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At least 217 records · Page 12Linked to original sources
USGS1989

A comparison of aquatic macrophyte communities in regulated and non-regulated lakes, Voyageurs National Park and Boundary Waters Canoe Area, Minnesota

The effects of water-level regulation on aquatic macrophyte communities, individual plant species, and potential faunal habitat were investigated in a study of two regulated lakes and an unregulated lake in northern Minnesota. Water levels in Rainy Lake and Namakan Reservoir in Voyageurs National Park are regulated by dams. Natural annual fluctuations of 1.8 m are replaced with fluctuations of 1.1 m in Rainy Lake and 2.7 m in the five lakes that comprise Namakan Reservoir. In addition, springtime peaking of water levels in Namakan Reservoir is delayed by one month. After reaching the peak, water levels in the regulated lakes are held at that level through the summer and allowed to gradually decline through autumn and winter. This study was conducted by estimating the cover of each plant species in randomly placed quadrats along transects that followed depth contours in the lakes. These contours were selected to represent different plant habitats, as defined by the timing and duration of flooding and dewatering in unregulated Lac La Croix. Detrended correspondence analysis showed that the macrophyte communities at all depths of the regulated lakes differed from those in the unregulated lake. The differences were more profound in deeper parts of the littoral zone. Lac La Croix contained taxonomically and structurally diverse plant communities at all depths, maximizing faunal habitat. The greatest effect of the regulation on Rainy Lake was along transects at the depth that is never dewatered. There were only four taxa present; they were all erect aquatics that extended through the entire water column and offered little structurally diverse faunal habitat. The greatest effect of regulation on Namakan Lake was along transects at the depth where drawdown occurs in early winter and disturbance results from ice formation in the sediments. Rosette and mat-forming species were dominant, providing minimal faunal habitat. The hydrologic regime at Lac La Croix results in intermediate disturbance that maintains high diversity. There is too little disturbance from water-level fluctuations in Rainy Lake and too much disturbance in Namakan Reservoir, resulting in reduced diversity in both cases. The macrophyte communities of the regulated lake systems would benefit from a return to more natural hydrologic regimes. Namakan Reservoir should be regulated to reach its peak water level at the beginning of June, summer drawdowns should occur at both Rainy Lake and Namakan Reservoir, and the amplitude of annual drawdowns should vary between years but approximate 1.8 m. These hydrologic conditions should, over time, result in more diverse macrophyte communities and more diverse faunal habitat throughout the littoral zone of the regulated lakes.

Research/Resources Management↗
USGS1999

Deposition of selenium and other constituents in reservoir bottom sediment of the Solomon River Basin, north-central Kansas

The Solomon River drains approximately 6,840 square miles of mainly agricultural land in north-central Kansas. The Bureau of Reclamation, U.S. Department of the Interior, has begun a Resource Management Assessment (RMA) of the Solomon River Basin to provide the necessary data for National Environmental Policy Act (NEPA) compliance before renewal of long-term water-service contracts with irrigation districts in the basin. In May 1998, the U.S. Geological Survey (USGS) collected bottom-sediment cores from Kirwin and Webster Reservoirs, which are not affected by Bureau irrigation, and Waconda Lake, which receives water from both Bureau and non-Bureau irrigated lands. The cores were analyzed for selected physical properties, total recoverable metals, nutrients, cesium-137, and total organic carbon. Spearman's rho correlations and Kendall's tau trend tests were done for sediment concentrations in cores from each reservoir. Selenium, arsenic, and strontium were the only constituents that showed an increasing trend in concentrations for core samples from more than one reservoir. Concentrations and trends for these three constituents were compared to information on historical irrigation to determine any causal effect. Increases in selenium, arsenic, and strontium concentrations can not be completely explained by Bureau irrigation. However, mean selenium, arsenic, and strontium concentrations in sediment from all three reservoirs may be related to total irrigated acres (Bureau and non-Bureau irrigation) in the basin. Selenium, arsenic, and strontium loads were calculated for Webster Reservoir to determine if annual loads deposited in the reservoir were increasing along with constituent concentrations. Background selenium, arsenic, and strontium loads in Webster Reservoir are significantly larger than post-background loads.

