also provides historical information of previous aerial imagery acquisition efforts and how that process has continued to advance in the 30 years since the Program’s genesis.

Long Term Resource Monitoring Technical Report↗

USGS1995

Overview of the influence of syn-sedimentary tectonics and palaeo-fluvial systems on coal seam and sand body characteristics in the Westphalian C strata, Campine Basin, Belgium

The Westphalian C strata found in the northeastern part of the former Belgian coal district (Campine Basin), which is part of an extensive northwest European paralic coal basin, are considered. The thickness and lateral continuity of the Westphalian C coal seams vary considerably stratigraphically and areally. Sedimentological facies analysis of borehole cores indicates that the deposition of Westphalian C coal-bearing strata was controlled by fluvial depositional systems whose architectures were ruled by local subsidence rates. The local subsidence rates may be related to major faults, which were intermittently reactivated during deposition. Lateral changes in coal seam groups are also reflected by marked variations of their seismic signatures. Westphalian C fluvial depositional systems include moderate to low sinuosity braided and anastomosed river systems. Stable tectonic conditions on upthrown, fault-bounded platforms favoured deposition by braided rivers and the associated development of relatively thick, laterally continuous coal seams in raised mires. In contrast, rapidly subsiding downthrown fault blocks favoured aggradation, probably by anastomosed rivers and the development of relatively thin, highly discontinuous coal seams in topogenous mires.

Campine Basin↗

USGS2018

Developing a shared understanding of the Upper Mississippi River: the foundation of an ecological resilience assessment

The Upper Mississippi River System (UMRS) is a large and complex floodplain river ecosystem that spans the jurisdictions of multiple state and federal agencies. In support of ongoing ecosystem restoration and management by this broad partnership, we are undertaking a resilience assessment of the UMRS. We describe the UMRS in the context of an ecological resilience assessment. Our description articulates the temporal and spatial extent of our assessment of the UMRS, the relevant historical context, the valued services provided by the system, and the fundamental controlling variables that determine its structure and function. An important objective of developing the system description was to determine the simplest, adequate conceptual understanding of the UMRS. We conceptualize a simplified UMRS as three interconnected subsystems: lotic channels, lentic off-channel areas, and floodplains. By identifying controlling variables within each subsystem, we have developed a shared understanding of the basic structure and function of the UMRS, which will serve as the basis for ongoing quantitative evaluations of factors that likely contribute to the resilience of the UMRS. As we undertake the subsequent elements of a resilience assessment, we anticipate our improved understanding of interactions, feedbacks, and critical thresholds will assist natural resource managers to better recognize the system’s ability to adapt to existing and new stresses.

