Evaluation of the long-term variations in stream flow regime over a 50-year period of Rajang River basin

dr-mhdProject Title: Evaluation of the long-term variations in stream flow regime over a 50-year period of Rajang River basin

Research ID: 3/2016/01

Principal Researcher: Dr. Mohammed A. B. Seyam

Co-Researchers: Dr. Augustine Chioma Affam, Syazie Nordzaima

Project Start Date: 9/1/2016

Duration of Project: 18 months

Research Summary: Stream flow is a river basin’s integrated reaction to rainfall and other relevant hydrological parameters under certain climatological conditions. Investigating the long-term changes of stream flow is an important tool for enhancing water resources and river systems planning, design and management. The stream flow regime of rivers is not only significant from a hydrologic viewpoint, but also from both socioeconomic and natural perspectives. Over the past century a significant decrease in annual stream flow has been observed in approximately a quarter of the world’s rivers, giving this project high importance.

The objective of this project is to identify the long-term variations in annual stream flow regime over a 50-year period from 1965 to 2015 in the Rejang River, which is one of the main rivers in Sarawak. Initially, the work starts with collecting the hydrological data, followed by the statistical analysis of data. The data will undergo preliminary independence, normality and homogeneity testing using the Pearson correlation co-efficient, Shapiro–Wilk and Pettitt’s tests respectively. The work includes analysis of the changes through nine variables describing the annual stream flow and variations in the yearly duration of high and low stream flow. The analyses were conducted via two time scales: yearly and sub-periodic. The sub-periods were obtained by segmenting the 50 years into seven sub-periods.

By the end of project, it is expected to develop a new advanced analytical approach to investigate into the long-term changes of the annual stream flow regime in the Rejang River. The expected results could draw attention to the necessity to improve flood protection plans in response to the increasing probability of future high stream events.