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Droogte preventiemaatregelen vergelijken : een vergelijkende casestudie van Zoetwatervoorziening Oost-Nederland maatregelen voor de Soestwetering bovenloop.

White, R.D. (2019) Droogte preventiemaatregelen vergelijken : een vergelijkende casestudie van Zoetwatervoorziening Oost-Nederland maatregelen voor de Soestwetering bovenloop.

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Abstract:Climate change is causing an increase in drought issues in the region Oost-Nederland. As a response, the project Zoetwatervoorziening Oost-Nederland (ZON) has been developed. In this project ZON-measures have been determined to prevent or reduce the adverse effects of drought. Within implementation projects opportunities for implementation of these measures is assessed. One of these projects is the project Soestwetering bovenloop en Breebroeksleiding by Waterschap Drents Overijsselse Delta (WDOD). However, WDOD encounters the problem of comparing ZON-measures. No standard procedure has yet been developed for this process. As a result, it is currently not possible to determine what the most effective measures are for the research area within the Soestwetering bovenloop. This report presents a method to compare different Zoetwatervoorziening Oost-Nederland measures with each other based on the effectiveness for the prevention of drought issues and apply this method in a case study for the Soestwetering bovenloop. The case study compares three different ZON-measures. The first ZON-measure (ZM1) consists of dividing water-level areas by constructing weirs combined with raising the target water levels in the water-level areas. The other two measures expand ZM1 by additionally applying compensation measures in the low-lying areas, namely the construction of groundwater drainage systems (ZM2) and raising of the surface level (ZM3). The method that is presented in this report consists of two sections. In the first section, the indicators for the effectiveness for the prevention of drought issues are determined. This is done based on the expectations and requirements of the most important actors in the Soestwetering bovenloop. These actors are Waterboard Drents Overijsselse Delta, IJsellandschap and Land en Tuinbouw Organisatie (LTO; in English: Agriculture and Horticulture Organisation). This results in indicators that are divided into the following categories: costs, benefits, effects and side effects. In this case study the following indicators are included in these categories: fixed and running costs (costs), crop yield (benefits), drought stress and oxygen stress (effects), and reduction of peak discharges, reduction of water supplement, reduction of nitrogen and phosphate leaching, improvement of the water quality and improvement of the nature score (side effects). In the second section the effectiveness of the three ZON-measures is determined. The dimensions of the measures are first determined in an expert consultation. The costs and direct effects of the measures follow from the dimensions. The costs are determined using key figures that result from existing cost estimates. The direct effects of the measures relate to the groundwater conditions (GHG and GLG). These are determined with the groundwater model MIPWA. The results for the direct effects are used to determine the indirect effects and benefits with the help of the Waterwijzer Landbouw (WWL) tool. Lastly, the side effects of the measures are expressed qualitatively, and each is provided with an explanation. The scores for the side effects are determined in an expert consultation. The analysis for the case study shows that the costs for all ZON-measures are relatively high in relation to the benefits and effects. From this, it can be concluded that the effectiveness for the prevention of drought issues in the Soestwetering bovenloop is relatively low for the three ZON-measures. However, the direct effects of the measures show that the measures do have a significant effect on the groundwater conditions. Based on this, it can be concluded that the ZON-measures may be effective for the prevention of the drought issues, but the results that follow from the WWL do not show this effectiveness. Moreover, it should be noted that the benefits, effects and side effects are fairly consistent for all measures (especially for ZM2 and ZM3). Because of this, it is not possible to establish a definitive ranking for the three ZON-measures based on the effectiveness of these measures. Based on the results for the case study, it can be concluded that the method used in this study is unsuitable for comparing the analysed ZON-measures within the Soestwetering bovenloop. This is mainly due to the use of the Waterwijzer Landbouw in this method. The discussion shows that the WWL is not suitable to be used in areas, including the research area for the case study, where controlled water level management is applied. Additionally, the WWL is not accurate enough to properly analyse the differences between the ZON-measures in the case study. Considering the significant direct effect of the measures on the groundwater conditions, it is recommended to increase the water levels in the water-level areas in the research area (ZM1). Based on this research, it cannot be determined whether it is also necessary to apply compensation measures in the low-lying areas of the water-level areas (ZM2 and ZM3). It is also recommended that the current version of the WWL is not used within the management area of WDOD, because within this area controlled water level management is applied in the majority of the water-level areas and the WWL is currently not suitable to be used under these circumstances.
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering BSc (56952)
Link to this item:https://purl.utwente.nl/essays/80194
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