Determination of Surface Water Quality at Bridge Construction Using Storet Method of Papua Barat Province

The construction of bridges and roads in Trans-Papua Barat, particularly in the Mameh-Windesi section, has the potential to reduce environmental quality. The purpose of this study is to determine the impact of bridge construction on the water quality of the Mawin River at the Mawin 14 Bridge. The impact on water quality was determined using the STORET method. In addition, the impact of bridge development on changes in land cover around the river and the level of river sedimentation are determined based on the surface water flow rate. The total score for the STORET method on the river at the Mawin 14 Bridge is –8. Therefore, the water quality statues at the Mawin River are categorized as fair (lightly polluted) according to the regulation ruled by the Ministry of Environment. After the construction of the bridge in 2021, the primary forest area decreased from 27 679.5 hectares (2020 data, before the construction) to 27 102 ha (2021 data, after the construction) due to land clearing for road and bridge construction. The quality of the surface water did not exceed the established regulatory quality standard value both before and after the construction of the bridge, except for the total suspended solids and turbidity caused by the remnants of the material used for bridge construction and particulate materials carried out by runoff water during the rain.