Variations in some groundwater characteristics, Belawai Water Supply, Sarikei Division, Sarawak

702001-101091-888-B
Author : Mohammed Hatta Abd. Karim
Publication : Bulletin of the Geological Society of Malaysia
Page : 109-132
Volume Number : 26
DOI : https://doi.org/10.7186/bgsm26199010

Bulletin of the Geological Society of Malaysia, Volume 26, April 1990, pp. 109 – 132

 

Variations in some groundwater characteristics, Belawai Water Supply, Sarikei Division, Sarawak

MOHAMMED HATTA ABD. KARIM

Geological Survey of Malaysia, Kuching, Sarawak

 

Abstract: A systematic monitoring programme has been carried out on the water supply in the Belawai catchment area since August 1987 to gather information and data on the quality and quantity of the water as well as the trend of domestic water demand; the information is essential for the proper development and management of the groundwater system of the Belawai water supply.

The aquifer in the Belawai Catchment Area is shallow and underlain by beach sand and marine sand.

The groundwater in general flows from southern part of the catchment area to the north. However, the water flow changes according to the recharge-discharge relationship of the catchment area. Recharge of the groundwater in the catchment area is mainly from precipitation and groundwater in flow. The response time is short where the rainwater available reached the water table almost immediately. Discharge is mainly by the abstraction of water from the production wells, evapotranspiration, groundwater outflow and surface drainage. During the dry season, the total discharge is more than the total recharge resulting in the water supply being supplemented by the aquifer storage. The effect of water use in the catchment area aquifer changes according to the pattern of abstraction and this groundwater table at the beginning.

The quality of water changes with every well and at different months. There appears to be relationship between chloride contents with the total rainfall. From the trilinear diagram, water quality changes becoming less satisfactory when the total recharge decreases.

 

Abstrak: Kajian pemonitoran yang bersistematik. telah dijalankan semenjak Ogos 1987 keatas Kawasan Tadahan Punca Air Tanah Belawai untuk memperolehi dan mengumpul data-data kuantiti dan kualiti air, juga jumlah permintaan penduduk; maklumat ini sangat diperlukan untuk pembangunan dan pengurusan yang berkesan kepada Punca Air Tanah Belawai.

Akuifer di Kawasan Tadahan Belawai adalah jenis terdedah yang cetek di mana ianya terdiri dari pasir pantai dan pasir laut.

Air tanah pada amnya mengalir dari selatan ke utara Kawasan Tadahan. Walau bagaimanapun aliran air akan berubah bergantung kepada pertalian antara imbuhan dan luahan air kawasan tadahan. Punca imbuhan adalah dari penyerapan air hujan dan larian air tanah. Masa sambutan adalah pendek dimana air hujan didapati sampai ke paras air tanah dengan kadar yang segera. Punca luahan adalah dari pemampaan perigi pengeluaran, evapotranpirasi, larian air tanah dan larian permukaan menerusi parit. Semasa musim kemarau, jumlah luahan adalah melebihi jumlah imbuhan yang mengakibatkan punca air terpaksa di ambil dari simpanan akuifer. Kesan kegunaan air dalam akuifer Kawasan Tadahan didapati berubahan mengikut corak pemampaan dan keadaan paras air tanah pada peringkat awal.

Kualiti air berubah pada setiap perigi dan pada bulan yang berlainan. Didapati ada pertalian antara kandungan klorida dengan jumlah hujan yang turun. Dari rajah triliner, kualiti air berubah menjadi kurang memuaskan apabila jumlah imbuhan berkurangan. 

https://doi.org/10.7186/bgsm26199010