A New Way for Incorporating GCM Information into Water Shortage Projections

Seung Seo,Cho-Rong Kim,Young-Oh Kim

doi:10.3390/w7052435

Abstract

Climate change information is essential for water resources management planning, and the majority of research available uses the global circulation model (GCM) data to project future water balance. Despite the fact that the results of various GCMs are still heterogeneous, it is common to utilize GCM values directly in climate change impact assessment models. To mitigate these limitations, this study provides an alternative methodology, which uses GCM-based data to assign weights on historical scenarios rather than to directly input their values into the assessment models, thereby reducing the uncertainty involved in the direct use of GCMs. Therefore, the real innovation of this study is placed on the use of a new probability weighting scheme with multiple GCMs rather than on the direct input of GCM-driven data. Applied to make future projections of the water shortage in the Han River basin of Korea, the proposed methodology produced conservative but realistic projection results (15% increase) compared to the existing methodologies, which projected a dramatic increase (144%) in water shortage over 10 years. As a result, it was anticipated that the amount of water shortages in the Han River basin would gradually increase in the next 90 years, including a 57% increase in the 2080s.

Highlights

An accurate water balance projection is essential to a successful water resources planning for an uncertain future, especially in a nonstationary world [1]
This study began with a broad review of studies that focused on water balance projection methodologies reflecting climate change impacts
Most studies utilized multiple general circulation model (GCM) climate change scenarios, and the average number of GCM scenarios used in these water balance projection studies ranges from four to five

Summary

Introduction

An accurate water balance projection is essential to a successful water resources planning for an uncertain future, especially in a nonstationary world [1]. Water balance projections calculate the difference between the total water demand and the total supply capability for a basin. When the demand exceeds the supply, water shortage occurs. Short- and medium-range water resource planning alternatives, which can reduce potential water shortages, should be established under a predefined long-range water resource plan encompassing at least 20 years. For such a long-range time scale, the impacts of climate change cannot be ignored. This study began with a broad review of studies that focused on water balance projection methodologies reflecting climate change impacts.

Objectives

Methods

Results

Conclusion