Kansas↗
USGS2004

Water Resources Data for Oregon, Water Year 2003

The annual Oregon hydrologic data report is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. This report includes records on both surface and ground water in Oregon and contains discharge records for 199 stream-gaging stations, 25 partial-record or miscellaneous streamflow stations, and 8 crest-stage partial-record streamflow stations; stage-only records for 6 gaging stations; stage and content records for 26 lakes and reservoirs; and water-quality records collected at 127 streamflow-gaging stations, 2 atmospheric deposition stations, and 11 ground-water sites.

Water Data Report↗
USGS2005

Water resources data for Oregon, water year 2004

The annual Oregon water data report is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local, Tribal, and Federal agencies and the private sector for developing and managing our Nation's land and water resources. This report contains water year 2004 data for both surface and ground water, including discharge records for 209 streamflow-gaging stations, 42 partial-record or miscellaneous streamflow stations, and 9 crest-stage partial-record streamflow stations; stage-only records for 6 gaging stations; stage and content records for 15 lakes and reservoirs; water-level records from 12 long-term observation wells; and water-quality records collected at 133 streamflow-gaging stations and 1 atmospheric deposition station.

Water Data Report↗
USGS2010

Application of the Systems Impact Assessment Model (SIAM) to fishery resource issues in the Klamath River, California

At the request of two offices of the U.S. Fish and Wildlife Service (FWS) located in Yreka and Arcata, Calif., we applied the Systems Impact Assessment Model (SIAM) to analyze a variety of water management concerns associated with the Federal Energy Regulatory Commission (FERC) relicensing of the Klamath hydropower projects or with ongoing management of anadromous fish stocks in the mainstem Klamath River, Oregon and California. Requested SIAM analyses include predicted effects of reservoir withdrawal elevations, use of full active storage in Copco and Iron Gate Reservoirs to augment spring flows, and predicted spawning and juvenile outmigration timing of fall Chinook salmon. In an effort to further refine the analysis of spring flow effects on predicted fall Chinook production, additional SIAM analyses were performed for predicted response to spring flow release variability from Iron Gate Dam, high and low pulse flow releases, the predicted effects of operational constraints for both Upper Klamath Lake water surface elevations, and projected flow releases specified in the Klamath Project 2006 Operations Plan (April 10, 2006). Results of SIAM simulations to determine flow and water temperature relationships indicate that up to 4 degrees C of thermal variability can be attributed to flow variations, but the effect is seasonal. Much more of thermal variability can be attributed to air temperature variations, up to 6 degrees C. Reservoirs affect the annual thermal signature by delaying spring warming by about 3 weeks and fall cooling by about 2 weeks. Multi-level release outlets on Iron Gate Dam would have limited utility; however, if releases are small (700 cfs) and a near-surface and bottom-level outlet could be blended, then water temperature may be reduced by 2-4 degrees C for a 4-week period during September. Using the full active storage in Copco and Iron Gate Reservoir, although feasible, had undesirable ramifications such as earlier spring warming, loss of hydropower production, and inability to re-fill the reservoirs without causing shortages elsewhere in the system. Altering spawning and outmigration timing may be important management objectives for the salmon fishery, but difficult to implement. SIAM predicted benefits that might occur if water temperature was cooler in fall and spring emergence was advanced; however, model simulations were based on purely arbitrary thermal reductions. Spring flow variability did indicate that juvenile fall Chinook rearing habitat was the major biological 'bottleneck' for year class success. Rearing habitat is maximal in a range between 4,500 and 5,500 cfs below Iron Gate Dam. These flow levels are not typically provided by Klamath River system operations, except in very wet years. The incremental spring flow analysis provided insight into when and how long a pulse flow should occur to provide predicted fall Chinook salmon production increases. In general, March 15th - April 30th of any year was the period for pulse flows and 4000 cfs was the target flow release that provided near-optimal juvenile rearing habitat. Again, competition for water resources in the Klamath River Basin may make implementation of pulsed flows difficult.

