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| | First, there are some '''general problems''' concerning knowledge on groundwater in principle. | | First, there are some '''general problems''' concerning knowledge on groundwater in principle. |
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| − | Groundwater is usually defined as the water contained in underground reservoirs, whereas surface water bodies are rivers, lakes or reservoirs. The hydrological cycle links surface and groundwater and its dynamic nature makes '''categorical definitions problematic'''. Through seepage into the ground surface water can recharge aquifers e.g. when water seeps in the river bed or flood water percolates. The other way round, groundwater can become surface water through discharge into rivers, lakes and springs. So the flow of both systems overlap and they are not fully additive <ref name="Siebert, 2010">Siebert, S., Burke, J., Faures, J.M., Frenken, K., Hoogeveen, J., Döll, P., Portmann, F.T., 2010. Groundwater use for irrigation: A global inventory. Hydrol Earth Syst Sci 14, 1863–1880. doi:10.5194/hess-14-1863-2010</ref><ref name="Vallee, 2003">Vallée, D., Margat, J., Eliasson, Å., Hoogeveen, J., Faurès, J.-M., 2003. Review of world water resources by country (No. 23), Water report. FAO, Rome</ref>. | + | Groundwater is usually defined as the water contained in underground reservoirs, whereas surface water bodies are rivers, lakes or reservoirs. The hydrological cycle links surface and groundwater and its dynamic nature makes '''categorical definitions problematic'''. Through seepage into the ground surface water can recharge aquifers e.g. when water seeps in the river bed or flood water percolates. The other way round, groundwater can become surface water through discharge into rivers, lakes and springs. So the flow of both systems overlap and they are not fully additive <ref name="Siebert, 2010">Siebert, S., Burke, J., Faures, J.M., Frenken, K., Hoogeveen, J., Döll, P., Portmann, F.T., 2010. Groundwater use for irrigation: A global inventory. Hydrol Earth Syst Sci 14, 1863–1880. doi:10.5194/hess-14-1863-2010</ref><ref name="Vallee, 2003">Vallée, D., Margat, J., Eliasson, Å., Hoogeveen, J., Faurès, J.-M., 2003. Review of world water resources by country (No. 23), Water report. FAO, Rome</ref>. |
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| − | Besides the issues of precisely defining what groundwater is, there are '''major uncertainties on the volumes and spatial distribution of both groundwater recharge and withdrawals <ref name="Gleeson, 2012">Gleeson, T., Wada, Y., Bierkens, M.F.P., van Beek, L.P.H., 2012. Water balance of global aquifers revealed by groundwater footprint. Nature 488, 197–200. doi:10.1038/nature11295</ref><ref name="Siebert, 2010" />. '''Accurate data is missing <ref name="Closas and Rapp, 2017">Closas, A., Rap, E., 2017. Solar-based groundwater pumping for irrigation: Sustainability, policies, and limitations. Energy Policy 104, 33–37. doi:10.1016/j.enpol.2017.01.035</ref> and as Morris er al. <ref name="Morris, 2003">Morris, B.L., Lawrence, A.R.L., Chilton, P.J.C., Adams, B., Calow, R.C., Klinck, B.A., 2003. Groundwater and its susceptibility to degradation: A global assessment of the problem and options for management, Eary warning and assessment report series. United Nations Environment Programme, Nairobi, Kenya</ref> argue, this chronic lack of data on groundwater conditions and trends results from an '''undervaluation of groundwater and the time lag between cause of the problem (e.g. over-abstraction) and effects (e.g. falling water levels). '''
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| | + | Besides the issues of precisely defining what groundwater is, there are '''major uncertainties on the volumes and spatial distribution of both groundwater recharge and withdrawals <ref name="Gleeson, 2012">Gleeson, T., Wada, Y., Bierkens, M.F.P., van Beek, L.P.H., 2012. Water balance of global aquifers revealed by groundwater footprint. Nature 488, 197–200. doi:10.1038/nature11295</ref><ref name="Siebert, 2010">_</ref>. '''Accurate data is missing <ref name="Closas and Rapp, 2017">Closas, A., Rap, E., 2017. Solar-based groundwater pumping for irrigation: Sustainability, policies, and limitations. Energy Policy 104, 33–37. doi:10.1016/j.enpol.2017.01.035</ref> and as Morris er al. <ref name="Morris, 2003">Morris, B.L., Lawrence, A.R.L., Chilton, P.J.C., Adams, B., Calow, R.C., Klinck, B.A., 2003. Groundwater and its susceptibility to degradation: A global assessment of the problem and options for management, Eary warning and assessment report series. United Nations Environment Programme, Nairobi, Kenya</ref> argue, this chronic lack of data on groundwater conditions and trends results from an '''undervaluation of groundwater and the time lag between cause of the problem (e.g. over-abstraction) and effects (e.g. falling water levels).''' |
