995 resultados para Watershed management.
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Multiple indices of biotic integrity and biological condition gradient models have been developed and validated to assess ecological integrity in the Laurentian Great Lakes Region. With multiple groups such as Tribal, Federal, and State agencies as well as scientists and local watershed management or river-focused volunteer groups collecting data for bioassessment it is important that we determine the comparability of data and the effectiveness of indices applied to these data for assessment of natural systems. We evaluated the applicability of macroinvertebrate and fish community indices for assessing site integrity. Site quality (i.e., habitat condition) could be classified differently depending on which index was applied. This highlights the need to better understand the metrics driving index variation as well as reference conditions for effective communication and use of indices of biotic integrity in the Upper Midwest. We found the macroinvertebrate benthic community index for the Northern Lakes and Forests Ecoregion and a coldwater fish index of biotic integrity for the Upper Midwest were most appropriate for use in the Big Manistee River watershed based on replicate sampling, ability to track trends over time and overall performance. We evaluated three sites where improper road stream crossings (culverts) were improved by replacing them with modern full-span structures using the most appropriate fish and macroinvertebrate IBIs. We used a before-after-control-impact paired series analytical design and found mixed results, with evidence of improvement in biotic integrity based on macroinvertebrate indices at some of the sites while most sites indicated no response in index score. Culvert replacements are often developed based on the potential, or the perception, that they will restore ecological integrity. As restoration practitioners, researchers and managers, we need to be transparent in our goals and objectives and monitor for those results specifically. The results of this research serve as an important model for the broader field of ecosystem restoration and support the argument that while biotic communities can respond to actions undertaken with the goal of overall restoration, practitioners should be realistic in their expectations and claims of predicted benefit, and then effectively evaluate the true impacts of the restoration activities.
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La microcuenca del río Poás (ubicada entre el volcán Barva y el volcán Poás, hasta la confluencia con el río Grande cerca de la ciudad de Alajuela) posee un alto potencial para la formación de acuíferos de alta calidad. Por este motivo sus recursos naturales deben utilizarse adecuadamente. La mejor manera de lograr lo anterior es mediante la planificación del uso de la tierra. En esta investigación se plantea para ello el ordenamiento territorial y el manejo de cuencas. Para este propósito se realiza una zonificación mediante la cual se identifican las siguientes zonas: sin restricción de uso, uso restringido y uso muy restringido. La mayor parte de la m icrocuenca (64,6%) se encuentra en la categoría de “sin restricción de uso”. Sin embargo. se hace necesaria la intervención con rapidez en sectores ubicados en la parte alta de la microcuenca que se clasifican de “uso muy restringido”. En relación con el recurso hídrico, en la microcuenca en los últimos 14 años y de acuerdo con la metodología aplicada, se ha elevado la producción hídrica, específicamente en la escorrentía y la ganancia. En general aumentó en 1,6%.Abstract:The Poas river micro watershed (located between the Barva and Poas volcanoes reaching the confluence of the Grande river near the city of Alajuela) has high potential for developing high quality aquifers, thus, its natural resnurces should be utilized adequately. This is best done by proper land use planning. In this study guidelines are presented for land use planning and watershed management. Land use is zoned or classified for the following uses:unrestricted use, restricted use, and highly restricted use. Most of the micro watershed (64.6 percent) is classified or zoned as ‘unrestricted use.’ However, urgent intervention is needed in demand and the possibility to export it. However, it is also possible to see the negative impaci of the project, such as: indigenous territories and a pan of the Interamerican Road being flooding, population displacement and the environmental ¡mpact on the Terraba-Sierpe mangrove. This diversity and incompatibility of factors and interest make a complex scenario that potentializes diverse conflicts.
