University of Twente Student Theses
Evaluating the effect of nature-based solutions on urban runoff using hydraulic modelling: a case study in Sekondi-Takoradi, Ghana
Borst, ir. R.H.C. (2023) Evaluating the effect of nature-based solutions on urban runoff using hydraulic modelling: a case study in Sekondi-Takoradi, Ghana.
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| Abstract: | African countries experience rapid urbanisation. In combination with climate change, this poses severe threats due to the disruption of the hydrological cycle in built-up areas. The purpose of this research report is to investigate the effects of several urban NBS on the water system in Sekondi-Takoradi (Ghana). A basic hydraulic HEC-RAS model from the company HKV lijn in water was enhanced. The most influential model parameter was found to be roughness. To enhance land cover representation, satellite images were utilized to refine the model grid significantly. Using a sensitivity analysis, NBS could be implemented. Considering different NBS effects, such as inundation depth, area, discharge, and surface runoff coefficient, is crucial for accurately simulating their impacts. Validation of the effects is only possible in terms of their magnitude and tendency due to spatial variability, lack of quantitative observations and limited hydraulic implementations. Nonetheless, the simulated NBS effects exhibited a significant reduction in the maximum discharge of hydrographs and surface runoff coefficient values. Combining NBS interventions could reduce these values by approximately 50%. Urban forest and bioretention areas demonstrated the largest absolute effects based on the given area characteristics, while check dams and stream renaturation NBS exhibited the largest unit effects. |
| Item Type: | Essay (Master) |
| Clients: | HKV lijn in water, Lelystad, Nederland |
| Faculty: | ET: Engineering Technology |
| Subject: | 43 environmental science, 56 civil engineering |
| Programme: | Civil Engineering and Management MSc (60026) |
| Link to this item: | https://purl.utwente.nl/essays/96387 |
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