Evangelos Baltas

National Technical University of Athens | NTUA · Department of Water Resources and Environmental Engineering

Expected global climate change is allegedly becoming more intense, and the impacts on water resources are being tracked in various hydroclimatic regimes. The present research investigates a hydrologically important area of Greece, where four natural lakes are concentrated. It aims to quantify any potential long-term trends in lake water area, preci...

This study develops a methodological framework to analyze raw weather radar datasets of fine temporal and spatial scale by implementing them into rainfall-runoff simulations. Since there is uncertainty in radar datasets, this study focuses on the error margins that can be produced in the discharge when various radar reflectivities (Z) are applied i...

We pose the following research question: “what is the effect of flood protection works on flood risk?” To answer this question, we developed a flood risk assessment method that combines the typical hazard assessment via integrated hydrological and hydrodynamic calculations using HEC-HMS and 1D/2D HEC-RAS, respectively, and an original procedure for...

Urban flooding can cause significant infrastructure and property damage to cities, loss of human life, disruption of human activities, and other problems and negative consequences on people and the local government administration. The objective of this research work is to investigate the relation between urban flood occurrence and potentially flood...

Soil transportation is a complex phenomenon and one of the most important environmental hazards, with potentially harmful consequences for humans, property, the environment and economies. Now, with climate change leading to extreme natural disasters, it is as critical as ever to probe this phenomenon in order to estimate it, which should help to pr...

Energy and water independence and reduction of the consumption of fossil fuels can be achieved by the exploitation of the rich wind potential of the Greek islands and the optimal management of water resources. Produced wind energy can be either sent directly to the Local Production Station or can be used for pumping and storing water in the upper r...

In weather radar applications, the Z-R relationship is considered one of the most crucial factors for providing quality quantitative precipitation estimates. However, the relationship’s parameters vary in time and space, making the derivation of an optimal relationship for a specific weather radar system challenging. This research focused on the an...

The flash flood in the town of Mandra, Attica, in 2017 that had a return period equal to approximately T = 150 years was one of the most disastrous floods in Greece. Four years later, flood protection works designed for T = 50 years were built. In this work, we pose the research question ‘How would this disastrous flood have behaved if flood protec...

The objective of this study consists of examining whether the coupling between wind turbines (WT) and photovoltaic modules (PV) with batteries (BT) or pumped hydro-storage (PHS) can produce a sufficient amount of energy in order to cover the electricity demands in an island, as well as the demand for producing desalinated water for drinking and irr...

The lack of fresh water and energy independence in remote islands leads to the investigation of Hybrid Systems (HS). In this paper, the implementation of wind energy for meeting energy, water, and electromobility demands on a Greek island is examined. The stochastic nature of wind potential leads to the introduction of energy storage units. Energy...

The impact of forest fires on the exposure of humans, properties, the environment, and the economy to flooding is of the utmost importance. This research paper proposes a holistic approach to specific fire events based on flood-susceptibility assessment, investigation of hydrological changes at the basin scale, and flood mapping of susceptible area...

The need for energy and water security on islands has led to an increase in the use of wind power. However, the intermittent nature of wind generation means it needs to be coupled with a storage system. Motivated by this, two different models of surplus energy storage systems are investigated in this paper. In both models, renewable wind energy is...

Rainfall intensity–duration thresholds are commonly used to assess flood potential in both urban and rural environments. Derivation of these thresholds is one of the approaches commonly used for the development of flash flood warning systems that are mainly based on rainfall predictions. This research work presents a detailed analysis on these thre...

The non-interconnected islands of Greece can benefit from the comprehensive use of RES to avoid water droughts and ensure energy autonomy. The present paper analyzes an HRES with two possible operating scenarios. Both of them include a wind park of 27.5 MW capacity, an 1175 m3/day desalination plant, and a 490,000 m3/day water tank in Lemnos, Greec...

Inland water resources are facing increasing quantitative and qualitative pressures, deriving from anthropogenic causes and the ongoing climate change. The monitoring of reservoirs is essential for sustainable management and preparation against water scarcity and extreme events, such as droughts. This research, relying on the Sentinel-2 and 3 missi...

