• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 26
  • 7
  • 5
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 48
  • 48
  • 26
  • 21
  • 20
  • 20
  • 20
  • 14
  • 12
  • 10
  • 10
  • 10
  • 9
  • 9
  • 8
  • 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.
11

Studie a posouzení protierozních opatření v katastrálním území Záborná

BŮŽKOVÁ, Jana January 2019 (has links)
The diploma thesis deals with an assessment of cadastral territory, which is going through a complex land consolidation. For these purposes, the cadastral area Záborná, that is located in the Vysočina Region, was selected. The main objective of this work is to compare the current state of the territory, in terms of erosion, with the area where the erosion control measures were proposed. Erosion will be calculated using by Wischmeier-Smith's universal soil loss equation. In this cadastral area, it will be necessary to assess in terms of climate, geology and hydrology.
12

IMPLEMENTATION COSTS OF KENTUCKY'S EROSION CONTROL BEST MANAGEMENT PRACTICES FOR SKID TRAILS

Shouse, Bennett Scott 01 January 2001 (has links)
This paper describes a study designed to determine average labor and machine times required to implement erosion control and revegetation best management practices (BMPs) for skid trails in Kentucky. Labor and machine activities were recorded for 14,400 feet of skid trail on 10 nonindustrial private logging sites. Water bar construction and reshaping activities such as filling ruts and berm removal were filmed continuously with a video camera and then analyzed using time-motion study techniques. Labor activities for revegetation such as seeding and application of fertilizer were also timed. The average total machine time for retirement activities per 1000 feet was 51 minutes for sites using dozers and 52 minutes for sites using skidders. The average water bar construction time using a bulldozer was 1.5 minutes (n=112) while the average construction time using a skidder was 3.5 minutes (n = 21). The average amount of labor time required to seed 1000 feet of skid trail was 23 minutes (n = 5). Three methods of water bar construction were observed and analyzed to identify differences among them. While there were significant differences among the three methods, the data suggest that skid trail percent slope may have the greatest effect on water bar construction times.
13

Determining Soil Erosion with Varying Corn Stover Cover Factors

Koeninger, Nicole K 01 January 2015 (has links)
Since the Dust Bowl, conservation agriculture has become a common practice globally. Because of the rising interest in the use of corn biomass as a feedstock for biofuel production, the effects of corn stover removal on soil erosion were explored. It was hypothesized that selective harvesting strategies would impact soil erosion differently across a variety of slopes. Soil erosion boxes were constructed, and a rainfall simulator with an intensity of 30 mm hr-1 for 46 min was used to create runoff from slopes of 1, 5, and 10% and three cover factor treatments (no removal and two simulated corn stover removal strategies). Due to research time constraints, simulated corn roots were constructed to emulate actual corn roots in all experiments. The corn stover harvest strategies change the distribution of cobs, husks, leaves, and stalks in field; these changes were represented as the cover factor treatments. Changing the type of plant material on the soil surface impacted the predicted soil erosion from the Revised Universal Soil Loss Equation (RUSLE). Based on the results from this study, the effect of corn stover cover percentages had a significant impact on the predicted and observed soil loss.
14

Uplatnění meziplodin jako stabilizujícího prvku v protierozní ochraně v oblasti podhůří Šumavy / The application of the intercrop as a stabilizing element in the erosion control in the area of the foothills of Sumava.

ŠLAPÁKOVÁ, Veronika January 2015 (has links)
The aim of this thesis is to evaluate the possibility of applying the intercrop in the erosion control crop rotation and their effect on the system of the sustainable agriculture and assess the suitability of utalizition of the intercrop as an element of the erosion control for the environmentally friendly farming on the arable ground. Erosion phenomena will be evaluated in the selected location and in the cadastral Borovany. The outcome will be the evaluation of the washes of the conventional crop rotation and of the process which uses the intercrop using the USLE method.
15

A erosão periurbana em Rancharia-SP: a análise espaço-temporal e as propostas de recuperação da boçoroca do Córrego do Grito / The periurban erosion in Rancharia: the space-temporal analysis and recovery proposals of gully Grito stream

