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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

Hydrogeomorphic Factors Influencing Clonal Recruitment of Cottonwoods in Mountain Valleys

Roberts, Michael D. 01 May 1999 (has links)
Riparian cottonwoods (populus spp.) are keystone pioneer species that contribute to critical streamside and in-stream habitats, water quality, and aesthetic and recreational value. Land use and river regulation have caused a widespread reduction in the extent and regeneration of this genus. The majority of research on Populus species' reproduction has examined seedling recruitment that dominates in wide alluvial valleys. In contrast, I evaluated reproductive strategies of Populus angustifoliain mountain valleys. Research was conducted in northern Utah on the Little Bear River, a gravel-bedded stream that flows north out of the Bear River Range onto deposits of Ancient Lake Bonneville. I used allozyme electrophoretic data and vegetation mapping to investigate recruitment mechanisms of cottonwoods at two steep, confined mountain valley sites and two wide, alluvial valley sites. Allozyme electrophoretic analysis on samples from sites one through four revealed 60%, 69%, 86%, and 84% clonal recruitment, respectively. The size of cottonwood clones may be on the order of 200-300 m in this system. Vegetation mapping supported allozyme data and suggested that clonal recruitment dominates the system. I also collected data at four sites containing no cottonwoods to compare hydrogeomorphic influences at non-cottonwood (NC) sites and cottonwood recruitment (CR) sites. CR sites possess a distinctive geomorphic template relative to NC sites and this template may facilitate root disturbance resulting in clonal recruitment. A high frequency of woody debris and mid-channel islands characterizes CR sites. Channels at CR sites are less entrenched, more sinuous, and exhibit larger bankfull channel width and width to depth ratios, and finer grain sizes than channels at NC sites. At CR sites, estimates of bankfull average boundary shear stress and unit stream power are less compared to those at NC sites. Cottonwood recruitment models that typically describe seedling reproduction in alluvial valley environments do not apply in narrow, steep-gradient environments. I found clonal recruitment of cottonwoods to correlate spatially and temporally with channel and root disturbance associated with rain on snow events on the order of the 25-30-yr flood event.
2

A Comparison of Three Rapid Evaluation Procedures for Pine Savanna Wetlands

Henderson, Cynthia Joan 04 August 2001 (has links)
Inception of the Clean Water Act in 1972 resulted in regulation of activities in wetlands through Section 404. Regulatory agencies like the Mississippi Department of Marine Resources (MDMR) have tried to find methods to rapidly evaluate wetlands. This study compares three rapid evaluation methods, Hydrogeomorphic Approach (HGM), Wetlands Rapid Assessment Procedure (WRAP), and Wetland Evaluation System (WES), based on their scoring of a group of reference and mitigation wetland sites. Repeatability was studied by scoring a group of sites twice. The non-parametric Spearman?s correlation was used to compare the three methods. In this study, HGM was most repeatable followed by WES and WRAP. Comparisons of overall scores using the Spearman correlation found the strongest correlation between HGM and WES, although all pairings were significantly correlated (p< 0.05). This study determined HGM was the optimum method for the MDMR because due to repeatability and producing results similar to the other two methods.
3

A Comparison of the HGM Approach to the RBP Method of Evaluating Reconstructed Streams on Surface Coal Mines

Osborne, Caudill 12 April 2019 (has links)
ABSTRACT A review of annual monitoring reports for stream restoration projects on surface coal mines in the central Appalachian Mountains found that the criteria used for judging the success of the projects was generally based on visual assessments of habitat structure which were evaluated using the Rapid Bioassessment Protocol (RBP) (Palmer and Hondula, 2014). In recent years the Hydrogeomorphic Approach (HGM), which was originally developed to evaluate wetlands, has been adapted for stream evaluations as well (Summers, et al., 2017). Both of these methods are primarily a means to determine if suitable habitat structure and riparian growth are present to support aquatic life. It is assumed that if habitat structure is suitable then macroinvertebrate and other life will be present. However, each of these two methods place emphasis on different aspects of habitat and riparian structure. The primary purpose of this project is to compare and contrast how effective these two methods are at evaluating reconstructed streams on surface coal mines. A secondary objective is to determine if macroinvertebrate assemblages in reconstructed streams is significantly different from that of reference streams not impacted by mining. Research on benthic community structure downstream of coal mining activities suggests that even after many decades taxa richness and abundance still have not recovered from indirect impacts (Petty, et al., 2010). Information on reconstructed streams directly impacted is lacking. This project evaluates streams that were reconstructed five years prior using the RBP and HGM methods, and compares them to local reference streams that have minimal to no mining impacts. Multiple benthic metrics are also used to evaluate community structure. REFERENCES Petty, J. Todd, Jennifer B. Fulton, Michael P. Strager, George T. Merovich Jr., James M. Stiles, and Paul F. Ziemkiewicz. 2010. Lanscape indicators and thresholds of stream ecological impairment in an intensely mined Appalachian watershed. Journal of the North American Benthological Society, 29(4): 1292-1309. Palmer, Margaret A., and Kelly L. Hondula. 2014. Restoration as mitigation: analysis of stream mitigation for coal mining impacts in southern Appalachia. Environmental Science and Technology 48: 10552-10560. Summers, Elizabeth A., Chris V. Noble, Jacob F. berkowitz, and Frank J. Spilker. 2017. Operational Draft Regional Guidebook for the Functional Assessment of High-Gradient Headwater Streams and Low-Gradient Perennial Streams in Appalachia. ERDC/EL TR-17-1.
4

CARBON SEQUESTRATION IN NATURAL AND CREATED WETLANDS

Bernal, Blanca 22 June 2012 (has links)
No description available.
5

Avaliação do perigo de inundações bruscas por meio de modelagem hidrogeomorfológica : estudo de caso, Bacia do Arroio Forromeco-RS

Zambrano, Fernando Campo January 2017 (has links)
O aumento da ocorrência de desastres hidrológicos relacionados a inundações bruscas tem recebido maior atenção dos diversos órgãos em suas diferentes escalas, com o objetivo de reduzir ao máximo suas causas. Justamente por isso, as medidas não estruturais são medidas de extrema importância na prevenção de tais desastres. Uma dessas medidas deve ser o mapeamento de áreas de perigo de inundações. Portanto, o objetivo do presente trabalho foi propor e avaliar o perigo de inundações bruscas por meio de modelagem hidrogeomorfológica na bacia do arroio Forromeco-RS. Para isso, foi utilizado o modelo CAESAR-LISFLOOD, para representar os processos hidrológicos em escala de bacia e canal. Em escala de bacia foram gerados hidrogramas a partir da criação de chuvas de projeto para diferentes tempos de retorno (TR), considerando como base o maior evento registrado nessa bacia associado a um TR de 22 anos. Esses hidrogramas foram utilizados nas simulações em escala de canal para gerar os diferentes mapas de inundação em termos de profundidade e velocidade do fluxo da água. Para analisar as áreas de perigo de inundação, foram determinados os índices de perigo (IP) associados aos diferentes TR, a partir da profundidade e a velocidade d’água. Através das análises do resultado de IP foi criado o mapeamento final de perigo associado a três tempos de retorno (5, 22, e 100 anos). Além disso, estabeleceu-se três zonas para identificar os níveis de perigo, considerando o cenário mais crítico dos três mapas. Os resultados mostraram que a maior área inundada se encontra em alto perigo, ocupando 77% da área total, o que significa que as pessoas que moram nessa região estão em perigo tanto em casa, como fora delas. Ao mesmo tempo as construções estão em alta possiblidade de serem danificadas. / The increase in the occurrence of hydrological disasters related to flash floods has begun to be more important for several organs at different scales in order to reduce their magnitude and frequency as much as possible. Precisely because of it, non-structural measures are extremely important measures for preventing such disasters. One of these important measures might be the mapping of flood hazard areas. Therefore, the objective of the present work was to propose and evaluate the flash flood hazard by means of hydrogeomorphic modeling of the Forromeco river basin, Rio Grande do Sul state. Thus, the CAESAR-LISFLOOD model was used to represent the hydrological processes at basin and channel scale. At basin scale hydrographs were generated from the creation of hyetographs for different return periods (RP), considering the largest event recorded in this basin. These hydrographs were used in the channel scale simulations to generate the different flood maps in terms of depth and velocity of water flow. In order to analyze the flood hazard areas, the hazard indexes (HI) associated with the different RPs were determined from the depth and water velocity. Through the IP analysis, the final hazard mapping associated with three RPs (5, 22, and 100 years) was created. In addition, three zones were established to identify the hazard levels, considering the most critical scenario of the three maps. The results showed that the largest flood area is in high degree hazard, occupying 77% of the total area. It indicates that people are in danger both inside and outside houses. At the same time buildings are in high possibility of being damaged.
6

