Bulletin of the Geological Society of Malaysia, Volume 45, May 2002, pp. 193 – 200
Department of Geology, University of Malaya, 50603, Kuala Lumpur, Malaysia
E-mail: j4ismail@umcsd.um.edu.my
Abstract: Assessment of the significance of climate change on water resources presents a considerable challenge. This study investigated the impacts of climate change on the Chalk aquifer of West Norfolk using a combination of a groundwater model (MODFLOW) and a climate change model (Hadley Centre‘s climate change experiment, HadCM2). Two future climate change scenarios were selected from the HadCM2 model: (i) a Medium-high (MH) emissions scenario and (ii) a Medium-low (ML) emissions scenario of greenhouse gases. Two future periods were considered: 2020-35 and 2050-65. Climate-change impacts were evaluated by incorporating the monthly estimated recharge inputs within the transient flow model and comparing the relative changes of groundwater levels and river baseflow volumes over monthly and annual timescales. Two opposite trends are predicted from the modelling of climate change scenarios for the two future periods considered (2020s and 2050s). The 2050ML scenario predicts an annual decrease in recharge of up to 13 mm, a monthly decrease in groundwater levels of up to 70 cm and a monthly decrease of up to 11% in the baseflow volume of the River Nar while the 2020ML scenario predicts an annual increase in recharge of up to 8 mm, a monthly increase in groundwater level of up to 50 cm and a monthly increase of up to 7% in the baseflow volume of the River Nar.
Abstrak: Penilaian keberkesanan perubahan cuaca ke atas sumber air merupakan suatu cabaran yang agak besar. Kajian ini bertujuan untuk menyiasat impak perubahan cuaca keatas akuifer batuan berkapur di Norfolk Barat dengan menggunakan kombinasi model air tanah (MODFLOW) dan model perubahan cuaca (HADCM2- Pusat ekperimen perubahan cuaca Hadley). Dua scenario perubahan cuaca masa hadapan telah dipilih daripada model HADCM2: perlepasan gas-gas rumah hijau yang i) sederhana-tinggi (MH) dan ii) sederhana-rendah (ML). Dua tempoh masa hadapan telah dipertimbangkan: 2020-35 dan 2050-65. Impak-impak perubahan cuaca telah dinilai dengan cara menggabungkan input angaran imbuhan bulanan ke dalam model aliran transient dan membandingkan perubahan-perubahan secara relatif paras air tanah dan isipadu aIiran dasar sungai mengikut skala masa bulanan dan tahunan. Dua trend yang bertentangan telah diramalkan daripada pemodelan scenario perubahan cuaca untuk kedua-dua tempoh masa hadapan yang dipertimbangkan (2020an dan 2050an). Senario 2050ML meramalkan pengurangan imbuhan tahunan sehingga 13 mm, penurunan paras air tanah bulanan sehingga 70 cm dan pengurangan isipadu aliran dasar bulanan Sungai Nar sebanyak 11%. Manakala scenario untuk 2020ML pula meramalkan peningkatan imbuhan tahunan sebanyak 8 mm, peningkatan paras air tanah bulanan sebanyak 50 cm dan peningkatan isipadu aliran dasar bulanan Sungai Nar sebanyak 7%.
https://doi.org/10.7186/bgsm45200229