Francisco, Alyson Bueno [UNESP] 31 July 2017 (has links)
Submitted by Alyson Bueno Francisco null (33432427808) on 2017-08-11T12:14:51Z No. of bitstreams: 1 Tese de doutorado A B Francisco.pdf: 10647120 bytes, checksum: b285cedbc09019fbb08981d29c331f11 (MD5) / Rejected by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br), reason: Solicitado pelo autor. on 2017-08-16T17:08:43Z (GMT) / Submitted by Alyson Bueno Francisco null (33432427808) on 2017-08-16T17:31:14Z No. of bitstreams: 1 Tese A B Francisco.pdf: 10686416 bytes, checksum: c31c9ad77d0f43445d40956e5016092b (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-08-23T14:29:47Z (GMT) No. of bitstreams: 1 francisco_ab_dr_prud.pdf: 10686416 bytes, checksum: c31c9ad77d0f43445d40956e5016092b (MD5) / Made available in DSpace on 2017-08-23T14:29:47Z (GMT). No. of bitstreams: 1 francisco_ab_dr_prud.pdf: 10686416 bytes, checksum: c31c9ad77d0f43445d40956e5016092b (MD5) Previous issue date: 2017-07-31 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Esta tese apresenta como objetivo realizar uma análise espacial e temporal da boçoroca do Córrego do Grito, localizada na área do perímetro urbano da cidade de Rancharia-SP e apresentar as propostas de controle desta erosão periurbana. Esta boçoroca apresenta indícios de desenvolvimento que remontam a década de 1960, episódios recentes de danos gerados à infraestrutura urbana e presença de processos erosivos ativos nas margens. Para apresentar uma análise geográfica deste caso de processo erosivo são apresentados aspectos do histórico de uso da terra no município de Rancharia e aspectos físico-geográficos e as mudanças de uso da terra na microbacia do Córrego do Grito e em escala de detalhe as informações cartográficas sobre a boçoroca. Diante deste caso de processo erosivo que se perpetua por cinco décadas, nesta tese são apresentadas informações geográficas detalhadas da boçoroca a partir de dados coletados em levantamentos topográficos com equipamentos geodésicos. Durante vinte e quatro meses foi realizado um monitoramento topográfico de parcelas da boçoroca, onde foi constatada uma erosão de rebordo superior a 1,5 m em quatro pontos e uma média de 0,85 m, em toda a parcela monitorada ocorreu uma perda de 305,9 metros quadrados de área. Em relação às propostas de controle do processo erosivo, foram implantados barramentos com fibra vegetal (Bambusa bambos L.) numa parcela experimental com o monitoramento do nível de solo por meio de pinos de erosão, e a partir de uma análise comparativa sendo constatada uma média de movimentação de solo superior na parcela experimental sem o uso de barramentos. A partir das mensurações dos níveis de movimentação do solo e de dados de densidade do solo foram apresentadas estimativas de perda de solo nas parcelas experimentais. Na área da parcela experimental com barramentos foram plantadas espécies vegetais nativas com o intuito de contribuir na recuperação da área degradada. Neste sentido, a partir de informações geográficas detalhadas sobre a área degradada pela boçoroca do Córrego do Grito, a tese visa contribuir no planejamento de futuras medidas para uma recuperação efetiva desta área em Rancharia. A partir da proposta empírica apresentada nesta tese, são apresentadas formas de se repensar sobre a filosofia de Francis Bacon e suas contribuições na Geografia. / This thesis aims to perform a spatial and temporal analysis of the gully of Grito Stream, located in the urban perimeter of the city of Rancharia, and present the proposals to control this peri-urban erosion. This gully presents evidence of development dating back to the 1960s, recent episodes of damage to urban infrastructure and the presence of active erosive processes at the banks. To present a geographic analysis of this case of erosion process are presented aspects of land use history in the municipality of Rancharia and physical-geographic aspects and land use changes in the watershed of the Grito Stream and in detail scale the cartographical information on the gully. In view of this case of erosive process that is perpetuated for five decades, in this thesis detailed geographic information of the gully is presented from data collected in topographic surveys with geodesic equipment. For twenty-four months, a topographic monitoring of borehole plots was carried out, where a ridge erosion greater than 1.5 m was observed in four points and an average of 0.85 m, in all the monitored plot there was a loss of 305.9 square meters of area. In relation to the erosion process control proposals, buses with plant fiber (Bambusa bambos L.) were implanted in an experimental plot with soil level monitoring by means of erosion pins, and from a comparative analysis there is a greater upper soil movement in the experimental plot without the use of buses. Based on the measurements of soil movement levels and soil density data, estimates of soil loss were presented in the experimental plots. In the area of the experimental plot with barriers native plant species were planted with the intention of contributing to the recovery of the degraded area. In this sense, based on detailed geographic information on the area degraded by the gully of the Grito Stream, the thesis aims to contribute in the planning of future measures for an effective recovery of this area in Rancharia. From the empirical proposal presented in this thesis are presented ways to rethink the philosophy of Bacon and his contributions on Geography. / FAPESP: 2013/05664-4
16

