Bulletin of the Geological Society of Malaysia, Volume 55, November 2009, pp. 55-59

Short-term sediment yields from small catchment of Sungai Anak Bangi Selangor

Mohd Ekhwan Toriman¹*, Mazlin Bin Mokhtar², Othman Karim³, M. Barzani Gasim⁴ & Raihan Taha³

¹Fakulti Sains Sosial & Kemanusiaan;

²Institut Alam Sekitar & Pembangunan (LESTARI);

³Fakulti Kejuruteraan; ⁴Fakulti Sains & Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM BANGI, Selangor, Malaysia

*E-mail address: ikhwan@ukm.my

Abstract— Suspended sediment yield from the forested catchment of Sg Anak Bangi was investigated from September to November 2006. Three main data were measured namely the rainfall depth, the suspended sediment concentration and river discharge (Q) at two sampling stations along the river. Twelve rainfall events were recorded with highest rainfall of 36.7 mm was received on October 02 2006, while the lowest rainfall depth was recorded on October 08 2006 (1.9 mm). Almost all the rainfall events occurred within the short and moderate durations (< 7 hours). Meanwhile, the daily Q sampled ranges from 172.8 m³/day to 6220.8 m³/day or 172,800 to 6220,800 L/day. The average suspended sediment concentration values recorded for both stations are considered low, with 19.47 mg/l and 25.23 mg/l recorded at Station 1 and Station 2, respectively. When converted to average suspended sediment yield per day, Sg Anak Bangi recorded 75.04 kg/day at Station 1 while at Station 2 was 103.26 kg/day. When converted into per square km, the gross value of suspended sediment yield leaved from Sg Anak Bangi is estimated to be about 27.91 kg/km²/day or 10,186 kg/km²/yr^-1.

Keywords: Suspended sediment concentration, rainfall, river discharge, concentration, Sg Anak Bangi

Abstrak— Penghasilan muatan sedimen terampai di kawasan tadahan Sg Anak Bangi telah diselidiki bagi tempoh September hingga November 2006. Tiga data utama telah diukur, iaitu kedalaman hujan, konsentrasi sedimen terampai dan luahan sungai (Q) di dua stesen pencerapan di sepanjang sungai. 12 kejadian hujan telah direkodkan dengan hujan tertinggi ialah 36.7 mm yang diterima pada 2 Oktober, 2006 sementara hujan terendah dicatatkan pada 08 Oktober 2006 (1.9 mm). Kebanyakan kejadian hujan berlaku dalam tempoh singkat dan sederhana (< 7 jam). Sementara itu, nilai Q harian adalah diantara 172.8 ke 6220.8 m³/hari atau 172,800 dan 6220,800 L/hari. Purata nilai konsentrasi sedimen terampai yang direkodkan bagi kedua-dua stesen adalah rendah, iaitu masing-masing 19.47 mg/l dan 25.23 mg/l yang direkodkan bagi Stesen 1 dan 2. Nilai ini bila ditukarkan kepada penghasilan muatan sedimen terampai bagi Sg Anak Bangi ialah 75.04 kg/hari di Stesen 1 manakala di Stesen 2 ialah 103.26 kg/hari. Angka ini jika ditakrifkan kepada setiap kilometer persegi menunjukkan anggaran sedimen yang diangkut keluar melalui Sg Anak Bangi ialah 27.91 kg/ km²/hari atau 10, 186 kg/ km²/tahun.

Kata kunci: Penghasilan muatan sedimen terampai, hujan, luahan sungai, konsentrasi, Sg Anak Bangi

https://doi.org/10.7186/bgsm55200909