Ecology and Society↗

USGS1952

Ground water in the Gila River Basin and adjacent areas, Arizona: a summary

This report is a resume' of the principal facts collected by the Geological Survey in the period 1890-1952 about the ground-water resources of the Gila River basin and certain other areas in Arizona. Since 1939 the Geological Survey has been making ground-water investigations on a continuing basis in cooperation with the State of Arizona. Since 1940 the cooperating agency has been the State Land Department. The occurrence of ground water in fifteen areas that form a part of the Gila River drainage basin is described in this report. The areas are denoted by the name of a town or geographic feature, and are as follows: Duncan, Safford, San Simon, Upper San Pedro, Lower San Pedro, Aravaipa Creek, Upper Santa Cruz, Lower Santa Cruz, Salt River Valley, Rainbow ValleyWaterman Wash, McMullen Valley, Harquahala Plain, Gila Bend, Palomas Plain, and Wellton-Mohawk. Data also are presented for several areas not in the Gila River system, including Ranegras Plain and the Willcox and Douglas basins. A summary of the data is given following the ground-water discussion in each area. A series of maps accompany the report, including an index map and maps of the principal areas of ground-water development. The mar,z, show the geology, the location of most of the irrigation wells and irrigated lands, and, where data were available, contours of the water table, depth to the water table, and changes in its position over a period of years. Ground water occurs in the region primarily in alluvial fill consisting of gravel, sand, silt, and clay which was deposited in structural troughs between mountain ranges. Ground water stored in these alluvial basins is derived from many sources. The principal sources are infiltration from runoff along the mountain fronts and seepage from irrigation water applied to cultivated lands. Of great interest in Arizona at the present time is the rate of depletion of ground-water reserves by withdrawals from storage. Use of ground water in Arizona increased by more than 50 percent in the 6-year period 1'46-51, from 2,400,000 acre-feet in 1946 to 3,750,000 acre-feet in 1951. The areas of greatest withdrawal are in Pinal and Maricopa Counties, in the southcentral part of the State. Maps and hydrographs accompanying this report show that the water table is declining in the heavily pumped areas, indicating that ground water is being withdrawn in excess of replenishment. The rate of decline has been as much as 10 feet per year in the most intensively pumped areas, and has been greatest during the past few years. In an effort to compensate for decreased well yields resulting from the decline of the water table in some areas, many deep wells have been drilled within the past few years. The deep aquifers do not represent a new source of water; their water is a part of the common supply of the structural basins in which they lie. The aquifers tapped by these deep wells generally yield less water per foot of drawdown than the shallower aquifers. The water in the deeper aquifers is variable in quality, ranging from water too high in dissolved solids to be usable for irrigation to water lower in concentration than that in the overlying aquifers. The quality of the ground waters in most of the region is considered suitable for irrigation. In local areas, however, the ground waters are naturally unsuitable for irrigation and, in other areas, the concentration of dissolved solids has increased sufficiently to make the waters harmful to some crops. The problem of salt balance is becoming increasingly important, not only in the Salt River Valley area, but also in other parts of the Gila River Basin. A discussion of the salt-balance problem is given in Part II of this report. It should be emphasized that ground waters in each of the individual areas in the Gila River drainage system are interrelated with ground waters in adjacent areas upstream and downstream. The connection is tenuous between some areas, but in central Arizona the ground waters in the different areas are closely related. Although subsurface barriers to ground-water movement exist in places, they are not everywhere fully effective. The ground-water--surface-water interrelationship is important in some areas. Those basins occupied by perennial streams, or by streams having large influent seepage losses, have not shown large, perennial declines of water levels in wells. Effluent seepage of ground water contributes to stream flow in the lower reaches of several basins.

Arizona↗

USGS2019

Estimating sand concentrations using ADCP‐based acoustic inversion in a large fluvial system characterized by bi‐modal suspended‐sediment distributions

Quantifying sediment flux within rivers is a challenge for many disciplines due, mainly, to difficulties inherent to traditional sediment sampling methods. These methods are operationally complex, high cost, and high risk. Additionally, the resulting data provide a low spatial and temporal resolution estimate of the total sediment flux, which has impeded advances in the understanding of the hydro‐geomorphic characteristics of rivers. Acoustic technologies have been recognized as a leading tool for increasing the resolution of sediment data by relating their echo intensity level measurements to suspended sediment. Further effort is required to robustly test and develop these techniques across a wide range of conditions found in natural river systems. This article aims to evaluate the application of acoustic inversion techniques using commercially available, down‐looking acoustic Doppler current profilers (ADCPs) in quantifying suspended sediment in a large sand bed river with varying bi‐modal particle size distributions, wash load and suspended‐sand ratios, and water stages. To achieve this objective, suspended sediment was physically sampled along the Paraná River, Argentina, under various hydro‐sedimentological regimes. Two ADCPs emitting different sound frequencies were used to simultaneously profile echo intensity level within the water column. Using the sonar equation, calibrations were determined between suspended‐sand concentrations and acoustic backscatter to solve the inverse problem. The study also analyzed the roles played by each term of the sonar equation, such as ADCP frequency, power supply, instrument constants, and particle size distributions typically found in sand bed rivers, on sediment attenuation and backscatter. Calibrations were successfully developed between corrected backscatter and suspended‐sand concentrations for all sites and ADCP frequencies, resulting in mean suspended‐sand concentration estimates within about 40% of the mean sampled concentrations. Noise values, calculated using the sonar equation and sediment sample characteristics, were fairly constant across evaluations, suggesting that they could be applied to other sand bed rivers.