Vyhodnocení erozní ohroženosti ve vybraném projektu komplexní pozemkové úpravy. / Evaluation of a soil erosion in a project of KPU

HAŇKOVÁ, Kateřina January 2008 (has links)
In the Czech Republic, about 50 per cent of agricultural land is affected by water erosion that adversely influences soil productivity and the environment. That´s why the goal of this work was an evaluation of soil erosion danger in an arbitrary area. And secondly, if high erosion danger found, there was a task to make a proposal of suitable erosion control measures. The chosen area is called Hosín, located northly close to České Budějovice. There were fifteen profiles found in the area which are most likely to be in a danger of increased water erosion. These fifteen profiles were proved by two different methods of soil erosion evaluation. The RUSLE method - revised universal soil loss equation, and SMODERP {--} a simulation model of overland flow and erosion processes. SMODERP method showed all the proved profiles beeing not in a high erosion danger. Which means no erosion control measures are needed. The result gained by the RUSLE method was: by more than one third of examined slopes the estimate average annual soil loss raises above the limits. In this case the erosion control measures are necessary. Four different possibilities were proposed, the final one was combination of two erosion control measures {--} mulching and using a vegetative stabilization while the soil is uncovered. This kind of control measure was found to be the best one because of its low financial costs and easy implementation. On the other hand this control measure doesn´t restrict the farmer´s choise of the crops kind to grow. An objective comparison of the different results gained of the two methods wasn´t possible because of different enter data.
17

Řešení protierozní ochrany na rozhraní povodí v různých projektech pozemkových úprav / Erosion control solutions on the boundary river basins in different projects land adjustment

HAKL, Filip January 2011 (has links)
Erosion is a natural life process. But man its activities and accelerating erosion phenomena that threatens one of the most valuable components of the environment - soil, which is difficult to make up for hundreds and thousands of years. The Czech Republic is threatened by water erosion over the third and wind erosion, about one-tenth of the local soil. When we add to the volume of soil that are occupied by new buildings, it turns out that the soil relatively quickly disappearing. This work deals with the calculation and solution of water erosion in the village Protivec, using the universal equation USLE, the modified equation MUSLE and CN curves method. The resulting values are compared with the values of a land adjustment project, landscaping and erosion control measures are proposed.
18

The Effects of Erosion-control Structures and Gully Erosion on Groundwater Dynamics Along the Kromrivier, Eastern Cape, South Africa

