a.l. ginting

The monitoring of the Brantas watershed showed a light-polluted status. This study began by identifying the priority of regional problems using importance-performance analysis. Furthermore, a hydrological analysis was conducted to determine the pollutant area of the Brantas watershed by applying terrain analysis. When terrain analysis in hydrology is combined with participatory community information, it can provide valuable insights into water pollution and help prioritize remediation efforts. Integrating local knowledge with scientific data can improve decision-making and increase the effectiveness of water management strategies. The methodological approach employed in this study included importance-performance analysis to determine priority problems in Batu City and terrain analysis as a hydrological analysis to determine the pollutant area in the Brantas watershed. The importance-performance analysis assessment data were obtained from 197 respondents representing the occupations of the people of Batu City. The terrain analysis data were derived from the surface elevation data in the form of a digital elevation model. According to the importance-performance analysis community assessment, urban trash management was one of the crucial yet low-rated features. The terrain analysis results demonstrated that business and industrial activities were distributed in locations with high flow accumulation values, indicating that the water pollution in Batu City was triggered by the presence of business and industrial activities in the watershed accumulation areas. Along the upstream Brantas watershed, 460 business and industrial activities were discovered. Therefore, the results of importance-performance analysis and terrain analysis had a correlation. They were also closely related to the assessment results of the contaminated Brantas watershed. The following are some recommendations for the watershed's quality improvement: 1) cooperation among the Government, communities, and the private sector for addressing water pollution issues; 2) the development of environmentally friendly technologies in water treatment; and 3) education and outreach to communities about the importance of preserving water resources. As a city experiencing rapid urban development, environmental degradation constitutes a risk to be borne. Accordingly, Batu City must continue to develop good environmental management for the sake of nature conservation because the urban system is a unit formed by the social economy and ecological environment subsystem.