Skip to main content
Advanced Search

Filters: Tags: Rivers and Streams (X)

41 results (79ms)   

Filters
Date Range
Extensions
Types
Contacts
Categories
Tag Types
Tag Schemes
View Results as: JSON ATOM CSV
My primary objective is to characterize the hydrology and water chemistry of watersheds and how they are affected by both natural factors and disturbance. I study the role of precipitation type, intensity, and spatial distribution in driving runoff and transport of sediment, carbon, nutrients, and major ions in both disturbed and undisturbed sites. My research incorporates field research and existing climate, hydrologic, and water-quality data to distinguish between the roles of climate, land-cover change, and disturbance in driving watershed processes. I strive to communicate research findings to scientists, regulators, and the public in order to support the management of water resources.
This hybrid medium-resolution national hydrography dataset with river corridor attributes (NHD-RC) for the conterminous United States (CONUS) was created by merging lentic and lotic attributes from the high-resolution NHDPlus (U.S. Geological Survey, 2020) into the medium-resolution NHDPlus Version 2.1 (U.S. Geological Survey, 2016). NHD-RC includes attributes from an additional 5.4 million small pond features and 5 million kilometers of small streams beyond the approximately 123,000 lentic waterbodies and 4 million kilometers of larger streams and rivers accounted for NHDPlus Version 2.1. This hybrid approach permitted the use of the many attributes that have been linked to NHD by others, including land cover and...
All stream or river-channel flows are time variant, or unsteady, in a different degree; steady flow is but an exception rather than the rule. These flows usually exist in different states, such as sub-critical, super-critical, and trans-critical flows. Alternative terms for different flow conditions are often used, such as continuous or discontinuous flows, flows through hydraulic jump or through channel constriction. A river basin, the basic geometric unit of the surface-water flow configurations, generally contains river reaches, branches, tributaries, junctions, and networks. Reasonable and rational definition and determination of all-weather, river-basin, unsteady flows, letting the last three quantifiers...
The geometry and pattern of river channels adjust to significant changes in the water discharge, size, and quantity of sediment supplied to the channel. When the quantity of water and sediment over a period of years remains relatively constant, the channel geometry and pattern vary about a mean of quasi-equilibrium conditions. Major watershed alterations that change the supply of water, sediment, and size of sediment reaching the channel necessitate an adjustment of the channel geometry and pattern. That is, the channel is transformed from one quasi-equilibrium state to another. Between the two quasi-equilibrium states, there is a period of instability and adjustment. The dynamics and rate of river channel adjustment...
thumbnail
Collection of 4 assessments for Med/Low-gradient Streams and Rivers. The Condition Index ranks stream segments according to how well they meet the Desired State described qualitatively and quantitatively in the draft Integrated Science Agenda (v4). From the Condition Index, 3 assessments are derived that rank opportunities for management and restoration of conditions included in the Condition Index – Watershed Land Use, Riparian Cover, and Stream Meander. Watershed Land Use management opportunities are based on the proportion of undisturbed land in the contributing (i.e. cumulative) watershed such that stream segments meeting the Desired State are considered Maintenance opportunities (values 5-6). Those that do...
This project focuses on sediment erosion and deposition processes associated with disturbed watersheds and the essential processes needed to predict evolution of river systems. The objectives are to understand: a. Spatial and temporal character of rainfall and the transformation of rainfall into runoff, which controls erosion and deposition. b. Hillslope runoff processes characterized by shallow, unsteady flow where the relative roughness causing friction can be much greater than, for example, in perennial channels with nearly steady flow. c. Geomorphic and scale effects of channel networks on the prediction of the runoff hydrographs. d. Coupling of biologic and geomorphologic processes to predict erosion and...
Technical solutions to the problem of investigating and managing waste movement and disposal in regulated rivers, estuaries, and embayments require qualitative and quantitative assessment of the interactions between waste constituents undergoing dynamic transport. Mathematical, numerical, computer-simulation models offer one very powerful solution. Because water is both the vehicle by which the waste constituents are transported and the media in which the constituent interactions occur, the temporal and spatial variations of the flow appreciably govern the interactions both qualitatively and quantitatively. Design of the desired simulation models depends in large measure upon accurate mathematical/numerical representation...
