Surface Runoff from an Urban Area Promotes Hydrological Connectivity and Soil Loss in a Tropical Riparian Forest

Studies on the effectiveness of riparian forests in decreasing runoff and sediment in rural areas abound in the literature. However, how effective are riparian forests in performing such functions in an urban context? Given the prediction of an increase in population growth and urbanization, it is necessary to understand the effectiveness of these ecosystems in the urban context. In this paper, we examine the effectiveness of riparian forests in retaining surface runoff and sediment. We compared surface runoff frequency and soil movement among plots with surface runoff presence (WUSR) and absence (WOUSR). WUSR had a higher runoff frequency and greater soil movement compared to WOUSR. There was a positive relationship between rainfall volumes, runoff frequency, and soil movement in both WUSR and WOUSR. However, this relationship was more significant in WUSR. Rain events greater than 25.1 mm generated surface runoff that crossed the riparian forest, indicating that this ecosystem did not interrupt hydrological connectivity under such conditions. The results revealed the limited effectiveness of riparian forests in promoting the infiltration of surface runoff from impervious urban areas. Additional watershed management measures must be taken to conserve these ecosystems and water resources.