Avaliação do perigo de inundações bruscas por meio de modelagem hidrogeomorfológica : estudo de caso, Bacia do Arroio Forromeco-RS

Zambrano, Fernando Campo January 2017 (has links)
O aumento da ocorrência de desastres hidrológicos relacionados a inundações bruscas tem recebido maior atenção dos diversos órgãos em suas diferentes escalas, com o objetivo de reduzir ao máximo suas causas. Justamente por isso, as medidas não estruturais são medidas de extrema importância na prevenção de tais desastres. Uma dessas medidas deve ser o mapeamento de áreas de perigo de inundações. Portanto, o objetivo do presente trabalho foi propor e avaliar o perigo de inundações bruscas por meio de modelagem hidrogeomorfológica na bacia do arroio Forromeco-RS. Para isso, foi utilizado o modelo CAESAR-LISFLOOD, para representar os processos hidrológicos em escala de bacia e canal. Em escala de bacia foram gerados hidrogramas a partir da criação de chuvas de projeto para diferentes tempos de retorno (TR), considerando como base o maior evento registrado nessa bacia associado a um TR de 22 anos. Esses hidrogramas foram utilizados nas simulações em escala de canal para gerar os diferentes mapas de inundação em termos de profundidade e velocidade do fluxo da água. Para analisar as áreas de perigo de inundação, foram determinados os índices de perigo (IP) associados aos diferentes TR, a partir da profundidade e a velocidade d’água. Através das análises do resultado de IP foi criado o mapeamento final de perigo associado a três tempos de retorno (5, 22, e 100 anos). Além disso, estabeleceu-se três zonas para identificar os níveis de perigo, considerando o cenário mais crítico dos três mapas. Os resultados mostraram que a maior área inundada se encontra em alto perigo, ocupando 77% da área total, o que significa que as pessoas que moram nessa região estão em perigo tanto em casa, como fora delas. Ao mesmo tempo as construções estão em alta possiblidade de serem danificadas. / The increase in the occurrence of hydrological disasters related to flash floods has begun to be more important for several organs at different scales in order to reduce their magnitude and frequency as much as possible. Precisely because of it, non-structural measures are extremely important measures for preventing such disasters. One of these important measures might be the mapping of flood hazard areas. Therefore, the objective of the present work was to propose and evaluate the flash flood hazard by means of hydrogeomorphic modeling of the Forromeco river basin, Rio Grande do Sul state. Thus, the CAESAR-LISFLOOD model was used to represent the hydrological processes at basin and channel scale. At basin scale hydrographs were generated from the creation of hyetographs for different return periods (RP), considering the largest event recorded in this basin. These hydrographs were used in the channel scale simulations to generate the different flood maps in terms of depth and velocity of water flow. In order to analyze the flood hazard areas, the hazard indexes (HI) associated with the different RPs were determined from the depth and water velocity. Through the IP analysis, the final hazard mapping associated with three RPs (5, 22, and 100 years) was created. In addition, three zones were established to identify the hazard levels, considering the most critical scenario of the three maps. The results showed that the largest flood area is in high degree hazard, occupying 77% of the total area. It indicates that people are in danger both inside and outside houses. At the same time buildings are in high possibility of being damaged.
7

Avaliação do perigo de inundações bruscas por meio de modelagem hidrogeomorfológica : estudo de caso, Bacia do Arroio Forromeco-RS