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| | = Challenges of Groundwater Pumping = | | = Challenges of Groundwater Pumping = |
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| | Arguments against the utilisation of SPIS concerning groundwater over-exploitation are actually arguments related to all water supply systems that run on groundwater in an ecologically unsustainable way. There are several issues that need to be considered when installing a water supply system of any kind (domestic and/or agricultural use) in order to operate in a way that the utilised water resource is not over-exploited. For the purpose of this work, the following arguments are related to the installation of groundwater-fed irrigation systems but could be generalised for other water resources and uses. | | Arguments against the utilisation of SPIS concerning groundwater over-exploitation are actually arguments related to all water supply systems that run on groundwater in an ecologically unsustainable way. There are several issues that need to be considered when installing a water supply system of any kind (domestic and/or agricultural use) in order to operate in a way that the utilised water resource is not over-exploited. For the purpose of this work, the following arguments are related to the installation of groundwater-fed irrigation systems but could be generalised for other water resources and uses. |
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| − | The '''evaluation of the water resource to be used''' '''should be the first step''' of any water supply project which should be done even before the conception of this project starts. The question here is e.g., if the water quality is appropriate for its planned usage. Possibly due to the already above mentioned lack of data, many studies fail to acknowledge and evaluate groundwater resources over the length of a project both in terms of quality and quantity which in consequence leads to the failure of the project <ref name="Closas and Rap, 2017" /><ref name="Fedrizzi, 2009" />. | + | The '''evaluation of the water resource to be used''' '''should be the first step''' of any water supply project which should be done even before the conception of this project starts. The question here is e.g., if the water quality is appropriate for its planned usage. Possibly due to the already above mentioned lack of data, many studies fail to acknowledge and evaluate groundwater resources over the length of a project both in terms of quality and quantity which in consequence leads to the failure of the project <ref name="Closas and Rap, 2017">_</ref><ref name="Fedrizzi, 2009" />. |
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| | = References = | | = References = |
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| | <references /> | | <references /> |
As an effect of the over-exploitation of a groundwater resource not only the environment but also the economy and society within the affected region have to suffer from several effects:
The following argumentation will further show that all kinds of irrigation – and not just the solar powered one – face the same problems. The general principle is that the smaller the restrictions (lack of a mechanism for control of consumption or fee for use) of a water provision system, the greater the consumption will be [3]. For that reason all irrigation in general requires the integration of principles of sustainable water management. Especially if groundwater regulation and protection in target countries is weak or even absent [2].
Groundwater is usually defined as the water contained in underground reservoirs, whereas surface water bodies are rivers, lakes or reservoirs. The hydrological cycle links surface and groundwater and its dynamic nature makes categorical definitions problematic. Through seepage into the ground surface water can recharge aquifers e.g. when water seeps in the river bed or flood water percolates. The other way round, groundwater can become surface water through discharge into rivers, lakes and springs. So the flow of both systems overlap and they are not fully additive [4][5].
Arguments against the utilisation of SPIS concerning groundwater over-exploitation are actually arguments related to all water supply systems that run on groundwater in an ecologically unsustainable way. There are several issues that need to be considered when installing a water supply system of any kind (domestic and/or agricultural use) in order to operate in a way that the utilised water resource is not over-exploited. For the purpose of this work, the following arguments are related to the installation of groundwater-fed irrigation systems but could be generalised for other water resources and uses.
