Estimating the Future Function of the Nipsa Reservoir due to Climate Change and Debris Sediment Factors

The constantly growing human needs for water aiming to supply urban areas or for energy production or irrigation purposes enforces the application of practices leading to its saving. The construction of dams has been continuously increasing in recent years, aiming at the collection and storage of water in the formed reservoirs. The greatest challenge that reservoirs face during their lifetime is the sedimentation caused by debris and by the effects of climate change on water harvesting. The paper presents an investigation on the amount, the position and the height of the debris ending up at the Nipsa reservoir. The assessment of the debris volume produced in the drainage basin was conducted by a geographical information system (GIS) based model, named TopRunDF, also used to predict the sedimentation area and the sediment deposition height in the sedimentation cone. The impact of climate change to the reservoir storage capacity is evaluated with the use of a water balance model triggered by the HadCM2, ECHAM4, CSIRO-MK2, CGCM1, CCSR-98 climate change models. The results predict a significant future decrease in the stored water volume of the reservoir, and therefore several recommendations are proposed for the proper future functioning and operation of the reservoir

Regional hazard analysis for use in vulnerability and risk assessment

A method for supporting an operational regional risk and vulnerability analysis for hydrological hazards is suggested and applied in the Island of Cyprus. The method aggregates the output of a hydrological flow model forced by observed temperatures and precipitations, with observed discharge data. A scheme supported by observed discharge is applied for model calibration. A comparison of different calibration schemes indicated that the same model parameters can be used for the entire country. In addition, it was demonstrated that, for operational purposes, it is sufficient to rely on a few stations. Model parameters were adjusted to account for land use and thus for vulnerability of elements at risk by comparing observed and simulated flow patterns, using all components of the hydrological model. The results can be used for regional risk and vulnerability analysis in order to increase the resilience of the affected population

Estimating the Future Function of the Nipsa Reservoir due to Climate Change and Debris Sediment Factors

The constantly growing human needs for water aiming to supply urban areas or for energy production or irrigation purposes enforces the application of practices leading to its saving. The construction of dams has been continuously increasing in recent years, aiming at the collection and storage of water in the formed reservoirs. The greatest challenge that reservoirs face during their lifetime is the sedimentation caused by debris and by the effects of climate change on water harvesting. The paper presents an investigation on the amount, the position and the height of the debris ending up at the Nipsa reservoir. The assessment of the debris volume produced in the drainage basin was conducted by a geographical information system (GIS) based model, named TopRunDF, also used to predict the sedimentation area and the sediment deposition height in the sedimentation cone. The impact of climate change to the reservoir storage capacity is evaluated with the use of a water balance model triggered by the HadCM2, ECHAM4, CSIRO-MK2, CGCM1, CCSR-98 climate change models. The results predict a significant future decrease in the stored water volume of the reservoir, and therefore several recommendations are proposed for the proper future functioning and operation of the reservoir

Comparative analysis of soil erosion sensitivity using various quantizations within GIS environment : an application on Sperchios river basin in Central Greece

Soil erosion is a prominent cause of land degradation and desertification in Mediterranean countries. The detrimental effects of soil erosion are exemplified in climate (in particular climate change), topography, human activities and natural disasters. Modelling of erosion and deposition in complex terrains within a geographic information system (GIS) requires reliable estimation of topographic factors, as well as the formulation of erosion models adequate for digital representation of spatially distributed parameters. In the current paper, two different approaches for the estimation of erosion in the Sperchios river basin are described and evaluated using GIS – the Revised Universal Soil Loss Equation and the Gavrilovič method. Implementing the ArcGIS 10.2.1 programme, the necessary input data for these approaches were estimated using four different quantizations that were created using topographic maps, courtesy of the Greek Geographical Army Service. The results indicated that even though a high-resolution quantization is always preferred for more reliable results, when there is a lack of available data, coarser quantizations can also be used to extract similar estimations.</p

Overflow Discharges and Flooding Areas from Flood Hydrographs Routing in Arda River, Greece

Flooding is a natural disaster that damages infrastructure, properties, and may even cause loss of life. Major floods occur in the Arda river basin, which is shared between Greece and Bulgaria in Southeastern Europe. A flood warning system can sufficiently minimize adverse effects by helping to create a more successful and well-organized response plan. This paper presents an extensive numerical simulation of flood hydrograph routing between levees of the downstream section of the Arda river for floods with return periods from 2 to 10,000 years, using the one-dimensional software HEC-RAS. The main objective is to calculate the inundation areas, travel times of flood waves, water depths, water levels, flow velocities, and overflow volumes by simulating the hydraulic behavior of the Arda river outside its mountain watershed, where it flows through agricultural plane land with very mild slope. The great importance of the water level at the confluence of the Arda and Evros rivers (downstream boundary condition) has been pointed out for the regions near the confluence because the flow is the subcritical type. A significant finding of this work is the determination of the upper limit of the peak discharge hydrograph entering from the Arda to the Evros river to prevent the flooding of the Evros river. This finding is very important for the management of the flood flows of the Evros river, which is a major river with a complicated river system

Regional hazard analysis for use in vulnerability and risk assessment

A method for supporting an operational regional risk and vulnerability analysis for hydrological hazards is suggested and applied in the Island of Cyprus. The method aggregates the output of a hydrological flow model forced by observed temperatures and precipitations, with observed discharge data. A scheme supported by observed discharge is applied for model calibration. A comparison of different calibration schemes indicated that the same model parameters can be used for the entire country. In addition, it was demonstrated that, for operational purposes, it is sufficient to rely on a few stations. Model parameters were adjusted to account for land use and thus for vulnerability of elements at risk by comparing observed and simulated flow patterns, using all components of the hydrological model. The results can be used for regional risk and vulnerability analysis in order to increase the resilience of the affected population