Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 80 for “"ditch"”.
-
Reframing the Ditch
Reframing the Ditch explores the application of native canopy using green street tools as a method to move beyond minimums and improve biological diversity of stormwater conveyances in a way that is consistent with visual landscape preference theory. Small stream water quality impairment is an …
-
Roadside Ditch Design and Erosion Control on Virginia Highways
The state of roadside ditch design and performance has become a topic of concern for the Virginia Department of Transportation. Erosion failures of roadside ditches have occurred frequently enough to indicate that it may be desirable to revise the current design practice. Through the Virginia …
-
Impact of Substrate on Nutrient Removal in In-Ditch Bioreactors
Drainage ditches, or grassed waterways, collect nutrient-laden runoff from agricultural fields and transport it to nearby waterbodies. The high nitrogen and phosphorus content in this water leads to negative effects, such as eutrophication in the receiving waters. In-ditch bioreactors are a simple, …
-
Evaluating the Two-Stage Ditch as a New Best Management Practice
<p>A two-stage ditch involves modifications of a traditional drainage ditch to resemble more the features of a natural stream. The idea is to create or simulate extended benches on both sides of the ditch that would develop naturally over a period of time in a stream because of geomorphological …
-
Ecological effects of ditching and ditch-plugging in New England salt marshes
… have received little attention. Specifically, ditches have existed on salt marshes for decades, but the effects of these hydrologic alterations are only poorly understood. Ditch-plugging is a more recent methodology used for salt marsh habitat enhancement and mosquito control, but the long-term …
-
Phosphorus fate and management on the Somerset Levels and Moors Ramsar ditch systems
… in surface waters worldwide. Freshwater wetland ditches afflicted by these conditions undergo a shift from primarily submerged aquatic vegetation to algae or duckweed dominance, leading to excessive shading and anoxic conditions. Phosphorus, from both point (e.g., wastewater treatment works) and …
-
Using temperature profiles to investigate the hyporheic zone in an agricultural drainage ditch
… water system to include the man-made drainage ditch environment. The goal of this research is to use vertical temperature profiles as a means to identify locations along the drainage ditch where surface water/ground water exchange takes place within the hyporheic zone. To achieve this, an array …
-
Rejuvenation of the ditch - redefining the landscape of the Embarras River with integrated analytical & design approaches
This thesis aims to redefine the traditional rural landscape of the upper section of the Embarras River (UER) in Champaign County, Illinois. To date, there are four issues existing in this landscape: flooding, impaired waterway, extinction of endangered species, and lack of identity. Integrated …
-
Using Digital Methods to Reconstruct Original Topography and Landscape Wetness in the Judicial Ditch 66 Watershed, Polk County, Minnesota
<p>The excavation of Judicial Ditch #66 has altered the topography of its hydrologic basin in Polk County, Minnesota. Records of how the pre-ditch landscape appeared do not exist. The original aim of this study was to develop and evaluate a method of manual data manipulation and combination to …
-
Evaluation of Oxidation Ditches; Based on Existing Plant Data and Site Trials
This thesis evaluates the Oxidation Ditch as a form of domestic effluent treatment. It uses as its basis a survey of the performance of existing plants in operation and reflective site trials of an existing plant in operation. <br/><br/>Based on the survey of existing plants, the design elements of …
-
A debris flow chronology and analysis of controls on debris flow occurrence in the Upper Colorado River valley, Rocky Mountain National Park, CO
… River was recently highlighted when the Grand Ditch, a 19th-century water-conveyance ditch, overtopped from snowmelt in 2003 and triggered a large debris flow along Lulu Creek, a tributary of the Colorado. Historical aerial photographs indicate that at least two other debris flows have been …
-
Computational fluid dynamics modelling of dissolved oxygen in oxidation ditches.
… aeration performance of a wastewater oxidation ditch. The literature is reviewed on the Computational Fluid Dynamics (CFD) modelling of wastewater aeration tanks. This study develops a CFD model of an aerated oxidation ditch, by taking into account two-phase gas-liquid flow, inter- phase oxygen …
-
Triggers, transitions, and trip decisions from 1976 to 2019: why utility cyclists in Cape Town choose to ‘ditch their cars’, and why bicycle advocacy says they should
Almost all cycling research in South Africa to date has focused on utility cyclists living with low incomes, the so-called ‘captive’ user who does not have access to a private car. Individual car drivers (particularly of single occupants), however, are a target of the City of Cape Town’s policy …
-
Genetic analysis reveals bidirectional fish movement across the Continental Divide via an interbasin water transfer
… organisms are poorly understood. The Grand Ditch is an interbasin water transfer that diverts water from tributaries of the upper Colorado River on the west side of the Continental Divide to the upper Cache la Poudre River on the east side of the Continental Divide. I used single nucleotide …
-
Characterization of legacy soil P and quantification of subsurface losses under artificial drainage
… to identify pathways of subsurface P loss in a ditch-drained field. ☐ Chapters 2 and 3 focused on characterizing the sources and solubility of soil P to predict the risk of P loss. The X-ray absorption near edge structure spectroscopy fitting results identified various aluminum (Al)-, calcium …
-
Soil Erosion from Forest Haul Roads at Stream Crossings as Influenced by Road Attributes
… from haul road stream crossing approaches and ditches. The three studies in this dissertation provide a quantitative assessment of sediment production and potential sediment delivery from forest haul roads in the Virginia Piedmont and Ridge and Valley regions. Sediment production rates were …
-
The economic feasibility of introducing aquaculture into traditional farming systems in Arizona
… for the farmer to make is to keep water in the ditches at all times. Water as a production variable for fish production was thus calculated only for the additional quantity required. Analysis of these production systems was accomplished by budgeting procedures as well as statistical analysis. …
-
A macroinvertebrate bioassessment of two streams on Turnbull National Wildlife Refuge (TNWR)
… focused on stream sections of the Company Ditch (CD) and Pine Draw (PD) watersheds. Company Ditch historically had very high nutrient levels and low water quality. Water quality may be improving since closure of a nearby dairy operation in 2008. Pine Draw includes several springs and the …
Page 1 of 4