California, Oregon↗
USGS2016

Hydrologic Conditions in Kansas, water year 2015

The U.S. Geological Survey (USGS), in cooperation with Federal, State, and local agencies, maintains a long-term network of hydrologic monitoring sites in Kansas. In 2015, the network included about 200 real-time streamgages (hereafter referred to as “gages”), 12 real-time reservoir-level monitoring stations, and 30 groundwater-level monitoring wells. These data and associated analyses provide a unique overview of hydrologic conditions and help improve the understanding of Kansas’s water resources. Real-time data are verified by the USGS throughout the year with regular measurements of streamflow, lake levels, and groundwater levels. These data are used in protecting life and property; and managing water resources for agricultural, industrial, public supply, ecological, and recreational purposes. Yearly hydrologic conditions are characterized by comparing statistical analyses of current and historical water year (WY) data for the period of record. A WY is the 12-month period from October 1 through September 30 and is designated by the year in which it ends.

Kansas↗
USGS2003

Water Resources Data for Oregon, Water Year 2002

The annual Oregon hydrologic data report is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. This report includes records on both surface and ground water in the State and contains discharge records for 181 stream-gaging stations, 47 partial-record or miscellaneous streamflow stations, and 8 crest-stage partial-record streamflow stations; stage-only records for 6 gaging stations; stage and content records for 26 lakes and reservoirs; and water-quality records for 127 streamflow-gaging stations, 2 atmospheric deposition stations, and 11 ground-water sites.

Water Data Report↗
USGS1984

Evaluation of alternative reservoir-management practices in the Rock River basin, Wisconsin

Simulation of the operation of upstream impoundments in the Rock River basin to reduce spring floods showed that such operation would reduce flood peaks by 0.11 foot on the average, and would increase flood peaks some years. The most significant reductions would occur during the average- size floods, whereas little or no reductions would occur for larger and smaller floods. Modifying the simulation of impoundment operations to reduce larger floods produced only minor reductions in flood peaks for the larger floods, and slightly increased flood peaks for average-size floods. Alternative operating procedures for Indianford Dam which controls Lake Koshkonong were simulated with estimated power generation and the use of flashboards during the summer, neither of which are currently used. The simulation showed that, for most periods without significant runoff, the stage of Lake Koshkonong would tend toward the stage at which power generation was prohibited. It also showed that use of flashboards to raise the minimum lake stage during the summer would not raise the peak stage of the lake measurably if the flashboards were removed when the stage rose above its normal level. Simulation showed that winter drawdown of Lake Koshkonong would not lower spring flood peaks significantly downstream.

Wisconsin↗
USGS2024

Evaluation of the lakes and impoundments drought index for the Massachusetts Drought Management Plan

The condition of surface water storage in lakes and impoundments is used as an index of drought in the Massachusetts drought management plan. The U.S. Geological Survey visited 28 of these lakes and impoundments at 14 single and multiple waterbody systems to evaluate their appropriateness for characterizing drought. The data collection and computation methods at each system were then reviewed and checked for consistency. The types of historical monthly data available varied by system and included water surface elevation, depth of water below the spillway, volume, or reservoir capacity (percent full). For this analysis, water surface elevations and reservoir capacities were converted to volumes to assess the interannual variability in lake volumes. As a second level of assessment, analysis was also done on water surface elevation variability. Systems that did not have enough differentiation in monthly values between lake volume or water surface elevations to clearly demarcate drought levels were identified as unsuitable for use in the drought index for that month. This report discusses the limitations of using the reviewed lakes and impoundments as a drought index, as well as a list of best practices for data collection techniques to improve the confidence and reliability of the data collected.

Massachusetts↗
USGS2015

Scientific information in support of water resource management of the Big River area, Rhode Island

