<![CDATA[Abstrak Sungai adalah salah satu bentuk dari suatu ekosistem perairan terbuka yang mengalir dari hulu ke hilir yang memiliki arti penting bagi kehidupan masyarakat serta pemanfaatan yang luas. Informasi mengenai kualitas air sungai sangat penting guna memberikan gambaran mengenai pengaruh pemanfaatan air sungai tersebut oleh manusia. Penelitian ini merupakan penelitian deskriptif tentang kualitas air sungai di Kabupaten Karangasem berdasarkan parameter fisika, kimia dan biologis dari 4 sungai dari total 54 sungai di wilayah Kabupaten Karangasem. Sungai yang diteliti yaitu Tukad Nyuling, Tukad Jangga, Tukad Pati dan Tukad Kerkuk dibandingkan dengan baku mutu Pemerintah yang diatur dalam Peraturan Gubernur No 16 Tahun 2016. tentang Baku Mutu Lingkungan Hidup dan Kriteria Baku Kerusakan Lingkungan Hidup melalui metode Indeks Pencemaran. Hasilnya, Sungai Nyuling memiliki indeks pencemaran 1.23 di hulu, 1.59 di tengah dan 1.31 di hilir. Sungai Jangga memiliki indeks pencemaran 1.43 di hulu, 1.67 di tengah dan 1.88 di hilir. Sungai Pati memiliki indeks pencemaran 1.98 di hulu, 1.29 di tengah dan 3.33 di hilir. Sedangkan, Sungai Kerkuk memiliki nilai indeks pencemaran 1.39 di hulu, 1.40 di tengah dan 3.29 di hilir. Semua titik dari keempat sungai tersebut termasuk dalam kategori cemar ringan. Kata kunci: air permukaan, kualitas air, sungai Abstract A river is one kind of an open water ecosystem that flows from upstream to downstream which has an important meaning for people's lives and for its wide use. The information about river water quality is very important in order to provide an overview of the effects of river water used by human. This research is a descriptive study of river water quality in Karangasem Regency based on the physical, chemical and biological parameters of 4 rivers from a total of 54 rivers in the Karangasem Regency area. The rivers studied were Tukad Nyuling, Tukad Jangga, Tukad Pati and Tukad Kerkuk compared to the Government quality standards stipulated in Governor Regulation No. 16/2016 on Environmental Quality Standards and Environmental Damage Standard Criteria through the Pollution Index method. The result shows that the Nyuling River has a pollution index of 1.23 in the upstream, 1.59 in the middle and 1.31 in the downstream. Jangga River has a pollution index of 1.43 in the upstream, 1.67 in the middle and 1.88 in the downstream.Pati River has a pollution index of 1.98 in the upstream, 1.29 in the middle and 3.33 in the downstream. While the Kerkuk River has a pollution index of 1.39 in the upstream, 1.40 in the middle and 3.29 in the downstream. The river points of that four rivers are categorized as light pollutants Keywords: river, surface water, water quality]]>