I study biogeochemical cycling in aquatic ecosystems. Current projects include 1) Trends in alkalinity and acidity in coastal rivers of the US and potential effects on coastal acidification (USGS NAWQA Trends Team). 2) Continental-scale synthesis of stream metabolism and its links to water quality and the aquatic carbon cycle (USGS Powell Center; USGS NAWQA; USGS NRP). 3) Carbon transport and cycling in the Upper Mississippi River basin (USGS LandCarbon). 4) Long-term trends in acidification of the Delaware River Estuary (Penn State University). 5) Hyporheic exchange in contrasting headwater streams of the Colorado Front Range (with Colorado School of Mines).
My research can be broadly characterized as the use of statistics to simplify, understand and address complex, cross-disciplinary water resource problems. I have a particular interest in using statistics to arrive at parsimonious characterizations of natural systems and I am employing this philosophy to advance understanding in the areas of ecohydrology, sustainable water management at unmonitored locations, and trends in long-term environmental time series. By pioneering original insights into the statistical properties of streamflow time series, I am opening new pathways to determine surface-water availability at unmonitored locations and to classify streamgauges into ecologically-relevant management groups. My...
The physical/chemical variability in our rivers and estuaries is large, but causes and interactions are not clearly defined. Variations forced by weather and climate appear to be very important, but we don't yet understand how riverine-estuarine systems operate on very short and moderately long time scales. Furthermore, the effect of anthropogenic activities also may be important. Without such information we cannot understand and predict how these systems respond to variations in climate and human activities including changes in the amount, character, and timing of freshwater, toxic- waste, sediment and plant-nutrient inflows to these environments. Project objectives were to better understand the variability of...
thumbnail
Collection of 3 assessments for Mainstem Big Rivers. The Condition Index ranks stream segments according to how well they meet the Desired State described qualitatively and quantitatively in the draft Integrated Science Agenda (v4). From the Condition Index 2 assessments are derived that rank opportunities for management and restoration of conditions included in the Condition Index – In-stream habitat diversity (also related to flow), and floodplain/riparian conditions. In-stream management opportunities are based on watershed-level (HUC12) scores for habitat diversity, sinuosity and impoundment conditions such that river segments meeting all desired states are considered Maintenance opportunities (values 5-6)....
To anticipate the effects of potential climate change (natural or anthropogenic) on hydrology and to assess hydrologic trends will require an understanding of past long-term hydrologic variability. There also is a critical need for data on extreme floods for better understanding flood processes, in engineering hydrology, flood-hazard mitigation, and other disciplines requiring flood-risk assessments. Probably the best information on hydrologic variability and extreme floods is provided by paleohydrologic and other proxy data analyzed with the help of hydrologic models. Methods for extending existing climatic and hydrologic records over long-time scales are needed. A relatively new approach, one that complements...
thumbnail
The purpose of this data set is support resource allocation decisions (i.e. where to invest conservation effort) within the Gulf Coastal Plains and Ozarks Landscape Conservation Cooperative. It represents a relative ranking of HUC12 watersheds according to the quantity and quality of habitat as described in the GCPO LCC’s draft Integrated Science Agenda (v4). Watersheds (HUC12) were ranked by calculating the length-weighted average Management Opportunity scores within them. Action classes are different for Mainstem Big Rivers than for for Med/Low-gradient Streams & Rivers of the coastal plains and Upland Streams & Rivers, so action and overall scores for this system were calculated separately. Unlike the terrestrial...