The Rhode Island Water Resources Board (RIWRB) is concerned that the demand for water may exceed the available public water supply in central and southern Rhode Island. Although water is often assumed to be plentiful in Rhode Island because of abundant rainfall, an adequate supply of water is not always available everywhere in the state during dry periods. Concerns that water demand may exceed supply are greatest during the summer, when lower water levels and increased drought potential combine with seasonal increases in peak water demand (Rhode Island Water Resources Board, 2012). High summer water demands are due to increases in outdoor water use, such as lawn watering and agricultural irrigation, and to increased summer population in coastal areas. Water-supply concerns are particularly acute in central and southern Rhode Island, where groundwater is the primary source of drinking water. The Big River and Mishnock River Basins are subbasins of the South Branch of the Pawtuxet River Basin in central and southern Rhode Island. These basins—referred to together as “the Big River area” for the purposes of this report—are undeveloped relative to other nearby areas and provide a potential source of high-quality public drinking water for central and southern Rhode Island. After the severe drought of the 1960s, the State of Rhode Island acquired land in the Big River area with the intention of building a water-supply reservoir. The reservoir was not built because of concerns over potential environmental impacts and projected statewide water-supply needs (U.S. Environmental Protection Agency, 1989). The land acquired for the reservoir (13.4 mi 2 ), called the Big River Management Area (BRMA), is currently managed by the RIWRB as a future source for public water supply and as open space. In the 1980s, the RIWRB began to consider whether the BRMA could supply water from its aquifers (groundwater). Groundwater withdrawals for public or other water-supply needs can alter the hydrologic conditions and ecologic communities of surrounding rivers, lakes, and wetlands by removing water from these systems. Consequently, the RIWRB was interested in determining optimal amounts of groundwater that could be withdrawn from the BRMA for public supply while minimizing the effects on rivers, lakes, streams, and wetlands that also rely on this water. For nearly two decades, the RIWRB has conducted a series of cooperative studies with the U.S. Geological Survey (USGS). The goals of these studies have been to (1) evaluate and characterize the water resources of the BRMA and the greater Big River area, and (2) identify sustainable levels of groundwater use that would minimize effects on water resources. This fact sheet describes the major findings of those studies.

Rhode Island↗
USGS2026

Spatial and temporal trends of mercury in fish from Duck Valley Reservation Reservoirs, southwestern Idaho and northern Nevada, 2007–24

The Shoshone-Paiute (Sho-Pai) Tribes of the Duck Valley Reservation, Nevada, manage reservoirs that support commercial and recreational activities, including robust Oncorhynchus mykiss (rainbow trout) fisheries that attract anglers year-round. Reservoirs are common environments for methylation and bioaccumulation of mercury, which is a potent neurotoxin when elevated levels are consumed. The U.S. Geological Survey (USGS), in cooperation with the Sho-Pai Tribes, measured total mercury concentrations in the muscle tissue of rainbow trout from three Reservation reservoirs in Idaho and Nevada in 2007, 2009, 2013, and 2024. This report highlights spatial and temporal trends of mercury concentrations in rainbow trout in the Duck Valley Reservation reservoirs from 2007 through 2024, and presents limited data on other commonly consumed species, specifically Perca flavescens (yellow perch), Micropterus dolomieu (smallmouth bass), and Micropterus salmoides (largemouth bass). Mercury data are also presented for nearby sites and lower trophic level species. In 2024, two fish sampling methods were used and compared: biopsy muscle plugs and muscle fillets. Results show good agreement between mercury concentrations of biopsy and fillet muscle samples taken from the same fish, with most sample pairs differing by less than 20 percent, though biopsied fish had an unexpectedly high mortality rate. Mercury concentrations increased in Sheep Creek Reservoir during the study period, but no significant trend was observed in Mountain View Reservoir or Lake Billy Shaw. Only 1 rainbow trout out of 160 sampled in the Reservation reservoirs during the study period exceeded the U.S. Environmental Protection Agency’s recommended methylmercury criterion of 0.3 milligram per kilogram of wet weight (mg/kg ww). Largemouth bass, smallmouth bass, and yellow perch had higher mercury concentrations than rainbow trout and may pose a greater risk to consumers. Mercury concentrations in largemouth bass exceeded 0.3 mg/kg ww, although only two fish were sampled, both from Sheep Creek Reservoir. Fish consumption advisories on Tribal lands are determined by the Tribes, and these results may help Sho-Pai managers determine the mercury exposure risk to Tribal members and visiting anglers.

