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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.
1

A METHODOLOGY FOR ENVIRONMENTAL PROTECTION OF ONTARIO WATERCOURSES WITH RESPECT TO THE PERMIT TO TAKE WATER PROGRAM

Watt, Sean Patrick 23 October 2007 (has links)
The Ontario Water Resources Act requires a Permit To Take Water (PTTW) for withdrawals greater than 50,000 L/day. The permitting process includes a requirement to minimize the environmental effects of the withdrawal, but does not include a specific framework to do so. A methodology is proposed for estimating the water supply, the water demand, both anthropogenic and ecological, and the amount available for withdrawal. Water supply is estimated using statistical analysis of recorded daily flows in the watershed of interest, in adjacent watersheds, and in the region. Anthropogenic demand is given by the Ontario Ministry of the Environment’s PTTW database. Ecological demand is also estimated using statistical analysis of recorded daily flows, and through field measurement methods such as the Wetted Perimeter method. A case study of Millhaven Creek in eastern Ontario shows that the methodology is appropriate for this area and, with minor modifications, would apply to the rest of Ontario. Evaluation of the existing methods for water supply estimation showed that using long-term data for analysis is the best method, and that the regional analysis work completed for Ontario is out of data and needs revising. Estimation methods for ecological demand are not necessarily appropriate for all areas. A single instream flow requirement based on the Mean Annual Flow is not appropriate for Millhaven Creek, and even a set of flows based on Mean Monthly Flows needs modification to be acceptable for Millhaven Creek. Supply minus demand varies from month to month, and therefore the decision on whether to issue a permit depends on the season as well as the duration of the withdrawal (e.g. seasonal vs. continuous) and type of use proposed (e.g. golf course irrigation vs. municipal drinking water). / Thesis (Master, Civil Engineering) -- Queen's University, 2007-10-22 23:08:00.728
2

Zooplankton in flowing waters /

Dickerson, Kelli Denise McCloud, January 1900 (has links)
Thesis (M.S.)--Missouri State University, 2008. / "May 2008." Includes bibliographical references (leaves 94-107). Also available online.
3

Estimation of Cost and Benefit of Instream Flow

Amirfathi, Parvaneh 01 May 1984 (has links)
Water flowing in streams has value for various types of recreationists and is essential for fish and wildlife. Since water demands for offstream uses in the arid west have been steadily increasing, increasing instream flows to enhance the recreational experience might be in conflict with established withdrawals for uses such as agriculture, industries and households. It is the intent of this study to contribute to an economic assessment of the tradeoff between maintaining instream flow for river recreation use and offstream uses; that is, to develop and apply a method to measure costs and benefits of water used for recreation on a river. Since market prices are not observable for instream flows, the estimation economic value of instream flow would present well known difficulties. The household production function theory was used to build the theoretical model to measure economic value of instream flow. Policy implication are discussed with emphasis on application of the information to water management decisions.
4

Trout Habitat in an Altered Gravel-Bed River with an Augmented Flow Regime

Stout, Jacob B. 01 August 2019 (has links)
The Diamond Fork River, and it’s tributary Sixth Water Creek, has been highly altered in terms of shape, function, and ecologicaly due to large, trans-basin flows additions to the system for irrigation starting in the early 1900s. Flows were exceptionally large for 80 years, after which they were reduced in 2004. Larger than natural flows during the low flow season were then added to the river in an effort to improve ecosystem health and recreational fishing opportunities. Since the prescription additional flow during low flow seasons, the river channel has undergone further change, most noticeably in the form of narrowing. With the channel change that has occurred over the past decade, it has been suggested that the additional flows, which augment baseflows, are too large and that key habitat elements, particularly pools, are lacking throughout the river. We evaluated trout habitat throughout the altered reaches of the Diamond Fork River and Sixth Water Creek which are still subject to flow additions. We used a model to estimate the number of fish a reach can support at a given flow in order to evaluate which flow produces the highest quality trout habitat. We found that the current summer baseflows of 80 cfs for the lower Diamond Fork and 32 cfs for Sixth Water Creek are less than desirable and that flows less than 40 cfs for the lower Diamond Fork and flows between 20 cfs and 30 cfs for Sixth Water Creek would increase the quality of trout habitat. We also evaluated the size and number of pools throughout the system and identified that pools are generally lacking both in size and number relative to standard requirements for trout success. We documented that as the channel narrowed, the number of pools/deep water disappeared. The lack of sediment and the limited number of flows capable of moving sediment were identified as key causes of the channel simplification and loss of pool habitat. Crucial components of future pool formation and maintenance are i) active sediment availability and ii) frequent sediment mobilizing flows. If the baseflow regime were to be lowered, we predict that the channel would narrow, which would increase the effectiveness of floods, increase mobility of sediment, and overall increase pool habitat. This research, as part of a larger, interdisciplinary project, lays the foundation for proposing new flows for the Diamond Fork River that targets ecological goals identified by stakeholders as well as providing information for future habitat restoration projects.
5