de Haan, Vincent January 2016 (has links)
The Palmiet wetlands located along the Kromrivier in the Eastern Cape province of South Africa have experienced severe degradation through gully erosion during the past decennia which has been threatening the water quality and water security of large towns in the Nelson Mandela Metropolitan hub. Water scarcity is a growing problem in this region as a result of land degradation and growing erratic rainfall patterns. The main causes of wetland degradation are argued to be land use and land cover change. With the aim of protecting the wetlands along the Kromrivier a total of eleven large gabion and concrete erosion-control structures were constructed between the 2002 and 2013 by the government initiate Working for Wetlands. This study aims to map the groundwater table in order to derive how erosion-control structures and gully erosion affect groundwater dynamics along the Kromrivier. This was achieved by several steps. Firstly, water table elevations were measured along several transects by installing a series of piezometers which allowed do investigate how the structures affected the water table. This also allowed for a comparison in groundwater dynamics between eroded and non-eroded reaches so that effects of gully erosion could be identified and potential causes discussed. Secondly, the analysis of aerial images allowed for the development of the aerial extent of the Palmiet wetland and gullies to be seen over a ten year period and longitudinal profiles provided specific characteristics of the wetland and gullies. Lastly, particle size distribution and organic matter content were analyzed as groundwater flow and gully erosion can vary greatly depending on soil characteristics. The hydraulic gradient was highest in proximity to the structures as a result of the created potential induced by the drop in surface water elevation. The radius of influence to where the structures were affected the water table was estimated to be approximately 40 m from the channel. Further away from the channel, the gradual slope of the water table indicated that the porous gabion side walls of the structures did not affect the water table. The groundwater flow is determined by Darcy's Law and the relatively flat water table along the non-eroded reaches of site A displayed local drainage points, thereby indicating variations in the local flow direction. In May the water table along the non-eroded reaches was sloping away from the channel resulting in an area of groundwater discharge with respect to the channel. Not only was the water table generally higher during August, the regime had also changed, indicating a potentially large seasonal variability. Along the eroded reaches downstream from the structures the water table was above the gully bottom during both months resulting in an area of groundwater recharge with respect to the channel. Also here the regime had changed from an approximately constant hydraulic gradient sloping towards the channel during May to a water table with a divide in flow direction. Since their implementation in 2003, the structures have been effective with respect to preventing the headcut in the main channel from migrating further upstream. However, the gullies downstream of the structures had significantly increased in width between 2003 and 2013 and the Palmiet wetland had also slightly decreased in size during the same period. However, it was unclear whether this decrease was part of the longer term ongoing trend or part of a shorter term cycle and/or seasonal fluctuation. For a gully bank to collapse, the shear strength of the slip surface needs to be exceeded and this often occurs because of an increase in pore water pressurewhich causes a reduction in shear strength. A large gully height of up to 4 m with nearly vertical slopes, a water table above the gully bottom and an increase in moisture content between May and August indicated that it is not unlikely that a high pore water pressure. played a significant role in the slumping of the gully walls. The two structures together were responsible for an surface water elevation difference of 7.76 m. Through damming this resulted in an elevated water table in the upstream Palmiet wetland, thereby increasing the saturation and promoting diffuse flow across the wetland. However, the structures also trap most of the sediment in upstream direction which appears to have resulted in the de-stabilization of the downstream streambed at site A as these eroded reaches now receive a significantly lower sediment load. By increasing the retention volume in the wetland, the structures also facilitated in ensuring flood retention as the wetland could now hold more water during high flows, thereby cutting off the peak flow. As gully erosion is known to occur during periods of high flow it is not unreasonable to argue that slumping of the gully walls would have been more severe without the structures in place. In this sense the structures increase the water quality and decrease the flux of sediment where the latter leads to a decrease in the sedimentation rate of the downstream Churchill Dam. Consequently, this contributes to securing the fresh water supply to towns in the Nelson Mandela Metropolitan hub. The discovery of Palmiet rests up to 2.6 m below the surface indicated that cycles of gully erosion followed by the re-establishment of Palmiet have been occurring in this valley for thousands of years. However, it seemed that land use and land cover changes had accelerated gully erosion during the past decades resulting in a loss of Palmiet wetland at a rate which was beyond 'natural'. Even though the structures could be seen as disruptions of long term natural cycles, they are in favor of the well-being of mankind as they protect the wetlands to a certain extent. The main results of this study provided a basic understanding of how the water table behaves in response to the structures and along eroded and non-eroded reaches of the Kromrivier. Furthermore, this study discussed the larger scale affects of the structures and showed how the gullies and the aerial extent of the Palmiet wetland have evolved since the implementation of the structures in 2003. In order to manage these Palmiet wetlands more effectively in the future, it is highly important that groundwater dynamics, gully erosion and the size and health of the wetland are annually monitored in order to get a more accurate idea of how effective these structures are. This new obtained knowledge could also assist in managing other peat lands in South Africa more effectively.
19

Návrh integrované ochrany území před povodněmi z přívalových srážek v povodí Stříbrného potoka / Proposal of integrated protection of the territory from floods from torrential rainfall in the Stříbrný brook basin

Kolajová, Lucie January 2020 (has links)
The subject of this master thesis is an integrated flood protection proposal in cadastral territory Jerlochovice and Fulnek. Area of interest is highly affected by soil loss caused by torrential rainfalls. Implemented measures are based on analysis results. The softwares used for analysis were ArcGIS, DesQ-MaxQ and USLE method for soil loss calculation. The final step was control erosion analysis which verified the implemented measures. The final analysis clearly shows the obvious reduction of erosion affection in the area.
20

Ohio Environmental Protection Agency: An Internship Report

Guckian, Jacqueline 27 November 2007 (has links)
No description available.

Page generated in 0.0613 seconds