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La microcuenca del río Poás (ubicada entre el volcán Barva y el volcán Poás, hasta la confluencia con el río Grande cerca de la ciudad de Alajuela) posee un alto potencial para la formación de acuíferos de alta calidad. Por este motivo sus recursos naturales deben utilizarse adecuadamente. La mejor manera de lograr lo anterior es mediante la planificación del uso de la tierra. En esta investigación se plantea para ello el ordenamiento territorial y el manejo de cuencas. Para este propósito se realiza una zonificación mediante la cual se identifican las siguientes zonas: sin restricción de uso, uso restringido y uso muy restringido. La mayor parte de la microcuenca (64,6%) se encuentra en la categoríade “sin restricción de uso”. Sin embargo. se hace necesaria la intervención con rapidez en sectores ubicados en la parte alta de la microcuenca que se clasifican de “uso muy restringido”. En relación con el recurso hídrico, en la microcuenca en los últimos 14 años y de acuerdo con la metodología aplicada, se ha elevado la producción hídrica, específicamente en la escorrentía y la ganancia. En general aumentó en 1,6%.Abstract: The Poas river micro watershed (located between the Barva and Poas volcanoes reaching the confluence of the Grande river near the city of Alajuela) has high potential for developing high quality aquifers. thus, its natural resources should be utilized adequately. This is best done by proper land use planning. In this study guidelines are presented for land use planning and watershed management. Land use is zoned or classified for the following uses: unrestncted use, restricted use, and highly restricted use. Most of the micro watershed (64.6 percent) is classified or zoned as ‘unrestricted use.’ However, urgent intervention is needed in the upper areas of the micro watershed cla.ssified as ‘highly restricted use.’ In the Iast l4years. according Lo the methodology applied, hydrologic production has increased about 1.6 percent. specifically in runoff and soil moisture surpius.
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En el siguiente artículo se analizan las transformaciones en el uso de la tierra en la microcuenca de la quebrada Estero en San Ramón, provincia de Alajuela. La investigación se basa en el análisis de fotografías aéreas pertenecientes a los períodos que abarcan 1979, 1989 y 1999. Se estiman los cambios en el área ocupada por los diferentes tipos de usos de la tierra. Se identifica su evolución y se muestran, a partir de suficiente información cuantitativa, los porcentajes de cambios en los distintos usos y las tendencias espaciales de éstos. La investigación demuestra que actualmente existe un acelerado crecimiento urbano con un inadecuado patrón de ordenamiento territorial y una disminución progresiva de áreas dedicadas a bosque, pasto y cultivos.ABSTRACT In the following article, transformation of land use in the microcuenca Estero in San Ramón, province of Alajuela is analyzed. The investigation is based upon the analysis of aerial photographs of three different periods of 1979, 1989 and 1999. This allows for the estimation of change in each distinct Land use type and the identification of the evolution of Land use, gives enough quantitative information to calculate the percentage of change between each period, and the tendencies of incremental expansion. The investigation shows a current, incremental acceleration of urban áreas with minimal territorial planning and a progressive decrease of áreas previously occupied by forests, pastures and agriculture.
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Riparian ecology plays an important part in the filtration of sediments from upland agricultural lands. The focus of this work makes use of multispectral high spatial resolution remote sensing imagery (Quickbird by Digital Globe) and geographic information systems (GIS) to characterize significant riparian attributes in the USDA’s experimental watershed, Goodwin Creek, located in northern Mississippi. Significant riparian filter characteristics include the width of the strip, vegetation properties, soil properties, topography, and upland land use practices. The land use and vegetation classes are extracted from the remotely sensed image with a supervised maximum likelihood classification algorithm. Accuracy assessments resulted in an acceptable overall accuracy of 84 percent. In addition to sensing riparian vegetation characteristics, this work addresses the issue of concentrated flow bypassing a riparian filter. Results indicate that Quickbird multispectral remote sensing and GIS data are capable of determining riparian impact on filtering sediment. Quickbird imagery is a practical solution for land managers to monitor the effectiveness of riparian filtration in an agricultural watershed.
