Sökning: "Dams"

Visar resultat 6 - 10 av 144 avhandlingar innehållade ordet Dams.

1. 6. Subsurface dams in water resource management : methods for assessment and location

   Författare :Imran Ali Jamali; Bo Olofsson; Stephen Foster; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Subsurface dams; Groundwater; GIS; Regolith thickness; Groundwater; Byggvetenskap; Civil and Architectural Engineering;

   Sammanfattning : Natural groundwater storage can be improved by constructing a subsurface barrier that is a subsurface dam, in order to capture the subsurface flows and raise the groundwater levels (GWLs) in the sediment layers. Subsurface dams are preferable to surface dams because of lower evaporation, higher functionality, lower cost of construction, lessened risk for contamination and the possibility of utilizing land over the dam. LÄS MER

3. 7. Ecohydrologic impacts of dams : A global assessment

   Författare :Catherine Reidy Liermann; Christer Nilsson; Angela Arthington; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; dam; reservoir; river regulation; flow alteration; fragmentation; freshwater biodiversity; Hydrology; Hydrologi;

   Sammanfattning : This dissertation aims to improve our understanding of how dams and reservoirs impact freshwater systems worldwide. The following questions were addressed specifically: 1) what are the spatial patterns and magnitudes of flow regulation and channel fragmentation by dams globally; 2) how are dam impacts distributed biogeographically, and which are the biogeographic regions and taxa most threatened by dam impacts; and 3) how can climate change and dams be expected to interact in basins, and what management actions would mitigate adverse interactions? Results show that the majority of the world’s large river systems are fragmented and have their flow altered by dams. LÄS MER

4. 8. Stability of tailings dams : focus on water cover closure

   Författare :Annika Bjelkevik; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Soil Mechanics; Geoteknik;

   Sammanfattning : Mining activities have been ongoing for thousands of years within Sweden. As the results of previous activities are evident today, i.e. for example acid mine drainage (AMD), the focus and interest on closure and remediation of mine sites and tailings storage facilities (TSFs) has increased. LÄS MER

5. 9. Stability of tailings dams : focus on numerical modelling

   Författare :Muhammad Auchar Zardari; Anders Sellgren; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Soil Mechanics; Geoteknik;

   Sammanfattning : Upstream tailings dams may experience slope stability problems when the rate of raising is too fast. Tailings consolidate slowly due to low hydraulic conductivity. The excess pore pressures can build up due to accelerated rate of raising. LÄS MER

7. 10. Predicting surfacing internal erosion in moraine core dams

   Författare :Hans Rönnqvist; Anders Wörman; Hans Bergh; Kaare Høeg; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; internal erosion; internal stability; filters; moraine core; embankment dams; sinkholes; internal erosion assessment; Geoengineering and mining engineering; Geoteknik och gruvteknik;

   Sammanfattning : Dams that comprise broadly and widely graded glacial materials, such as moraines, have been found to be susceptible to internal erosion, perhaps more than dams of other soil types. Internal erosion washes out fine-grained particles from the filling material; the erosion occurs within the material itself or at an interface to another dam zone, depending on the mode of initiation. LÄS MER