• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 61
  • 19
  • 4
  • 1
  • 1
  • 1
  • Tagged with
  • 86
  • 45
  • 38
  • 38
  • 38
  • 35
  • 19
  • 14
  • 14
  • 14
  • 13
  • 13
  • 13
  • 13
  • 13
  • 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.
71

Household water security and water demand in the Volta basin of Ghana /

Osei-Asare, Yaw. January 2005 (has links)
Zugl.: Bonn, University, Diss., 2004.
72

Impact of Land Use and Climate Change on Hydrological Ecosystem Services (Water Supply) in the Dryland Area of the Middle Reaches of the Yellow River

Zhang, Lulu 11 November 2015 (has links) (PDF)
Driven by many factors, the water supply services (streamflow and groundwater) of many rivers in the dryland area of China have declined significantly. This aggravates the inherent severe water shortages and results in increased severity in the water use conflicts that are threatening sustainable development in the region. Innovative strategies towards more water-efficient land management are vital for enhancing water quantity to ensure water supply security. A key step in the successful development and implementation of such measures is to understand the response of hydrological processes and related services to changes in land management and climate. To this end, it was decided to investigate these processes and responses in the upper reaches of the Jing River (Jinghe), an important meso-scale watershed in the middle reaches of the Yellow River on the Loess Plateau (NW China). It has been shown that vegetation restoration efforts (planting trees and grass) are effective in controlling soil erosion on the Loess Plateau. Shifts in land cover/use lead to modifications of soil physical properties. Yet, it remains unclear if the hydraulic properties have also been improved by vegetation restoration. A better understanding of how vegetation restoration alters soil structure and related soil hydraulic properties, such as water conductivity and soil water storage capacity, is necessary. Three adjacent sites, with comparable soil texture, soil type, and topography but contrasting land cover (Black locust forest, grassland, and cropland), were investigated in a small catchment in the upstream Jinghe watershed (near Jingchuan, Gansu province). Seasonal variations of soil hydraulic properties in topsoil and subsoil were examined. Results revealed that the type of land use had a significant impact on field-saturated, near-saturated hydraulic conductivity, and soil water characteristics. Specifically, conversion from cropland to grass or forests promotes infiltration capacity as a result of increased saturated hydraulic conductivity, air capacity, and macroporosity. Moreover, conversion from cropland to forest tends to promote the formation of mesopores that increase soil water storage capacity. Tillage in cropland temporarily created well-structured topsoil, but also compacted subsoil, as indicated by low subsoil saturated hydraulic conductivity, air capacity, and plant available water capacity. An impact of land cover conversion on unsaturated hydraulic conductivities was not identified, indicating that changes in land cover do not affect functional meso- and microporosity. Changes in soil hydraulic properties and associated hydrological processes and services due to soil conservation efforts need to be considered, should soil conservation measures be implemented in water-limited regions for sustaining adequate water supply. To differentiate between the impacts of land management and climate change on streamflow, the variation of annual streamflow, precipitation, potential evapotranspiration, and climatic water balance in a small catchment of the upstream Jinghe watershed (near Pingliang, Gansu province) was examined during the period of 1955 – 2004. During this time the relative contributions of changes in land management and climate to the reduction of streamflow were estimated. A statistically significant decreasing trend of -1.14 mm y-1 in annual streamflow was detected. Furthermore, an abrupt streamflow reduction due to afforestation and construction of terraces and check-dams was identified around 1980. Remarkably, 74% of the total reduction in mean annual streamflow can be attributed to the soil conservation measures. Among various conservation measures, streamflow could be considerably reduced by afforestation and terracing (including damland creation), due to their low contribution to water yield. In contrast, slope farmland and grassland can maintain a certain level of water supply services due to higher runoff coefficients. According to a meta-analysis of the published studies on the Loess Plateau, the impact of changes in land management on annual streamflow appears to diminish with increasing catchment size while the impact of climate change appears uniform across space. This means that there is a dependency between the catchment size and the response of hydrological processes to environmental change. At least at the local scale, it appears that well-considered land management may help to ensure the water supply services. Due to limited surface water availability, groundwater is an essential water source for supporting ecosystem and socio-economic development in the dryland region. However, the groundwater process is susceptible and vulnerable to changes in climate and landscape (i.e., land cover and form) that in turn can result in profound adverse consequences on water supply services in water-limited regions. In addition, an improved understanding of the response of groundwater related processes to natural and artificial disturbances is likely to ensure more secure and more sustainable governance and management of such regions, as well as better options for adapting to climate change. Yet, this topic has seldom been researched, especially in areas that have already experienced large-scale alteration in landscape and are located in dryland regions, such as the Loess Plateau. Therefore, an investigation of the baseflow variation along the landscape change was conducted. The average annual baseflow has significantly decreased at catchment scale during the period of 1962 – 2002 without any obvious significant change in climate. At decadal scale, the reduction accounts for approximately 9% in the 1970s, 48% in the 1980s, and 92% in the 1990s, while the baseflow index declines averaging 5%, 16% and 67%, respectively. All of the monthly baseflow levels dropped at varying rates except in January, among which July was the most severe in terms of both magnitude (-4.17) and slope (-0.09 mm y-1). In perspective of landscape change, landform change (terrace and check-dam) tends to reduce baseflow by reallocation of surface fluxes and retention for crop growth causing limited deep drainage in other areas. Land cover change (i.e., afforestation) reduced the baseflow to a larger extent by enhanced evapotranspiration and thus hampered deep drainage as suggested by the soil moisture measurement underneath. The study indicates that knowledge about baseflow formation on catchment scale needs further improvement. Integrated soil conservation and water management for optimizing landscape structure and function in order to balance soil (erosion) and water (supply) related hydrological ecosystem services is vital. The governing processes to the changes of water-supply-services-related hydrological process (e.g., streamflow) are assumed to be different across space. To this end, the factors controlling streamflow were investigated on both a small and large scale. Streamflow in small catchments was found to be mainly controlled by precipitation and land cover type. On a larger scale, evaporative demand was found to be another additional major driving force. Hydrological modeling is a frequently used tool for the assessment of impacts of land use and climate change on water balance and water fluxes. However, application of the Soil and Water Assessment Tool (SWAT) model in the upstream Jinghe watershed was unsuccessful due to difficulties in calibration. The inability of the SWAT model to take the influence of terraces on steep slopes into consideration and the method how to calculate lateral flow were the main reasons for unsatisfactory calibration, at least for the current version of SWAT used in this study. Alternatively, Budyko’s frameworks were applied to predict the annual and long-term streamflow. However, the effect of changes in land management (e.g., afforestation) on streamflow could not be assessed due to a lack of vegetation factors. Therefore, an empirical analysis tool was derived based on an existing relationship for estimation. This method was found to be the most effective in reproducing the annual and long-term streamflow. The incorporation of temporal changes in land cover and form in the approach enables the estimation of the possible impact of soil conservation measures (e.g., afforestation or terracing). The importance of adaptive land management strategies for mitigating water shortage and securing the water supply services on the Loess Plateau was highlighted. A cross-sectoral view of the multiple services offered by managed ecosystems at different spatial scales under changing environments needs to be integrated to improve adaptive land management policy. In a water limited environment, such as the Loess Plateau, multiple ecosystem services including hydrological services need to be balanced with minimum trade-offs. This can only be achieved when management is based on a holistic understanding of the interdependencies among various ecosystem services and how they might change under alternative land management.
73