In this research work, an implementation of the gridded Flash Flood Guidance (FFG) method is conducted for the prediction and evaluation of flash floods in Greece. The FFG system is a well-established Early Warning System (EWS) for the estimation of flash flood threats, especially in small ungauged basins, where flash floods are the most dominant f...

There is a global effort to integrate renewable energy sources (RES) into the energy balance, setting out to develop a more sustainable future. The dependence of RES on natural phenomena and their low reliability can be mitigated by hybrid renewable energy systems (HRES). In this paper, an evaluation of an under-study HRES in Leros, Greece, is carr...

Identifying the core hydrological processes of catchments is a critical step for operative hydrological modeling. This study attempts to assess the long-term alterations in streamflow in three adjacent catchments of Upper East Fork White River, Indiana USA, by employing the SWAT hydrological model. The model simulations are spanning from 1980 up to...

The design of an optimum hydrometeorological and hydrometric station network constitutes a key factor for the collection of comprehensive and reliable hydrometeorological and flow data that are necessary both for decision making in water resources policy and management, and for the hydrometeorological risk assessment. This article describes a metho...

This paper describes an approach for the identification of flood-susceptible areas contributing to the sustainability of these in the Giofiros river basin covering an area of 184 km2, located in Southern Greece. This basin is prone to flooding with devastating consequences on people, environment, and the economy. In this context, a geographic infor...

Greece depends on reservoirs for water supply. However, lack of data is observed regarding the monitoring of their quantitative parameters. This research assesses the efficiency of remote sensing methods to increase monitoring capacity over water reservoirs. The Normalized Difference Water Index (NDWI) is tested on Yliki reservoir, towards the extr...

This research work focuses on the investigation of the Z-R relationship impact on weather radar rainfall estimates, through the correlation of a X-Band weather radar estimates and rain gauge measurements in the region of Attica, Greece. The methodology followed in this work is performed into two sections, where first, a framework is applied in orde...

An evaluation of the Sacramento Soil Moisture Accounting (SAC-SMA) model was conducted to be used in flood event simulations with datasets at a time step up to one hour. The SAC-SMA model is a complex conceptual model which integrates two soil zones, the upper and lower zone, in order to provide current soil moisture conditions and generated stream...

The exploitation of RES and their combination with desalination may be the solution to water scarcity and volatility of the electricity grids in remote offshore areas around the world. This research work investigates an HRES of a 12 MW wind park, a 1.8 MW photovoltaic park and a 1000 m 3/d desalination plant in Karpathos, Greece. Concerning the win...

The design of an optimum hydrometeorological and hydrometric station network constitutes a key factor for the collection of comprehensive and reliable hydrometeorological and flow data that are necessary both for decision making in water resources policy and management and for the hydrometeorological risk assessment. This article describes a method...

In this research work, an analysis is conducted concerning the impact on rainfall-runoff simulations of utilizing rain gauge precipitation measurements against weather radar quantitative precipitation estimates. The study area is the Sarantapotamos river basin, a peri-urban basin located in the greater area of Athens, and measurements from a newly...

In an era when flood phenomena intensify worldwide, the scarcity of proper and systematic flood flow measurements has become a conundrum. As an answer, the non-intrusive Large-Scale Particle Image Velocimetry (LSPIV) method has recently advanced to a contemporary gauging alternative, though several limitations in the field application pose question...

The need for energy independence of small remoted islands, promote the exploration of renewable energy sources. Greek islands have rich wind potential and subsequently, the attention is being drawn to the use of wind turbines to meet their energy needs. However, the optimal location of wind turbines installation is the basis for the exploitation of...

An integrated methodological framework for assessing different flood mitigation measures in urban catchments is presented. The framework comprises hydrologic, hydraulic and economic indices aiming at quantifying the effect of different alternatives regarding flood hazard mitigation. The alternatives evaluated include both conventional drainage solu...