Idaho, Nevada↗
USGS2024

Estimating age and growth of Largemouth Bass in southwestern reservoirs using otoliths and scales

Age and growth data are frequently used to monitor and manage important North American sport fishes such as Largemouth Bass Micropterus salmoides . Continental and regional growth standards have been developed for this species to assess fish growth over time and across space. However, Largemouth Bass age and growth data are infrequently collected in Arizona and the reliability of age estimates derived from typical structures (e.g., scales, otoliths) in the Southwest is uncertain. Our objectives were to 1) compare precision and bias of age estimates from scales with those from otoliths and 2) estimate Largemouth Bass growth in several southwestern warmwater reservoirs by using otoliths. We collected Largemouth Bass from three Arizona reservoirs—Alamo, Peña Blanca, and Roosevelt—by boat electrofishing in spring 2021. We removed scales and sagittal otoliths from fish and then prepared and independently aged them three times. We compared differences in precision and bias between scales and otoliths using reader agreement percentages, confidence ratings, average coefficients of variation, and age-bias plots. We used age estimates from Largemouth Bass otoliths to calculate mean lengths-at-age at capture and relative growth indices based on published growth standards in each reservoir. Largemouth Bass scale age estimates were less precise, overestimated ages of younger fish, and underestimated age of older fish compared with those of otoliths. Growth was lower in Peña Blanca Lake than in the other two reservoirs according to mean length-at-age estimates, and relative growth indices suggested that Largemouth Bass growth in all three reservoirs was above average at younger ages, but less so at older ages. The results from this study add to a growing body of literature supporting the use of otoliths for estimating age and growth of Largemouth Bass.

Arizona↗
USGS2016

Roost site selection by ring-billed and herring gulls

Gulls ( Larus spp.) commonly roost in large numbers on inland and coastal waters, yet there is little information on how or where gulls choose sites for roosting. Roost site selection can lead to water quality degradation or aviation hazards when roosts are formed on water supply reservoirs or are close to airports. Harassment programs are frequently initiated to move or relocate roosting gulls but often have mixed results because gulls are reluctant to leave or keep returning. As such, knowledge of gull roost site selection and roosting ecology has applied and ecological importance. We used satellite telemetry and an information-theoretic approach to model seasonal roost selection of ring-billed ( L. delawarensis ) and herring gulls ( L. argentatus ) in Massachusetts, USA. Our results indicated that ring-billed gulls preferred freshwater roosts and will use a variety of rivers, lakes, and reservoirs. Herring gulls regularly roosted on fresh water but used salt water roosts more often than ring-billed gulls and also roosted on a variety of land habitats. Roost modeling showed that herring and ring-billed gulls selected inland fresh water roosts based on size of the water body and proximity to their last daytime location; they selected the largest roost closest to where they ended the day. Management strategies to reduce or eliminate roosting gulls could identify and try to eliminate other habitat variables (e.g., close-by foraging sites) that are attracting gulls before attempting to relocate or redistribute (e.g., through hazing programs) roosting birds.

Massachusetts↗
USGS2019

Hydrologic conditions in Kansas, water year 2018

The U.S. Geological Survey, in cooperation with Federal, State, and local agencies, maintains a long-term network of hydrologic monitoring stations in Kansas. In water year 2018, this network included 219 real-time streamgages. A water year is the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends. Real-time data are calibrated and validated by U.S. Geological Survey personnel throughout the year with regular measurements of streamflow, streamgage height, and lake levels. These data and accompanying analyses provide an overview of hydrologic conditions in Kansas and help advance the understanding of water resources in the State. Annual assessments of hydrologic conditions are made by comparing statistical analyses of current and past water year data for the period of record. Long-term monitoring of hydrologic conditions in Kansas provides imperative information for protecting human life and property, managing water supplies, forecasting floods, operating reservoirs, designing bridges and culverts, processing interstate and intrastate water rights claims, forecasting ecological conditions, and many other uses.

Kansas↗
USGS2015

Hydrogeology and sources of water to select springs in Black Canyon, south of Hoover Dam, Lake Mead National Recreation Area, Nevada and Arizona

