Sediment Transport And Hydropower Development In Glacier Fed Rivers

The objective of this paper is to discuss and review experiences related to sediment transport and sediment handling during planning, construction and operation of hydropower plants in glacierized basins in Norway. Monitoring methods based on automatic sampling techniques have been developed and shown to be able to record the large variability of sediment concentration in glacier fed rivers. To evaluate the risk of turbine wear it is also important to measure grain size, shape, density, mineral composition and hardness of the sediment. The measurements of bed load and suspended load in the glacial meltwater rivers showed that the two modes of sediment transport are related as G(b)=kG(s), where k is varying between 0.67-1.0 for different glaciers. Inside the same climatic region, one representative station may be selected to obtain information about year to year variability of the whole region and to estimate mean sediment delivery to each individual intake. Subglacial intakes have successfully been connected to the subglacial drainage system to collect water at a higher level than the glacier front elevation. A comparison of sediment transport measurements from glacier fed rivers across the globe shows that the sediment yields of Norwegian glaciers are typically in the range of 10(2) to 10(3) t/km(2)yr, whereas erosion rates of 10(4) to above 10(6)t/km(2) yr are found in young mountain chains in Alaska, Central Asia, and Iceland of less consolidated bedrock.