The current analysis attempts to quantify the interlinkages between the water, energy and food sectors of California covering the period 2002–2015. The results reveal that 25% (60,696 GWh) of the annual energy consumption is attributed to agriculture, while 75% (174,709 GWh) is used for water supply purposes. The agricultural sector consumes 77% (3...

Water scarcity is a serious problem for the Aegean Islands in Greece. Due to the fact that tourist development grows in a continuous way, the situation has deteriorated over the last years. Current water resources management practices involving the exploitation of the groundwater reservoirs have provoked the salty water intrusion into the aquifers...

The prolonged issues regarding the quantitative and qualitative characteristics of the water resources in the River Basin District of Thessaly (TRBD) have resulted in the environmental degradation and the reduction of the availability of water. Agriculture is the major water user, constituting up to 95% of total water demand. The pressures anticipa...

This research work deals with an integrated assessment regarding a hydrosystem’s resilience under changing conditions. Particularly, the analysis is performed for Florina, a rural area in Northern Greece. In Florina, four reservoirs operate to meet water requirements for agriculture and industrial use, as well as, to satisfy the urban water demand...

The design of a proper stream gauging network is a requirement in order to obtain accurate flow information, important for various purposes such as water resources management, flood forecasting and climate change impact assessment. Therefore, while it is necessary to minimise the number of stations in terms of feasibility and cost, the most suitabl...

Five different water resource management scenarios are examined on eight dry islands of the Aegean Sea in Greece, pitting the current practice of water hauling via ship against alternative water supply schemes in delivering a sustainable solution for meeting water demand. The first scenario employs current water supply practices along with the oper...

The identification of flood‐prone areas is a fundamental component of rational urban planning and proper natural disaster management policy. The aim of the present study is to introduce a framework for the identification of flood‐prone areas using GIS techniques and decision making, based on a comparative evaluation for various scenarios. As a case...

Attica, which is the region with the largest population in Greece, suffers from numerous high rainfall intensity events inducing flash floods and, consequently, significant damages in the urbanized areas. High rainfall intensities are frequently connected with convection, a quiet often phenomenon during either the transitional seasons or the late s...

Urban areas often experience high precipitation rates and heights associated with flash flood events. Atmospheric and hydrological models in combination with remote-sensing and surface observations are used to analyze these phenomena. This study aims to conduct a hydrometeorological analysis of a flash flood event that took place in the sub-urban a...

Land is a highly valuable natural resource, where all human activities take place by exploiting natural goods for socio-economic development. The competition for land resources is increasing with pristine soils of unoccupied land being very precious for agricultural use (food production) and infrastructure development. International efforts have be...

Attica region suffers from frequent extreme rainfall events, inducing flash-floods and consequently significant damages in the urbanized areas. Among them, most flash-flood events are related to deep, moist convection. This analysis concerns the determination of the synoptic features for both stratiform and convective rainfall events that caused ex...

This research work focuses on the analysis of the involved uncertainty and the corresponding reliability in the sizing of rainwater harvesting systems. For this reason, an uncertainty analysis was carried out, based on 23 years of historic daily record of a station in Kimolos Island (Aegean, Greece). In order to produce the synthetic daily timeseri...

Changes in land cover is a dynamic phenomenon that is mainly influenced both by human interventions and physical processes, which play a significant role in water resources management. The study area was the Aliakmonas river basin in Greece, which is one of the important agricultural and energy provinces of the country. In this study, satellite ima...

Changes in land cover is a dynamic phenomenon that is mainly influenced both by human interventions and physical processes, which play a significant role in water resources management. The study area was the Aliakmonas river basin in Greece, which is one of the important agricultural and energy provinces of the country. In this study, satellite ima...

The main aim of EU water policy is to ensure that a sufficient quantity of good-quality water is available for both people's needs and the environment. The Water Framework Directive (WFD), which came into force in 2000, established a framework for the assessment, management, protection and improvement of the quality of water resources across the EU...

