ABSTRAK

Waduk Sempor merupakan salah satu waduk di Jawa Tengah yang memiliki fungsi utama selain sebagai irigasi dan PLTA juga dimanfaatkan dibidang perikanan dan wisata. Pemanfaatan waduk yang belum optimal perlu disesuaikan dengan kualitas air dan status kesuburan perairan agar tidak mengganggu fungsi waduk. Penelitian bertujuan untuk mengetahui kualitas air dan status kesuburan perairan di Waduk Sempor. Penelitian dilakukan pada bulan Januari Maret 2014 dengan frekuensi pengambilan contoh air setiap 1 bulan. Metode pengumpulan data menggunakan metode survey dengan stratified random sampling pada empat stasiun yang mewakili. Penentuan status kesuburan berdasarkan perhitungan Carlson Indeks Status Trofik (Trophic State Index (TSI)) yang menggunakan perwakilan parameter fisika, kimia, dan biologi, yaitu kecerahan, total fosfor, dan klorofil-a. Hasil penelitian menunjukkan bahwa kualitas air di Waduk Sempor masih baik untuk kegiatan perikanan. Status kesuburan perairan Waduk Sempor berdasarkan TSI Carlson termasuk kategori eutrofik ringan-sedang dengan kisaran 50,71 64,91. Daerah inlet merupakan satu-satunya yang mengalami eutrofik sedang karena tingginya kandungan unsur hara yang berasal dari masukan aktivitas masyarakat sekitar.

Kata kunci: carlson trophic state index, status kesuburan perairan, waduk sempor

ABSTRACT

Sempor Reservoir is one of the reservoir in Central Java. This reservoir has primary function as irrigation and hydropower source. Beside, it also has some benefit for fisheries and tourism activities. Reservoir utilization which has not been optimum yet need some adjustments with water quality and aquatic trophic state in Sempor Reservoir. This study was aimed to determine water quality and aquatic trophic state of Sempor Reservoir. This study was conducted from January to March 2014 with monthly water sampling. Survey method to collect data with stratified random sampling was used for four represented station. Aquatic trophic state determination was based in Carlson Trophic State Index (TSI) measurement. This method used some represented parameters of physics, chemistry and biology such as water transparency, total phosphorus, and chlorophyll-a. The results showed that water quality of Sempor Reservoir was still good for fishery activities. Aquatic trophic state of Sempor Reservoir based on Carlson TSI was classified to low-medium in euthropic category ranging from 50.71 64.91. Inlet was the only area which had medium category of eutrophic due to highly nutrient content derived from anthropogenic activities nearby.

Keywords: aquatic trophic state, carlson trophic state index, sempor reservoir