Influence of Wind Velocity and Salt Spray through the Mound Facilities at Nanbin Park, Hualien, Taiwan

Nanbin Park was originally formed from a low seacoast windbreak along the Hualien County coast with a pad of deposited waste soil and garbage, and was later developed through landscape planting practices into a multifunctional seashore park. In order to understand the physical benefits of the mound facilities of Nanbin Park, a multi-layer anemometer was used in this study to investigate changes in wind velocity and salinity occurring at varying distances for 2 types of mounds located in areas with different topographic characteristics. The wind velocity survey showed that owing to the mound alignment being nearly parallel to the wind direction (the included angle was only 5o), the wind reduction was not substantial because of the insignificance of the flow compression effect caused by topographic lifting. The wind velocity at the windward side of the mound decreased an average of about 32% and 38% for rounded and slender mounds, respectively. The wind velocity on the leeward side of the mound was reduced by up to 25% on average within 156 m. Results of the salinity reduction survey showed that, on average, the salinity reduction on the leeward side of the round mound reached 50%, and was 60% for the leeward side of the slender mound. Therefore, salt reduction showed better performance compared with wind velocity reduction. The salinity observed at the wind gap decreased with the increasing of distance from wind gap, but between round and slender mounds, no significant difference was detected. In summary, the wind velocity and salinity reduction functions can be achieved only if the alignment of the mound is perpendicular to the wind direction. As the park mound was constructed principally with the landscape in mind (i.e., parallel to wind direction) and without considering airflow reduction, the ability to reduce the wind velocity was degraded, which therefore, accounts for the poor growth of the planted trees.