The present work aims at quantifying the benefit of Low Impact Development (LID) practices in reducing peak runoff and runoff volume, and at comparing LID practices to conventional stormwater solutions. The hydrologic-hydraulic model used was the Storm Water Management Model (SWMM5.1). The LID practices modeled were: (i) Green roofs; and (ii) Perme...

Adequate and accurate hydrometeorological data are very important for performing a range of hydrologic purposes, including water resources management, assessment of the impacts of climate change, and flood forecasting and warning. The rational prevention of natural disasters, such as floods and droughts, is strongly connected with a forecasting tec...

In this research work, the latest version 7 (V7) of the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B42 product is evaluated over Greece, at five different temporal scales; 3, 6, 12, 24 and 48 hrs. Evaluation consists in assessing the performance of the product in reproducing observed, non-zero precipit...

The necessity of mitigating the consequences of energy dependence and water scarcity in remote areas, such as small islands puts forward the investigation of renewable energy sources. Especially in Aegean, the rich wind potential and natural topography favors the use of Hybrid Renewable Energy System (HRES). In this research work, a HRES in Fournoi...

The purpose of this research work is the analysis of a number of precipitation events, using the RD-69 Joss-Waldvogel Disdrometer measurements. This instrument measures the raindrop size distributions continuously and automatically by transforming the vertical momentum of an impacting raindrop, whose amplitude is a function of the drop diameter. Th...

The gradual degradation of fresh water reserves, coupled with its essential role in supporting life, is prompting the research for alternative and sustainable methods of supplying water for domestic, irrigation and industrial use worldwide. The harvesting, storage and use of rainwater have been traditionally employed as a water management practice...

Water availability and allocation are connected to various activities (e.g. irrigation, urbanisation, industrial production, recreation), which are taking place on the terrestrial surface. Considering the variation of the driving forces, it is necessary to examine possible patterns and trade-offs between land, water and social welfare. Land cover r...

Land is a resource that affects all dimensions of the natural environment, as all the human and natural activities occur on it. World development is exerting increasing pressures on the natural systems, such as: urban sprawl and population increase, agricultural expansion and deforestation, new infrastructure and industrial establishments construct...

Poster of our work on "Land accounting perspective on water resources management" in the EWRA 2017 World Congress

The presentation of our work regarding the use of environmental accounting concepts under System of Environmental and Economic Accounting - CF in recognizing and defining the main drivers of change in the Wabash River Basin, Indiana

Rainwater harvesting is an ancient practice aiming to cover water needs for domestic, irrigation and livestock uses. In this study, the rainwater harvesting tank size was investigated to meet five waterneed levels of a mixed goat-sheep farm using a daily water balance method. This method was applied using daily rainfall data for a period of 16 year...

This research work focuses on the analysis of the Standardized Precipitation Index (SPI) over Greece for three time scales; three, six and 12 months (SPI 3 , SPI 6 , SPI 12 ; respectively). The SPI i timeseries were calculated using the DrinC open-access software.. The estimation of the index, as well as, its mean values and trends were based on th...

The aim of this research work is the optimization of the existing hydro-meteorological and hydrometric networks in the District of Evia, through the implementation of a multi-criteria analysis, which is based on international guidelines, using GIS techniques. Criteria such as, geomorphological, technical, geometrical and administrative, concerning...

In this research work, a hydrological and a geomorphological analysis have been performed in the municipality of Florina, located in Northern Greece. Two water balance models, the ABCD and the WBUDG were implemented for the simulation of the hydrologic regime of the region on a monthly basis. Due to the limited stream flow data in the region, the m...

Abstract The European Topic Centre on Inland, Coastal and Marine Waters published the first report on Use of freshwater resources in Europe 2002-2012 - Supplementary document to the European Environment Agency’s core set indicator 018 in April 2016. This second report is the updated version of that report by means of new data involvement. The curr...

This research paper focuses on the implementation of the "abcd" water mass balance model in Evrotas River Basin for the runoff simulation. The study area, which is located in Greece and more specifically at SE. Peloponnese, is the Evrotas river basin, covering a total area of 1739 km 2 with its main watercourse of 90 km length. The model is perform...