Applying Biological and Physical Templates to Perform Instream Habitat Mapping in the Northeast

Walden, Diana L 01 January 2008 (has links) (PDF)
Most northeastern river basins are stressed by the effects of development but the complexity of evaluating rivers often hinders the establishment of effective management regulations. Many methodologies have been proposed for assessing instream habitat, determining critical flow levels, and evaluating biological communities, but no one approach is universal. The overall objective of this thesis is to move towards standardizing components of river modeling. Rather than examine a full model, I investigated individual steps of MesoHABSIM, an instream habitat modeling approach. The two components studied involved applying the Reference Fish Community (RFC) method to identify a biological reference; and using depth and velocity data to standardize the description of hydraulic types. The RFC approach identifies the fish species and the expected proportions that should be present in a less impacted version of a river system. The Eightmile River watershed, was the focus of the study in which the RFC approach was employed to determine whether the fish community of this rural watershed, meets or exceeds a community developed using reference rivers. Similarity indices were used to identify differences between the existing (field-sampled) and expected communities. While the analysis of the Eightmile community indicates that it is in a better condition than the majority of rivers studied, it also shows some deviation from the reference, most likely due to elevated water temperatures and regional declines. The hydraulic type characterization study was developed to reduce the effort needed in depth and velocity measurement after this was identified as the most time consuming portion of the MesoHABSIM methodology. I used a series of pair-wise, independent-sample, Kolmogorov-Smirnov tests on a large bank of depth and velocity data to determine if patterns could be confirmed for each type of hydromorphological unit (HMU) across various streamflows. Few of the data sets were statistically similar enough to be combined and the mapping effort could not be simplified based on this investigation. Neither investigation provided the intended reference for the particular component of river modeling, further emphasizing the complexity in this area of study. However, the information gathered can be used as pioneering steps in future investigations.
6

Birds, Water, and Saltcedar: Strategies for Riparian Restoration in the Colorado River Delta

Hinojosa-Huerta, Osvel January 2006 (has links)
I evaluated the spatial and temporal patterns of the avian communities in the Colorado River delta, Mexico, and their relationship with vegetation type and surface water. I also developed plausible conservation and restoration guidelines for riparian areas and native birds in the region. The study included monthly point counts at 30 transects (240 points) from May 2002 to July 2003, breeding counts at 175 sites (3 times per year) during 2002 and 2003, and habitat measurements at the survey points.The most common species were Mourning Doves, Red-winged Blackbirds, and Brown-headed Cowbirds, but another 64 species were commonly found, including Verdins, Song Sparrows, Yellow-breasted Chats and Abert's Towhees. Surface water was the most important habitat feature related to avian richness and density regardless of vegetation type or land cover (P < 0.005). During summer, species richness was explained by variations in water and the cover of cottonwoods (r2 = 0.56, P < 0.001), and the variation in bird densities was explained by variations in water and the cover of willows (r2 = 0.35, P = 0.003).When comparing native versus saltcedar dominated sites, both with the presence (wet) or absence (dry) of surface water, the diversity of birds was more influenced by the presence of water than by vegetation type. Bird abundance was more influenced by vegetation type, but water also had an important effect, as wet sites had higher bird abundance than dry sites with the same vegetation type, and saltcedar wet areas had similar avian abundance to native dry sites. On all cases, the presence of water was an important factor determining the ecological value, in terms of avian richness, abundance, and diversity, of both native riparian and saltcedar areas. Saltcedar areas with surface water had avian characteristics similar to native riparian sites.The dedication of instream flows and pulse floods, the maintenance of vegetation cover and structural diversity, and an increase of older riparian stands will secure the viability of existing bird populations and will increase the probability of recovery of the species that are still extirpated from the floodplain of the Colorado River in Mexico.
7

Effects of restoration on instream bryophyte communities : Monitoring of two different restoration techniques in the Vindel River system

