A New Approach for Effect Evaluation of Sediment Management

Authors: Jazaul Ikhsan, Masaharu Fujita

Abstract:

Safety, river environment, and sediment utilization are the elements of the target of sediment management. As a change in an element by sediment management, may affect the other two elements, and the priority among three elements depends on stakeholders. It is necessary to develop a method to evaluate the effect of sediment management on each element and an integrated evaluation method for socio-economic effect. In this study, taking Mount Merapi basin as an investigation field, the method for an active volcanic basin was developed. An integrated evaluation method for sediment management was discussed from a socio-economic point on safety, environment, and sediment utilization and a case study of sediment management was evaluated by means of this method. To evaluate the effect of sediment management, some parameters on safety, utilization, and environment have been introduced. From a utilization point of view, job opportunity, additional income of local people, and tax income to local government were used to evaluate the effectiveness of sediment management. The risk degree of river infrastructure was used to describe the effect of sediment management on a safety aspect. To evaluate the effects of sediment management on environment, the mean diameter of grain size distribution of riverbed surface was used. On the coordinate system designating these elements, the direction of change in basin condition by sediment management can be predicted, so that the most preferable sediment management can be decided. The results indicate that the cases of sediment management tend to give the negative impacts on sediment utilization. However, these sediment managements will give positive impacts on safety and environment condition. Evaluation result from a social-economic point of view shows that the case study of sediment management reduces job opportunity and additional income for inhabitants as well as tax income for government. Therefore, it is necessary to make another policy for creating job opportunity for inhabitants to support these sediment managements.

Keywords: Merapi, sediment, management, evaluation

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1080938

References:

[1] S. Aisyah, "Economical potency of sand mining on the Gendol River", Thesis presented to Gadjah Mada University, Indonesia, 2008, unpublished
[2] Directorate General of Water Resources (DGWR), Ministry of Settlement and Regional Infrastructure, Republic of Indonesia ,"Review master plan study on Mt Merapi, supporting report (B) volcanic disaster", 2001, unpublished
[3] Directorate General of Water Resources (DGWR), Republic of Indonesia , "Review master plan study on Mt Merapi. supporting report (C) regional development and sustainable sand mining",2001, unpublished
[4] I. Kelman,, and T.A. Mather, "Living with volcanoes: the sustainable livehoods approach for volcano-related opportunities", Journal of Volcanology and Geothermal Research, Vol. 172, pp.189-198.