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Watershed services are the benefits people obtain from the flow of water through a watershed. While demand for such services is increasing in most parts of the world, supply is getting more insecure due to human impacts on ecosystems such as climate or land use change. Population and water management authorities therefore require information on the potential availability of watershed services in the future and the trade-offs involved. In this study, the Soil and Water Assessment Tool (SWAT) is used to model watershed service availability for future management and climate change scenarios in the East African Pangani Basin. In order to quantify actual “benefits”, SWAT2005 was slightly modified, calibrated and configured at the required spatial and temporal resolution so that simulated water resources and processes could be characterized based on their valuation by stakeholders and their accessibility. The calibrated model was then used to evaluate three management and three climate scenarios. The results show that by the year 2025, not primarily the physical availability of water, but access to water resources and efficiency of use represent the greatest challenges. Water to cover basic human needs is available at least 95% of time but must be made accessible to the population through investments in distribution infrastructure. Concerning the trade-off between agricultural use and hydropower production, there is virtually no potential for an increase in hydropower even if it is given priority. Agriculture will necessarily expand spatially as a result of population growth, and can even benefit from higher irrigation water availability per area unit, given improved irrigation efficiency and enforced regulation to ensure equitable distribution of available water. The decline in services from natural terrestrial ecosystems (e.g. charcoal, food), due to the expansion of agriculture, increases the vulnerability of residents who depend on such services mostly in times of drought. The expected impacts of climate change may contribute to an increase or decrease in watershed service availability, but are only marginal and much lower than management impacts up to the year 2025.
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In Nepal, changing demographic patterns are leading to changes in land use. The high level of outmigration of men in the hills of Kaski District, Western Development Region of Nepal, is affecting the household structure but also land management. Land is often abandoned, as the burden on those left behind is too high. How do these developments affect the state of the land in terms of land degradation? To find out, we studied land degradation, land abandonment caused by outmigration, and existing sustainable land management practices in a subwatershed in Kaski District. Mapping was done using the methodology of the World Overview of Conservation Approaches and Technologies (WOCAT). While previous studies expected land abandonment to exacerbate slope erosion, we demonstrate in this paper that it is in fact leading to an increase in vegetation cover due to favourable conditions for ecosystem recovery. However, negative impacts are several, including the increase of invasive species harmful to livestock and a decline in soil fertility. Traditional land management practices such as terraces and forest management exist. To date, however, these measures fail to take account of the changing population dynamics in the region, making the question of how migration and land degradation are linked worth revisiting.
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Mountaintop removal (MTR) coal mining has had a significant influence on the water sources within the Coal River watershed of West Virginia. Using an approach such as Integrated Water Resources Management (IWRM) may improve management for the long-term protection and sustainability of the Coal River watershed‰Ûªs water resources. This Capstone project analyzes current site-specific information related to water quality and quantity and the impacts of MTR in the region, reviews current management challenges, and identifies key stakeholders to be included in IWRM planning. This information provided a foundation for the development of a preliminary IWRM coordination plan for the Coal River watershed based on IWRM principles and guidelines. It is hoped that this preliminary plan will contribute to the development of a final coordinated IWRM plan.
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The Mara River in East Africa is currently experiencing poor water quality and increased fluctuations in seasonal flow. This study investigated technically effective and economically viable Best Management Practices for adoption in the Mara River Basin of Kenya that can stop further water resources degradation. A survey of 155 farmers was conducted in the upper catchment of the Kenyan side of the river basin. Farmers provided their assessment of BMPs that would best suit their farm in terms of water quality improvement, economic feasibility, and technicalsuitability. Cost data on different practices from farmers and published literature was collected. The results indicated that erosion control structures and runoff management practices were most suitable for adoption. The study estimated the total area that would be improved to restore water quality and reduce further water resources degradation. Farmers were found to incur losses from adopting new practices and would therefore require monetary support.