Earth Surface Processes and Landforms↗

USGS2013

Development of CE-QUAL-W2 models for the Middle Fork Willamette and South Santiam Rivers, Oregon

Hydrodynamic (CE-QUAL-W2) models of Hills Creek Lake (HCL), Lookout Point Lake (LOP), and Dexter Lake (DEX) on the Middle Fork Willamette River (MFWR), and models of Green Peter Lake and Foster Lake on the South Santiam River systems in western Oregon were updated and recalibrated for a wide range of flow and meteorological conditions. These CE-QUAL-W2 models originally were developed by West Consultants, Inc., for the U.S. Army Corps of Engineers. This study by the U.S. Geological Survey included a reassessment of the models’ calibration in more recent years—2002, 2006, 2008, and 2011—categorized respectively as low, normal, high, and extremely high flow calendar years. These years incorporated current dam-operation practices and more available data than the time period used in the original calibration. Modeled water temperatures downstream of both HCL and LOP-DEX on the MFWR were within an average of 0.68 degree Celsius (°C) of measured values; modeled temperatures downstream of Foster Dam on the South Santiam River were within an average of 0.65°C of measured values. A new CE-QUAL-W2 model was developed and calibrated for the riverine MFWR reach between Hills Creek Dam and the head of LOP, allowing an evaluation of the flow and temperature conditions in the entire MFWR system from HCL to Dexter Dam. The complex bathymetry and long residence time of HCL, combined with the relatively deep location of the power and regulating outlet structures at Hills Creek Dam, led to a HCL model that was highly sensitive to several outlet and geometric parameters related to dam structures (STR TOP, STR BOT, STR WIDTH). Release temperatures from HCL were important and often persisted downstream as they were incorporated in the MFWR model and the LOP-DEX model (downstream of MFWR). The models tended to underpredict the measured temperature of water releases from Dexter Dam during the late-September-through-December drawdown period in 2002, and again (to a lesser extent) in 2011, but simulations were much more accurate in 2006 and 2008. This episodic model bias may have been a result of hot, dry conditions; lower lake elevations; and earlier drawdown at both HCL and LOP in 2002. These dry conditions in 2002 may have contradicted assumptions inherent in the estimation of certain model inputs, such as unmeasured inflows and water temperatures, which may respond differently during dry years than during normal and wet years. This report documents the development and calibration of new and revised flow and water-temperature models for riverine and reservoir reaches in the Middle Fork Willamette River and South Santiam River systems. Methods and model parameter values were established for the accurate simulation of flows and temperatures in these systems under current conditions. By extension, these models should be able to accurately simulate flows and temperatures under potential future conditions in which dam operations and dam outlet structures may be changed as part of a strategy to improve habitat, fish passage, and temperature conditions for endangered fish.

Oregon↗

USGS2018

Suspended-sediment concentrations and loads in the lower Mississippi and Atchafalaya rivers decreased by half between 1980 and 2015