Zambrano, Fernando Campo January 2017 (has links)
O aumento da ocorrência de desastres hidrológicos relacionados a inundações bruscas tem recebido maior atenção dos diversos órgãos em suas diferentes escalas, com o objetivo de reduzir ao máximo suas causas. Justamente por isso, as medidas não estruturais são medidas de extrema importância na prevenção de tais desastres. Uma dessas medidas deve ser o mapeamento de áreas de perigo de inundações. Portanto, o objetivo do presente trabalho foi propor e avaliar o perigo de inundações bruscas por meio de modelagem hidrogeomorfológica na bacia do arroio Forromeco-RS. Para isso, foi utilizado o modelo CAESAR-LISFLOOD, para representar os processos hidrológicos em escala de bacia e canal. Em escala de bacia foram gerados hidrogramas a partir da criação de chuvas de projeto para diferentes tempos de retorno (TR), considerando como base o maior evento registrado nessa bacia associado a um TR de 22 anos. Esses hidrogramas foram utilizados nas simulações em escala de canal para gerar os diferentes mapas de inundação em termos de profundidade e velocidade do fluxo da água. Para analisar as áreas de perigo de inundação, foram determinados os índices de perigo (IP) associados aos diferentes TR, a partir da profundidade e a velocidade d’água. Através das análises do resultado de IP foi criado o mapeamento final de perigo associado a três tempos de retorno (5, 22, e 100 anos). Além disso, estabeleceu-se três zonas para identificar os níveis de perigo, considerando o cenário mais crítico dos três mapas. Os resultados mostraram que a maior área inundada se encontra em alto perigo, ocupando 77% da área total, o que significa que as pessoas que moram nessa região estão em perigo tanto em casa, como fora delas. Ao mesmo tempo as construções estão em alta possiblidade de serem danificadas. / The increase in the occurrence of hydrological disasters related to flash floods has begun to be more important for several organs at different scales in order to reduce their magnitude and frequency as much as possible. Precisely because of it, non-structural measures are extremely important measures for preventing such disasters. One of these important measures might be the mapping of flood hazard areas. Therefore, the objective of the present work was to propose and evaluate the flash flood hazard by means of hydrogeomorphic modeling of the Forromeco river basin, Rio Grande do Sul state. Thus, the CAESAR-LISFLOOD model was used to represent the hydrological processes at basin and channel scale. At basin scale hydrographs were generated from the creation of hyetographs for different return periods (RP), considering the largest event recorded in this basin. These hydrographs were used in the channel scale simulations to generate the different flood maps in terms of depth and velocity of water flow. In order to analyze the flood hazard areas, the hazard indexes (HI) associated with the different RPs were determined from the depth and water velocity. Through the IP analysis, the final hazard mapping associated with three RPs (5, 22, and 100 years) was created. In addition, three zones were established to identify the hazard levels, considering the most critical scenario of the three maps. The results showed that the largest flood area is in high degree hazard, occupying 77% of the total area. It indicates that people are in danger both inside and outside houses. At the same time buildings are in high possibility of being damaged.
8

RIPARIAN ZONE HYDROLOGY AND HYDROGEOMORPHIC SETTING OF A GLACIATED VALLEY IN CENTRAL INDIANA

Smith, Andrew Philip January 2007 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / This study investigates the hydrological functioning of a riparian zone in central Indiana in a glaciated valley with concave topography (16% slope gradient) and ground water seeps on the valley walls. Unlike sites found in most riparian zone studies with lateral ground water inputs (Clement et al., 2003; Jordan et al., 1993; Blicher-Mathiesen and Hoffman, 1999; Hoffman et al., 2000), the site in this study is connected to thin, permeable upland sediments (≈2 m). The objectives of this research include: 1) understanding the influence of the hydrogeomorphic (HGM) setting on riparian hydrology (including determining the sources of water to the site), 2) determining how the HGM setting influences riparian zone water quality functioning, and 3) comparing the results from this site with conceptual models of riparian zone hydrologic functioning. Water chemistry and hydrometric data were collected over a 16-month period. Three factors influence riparian zone hydrological functioning at the site: 1) the nature of water contributions from upland sources, 2) riparian zone soil texture, and 3) the location of a preWisconsinan till unit. When the uplands are contributing water to the riparian zone a shallow water table is found near the hillslope and ground water flows from the hillslope to the stream. Conversely, when upland contributions cease a large water table drop occurs and ground water flows in a downvalley direction. Fine textured soils near the hillslope result in shallow water tables and small ground water fluxes. Hydrometric data, water chemistry, and statistical analyses suggest water from an intertill layer adjacent to the site is the primary source of water to the site. NO3- concentrations decreased in ground water flow in the riparian zone suggesting the site is removing nutrients. A preWisconsinan glacial till deposit at shallow depths in the riparian zone limits ground water flow to horizontal flow paths. Overall, the hydrologic functioning of the site agrees well with riparian zone conceptual models (Vidon and Hill, 2004a; Vidon and Hill, 2004b; Devito et al., 1996; Hill, 2000; Baker et al., 2001; Burt et al., 2002). The results of this study are important additions towards conceptualizing riparian zone hydrologic functioning.

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