Entwicklung eines Konzepts zur computergestützten Modellierung der touristischen Wassernutzung im Einzugsgebiet der oberen Donau unter Berücksichtigung des Klimawandels

Sax, Mario. January 2008 (has links)
Zugl.: Regensburg, Universiẗat, Diss., 2008.
74

Trinkwasserschutzgebiete: Empfehlungen zur Erarbeitung von Fachgutachten zur Bemessung und Ausweisung von Trinkwasserschutzgebieten für Grundwasser und Oberflächenwasser sowie von Heilquellenschutzgebieten

16 September 2021 (has links)
Die hier nachfolgend zusammengestellten Empfehlungen sollen Sachverständige, Ingenieurbüros, Wasserversorgungsunternehmen und Behörden bei der Erarbeitung der Fachgutachten bzw. der Leistungsbeschreibungen zur Auftragsvergabe für Gutachten unterstützen. Die unter Heranziehen dieser Arbeitshilfe erstellten Gutachten beschleunigen und vereinfachen das Verfahren zur Gutachtenbestätigung durch das LfULG und stellen einen landeseinheitlichen Vollzug sicher. 2. Auflage (Februar 2018, unverändert), Redaktionsschluss: 10.10.2015
75

How do water companies adapt to climate change impacts?: A literature review

Weber, Marie-Christin January 2011 (has links)
The primary objective of this work was to analyse how water companies are affected by climate change and how they try to adapt to it. Therefore, a systematic literature review was being accomplished. The work is being divided into a theoretical and a methodological part. First of all an overview of the climatic changes that are projected to occur during the next years is being given. Then, resulting impacts on the water cycle are being pointed out. Furthermore, raw water sources, water companies obtain water from are being defined as well as the treatment process. Within the methodological part the approach of a systematic literature review is being applied, which includes the selection of references as well as their evaluation. The results of the literature review are that concerning the effects of climate change on water companies, the risks water providers might face, clearly predominate possible opportunities. Especially the deterioration of the raw water quality caused by increasing temperatures, floods as well as heavy rainfalls can be seen as a serious problem. Moreover, the most often mentioned adaptation strategies are dealing with quantitative water problems such as measures to increase storage as well as treatment capacity or leakage reductions. All in all it can be stated that there is still uncertainty about how climate change is going to effect water companies, especially concerning water quality changes and the treatment process.
76

Die Pferdeschwemme – Bad, Tränke und Erfrischung nicht nur für Pferde

Schönfuß-Krause, Renate 01 July 2021 (has links)
Rückblick auf Klimaverhältnisse vor 100 Jahren, schwierige Trinkwasserversorgung der dörflichen Bevölkerung durch Brunnen mit Handschwengel, Tierversorgung zur Reinigung und Tränke in Schwemmen, natürliche in Bächen und Flüssen, künstliche als Bassins in Städten und Residenzen.
77

»Wegen des Brunnens alhir zum Stolpen«: Zur Geschichte des Stolpener Burgbrunnens bis zu seiner Verfüllung 1756

Gaitzsch, Jens 20 January 2020 (has links)
Bisher existierte über den Stolpener Burgbrunnen keine Einzeldarstellung. Der Autor entwirft einen ersten detailreichen Überblick von der Technologie zur Errichtung des strategisch bedeutenden Bauwerks, über Lebensumstände der Bergleute und Handwerker, bis zur Verschüttung des Brunnens am Beginn des Siebenjährigen Krieges.
78

Decision-Oriented Implementation of Sustainable Development: Empirical Analysis of the Public Water Supply and Waste Water Disposal in the Free State of Saxony

Günther, Edeltraud, Schuh, Heiko 29 September 2001 (has links)
In the empirical study in question, the current situation concerning the public water supply, waste water disposal, and water pollution prevention in Saxony with regard to the decision makers' knowledge of and approach towards "sustainable development" and its implementation is dealt with. Important results of the study are: · A comprehensive and uniform familiarity with the term and the contents of "sustainable development" is not present on all relevant decision-making levels. · The main area of activity of an institution influences its familiarity with the term "sustainable development." If the main area of activity of an institution lies in the field of water supply or water pollution prevention, familiarity with the term is greater. · Familiarity with the term "sustainable development" depends on the size of the respective institution with regard to the number of residents that it is responsible for supplying and the number of employees working for it. In larger institutions, familiarity with the term is more widespread. · The fact that many institutions are more committed ecologically and socially shows the fundamental possibility of incorporating these goals. Nevertheless, economic goals are given the highest practical importance, because of their limiting effects with regard to implementation of goals and decisions. · The significance of economic goals depends on the type of institution. In private-sector and public businesses they tend to have the greatest significance. For ecological and social goals, such dependence cannot be proved. · The greatest problems perceived in making "sustainable development" materialize depend on the type of institution. Whereas communities see such problems equally for all goals, economic and social goals are what cause problems for special purpose associations. In all other types of institutions such problems exist primarily for economic goals. · The organizational form influences the effects with regard to sustainable development. Possible privatization in various forms therefore should always be judged by the resulting effects on "sustainable development."
79

Die frühe Planungs- und Baugeschichte des Schlossparks Großsedlitz: Unter besonderer Betrachtung der Wasserversorgung

Olbrich, Hartmut 25 June 2022 (has links)
Der Aufsatz befasst sich mit der Wasserversorgung im Schlosspark Großsedlitz. Ein weitläufiger Terrassengarten erforderte im frühen 18. Jahrhundert reichhaltige Wasserspiele. Nach bisherigen Erkenntnissen war dies in Großsedlitz aufgrund der topografischen Lage auf dem Bergrücken kaum zu gewährleisten. Die jüngste Betrachtung zeigt allerdings, dass der frühe Garten unter Wackerbarth nicht nur auf Größe, sondern auch auf einen sehr nachhaltigen Umgang mit den Wasserressourcen ausgerichtet war. Nach Berechnungen war durch das vorhandene Reservoir nur eine Betriebsdauer der Wasserspiele von dreieinhalb bis vier Stunden möglich. / The article deals with the water supply to the Baroque gardens at Großsedlitz. In the early 18th century such extensive terraced gardens demanded the inclusion of an elaborate set of water features. It has been known for some time that the location of Großsedlitz on the crest of a hill made it very difficult to satisfy this requirement. Recent research shows, that in the early Wackerbarth days the gardens were not served by a large and sustainable water supply, and calculations show that the available water reserves were only sufficient to enable the water features to operate for three and a half to four hours at a time.
80

Eine Zeitreise in die sächsische Wasserwirtschaft

03 January 2023 (has links)
Die Chronik der Landestalsperrenverwaltung reicht von den Anfängen der sächsischen Wasserwirtschaft im 15. Jahrhundert bis zur Gegenwart. Redaktionsschluss: 19.10.2017

Page generated in 0.0791 seconds