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The recognition of temporally stable locations with respect to soil water content is of importance for soil water management decisions, especially in sloping land of watersheds. Neutron probe soil water content (0 to 0.8 m), evaluated at 20 dates during a year in the Loess Plateau of China, in a 20 ha watershed dominated by Ust-Sandiic Entisols and Aeolian sandy soils, were used to define their temporal stability through two indices: the standard deviation of relative difference (SDRD) and the mean absolute bias error (MABE). Specific concerns were (a) the relationship of temporal stability with soil depth, (b) the effects of soil texture and land use on temporal stability, and (c) the spatial pattern of the temporal stability. Results showed that temporal stability of soil water content at 0.2 m was significantly weaker than those at the soil depths of 0.6 and 0.8 m. Soil texture can significantly (P<0.05) affect the stability of soil water content except for the existence of an insignificant difference between sandy loam and silt loam textures, while temporal stability of areas covered by bunge needlegrass land was not significantly different from those covered by korshinsk peashrub. Geostatistical analysis showed that the temporal stability was spatially variable in an organized way as inferred by the degree of spatial dependence index. With increasing soil depth, the range of both temporal stability indices showed an increasing trend, being 65.8-120.5 m for SDRD and 148.8-214.1 m for MABE, respectively. This study provides a valuable support for soil water content measurements for soil water management and hydrological applications on sloping land areas. (C) 2010 Elsevier B.V. All rights reserved.
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The knowledge of soil water storage (SWS) of soil profiles is crucial for the adoption of vegetation restoration practices. With the aim of identifying representative sites to obtain the mean SWS of a watershed, a time stability analysis of neutron probe evaluations of SWS was performed by the means of relative differences and Spearman rank correlation coefficients. At the same time, the effects of different neutron probe calibration procedures were explored on time stability analysis. mean SWS estimation. and preservation of the spatial variability of SWS. The selected watershed, with deep gullies and undulating slopes which cover an area of 20 ha, is characterized by an Ust-Sandiic Entisol and an Aeolian sandy soil. The dominant vegetation species are bunge needlegrass (Stipa bungeana Trim) and korshinsk peashrub (Carugano Korshinskii kom.). From June 11, 2007 to July 23,2008, SWS of the top1 m soil layer was evaluated for 20 dates, based on neutron probe data of 12 sampling sites. Three calibration procedures were employed: type 1, most complete, with each site having its own linear calibration equation (TrE); type II. with TrE equations extended over the whole field: and type III, with one single linear calibration curve for the whole field (UnE) and also correcting its intercept based on site specific relative difference analysis (RdE) and on linear fitting of data (RcE), both maintaining the same slope. A strong time stability of SWS estimated by TrE equations was identified. Soil particle size and soil organic matter content were recognized as the influencing factors for spatial variability of SWS. Land use influenced neither the spatial variability nor the time stability of SWS. Time stability analysis identified one site to represent the mean SWS of the whole watershed with mean absolute percentage errors of less than 10%, therefore. this site can be used as a predictor for the mean SWS of the watershed. Some equations of type II were found to be unsatisfactory to yield reliable mean SWS values or in preserving the associated soil spatial variability. Hence, it is recommended to be cautious in extending calibration equations to other sites since they might not consider the field variability. For the equations with corrected intercept (type III), which consider the spatial variability of calibration in a different way in relation to TrE, it was found that they can yield satisfactory means and standard deviation of SWS, except for the RdE equations, which largely leveled off the SWS values in the watershed. Correlation analysis showed that the neutron probe calibration was linked to soil bulk density and to organic matter content. Therefore, spatial variability of soil properties should be taken into account during the process of neutron probe calibration. This study provides useful information on the mean SWS observation with a time stable site and on distinct neutron probe calibration procedures, and it should be extended to soil water management studies with neutron probes, e.g., the process of vegetation restoration in wider area and soil types of the Loess Plateau in China. (C) 2009 Elsevier B.V. All rights reserved.
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Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies