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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Flow estimation for stream restoration and wetland projects in ungaged watersheds using continuous simulation modeling

Henry, Janell Christine 06 May 2013 (has links)
More than a billion dollars are spent annually on stream restoration in the United States (Bernhardt et al., 2005), but the science remains immature. A promising technique for estimating a single or range of design discharges is the generalization of a parsimonious conceptual continuous simulation model. In this study the Probability Distributed Model (PDM), was generalized for the Maryland and Virginia Piedmont. Two hundred and sixty years of daily average flow data from fifteen watersheds were used to calibrate PDM. Because the application of the study is to stream restoration, the model was calibrated to discharges greater than two times baseflow and less than flows with a return period of ten years. The hydrologic calibration parameters were related to watershed characteristics through regression analysis, and these equations were used to calculate regional model parameters based on watershed characteristics for a single "ungaged" independent evaluation watershed in the region. Simulated flow was compared to observed flow; the model simulated discharges of lower return periods moderately well (e.g., within 13% of observed for a flow with a five year return period). These results indicate this technique may be useful for stream restoration and wetland design. / Master of Science
42

USE OF ADULT ANURAN COMMUNITIES AND DIETS TO ASSESS THE EFFECTS OF STREAM RESTORATION ON AQUATIC TO TERRESTRIAL FOOD WEB SUBSIDIES

Bowe, Kelsey Lyn 01 December 2019 (has links)
The boundaries between freshwater and terrestrial ecosystems can be areas of important subsidy transfers. These subsidies, such as leaf litter inputs to streams or aquatic emerging insects into riparian zones, link food webs and provide benefits to consumers in the form of nutrients and energy. Subsidies from aquatic systems tend to have high levels of essential long chain polyunsaturated fatty acids (LC-PUFAs), such as eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) that are only produced by certain forms of aquatic algae. These LC-PUFAs are highly important in growth, development, and other metabolic functions across animal groups (Brett and Muller-Navarra 1997, Gladyshev et al. 2009).
43

Longitudinal Processes in Stream Ecosystems: Examining Connections between Stream Characteristics at a Reach-scale

Hintz, Chelsea 25 May 2022 (has links)
No description available.
44

Sedimentological and Biological Analyses on Hobble Creek Prior to Restoration

Brown, Jaron Michael 25 January 2008 (has links) (PDF)
Hobble Creek is one of several inflowing streams and rivers into Utah Lake, Utah, USA. Historically, June sucker (Chasmistes liorus), a federally listed endemic fish, spawned up all the major inflowing streams and rivers but is now limited to just the Provo River. The State of Utah has recently proposed restoring the lower reaches of Hobble Creek for additional spawning and rearing needs. This restoration effort will likely involve removal of migration barriers, re-aligning the stream, and removing existing levees that prevent floodplain access. These changes have raised several questions that this study aims to answer. First, what are the sediment transport rates under current flow conditions in Hobble Creek, and how well do various predictive models match the actual rates? Secondly, assuming a successful introduction of adult June sucker into the Hobble Creek system, will the existing flow regime be capable of transporting the fry to an area adequate for successful population growth? Four bedload predictive models were used to create sediment rating curves for flows typically found in Hobble Creek: the Meyer-Peter, Muller equation (MPM), Wilcock's two parameter model, Rosgen's Pagosa reference curve, and Bathurst's Phase 2 equation. Each were used and compared to data obtained on Hobble Creek during the spring 2006 snowmelt runoff season. Results show that the uncalibrated MPM formula over predicted bedload rates by several orders of magnitude, while the Wilcock model sometimes performed more accurately, but was also prone to inaccuracies greater than an order of magnitude. The Rosgen and Bathurst predicted rates were consistently within an order of magnitude of observed rates. Areas of optimal rearing potential were determined by separating the stream-lake interface into four zones: dense vegetation, sparse vegetation, open lake, and within the creek. These four zones were analyzed for rearing potential based on food resources, temperature patterns and existing small fish densities. Larval drift modeling was performed to characterize the ability of the stream to transport larvae to the zones studied. We found that highest food density occurs in the open lake; small fish were most abundant in the open lake as well. The open lake is also better for rearing habitat in terms of temperatures between zones. Furthermore, larval drift studies show that the current geometry and flow regime is incapable of transporting larvae to zones in the lake where food and warm water are both available, and that larvae are likely to die before reaching those areas.
45

Comparison of Hydraulic Function and Channel-Floodplain Connectivity Between Actively and Passively Restored Reaches of Stroubles Creek 11 Years After Restoration

Christensen, Nicholas Daniel 24 June 2022 (has links)
A hydraulic model was developed to determine differences in the hydraulic characteristics of three different reaches of an urban- and agriculturally-impacted stream in southwest Virginia. The three reaches all had cattle excluded from the channel in 2010. The farthest upstream, Treatment 1, was left to progress without intervention beyond cattle removal while the other two, Treatments 2 and 3, were regraded and stabilized using common stream restoration techniques and a forested riparian was established. The banks of Treatment 2 were regraded to a slope of 3:1 while Treatment 3 was designed with a flat inset floodplain cut into the banks. The model results showed that the self-adjustment in Treatment 1 exhibited inset floodplains with diverse topographical structure including floodplain channels. These adjustments provided higher floodplain volume and mass exchange between the channel and the floodplain when compared with the stable, straight Treatment 2. Comparisons between Treatment 1 and Treatment 3 did not clearly show which treatment was more well connected, with some metrics showing Treatment 1 was more connected while others indicated the opposite. Overall, the findings indicate that stabilization of channelized streams without consideration of the natural planform prolongs adjustment to a channel-floodplain form with more exchange of water, sediment, nutrients and providing refuge for biota. / Master of Science / A water flow model was developed to determine differences in between sections with different management practices an urban- and agriculturally-impacted stream in southwest Virginia. The three reaches all had cattle excluded from the channel in 2010. The farthest upstream, Treatment 1, was left to progress without intervention beyond cattle removal while the other two, Treatments 2 and 3, were stabilized by changing the bank slope and planting trees. The banks of Treatment 2 were regraded to a slope of 3:1 while Treatment 3 was designed with a flat section cut into the banks. The model results showed that the self-adjustment in Treatment 1 created an bench similar to Treatment 3. This section flooded more readily and allowed for higher flow of water between the channel and the floodplain when compared with the stable, straight Treatment 2. Comparisons between Treatment 1 and Treatment 3 did not clearly show which treatment was more well connected, with some metrics showing Treatment 1 was more connected while others indicated the opposite. Overall, the findings indicate that stabilization of channelized streams in their man altered state prolongs adjustment to a more natural form which provides services including flood mitigation, sediment cycling, nutrient cycling and habitat for plants and animals in and along the stream.
46

Development of Design Guidelines for In-Stream Flow Control Structures

Radspinner, Robert Ryan 18 June 2009 (has links)
The use of in-stream flow control structures for channel stabilization has become increasingly popular due to its potential cost-effectiveness and ecological benefits. These structures help to protect the bank from erosion and lateral migration. However, a large number of these projects fail due to inadequate design guidelines. This study aims to create authoritative design guidelines which are based on hydraulic and physical criteria attributed to the channel reach. In this report, some of the most common types of in-stream structures have been reviewed and results from a practitioner experience survey have been analyzed. This research has allowed for the selection of the most promising structures which will be studied later in the project. / Master of Science
47

Monitoring and Managing River Corridors in the Midst of Growing Water Demand

Keys, Tyler Adam 26 April 2018 (has links)
Rivers and their surrounding riparian and subsurface ecosystems, known as river corridors, are important landscape features that provide a myriad of ecological and societal benefits. While the importance of riverine flooding has been widely acknowledged and extensively studied, very little research has been conducted on the interactions between river channels and their adjacent floodplains. The importance of this hydrologic connectivity between rivers and floodplains has been emphasized in recent decades and now ecological engineering techniques such as stream restoration are often utilized to restore connectivity between streams and their riparian ecosystems. Despite its ubiquity in practice, there are still many basic components of river-floodplain connectivity that are not well understood. Furthermore, a lack of cost-effective monitoring techniques makes sustainable management of river corridors quite challenging. Thus, the overall goals of my dissertation were: 1) develop user-friendly river corridor monitoring techniques utilizing cost-effective approaches such as time-lapse digital imagery and satellite remote sensing and 2) identify the effects of anthropogenic activities on river corridor hydrologic and biogeochemical processes that occur at varying spatial and temporal scales during flood events. These goals were addressed through five independent studies that span spatiotemporal scales. The five studies utilized a combination of novel remote sensing, hydrologic/hydraulic modeling, and high frequency spatial sampling techniques to analyze river corridor dynamics. Results highlight that digital imagery and satellite remote sensing can be effective tools for monitoring river corridors in data scare regions. Additionally, impounding streams and river corridors alters floodplain connectivity and biogeochemical processing of reactive solutes such as nitrogen and phosphorus. Findings from this work highlight the important role that spatial and temporal scale plays in river corridor dynamics. Overall, this research provides new analytical techniques and findings that can be used to effectively monitor and manage river corridors. / PHD
48

Daylighting Pogues Run : an urban stream solution

Rippey, Heather A. January 2003 (has links)
This creative project has culminated in a design solution to a water quality problem in the City of Indianapolis, Indiana. Pogues Run is a stream that has been buried in an underground culvert for almost a century. It has a long history of water quality problems including high bacteria levels and nonpoint source pollution. In addition, it has long been a flood threat to neighboring communities.To address the issue, a master plan was created for the last 1400' of Pogues Run before it emptied into the White River. The stream was removed from the culvert, brought back up to grade, a series of wetlands were developed to slow and filter stream flow, and an urban revitalization project was developed centering on the stream. The design solution provided flood control, stormwater storage and treatment, mixed-use redevelopment of historical buildings, a recreational area, and a high-density residential community. / Department of Landscape Architecture
49

From engineered channel to functioning stream ecosystem : rates, patterns and mechanisms of development in a realigned river channel

Perfect, Charles January 2010 (has links)
1. Realigning rivers is becoming common as a solution to conflicting needs of land development and ecosystem preservation. Although an increasing number of projects are monitored, exactly how these channels develop as functional stream ecosystems is still poorly understood. Mining in the upper catchment of the River Nith (Scotland) required the realignment of 3km (approx.) of river. The engineered channel was designed around sound geomorphological principles of sediment transport and supply with a sinuous planform and pool-riffle sequences along the installed gravel-bed. 2. A comprehensive survey covering biotic and abiotic development was devised and implemented to test models and hypotheses relating to the development riverine habitats over the first three years. 2. Physical habitat development at the reach scale was investigated using fixed-point photography and differential GPS surveys of the thalweg and of cross-sectional form every 100m. This revealed the development of a relatively diverse streambed habitat in response to both the channel slope and planform. However, other than at meander bends where asymmetry developed over several years, little change was observed to the form of the engineered riverbanks. 3. Kick-net surveys of benthic invertebrate communities at 10 sites showed a negative relationship between specific measures of diversity and downstream distance during the early stages of development. (e.g. Richness with chainage at the 6 month stage) but the relationship degrades rapidly and is likely in part to appear as a result of low population densities. 4. Survey of transects through the riparian zone perpendicular to the river indicated that colonisation by vegetation is also related to distance along the realignment but physical habitat and geographical factors play a more dominant role over development (Canonical correspondence analysis of vegetation data in 2007) 5. Many of the indices of diversity for both biotic and abiotic elements of the ecosystem proved ineffective at detecting development at the reach scale. This may be because significant changes occur at a smaller scale than was detected by the surveys. It is likely that greater resolution is required to detect more ecologically meaningful relationships and patterns. 6. Overall study shows constructed realignments can rapidly develop a diverse streambed community within 24 months. Riparian communities are slower to develop because of the slow development of riverbank habitat diversity. Other ecosystem properties such as resilience and connectivity may take much longer.
50

Quantifying the physical effects of stream restoration: With unmanned aerial vehicles and geographic information systems

Karlsten, Annika January 2019 (has links)
Stream restoration efforts often aim at restoring the physical complexity in streams, as an increased habitat heterogeneity is believed to increase biodiversity. It is important to quantify the physical complexity of streams before and after restoration, to know what actions are needed, and to monitor the results of the restoration. The use of unmanned aerial vehicles (UAVs) and geographic information systems (GIS) for data acquisition is rapidly increasing, and the use of UAVs and GIS could facilitate the monitoring process. The aim of this study was to determine how the spatial complexity in streams can be determined by using UAVs and GIS. The physical features and the spatial complexity were quantified in five reaches in the Lögde River, pre- and post-restoration, by analyzing UAV photos in a GIS program. Three of six reach descriptive metrics, and three of seven complexity metrics, were shown significantly different after restoration. To validate the GIS analyzing method, a qualitative comparison of data from the GIS analysis to field survey data was conducted. The GIS method was shown effective for distinguishing morphological features on a larger spatial scale, and to show the spatial distribution of instream features, such as wood pieces and boulders. The accuracy when digitizing the bankfull edge of the stream was low on small scales, and the method likely underestimates the number of wood pieces and boulders in the streams. Preferable camera settings and weather conditions to avoid blurry UAV photos, and thereby enhance the accuracy of the GIS analysis, are discussed.

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