The formation and development of hydrological drought – Kamienna River case study

Abstract:

Human activities affecting hydrological processes in a catchment have many forms and the effect of those activities on propagation of drought in a catchment depends on the relevant scales of the processes involved. The research presented focuses on the influence of reservoir operation and land use on drought dynamics. As a case study we use the River Kamienna, Swietokrzyskie mountains, Poland. The Kamienna River has a mountainous character, with a number of water retention reservoirs and a history of industrial activities in the region. Annual water balance is also affected by water withdrawals in the catchment. Modelling tools in the form of lumped and semi-distributed hydrological models are applied to analyse hydrological processes in the catchment and to separate climatological and human-related factors affecting them. Two main goals of the modelling can be summarised as an investigation of the effects of reservoir operation on hydrological processes, especially dry season runoff and an analysis of impacts of land use change on the spatio-temporal characteristics of hydrological drought propagation. We apply three different models to simulate the catchment hydrological processes; two semi-distributed models, SWAT and TOPMODEL, and the lumped hydrological model HBV. We present the calibration and verification of the models applied and a comparison of results using the goodness of fit criteria. Both HBV and TOPMODEL are calibrated using the Generalised Likelihood Uncertainty Estimation method (GLUE). The estimated predictions at gauging stations along the Kamienna River are compared with SWAT model results. The results show that monthly flow values are adequately modelled by all three modelling approaches. The study applies a number of flow-related indices to understand how the climate and human induced changes are affecting flow patterns in the region. Flow regime is described using a baseflow index and runoff coefficient. The standardized runoff index (SRI) and runoff coefficients are also derived for the catchment. The research is part of the project “Human and climate impacts on drought dynamics and vulnerability” HUMDROUGHT (http://HUMDROUGHT.igf.edu.pl).