Estimating the uncertainty in simulating the impacts of small farm dams on streamflow regimes in South Africa |
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| Authors: | D A Hughes S K Mantel |
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| Institution: | 1. Institute for Water Research, Rhodes University, PO Box 94 , Grahamstown, South Africa d.hughes@ru.ac.za;3. Institute for Water Research, Rhodes University, PO Box 94 , Grahamstown, South Africa |
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| Abstract: | Abstract Small dams represent an important local-scale resource designed to increase water supply reliability in many parts of the world where hydrological variability is high. There is evidence that the number of farm dams has increased substantially over the last few decades. These developments can have a substantial impact on downstream flow volumes and patterns, water use and ecological functioning. The study reports on the application of a hydrological modelling approach to investigate the uncertainty associated with simulating the impacts of farm dams in several South African catchments. The focus of the study is on sensitivity analysis and the limitations of the data that would be typically available for water resources assessments. The uncertainty mainly arises from the methods and information that are available to estimate the dam properties and the water use from the dams. The impacts are not only related to the number and size of dams, but also the extent to which they are used for water supply as well as the nature of the climate and the natural hydrological regimes. The biggest source of uncertainty in South Africa appears to be associated with a lack of reliable information on volumes and patterns of water abstraction from the dams. Citation Hughes, D. A. & Mantel, S. K. (2010) Estimating the uncertainty in simulating the impacts of small farm dams on streamflow regimes in South Africa. Hydrol. Sci. J. 55(4), 578–592. |
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| Keywords: | farm dams hydrological impacts modelling uncertainty |
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