Springs in Black Canyon of the Colorado River, directly south of Hoover Dam in the Lake Mead National Recreation Area, Nevada and Arizona, are important hydrologic features that support a unique riparian ecosystem including habitat for endangered species. Rapid population growth in areas near and surrounding Black Canyon has caused concern among resource managers that such growth could affect the discharge from these springs. The U.S. Geological Survey studied the springs in Black Canyon between January 2008, and May 2014. The purposes of this study were to provide a baseline of discharge and hydrochemical data from selected springs in Black Canyon and to better understand the sources of water to the springs. Various hydrologic, hydrochemical, geochemical, and geologic data were collected and analyzed during this study. More than 100 hydrologic sites consisting of springs, seeps, pools, rivers, reservoirs, and wells were investigated, and measurements were taken at 75 of these sites. Water levels were measured or compiled for 42 wells and samples of water were collected from 36 unique sites and submitted for laboratory analyses of hydrochemical constituents. Measurements of discrete discharge were made from nine unique spring areas and four sites in Black Canyon were selected for continuous monitoring of discharge. Additionally, samples of rock near Hoover Dam were collected and analyzed to determine the age of spring deposits. Results of hydrochemical analyses indicate that discharge from springs in Black Canyon is from two sources: (1) Lake Mead, and (2) a local and (or) regional source. Discharge from springs closest to Hoover Dam contains a substantial percentage (>50 percent) of water from Lake Mead. This includes springs that are between Hoover Dam and Palm Tree Spring. Discharge from springs south of Palm Tree Spring contains a substantial percentage (>50 percent) of the water that is believed to come from a combination of other local and regional sources, although the exact location and nature of these sources is not clear. The unique hydrochemistry of some springs, such as Bighorn Sheep Spring and Latos Pool, suggests that little if any water discharging from these springs comes from Lake Mead. Geochronological results of spring deposits at several sites near Hoover Dam indicate that most deposits are young and likely formed after the construction of Hoover Dam. Several major faults, including the Salt Cedar Fault and the Palm Tree Fault, play an important role in the movement of groundwater. Groundwater may move along these faults and discharge where faults intersect volcanic breccias or fractured rock. Vertical movement of groundwater along faults is suggested as a mechanism for the introduction of heat energy present in groundwater from many of the springs. Groundwater altitudes in the study area indicate a potential for flow from Eldorado Valley to Black Canyon although current interpretations of the geology of this area do not favor such flow. If groundwater from Eldorado Valley discharges at springs in Black Canyon then the development of groundwater resources in Eldorado Valley could result in a decrease in discharge from the springs. Geology and structure indicate that it is not likely that groundwater can move between Detrital Valley and Black Canyon. Thus, the development of groundwater resources in Detrital Valley may not result in a decrease in discharge from springs in Black Canyon.

Arizona, Nevada↗
USGS2007

A Dreissena Risk Assessment for the Colorado River Ecosystem

Executive Summary Nonnative zebra and quagga mussels (Dreissena polymorpha and Dreissena bugensis, respectively; see photo above) were accidentally introduced to the Great Lakes in the 1980s and subsequently spread to watersheds of the Eastern United States (Strayer and others, 1999). The introduction of Dreissena mussels has been economically costly and has had large and far-reaching ecological impacts on these systems. Quagga mussels were found in Lakes Mead and Havasu in January 2007. Given the likelihood that quagga mussels and, eventually, zebra mussels will be introduced to Lake Powell and the Colorado River at Lees Ferry, it is important to assess the risks that introduction of Dreissena mussels pose to the Colorado River ecosystem (here defined as the segment of river from just below Glen Canyon Dam to Diamond Creek; hereafter CRE). In this report, I assess three different types of risks associated with Dreissena and the CRE: (1) the risk that Dreissena will establish at high densities in the CRE, (2) the risk of ecological impacts should Dreissena establish at high densities in the CRE or in Lake Powell, and (3) the risk that Dreissena will be introduced to tributaries of the CRE. The risk of Dreissena establishing within the CRE is low, except for the Lees Ferry tailwater reach where the risk appears high. Dreissena are unlikely to establish at high densities within the CRE or its tributaries because of high suspended sediment, high ratios of suspended inorganic:organic material, and high water velocities, all of which interfere with the ability of Dreissena to effectively filter feed. The rapids of Grand Canyon may represent a large source of mortality to larval Dreissena, which would limit their ability to disperse and colonize downstream reaches of the CRE. In contrast, conditions within the Lees Ferry tailwater generally appear suitable for Dreissena establishment, with the exception of high average water velocity. If Dreissena establish within the CRE, the risks of negative ecological impacts appear low. If Dreissena are able to attain moderate densities in Lees Ferry, estimates of filtration capacity indicate they are unlikely to substantially alter the composition (e.g., nutrient concentrations, suspended organic matter concentrations) of water exported from Lees Ferry. Further, a moderate density of Dreissena within Lees Ferry may actually increase food available to fishes by increasing habitat complexity and stimulating benthic production. If Dreissena attain moderate densities in the CRE mainstem, which seems unlikely, ecological impacts will probably be comparable to Lees Ferry-an increase in benthic production. Dreissena may have ecological impacts on the CRE, if they become established in Lake Powell and substantially alter the composition of water released from Glen Canyon Dam; however, it is unclear whether changes in the composition of water released from Glen Canyon Dam will have a net positive or negative impact on food availability in the CRE mainstem. The risk of Dreissena introduction to tributaries appears low. None of the tributaries have upstream lakes or reservoirs that could actually serve as a source population for Dreissena; reservoirs on the Little Colorado River may eventually support Dreissena, but they are far up in the watershed and the segment of river connecting them with the mainstem CRE is intermittent. If the CRE mainstem is colonized by Dreissena, there are no significant vectors for transporting them upstream into the tributaries. In addition, lethally high summer water temperatures make it unlikely that Dreissena will establish in many tributaries. Lake Powell is a logical focus for management and research efforts, given that maintenance of Dreissena populations within the CRE will require an upriver source population and the uncertainty associated with the downstream impact of changes in Lake Powell water quality.