The Weighted Regressions on Time, Discharge, and Season (WRTDS) model was used to derive estimates of suspended-sediment concentration (SSC) and suspended-sediment load (SSL), their dependence on discharge, and their trends with confidence intervals, for one site each on the lowermost Mississippi and Atchafalaya Rivers. The WRTDS model reduces uncertainty in SSCs related to variable streamflow conditions. Flow-normalized SSCs in each river were similar, and decreased from about 260 mg/L to 130 mg/L from 1980 through 2015; combined annual SSL in the two rivers decreased from about 200 Megatons per year (MT/y) to about 100 MT/y. Declines in SSC and SSL were more gradual from 2005 through 2015 and show signs of stabilizing. Our estimates of SSL in 2015 differ markedly from several recently published estimates of current and projected future Mississippi River SSLs, which were generally around 200 MT/y. However, these values came mostly from a different site upstream on the Mississippi River. The relationship between SSC and streamflow differed in an important way between the two rivers. SSC increased as streamflow increased for the entire range of observed streamflow in the Atchafalaya River. In the Mississippi River, SSC followed the same pattern during low and moderate streamflow but decreased at the highest streamflow that tended to occur between January and July. Since much of the water flowing in the Atchafalaya originates from the Mississippi River, the difference suggests a within-basin source of suspended sediment for the Atchafalaya River that is absent in the lower Mississippi River. These findings have important implications for the restoration of deltaic wetlands in coastal Louisiana. Accurate estimates of the SSL available in each river are crucial for understanding how effective diversions of river water into adjacent estuaries will be in sustaining these wetlands. Our study demonstrates that there might be far less sediment available than previously reported. Further, the difference in the relationship between SSC and streamflow in the two rivers is highly relevant to the ongoing discussion of coastal restoration strategies because the delta building that is occurring at the mouth of the Atchafalaya River is frequently used as a model of what could be expected with controlled diversions in the lower Mississippi River delta. The differences in the SSC behavior with changes in streamflow between the two rivers needs to be considered when results from the Atchafalaya River system are projected to those of the Mississippi River.

Louisiana↗

USGS2008

Streamflow conditions in the Guadalupe River Basin, south-central Texas, water years 1987-2006— An assessment of streamflow gains and losses and relative contribution of major springs to streamflow

The U.S. Geological Survey, in cooperation with the Edwards Aquifer Authority, assessed available streamflow data in the Guadalupe River Basin to determine streamflow gains and losses and the relative contribution of flow from major springs - Comal Springs, San Marcos Springs, and Hueco Springs - to streamflow in reaches of the Guadalupe River and its tributaries. The assessment is based primarily on long-term (1987-2006) and short-term (January 1999, August 1999, August 2000, and August 2006) streamflow conditions. For each analysis period, the ratio of flow from the major springs (measured at the spring source) to the sum of inflows (measured at the source of inflow to the river system) is computed for reaches of the Comal River and San Marcos River that include springflows from major springs, and for Guadalupe River reaches downstream from Canyon Dam. The ratio of springflow to the sum of inflows to the reach is an estimate of the contribution of flows from major springs to streamflow. For 1987-2006, the ratio of springflow from the major springs to the sum of inflows for the most upstream reach that includes inflow from all three major springs, Guadalupe River - above Comal River to Gonzales, is 27 percent. At the lowermost downstream reach, Guadalupe River - Bloomington to the San Antonio River, the percentage of the sum of inflows attributed to springflow is 18 percent. At that lowermost reach, the ratio of Canyon Lake releases to the sum of inflows was 20 percent. For the short-term periods August 2000 and August 2006 (periods of relatively low flow), springflow in the reach Guadalupe River - above Comal River to Gonzales accounted for 77 and 78 percent, respectively, of the sum of inflows in that reach. At the lowermost reach Guadalupe River - Bloomington to San Antonio River, springflow was 52 and 53 percent of the sum of inflows, respectively, during August 2000 and August 2006 (compared with 18 percent during 1987-2006); and during August 2000 and August 2006, the ratios of Canyon Lake releases to the sum of inflows were less than 10 percent (compared with 20 percent during 1987-2006)

Texas↗

USGS2022

The thermal landscape of the Willamette River—Patterns and controls on stream temperature and implications for flow management and cold-water salmonids

