SYSTEM DYNAMICS MODELLING FOR BOD TOTAL MAXIMUM DAILY LOAD (TMDL) IN UPPER CITARUM WATERSHED

• Main Author: Reza Rahmaditio, Muhammad
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/65826
• Institution: Institut Teknologi Bandung

The Upper Citarum watershed has a vital role in maintaining the sustainability of socio- economic activities and the preservation of the Citarum watershed ecosystem. On the other hand, the Upper Citarum sub-watershed also contributes 50,7% of the BOD pollution load in the Citarum watershed. This value is equivalent to four times the value of the Total Maximum Daily Loads (TMDL). The problem of water pollution in Upper Citarum is complex because it involves interdisciplinary interactions between socio- economic and bio-physical-chemical components. Therefore, this study uses a systems approach with DPSIR and System Dynamics analysis tools. The results of the conceptual analysis show that the problem of water resources in Upper Citarum is driven by population and industry growth which is not accompanied by the development of sanitation infrastructure and strong law enforcement. These factors affect BOD pollution directly (through the pollution load) and indirectly through hydrological disturbances. Based on the conceptual analysis, a formal model is made in the form of a stock-flow diagram (SFD) consisting of seven sub-models. The results of historical simulations spanning 2014 to 2019 have been validated with Nash- Sutcliffe Efficiency (NSE) and behavior pattern tests. An advanced simulation with a span of 2014 to 2030 shows that the pollution load will fluctuate from 243,06 tons/day in 2014 to 307,24 tons/day in 2030. As a result, the waste load allocation (WLA) will fluctuate from -201,15 tons/day in 2014 to -257,71 tons/day in 2030. Even so, the BOD concentration value does not show a significant increasing trend due to the influence of river discharge pattern that is influenced by rainfall.