Development river management model based on ecohydraulic concept. (case Study at Lawo River of Soppeng Regency, Province of South Sulawesi)

Abstract

managing river environment. The ecological issues in this research is the vegetation grown in the river bank as flood retention, while hydraulical aspect refers to the flows of water in river bank to reduce flooding. The aims of the research were : 1) to develop a river management model based on ecohydraulic concept; to characterize the optimal width of riverbank and appropriate vegetation; 2) to develop government policies to support river management based on ecohydraulic concept, and 3) to study the implementation of the model at Lawo River of Soppeng Regency. The output of river management model can be used as the recommendation of demarcation line of the river, while the policies can be used as a basis of policies of local government. As the implementation of the models, the data were collected from the Lawo River South Sulawesi between May 2010 to December 2010. River management model is based on ecohydraulic concept, it uses six variables were rainfall intensity, channel roughness, water level (without management), land use score, flooding and the height of inundation. The policies model were developed in four steps : community participation level, study of social economic condition of community, study of effect social economic condition to the participation and study of policies of river management. The policies model can be used to determine scenarios and strategic activities which can effect the implementation of river management model. The optimal width of riverbanks at Lawo River varies between 100 m and 150 m with vegetation diameter between 10 cm and 20 cm. This implies to the flooding water level less then 2.5 m and velocity of flow can be reduced to 76%. The best scenario found in this research suggests the improvement of infrastructure in order to increase the value of land. The best government program is increasing the population of vegetation in the river bank.