Water temperature is a primary control on the health, diversity, abundance, and distribution of aquatic species, but thermal degradation resulting from anthropogenic influences on rivers is a challenge to threatened species worldwide. In the Willamette River Basin, northwestern Oregon, spring-run Chinook salmon ( Oncorhynchus tshawytscha ) and winter-run steelhead ( O. mykiss ) are formerly abundant cold-water-adapted species that are now protected under the Endangered Species Act. Among the challenges to the health of cold-water salmonids in the Willamette River Basin, disruptions in the seasonal patterns of stream temperature imposed by 13 large, multipurpose dams on tributaries to the Willamette River, as well as temperatures routinely in excess of regulatory limits in the Willamette River Basin, are contributing factors. To better understand controls on stream temperature, the sensitivity of stream temperature to flow augmentation as a management tool for suppressing high temperatures, and the implications for threatened salmonids, this study used a two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) to investigate spatial and temporal patterns of stream temperature in the Willamette River Basin. This study focused on the upper 160.4 river miles of the Willamette River from the confluence of the Middle Fork and Coast Fork Willamette Rivers (river mile 187.2) to Willamette Falls (river mile 26.8), three representative climate years (2011, a cool and wet year; 2015, an extremely hot and dry year; and 2016, a moderately hot and dry year), and a series of flow-augmentation scenarios. Model results show that the Willamette River upstream from Willamette Falls is divisible into four characteristic “thermal reaches” with similar thermal patterns, depending on tributary input, warming rate, and the timing of thermal response. In general, the Willamette River warms downstream during spring and summer, but patterns are complex, influenced by tributary inflows, and seasonally variable. Except in cool wet years (as illustrated by 2011), modeling suggests that adversely warm conditions for spring-run Chinook salmon are extensive from June or July through August. The thermal influence of flow augmentation from dam storage on four tributaries with U.S. Army Corps of Engineers dams varies spatially along the Willamette River, seasonally, and in magnitude, depending on a range of factors like distance from the Willamette River, the temperature of dam outflow, and the thermal template of tributary reaches controlling stream temperature adjustment to environmental heat fluxes. Modeling suggests that targeted flow management (via augmentation from dam storage) can reduce the extent and duration of thermally stressful conditions for Chinook salmon for short periods, but modeling suggests that flow augmentation is limited in its ability to fundamentally alter the “thermal landscape” (the entire range of temperature variation in a river system over space and time) of the Willamette River. While this research provides general insights into the thermal landscape of the Willamette River and its sensitivity to flow management, additional investigation into the thermal landscape of tributaries downstream from U.S. Army Corps of Engineers dams, as well as the thermal management of reservoirs, storage availability, and dam outflows, would be necessary to target specific management actions for supporting specified rearing or migration conditions for spring-run Chinook salmon and other cold-water-adapted species in the Willamette River Basin.

Oregon↗

USGS2003

Preliminary analysis of cores from north San Francisco Bay, California

During the mid-to late-1800's, large quantities of tailings from hydraulic gold mining in the Sierra Nevada were deposited in San Francisco Bay (Gilbert, 1917; Jaffe et al., 1998; Capiella et al., 1999). This rapid deposition also choked river systems and deposited mercury-contaminated sediments in the rivers and Bay. Hydraulic mining was stopped in 1884 by a California Supreme Court decision. Deposition in the Bay slowed in the late 1800's and early 1900's as a result of this decrease in sediment supply (Jaffe et al., 1998; Capiella et al., 1999). During the mid-1900's, sediment supply was further reduced by water works projects (dams, diversions, etc.), creating an erosional system in the study area by the late 1900's. The re-working of these sediments poses environmental and biological concerns regarding mercury in the bay. The location of these deposits is important for understanding the health of the bay waters. In March 2000, the U.S. Geological Survey collected sediment cores in the study area to determine the location of mercury-contaminated hydraulic mining debris. The study area (Figure 1) comprises 400 km2 and consists of San Pablo Bay and Suisun Bay, both of which are part of the San Francisco Bay estuary. Grizzly Bay, a subembayment of Suisun Bay, is also part of the study area. For the purpose of this report the term Suisun Bay will be used collectively for both areas. The present channel system in Suisun Bay is composed of three channels that flow through the bay. The primary channel runs in the southern section of Suisun Bay. A smaller channel flows between Roe Island and Ryer Island. The deepest channel flows through Suisun Cutoff, north of Ryer Island, and past Grizzly Bay. All three channels join at Carquinez Strait where they continue through the southern section of San Pablo Bay, and into San Francisco Bay. The average depths in San Pablo and Suisun Bays at mean sea level are 3.7 m and 5.8 m, respectively (Smith et al., 2002).

California↗