Open-File Report↗
USGS2003

The importance of environmental quality and catch potential to fishing site selection by freshwater anglers in Mississippi

We measured the importance of 24 fishing site attributes to Mississippi freshwater anglers. Factor analysis identified four multiattribute factors as important in the selection of fishing location: CLEAN ENVIRONMENT CATCH, COST AND HARVEST and AMENITIES AND SAFETY. In general, the importance of site selection factors differed little among anglers grouped by preferred type of fish, preferred fishing location (lakes and reservoirs, rivers and streams, ponds, or reservoir tailwaters), usual manner of fishing (engine-powered boat, nonpowered boat, or shore), or change in fishing frequency. COST AND HARVEST was more important to anglers with high harvest orientations. We found low correlations between site selection factor importance scores and angler age, fishing frequency, fishing expenditures, or fishing motivation factors. We suggest that the general lack of differences in site selection factors among angler groups indicates that management strategies to improve fishing site attributes should benefit all angler groups. Clean fishing environments and awareness of the availability of desired sport fishes were "very" or "extremely" important to fishing site selection by more than 70% of Mississippi freshwater anglers and should be priority management objectives.

North American Journal of Fisheries Management↗
USGS2019

Age and growth of Freshwater Drum and Gizzard Shad occupying two reservoir-river complexes with different groundwater contributions

Restoring groundwater flow is a management option that improves water temperature regimes and benefits fishes. Although this strategy applies more readily to river systems, the thermal character of reservoirs is heavily influenced by inflowing rivers. We examined differences in age, structure, and growth of both Freshwater Drum Aplodinotus grunniens and Gizzard Shad Dorosoma cepedianum that occupy catchments with varying groundwater contributions in the south‐central United States. Seepage run data indicated that the Kiamichi River was losing surface water to groundwater in summer 2016, whereas groundwater inflows were apparent in the Elk River basin. Summer 2016 data showed that the Elk River had cooler water temperatures than the Kiamichi River and Grand Lake O’ the Cherokees water temperatures were similar to those in the incoming Elk River. We found higher densities of older Freshwater Drum and Gizzard Shad (maximums of 32 and 8 years old, respectively) in samples from the Grand basin than among fish that were sampled from the Kiamichi River basin (21 and 6 years old, respectively). Freshwater Drum grew at similar rates in both basins even though they reached larger maximum lengths in the Grand basin (649 mm TL) than in the Kiamichi River basin (600 mm). The average asymptotic length was greater for the Kiamichi population ( L ∞ = 613 mm) than for the Grand population ( L ∞ = 557 mm). Gizzard Shad from the Grand basin were larger than those from the Kiamichi River basin, though the latter population grew faster initially (Brody growth coefficient: K = 0.787 versus K = 0.179, respectively), but they had smaller asymptotic length ( L ∞ = 206 mm versus L ∞ = 343 mm). The role that groundwater plays in temperature regulation in these basins partially explains the observed differences. Our results suggest that the metabolic theory of ecology can be applied to fisheries management at a finer spatial scale.

Oklahoma↗