Journal of System Dynamics Volume 1  Number 1  June 2020  pp. 26-33 26 WATER CAPACITY MODEL OF POLLUTION LOAD IN KALIAJI RIVER Ira Mulyawati 1 , Erliza Noor 2 1 Sahid University Jakarta, Environmental Engineering Study Program 2 Agricultural Industrial Engineering, IPB University Corresponding author: Universitas Sahid Jakarta Jurusan Teknik Lingkungan Jl. Prof.Dr. Soepomo 84, Tebet Jakarta 12870 phone: (021) 83785303 e-mail: iramulyawati@gmail.com ABSTRACT This research aims to analyze the water quality condition of Kaliaji river based on physical and chemical water river factors. The analysis was conducted on observation points in downstream by testing the water pollution parameters compared to the water quality standard of water Pollution Control for Class III. The parameters observed in this study were TSS, TDS, BOD, COD, Phosphat, Nitrat and Flourida. Determination of water quality status using pollution index method was compared to water quality standard Governmental Regulation No. 82/2001 class III. The water quality of Kaliaji river from downstream observation points generally had no decreased quality according to the parameters which fulfill the quality standard. The carrying capacity index of Kaliaji river was categorized as very good because the index value was still below 1. Prediction result of the simulation of carrying capacity index was increased along with increase in the number of industries. Further this situation will have already exceeded the ideal value in 2031. The implication of this conclusion will be the policy makers need to conduct environmental monitoring on a regular basis. The provision of green space in industrial areas needs to be directed at the flood retardant plant planting program. KEYWORDS Carrying capacity index, system dynamics, simulation, water pollution, water quality status Introduction Community development in the Kaliaji River watershed was followed by changes in the structure of life according to community needs. One of these impacts was discovered on the pattern of natural resource use around the river. The need for high water resources resulted in over-exploitation of the river. This has caused various negative impacts that will affect the sustainability of the river's function. In addition, the development of population and settlements have also led to changes in land use in the upstream area of the river. It is usually marked by changes of agricultural land to non-agricultural land, or forest areas to residential areas. The rapid development requires enormous natural resources. The economy of Kendal district is increasing quite rapidly. This is due to the existence of the Kendal Industrial Zones / KIZ ( Kawasan Industri Kendal / KIK) which provides a multiplier effect so that boosts economic growth in both Kendal and Central Java districts [1]. In addition, Kendal district is also one of the Special Economic Zones / SEZ ( Kawasan Ekonomi Khusus / KEK) based on KIZ. The Special Economic Zones (SEZ) is a policy plan to determine a region to be the center of the economy with a focus on the industrial sector. The impact of this SEZ will not only provide positive benefits to the development of the main SEZ, but will also provide a positive stimulus to increase regional economic activity around the SEZ [2]. To support this, infrastructure development [3] in Kendal district prioritizes the construction of roads and bridges to support various industrial and domestic activities. This situation has positive and negative impacts for Kendal district. One of the positive impacts is the increase of labor absorption which contributes to the income of Kendal district. On the other hand, this also has a negative impact on the environment if it is not managed properly, such as the increase of river pollution load. Contamination of the river can be identified by the levels of Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand