Impact of climate and land-use changes on hydrological processes and sediment yield—a case study of the Be River catchment,Vietnam

Abstract

The impact of climate and land-use changes on hydrological processes and sediment yield is investigated in the Be River catchment, Vietnam, using the Soil and Water Assessment Tool (SWAT) hydrological model. The sensitivity analysis, model calibration and validation indicated that the SWAT model could reasonably simulate the hydrology and sediment yield in the catchment. From this, the responses of the hydrology and sediment to climate change and land-use changes were considered. The results indicate that deforestation had increased the annual flow (by 1.2%) and sediment load (by 11.3%), and that climate change had also significantly increased the annual streamflow (by 26.3%) and sediment load (by 31.7%). Under the impact of coupled climate and land-use changes, the annual streamflow and sediment load increased by 28.0% and 46.4%, respectively. In general, during the 1978–2000 period, climate change influenced the hydrological processes in the Be River catchment more strongly than the land-use change.

Editor Z.W. Kundzewicz; Associate editor Q. Zhang

Citation Khoi, D.N. and Suetsugi, T., 2014. Impact of climate and land-use changes on hydrological processes and sediment yield—a case study of the Be River catchment, Vietnam. Hydrological Sciences Journal, 59 (5), 1095–1108.     

Measured effects of new lake surfaces on regional precipitation

Abstract

Although often modelled, empirical evidence for regional water balance shifts, due to local land-use changes, is rare. The same holds for the quantification of such effects by measurement. The flooding of former open-cast mining areas in Lusatia, eastern Germany, delivers a unique opportunity to address this topic in a well-gauged region. During two decades, flooding changed about 60 km² of lignite pits to lake surfaces. To quantify possible shifts in the regional precipitation pattern, the background of general precipitation dynamics within the research area was separated from all raingauge records using principal component analysis (PCA). Linear models with the dominating PCA component as independent variable were fitted to the single station records. The residuals of these fits represent the local deviations from the general dynamics, and they contain the signals of climate alterations within the region. The analysis of these residuals revealed a shifting precipitation pattern with significant increases (up to 10% of the former mean annual precipitation, which is approximately 650 mm) on the lee side of the developing lake area. Further analysis showed that most of the observed changes are due to more frequent and intense convective storms. Water balance estimations indicate that the additional evaporation approximately equals the precipitation increase.     

A new method for modelling flow duration curves and predicting streamflow regimes under altered land-use conditions / Une nouvelle méthode de modélisation des courbes de débits classés et de prévision des régimes d'écoulement sous conditions modifiées d'occupation du sol

Abstract

The impact of changes in land-use/cover on streamflow at short time scales is evaluated by examining the changes in the flow duration curve (FDC) before and after land-use/cover change. The FDC characterizes the relationship between the magnitude and frequency and hence provides the complete range of streamflow over time. Two issues need to be considered in predicting the FDC due to land-use changes: (a) the appropriate parametric form of the FDC that enables application of the same expression of FDCs before and after the changes; and (b) the ability of parameters to capture and characterize the effect of land-use changes. In this paper, we propose a model which is a four-parameter double power form as a function of the FDC, where the two hydrological parameters represent the mean annual flow ([Qbar]) and the cease-to-flow point (τ expressed as a percentage), while the other two parameters (α and β) determine the shape of the FDC. The properties of this function are investigated in order to assign parameters to cope with the land-use changes. The model is used for several typical catchments in Australia for demonstration.     

3S 技术在土地利用变化监测中的应用

土地是人类赖以生存和社会赖以发展的重要资源,是人类生存和发展的物质基础。实现土地利用变化信息的动态监测,对于土地资源合理规划、科学管理具有重要的意义。本文以滁州市不同时相Landsat5 TM遥感影像为主要数据源,结合其他辅助数据,利用3S技术提取土地利用变化信息,分析和评价了该区域土地利用的变化特征。结果表明：2004～2009年间该市土地利用类型发生较大变化,其中耕地面积明显减少,建设用地面积大幅度增加。