Hydrological Analysis of a Drained Peat Basin Using Time Series Correlation and Cross–correlation Functions

Abstract

Satu pendekatan algebra mudah korelasi dan korelasi silang telah digunakan untuk mengkaji hidrograf aliran sungai di lembangan tanah gambut. Analisis melibatkan pemindahan pemboleh ubah input (hujan) and pemboleh ubah output (aliran sungai atau paras air tanah). Analogi kepada sistem signal input-output dalam bidang elektronik, akuifer tanah gambut dianggap sebagai suatu sistem penapis. Sistem penapis tersebut mampu untuk memindah, menahan atau menghapus pemboleh ubah input (signal input) sebelum pemboleh ubah output dihasilkan. Sifat aliran yang melalui sistem akuifer boleh diterjemahkan daripada darjah pindahan signal input. Beberapa parameter akuifer penting telah dikenal pasti, iaitu tempoh masa gerak balas, perbezaan antara jenis aliran (aliran cepat, sederhana atau aliran dasar) dan masa tunda. Kesemua parameter hidrologi tersebut diperlukan sebagai parameter reka bentuk bagi suatu projek sumber air dalam kawasan yang dilitupi oleh akuifer bertanah gambut. Kata kunci: Hidrologi gambut; fungsi; korelasi silang; fungsi korelasi spektra; lembangan kompleks A simple algebraic correlation and cross–spectral approach was applied to study the stream flow hydrograph of peat basin. The analysis involved the transformations of input variables (rainfall) and output variables (stream flow and water table). Analogous to the input–output signal in electronics, the peat aquifer is considered as a filtering system. The filter is able to transform, retain or eliminate the input variables (input signal) before the output variables (output signal) are created. The behaviour of flow through basin aquifer system is deduced from the degree of the transformation of the input signal. Several important aquifer parameters were deduced from the transformation process. They are the response time, the distinction between flows (quick–flows, intermediate flow or base–flow) and the delay. These hydrological parameters are required as design parameters for a water resource project within a basin–underlain peat soil aquifer. Key words: Peat hydrology; cross correlation function; spectral correlation function complex basin