| dc.description.abstract | Due to abnormal climate conditions, Taiwan has experienced increasingly frequent droughts and floods in recent years, resulting in significant economic losses for crops in rural areas. This study focuses on the Xi Hai village in Dayuan District, Taoyuan City, and utilizes the Storm Water Management Model (SWMM) to simulate two types of Nature-based Solutions (NbS) facilities. The large-scale NbS approach involves raising the agricultural land′s ridge elevation as a means to detain floodwater, in accordance with the Water Resources Agency′s recommendation. On the other hand, the small-scale NbS approach utilizes green roofs. The parameters of the green roof were calibrated and validated using hourly rainfall events, and the flood potential maps were used to verify the results with design rainfall events of 5, 10, and 20-year return periods. The simulations showed a strong correlation with the validation results, with R2 values of 0.96 and 0.98 for the green roof and on-site flood detention, respectively. Utility analysis was conducted for eight scenarios, which combined different ridge elevations (10 cm, 20 cm, and 30 cm) with and without green roofs. The flood volume ratio was used as an indicator, along with four color-coded indicators, to evaluate the severity of flooding. The results indicated that green roofs had a minor detention effect during the initial rainfall, reducing flooding by approximately 4 mm. On the other hand, on-site flood detention proved effective, with ridge elevations of 10 cm, 20 cm, and 30 cm detaining floodwater by 59 mm, 130 mm, and 200 mm, respectively, for rainfall events exceeding the 10-year return period. By implementing a 30 cm ridge elevation, the flood protection standard in the study area could be improved from a 5-year to a 20-year return period. Regarding water supply, a mechanism was designed to determine the timing of supply and storage. After flood detention, the storage capacity was limited to 3% of the total irrigation water volume for paddy field irrigation. Daily rainfall data from 2009 to 2022 were analyzed, showing that the agricultural land detention mechanism collected the highest amount of water during moderate to small-scale rainfall events, while less water was collected during short-duration heavy rainfall events. Overall, the timing of rainfall relative to the water depth requirements during different stages of rice growth significantly affected water supply effectiveness in paddy fields. | en_US |