Bulletin of the Geological Society of Malaysia, Volume 51, June 2005, pp. 187 – 191

The Relationship between Morphometry and Hydrologic Properties of the Semenyih River Basin and Their Significance 

(Perkaitan Diantara Ciri Morfometri dan Sifat Hidrologi Lembangan Sungai Semenyih dan Kepentingannya)

Muhammad Barzani Gasim¹, Abd. Rahim Samsudin¹, Wan Nor Azmin Sulaiman² and Mohd. Ismail Yaziz²

¹School of Environment and Natural Resource Sciences, Faculty Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.

Phone: 603-89213213, e-mail: dr.zani@pkrisc.cc.ukm.my

²Department of Environmental Sciences, Faculty of Environmental Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.

Abstract: A study was carried out to evaluate the characteristics of surface landforms of the Semenyih River Basin. The study was based on quantitative measurements of land surface geometry such as topography, basin area, basin shape, slope angles, drainage patterns, stream lengths and stream frequency of the 36 sub catchments in the basin. Field observations showed that the study area generally consists of weathered rock, with a high permeability soil cover and dominated by sand particles. The bedrock in the Semenyih Basin is characterized by a large number of discontinuities due to the development of structures such as folds, joints and faults due to past tectonic events. The morphometry of drainage density and bifurcation ratio shows that the Semenyih Basin can be characterized as a homogenous rock, with high permeability and sparse vegetation and is dominated by high rates of infiltration and sub-surface flow. From the available hydrological data, it was interpreted that only 35% to 45% of the total rainfall was transformed into surface runoff and the rest (55% to 65%) as seepage into the ground after evaporation and interception. Five main tributaries, namely Sg. Lalang, Sg. Batangsi, Sg. Tekala, Sg. Rinching and Sg. Saringgit were identified as significantly contributing to the Semenyih River.

Abstrak: Satu kajian telah dijalankan untuk menilai ciri-ciri bentuk muka bumi di Lembangan Sungai Semenyih berdasarkan kepada pengukuran kuantitatif geometri permukaan bumi seperti topografi, keluasan lembangan, bentuk lembangan, kemiringan cerun, sistem saliran, serta panjang dan kekerapan sungai di 36 sub lembangan kawasan kajian. Hasil cerapan lapangan menunjukkan kawasan kajian terdiri dari batuan yang terluluhawa, dengan permukaan tanah yang mempunyai ketelapan tinggi yang didominasi oleh pasir. Jasad batuan di Lembangan Semenyih adalah dicirikan dengan nilai ketidakselanjaran yang tinggi yang disebabkan oleh pembentukan struktur geologi, seperti perlipatan, kekar dan sesar akibat peristiwa tektonik masa lampau. Aspek morphometri seperti ketumpatan saliran dan nisbah bifurkasi menunjukkan Lembangan Semenyih dicirikan sebagai terdiri dari batuan yang homogen, mempunyai ketelapan tinggi dan taburan tumbuhan yang jarang serta didominasi oleh kadar penyusupan air dan pergerakan air bawah tanah. yang tinggi. Daripada data hidrologi, ditafsirkan bahawa hanya 35-45% dari jumlah hujan terubah menjadi aliran permukaan dan bakinya (55-65%) sebagai tirisan air bawah tanah selepas pengwapan dan proses sejatan. Lima cabang sungai utama, seperti Sg. Lalang, Sg. Batangsi, Sg. Tekala, Sg. Rinching dan Sg. Saringgit dikenal pasti sebagai pembekal utama kepada aliran Sungai Semenyih.

https://doi.org/10.7186/bgsm51200523