1 MASALAH SEDIMENTASI DAN PENYELESAIANNYA MELALUI KAEDAH PENGURUSAN PERSEKITARAN: SATU KAJIAN KES DI SUNGAI CHINI, PAHANG. (Sedimentation issue and Its Solution Through Environmental Management Approach: A Case Study in Sungai Chini, Pahang) Mohd Ekhwan Toriman, Mohd Khairul Amri Kamarudin, Mushrifah Hj Idris, Muhammad Barzani Gasim & Nor Rohaizah Jamil ABSTRAK Sungai Chini merupakan satu-satunya sungai yang mengalir keluar daripada Tasik Chini ke Sungai Pahang. Semenjak beberapa tahun kebelakangan ini, Sungai Chini mengalami kemerosotan kualiti air akibat proses sedimentasi dan ketidakseimbangan pembangunan di sekitar lembangannya. Kajian dijalankan bertujuan menganggarkan penghasilan muatan sedimen tahunan (tan/km 2 /tahun), membina model hidraulik berdasarkan kapasiti sungai dan cadangan kepada kaedah pengurusan sedimen. Persampelan kajian telah dijalankan pada Julai 2008 sehingga Jun 2009 melibatkan tiga musim berbeza iaitu musim normal, hujan dan selepas hujan. Sebanyak tiga stesen persampelan telah dipilih. Keputusan kajian menunjukkan anggaran purata tahunan sedimen yang diangkut keluar dari Sungai Chini ialah 787.621 tan/km²/tahun. Hasil analisis statistik korelasi bagi hubungan antara muatan sedimen dan luahan kajian pula adalah sangat signifikan, iaitu R 2 =0.980. Hubungan luas kawasan tadahan dan muatan sedimen bagi kajian sungai terpilih juga menunjukkan hubungan yang signifikan, iaitu R 2 =0.824 membuktikan kaitan kuat diantara penghasilan sedimen dengan perubahan guna tanah yang berlaku di sekitar lembangan ini. Hasil kajian mendapati sedimentasi yang tinggi berpunca daripada aktiviti guna tanah, kewujudan baraj di hilir Sungai Chini yang memerangkap sedimen, aliran songsang dari Sungai Pahang masuk ke Sungai Chini dan faktor hakisan tebing. Kajian ini mencadangkan langkah kawalan sedimen seperti mewujudkan rizab pemuliharaan bagi sebahagian lembangan tasik, mengubahsuai sistem baraj, mengaplikasikan sistem “Monkey Cheek” yang bertujuan mengalir serta membersihkan sedimen terampai yang tinggi dan cadangan kawalan hakisan tebing sungai. Kata kunci: Sedimentasi, Pengurusan persekitaran, Pemodelan sedimen, XPSWMM, Sungai Chini ABSTRACT Sungai Chini is the only river that flows out of Lake Chini to Pahang River. Over the years, Sungai Chini experienced water quality detereoration due to sedimentation process and imbalance of development surrounding the catchment. The study was conducted in order to estimate the annual sediment load (tons/km 2 /yr), building a hydraulic model based on the capacity of the river and proposed of sediment management. Sampling survey was conducted in July 2008 until June 2009 involved three different seasons namely the normal season, wet and after raining. Three sampling stations were selected. The results showed that the estimated mean annual sediment transported out of Sungai Chini is 787,621 tons / km ² / year. Based on the statistical analysis indicates very significant correlation (R 2 = 0.980) between sediment load and discharge. The relationships between catchment size and sediment loads for selected streams within the lake basin also showed a significant correlation of R 2 = 0824 which proved sediment production is associated with changes in land use. The study found that major sediment contributions are mainly from land use activities, the existence of weir at downstream site which trapped the sediment movement, back water flowing from Sungai Pahang and river bank erosion. This study suggests sediment control measures such as gazetting JILID 3, BILANGAN 3,Januari-Disember, 14, 2008. ISBN: 1823-884x