University of Twente Student Theses
The correlation between the precipitation and the representative high groundwater level (RHG) in urbanized Hengelo
Breel, P.M. (2023) The correlation between the precipitation and the representative high groundwater level (RHG) in urbanized Hengelo.
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| Abstract: | This thesis researches the relationship between precipitation and its impact on groundwater levels, specifically focusing on the representative high groundwater level (RHG) in Hengelo. The RHG is defined as the height that is exceeded or met on only 10% of days in a year, often leading to a rise in water levels and resulting in damage. The aim of this study is to determine this relationship, using historical data, where groundwater levels were measured through the monitoring well network in Hengelo, and precipitation was measured by the weather station installed by the Dutch weather institute. To address the main research question, the first step involves determining the amount of data necessary to accurately describe the RHG in Hengelo. Once this is established, a minimum threshold for data can be set, which should be followed when utilizing historical data. The found threshold stands at 6 years, however, the spread in earlier years are very small and thus in this area also can be used. Subsequently, the study examines the extent to which the groundwater level rises before reaching an RHG situation. The investigation focuses on understanding the increase and exploring potential relationships with the number of days preceding an RHG event, aiming to identify any predictive capabilities. It was found that there is a linear relationship between the groundwater level rise and the number of days before a RHG, with a very high R2 value. Finally, the thesis delves into the precipitation patterns preceding an RHG occurrence. Similar to the groundwater level rise analysis, the study evaluates the relationship between precipitation and the number of days leading up to an RHG event, with the intention of determining predictive capabilities. These findings are then compared to the STOWA values for extreme precipitation, which are utilized in the absence of sufficient data. The study reflects on how the observed precipitation relates to the specified STOWA values and investigates the factors contributing to potential differences, while also discussing the appropriate and feasible usage of these values. The results showed that the precipitation and number of days before a RHG also had a linear relationship also with a very high R2 value and that the STOWA value often overestimate the RHG levels. As a result of both a linear relationship between the precipitation and groundwater level rise, the relation between these is also seen to be linear. The conclusion of this research shows the predictive formula that can be used to describe an RHG situation with precipitations in certain time frames. Although this correlation has a very high accuracy it should be noted that only two variables are taken into account. It is therefore advised in following research to build a model that looks at more factors such as topography and geology. |
| Item Type: | Essay (Bachelor) |
| Faculty: | ET: Engineering Technology |
| Programme: | Civil Engineering BSc (56952) |
| Link to this item: | https://purl.utwente.nl/essays/96627 |
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