Editorial: Integrated modelling for regional water management

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MSc, PhDIntegrated hydrological and hydrogeological modelling playsan important role in regional water management. Numericalmodelling of the complicated components of the hydrologicalcycle and related quality characteristics can be an effective toolfor decision support in water management. This is becausesome inherent mechanisms and system behaviours cannoteasily be quantitatively measured and are not experimentallyaccessible in the systems of hydro-geo-atmospheres. The EUwater framework directives introduced an innovative,integrated and holistic approach to the protection andmanagement of water resources which requires integratedmodelling approaches at catchment scale for its properimplementation (Yang and Wang, 2010).This issue of Water Management brings together recentprogress and advances in the numerical modelling tools used tosupport water management. A number of interesting and novelnumerical models are used to study precipitation that couldprovide useful input to other hydrological and hydrogeologicalmodels. Rainfall was also linked to sooding forecast by way ofnumerical models. Some of the papers presented in this issueextend further studies of hydrogeological modelling forparameter estimation, saline intrusion and density dependentÞnite difference modelling. These works provide integratedmodelling approaches for precipitation, sooding andgroundwater issues, not only in quantity but also for quality.In the Þrst paper, Cao et al. (2010) present a new approach todetermine the distributed threshold rainfall for sash sooding tosupport practical sood warning. It is built upon a 2D fullhydrodynamic model incorporating rainfall, inÞltration loss andboundary resistance. The numerical solution of the model wasachieved by the second-order total-variation-diminishingversion of the weighted-average-sux method along with theHarten-LaxÐvan Leer contact (HLLC) approximate Riemannsolver for the homogeneous equations, and a RungeÐKuttascheme for the ordinary differential equations of the sourceterms. The applicability of the new approach is demonstrated asapplied to real sash sooding-prone areas in Hunan Province,China. The threshold rainfall for sash sooding, resulting fromrainfall of short durations, was quantiÞed, which indicated ahigh risk of sash sooding in the local areas and promptedeffective measures to avoid economic and social losses.Creating a harmony between hydraulic constructions and anatural water environment for people to live in is a veryinteresting issue for watershed management. Attempts to bringtwo consicting viewpoints from hydraulic engineers andecologists into reconciliation show the practical difÞculties ofsuch a harmony. In the paper by Chou et al. (2010) the conceptof emergy is introduced and used to assess the contribution ofnatural environment to the human economic system. Theauthors applied the emergy synthesis in this paper as a tool tostudy the catchment management approach in Taiwan. Theemergy contributions of a river at different levels of the globaland regional hydrological cycle are evaluated. Two newindicators for river management Ð river pulsing index andemergy matching index Ð are developed to judge the trade-offbetween economy and ecology.Hydrological modelling in ungauged catchments has alwaysbeen a complicated issue due to scarcity of the requisite data.In most cases, hydrologists quite often have to rely on indirectestimations based upon limited data or desk studies. Shamim etal. (2010) propose a novel approach for solar radiationestimation in ungauged catchments using readily availabledatasets of temperature and precipitation using a non-linearartiÞcial neural network model. The rationale is that theextraterrestrial radiation is attenuated not only by differentatmospheric processes, but also by weather phenomena. Acomparison of four clear sky radiation models was made andthe best model output together with temperature andprecipitation data was analysed using the gamma test for bestinput combination and data length selection. The work showeda good calibration between the observed and estimated valuesusing gamma test in model development.Reliable and accurate estimation of aquifer parameters is a keyprocess for reliable groundwater management. A number ofstochastic optimisation tools are available to solve the non-linear aquifer parameters using gradient-based techniques butalso conventional stabilisation techniques. The paper byKambhammettu and King (2010) demonstrates how toaccelerate and stabilise the conventional LevenbergÐMarquardtalgorithm. A generalised Matlab code was developed toestimate the transmissivity and storage coefÞcient of theconÞned aquifer using residual drawdowns in an observationwell. The application of the method was illustrated by twodatasets from different sources and the results were comparedwith previous studies. The paper demonstrates that this methodcan estimate the parameters accurately with a more rapidconvergence in comparison with the conventional algorithms.Water Management 163 Issue WM7 Editorial Yang 325