Sandberg, Lisa January 2015 (has links)
Ecological restoration is the practice of assisting the recovery of a degraded, damaged or destroyed ecosystem. The aim of this study was to analyse the effects of two different restoration techniques on instream bryophyte abundance, species richness and diversity as well as community composition, in streams channelized for timber-floating. Instream bryophytes were collected from 10 tributaries of the Vindel River in boreal northern Sweden, from five stream reaches each of channelized reaches, which had not been restored; reaches restored in the early 2000s, using best-practice techniques; and reaches restored in the early 2000s and then re-restored in 2010 using the new “demonstration” techniques. A multitude of environmental variables were also measured at the sites. Bryophyte abundance was lower in demonstration restored sites than unrestored or best-practice restored sites but no significant difference was found in bryophyte species richness, diversity or species composition. Environmental variables correlated with bryophyte abundance, species richness, diversity and composition largely reflected effects of restoration, and probably the disturbance associated with restoration. Small sediment grain sizes also had a negative effect on species richness. Other environmental variables that influenced bryophyte species composition were the large-scale factors of latitude, longitude and elevation and reach-scale factors of potassium concentration and light absorbance. It is not yet possible to fully evaluate the effectiveness, in terms of bryophyte response, of the new demonstration restoration compared with best-practice since the recovery time between them differs and has not been sufficient. Long-term monitoring of the effects of restoration is needed in order to better evaluate success.
8

Environmental Assessment of Streams: Linking Land Use, Instream Stressors, and Biological Indices to Infer Likely Causes of Ecological Impairment

Vander Laan, Jacob J. 01 May 2012 (has links)
To protect and restore the biological integrity of streams, we need to be able to both detect biological degradation and infer likely causes of impairment. Managers often use biological indices to measure biological condition and detect degradation. However, the ability to detect degradation can be limited by the performance of the indices we develop. Index performance varies widely, but the sources of this variation are often unclear. In addition, although bioassessments are useful tools for detecting biological degradation, they do not identify stressors associated with impairment. My thesis research had two general goals: 1) develop statistically and ecologically robust indices to measure biological condition in Nevada streams and 2) quantify relationships between land uses, stressors, and biological condition to infer likely causes of degradation. I developed two biological indices for Nevada streams, a multimetric index (MMI) and observed to expected (O/E) taxa ratios, and determined if index performance was related to site isolation and sample evenness. The Nevada O/E indices were relatively imprecise compared with those from other regions, which likely results from low assemblage predictability associated with spatial isolation of aquatic habitats in arid regions. In contrast, the Nevada MMI was more precise than most previously developed MMIs, likely the result of using models to reduce natural variation in index scores. Sample evenness was positively associated with both O/E and MMI scores. Adjustments of index scores for sample evenness increased index precision, but also altered relative differences in index values and therefore inferences of biological impairment at specific sites. I also quantified relationships between biological condition, instream stressors, and land uses and used a weight of evidence approach to infer likely causes of degradation. Land uses such as agriculture, urbanization, and mining were associated with the spatial distributions of instream stressors, and these stressors were associated with variation in biological condition. Total dissolved solids and metal contamination were the stressors most strongly associated with biological condition. By detecting biological degradation and identifying important stressors and their potential sources, the tools I developed should help managers target conservation and restoration efforts and improve their ability to protect freshwater resources.
9

Klimatförändringarnas påverkan på juvenila laxfiskars vinteröverlevnad och tillväxt i ett korttidsreglerat vattendrag

Schill, Joel January 2022 (has links)
Already within 10-20 years, the average temperature risks exceeding the 1.5 degree target limit and we can expect more extreme weather in the form of increased precipitation. Hydropower plants hinder the possibility of freshwater species to migrate between for example their spawning grounds and rearing habitat. This effect is a contributing factor to the fact that populations of migrating freshwater species have decreased by 93% in Europe. The purpose of this study is to investigate overwinter growth and survival of juvenile brown trout and Atlantic salmon in a hydropeaking river which is affected by a future climate change. In this study, juvenile brown trout and Atlantic salmon in the river Gullspång were investigated using simulations in an agent-based model (inSTREAM 7-SD). An existing model parameterized in another study was used, and I manipulated two parameters: water temperature and flow, to investigate their effects on salmonid growth and survival. Increased flow did not have a statistically significant effect on the growth or survival of juvenile salmonids during the winter, but an increased temperature had a positive effect on growth. An elevated temperature also had a negative effect on the survival of 0+ salmonids. The salmonid populations in river Gullspång may be negatively affected by future climate change and the hydropower operation may need to be adapted to preserve the endangered Gullspång salmon and Gullspång trout.
10

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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