The regional nature of hydrologic processes is generally defined in terms of shared meteorological and basin characteristics. Inferences have been attempted by regressing the parameters of hydrologic interest against these characteristics. Such analyses have not been able to fully explain the variations, extremes or persistence of discharge patterns observed within a geographic area. An accounting of anthropogenic effects on basin characteristics needs to be made. Longer term influences such as decadal to centennial, and millennial climatic fluctuations need to be considered, and the stochastic structure of the hydrologic process itself needs to be studied. The objectives of this project are (1.) to develop secular...
The broad objective of my research is to determine rates and controls of organic carbon metabolism as a fundamental component of the terrestrial-aquatic-atmospheric exchange of carbon. I quantify the relative importance of intrinsic substrate properties and environmental variables to carbon metabolism, and the impact of climate change and other disturbances. I combine field and laboratory study approaches to understand the numerous controls on carbon cycling processes. Much of my research has focused on boreal and arctic systems, where nearly ½ of the global soil organic pool resides and is vulnerable to climate change. My research objectives in boreal and arctic regions include: 1) quantifying the release...
thumbnail
The purpose of this data set is support resource allocation decisions (i.e. where to invest conservation effort) within the Gulf Coastal Plains and Ozarks Landscape Conservation Cooperative. It represents a relative ranking of HUC12 watersheds according to the quantity and quality of habitat as described in the GCPO LCC’s draft Integrated Science Agenda (v4). Watersheds (HUC12) were ranked by calculating the length-weighted average Management Opportunity scores within them. Because the 3 actions are identical for Med/Low-gradient Streams & Rivers of the coastal plains and Upland Streams & Rivers, (and because some watersheds contain both system types), we considered these systems simultaneously and calculated only...
thumbnail
These data show the results of the stream bank assessment for Rivers and Streams of Florida for 2018. River/Stream Bank Stability is an ecological indicator for the Landscape Conservation Project for Florida. The Project entails a large-scale assessment of and planning for the health of important natural resources, known as Conservation Assets (CAs), in Florida. Conservation planning at the landscape scale provides a framework for safeguarding functional ecosystems, and their interconnected processes necessary to achieve true preservation of healthy resources. Spatially explicit data from the project informs coordination and prioritization for making conservation decisions. A suite of ecological indicators was carefully...
The acquisition and meaningful interpretation of sediment data from areas disturbed by land-use activities or natural processes are two of the most deficient areas of recognizing nonpoint-source pollution in the United States. The comparison of sediment data from disturbed and undisturbed areas provides a means to (1) evaluate the effects that land-use activities cause, (2) investigate the geomorphic processes that regulate the detachment and transport of sediment, and (3) develop strategies for remedial action to reduce excessive sediment discharges. This information is especially necessary to minimize sediment discharges and sorbed chemical loads from surface-mine, industrial, agricultural, and urban areas. Objectives...
Channel responses to flow depletions in the lower Duchesne River over the past 100 years have been highly complex and variable in space and time. In general, sand-bed reaches adjusted to all perturbations with bed-level changes, whereas the gravel-bed reaches adjusted primarily through width changes. Gravel-bed reaches aggraded only when gravel was supplied to the channel through local bank erosion and degraded only during extreme flood events. A 50% reduction in stream flow and an increase in fine sediment supply to the study area occurred in the first third of the 20th century. The gravel-bed reach responded primarily with channel narrowing, whereas bed aggradation and four large-scale avulsions occurred in the...
map background search result map search result map Mainstem Big Rivers Watershed Ranks Combined Med/Low-gradient & Upland Streams & Rivers Watershed Ranks Mainstem Big Rivers Grouped Assessments Med/Low-gradient Streams & Rivers Grouped Assessments NHD-RC: Extension of NHDPlus Version 2.1 with high-resolution river corridor attributes Rivers and Streams - Bank Stability Indicator Rivers and Streams - Bank Stability Indicator Mainstem Big Rivers Grouped Assessments Med/Low-gradient Streams & Rivers Grouped Assessments Mainstem Big Rivers Watershed Ranks Combined Med/Low-gradient & Upland Streams & Rivers Watershed Ranks NHD-RC: Extension of NHDPlus Version 2.1 with high-resolution river corridor attributes