Hydrology and water resources management

Drought is a complicated natural extreme event associated with the decline of water availability below the normal conditions of a hydrological system, both from a temporal and from a spatial point of view. This work aims to assess the drought impacts on groundwater fluctuation in a shallow coastal unconfined aquifer via fuzzy approach. Meteorological drought intensity is estimated by the Standardized Reconnaissance Drought Index (RDIst) based on precipitation (P) and potential evapotranspiration (PET). In addition, groundwater modeling is carried out using MODFLOW and then, the simulated values of water table (WT) of a coastal unconfined aquifer are utilized. In order to relate the RDIst with WT, a fuzzy linear regression (FLR) is applied. FLR based on Tanaka model produces a fuzzy band, where all the data must be included within, incorporating the system uncertainty. The suitability of the achieved fuzzy regression model is tested by using appropriate measures. The propounded methodology is applied in the eastern area of Nestos River Delta, Prefecture of Xanthi, Greece.

In this study, shoreline morphometry of the Karaboğaz, Balık, Uzun, Cernek, Liman, Gıcı and Tatlı lagoons which are located in the Kızılırmak Delta, was investigated by using fractal dimension and shoreline development index. The shorelines of the lagoons were obtained from Landsat 8 OLI satellite images of June 4, 2017, using remote sensing-image processing techniques including Normalized Difference Water Index (NDWI), Modified Normalized Difference Water Index (MNDWI), Gram-Schmidt pan-sharpening method and Iterative Self Organizing Data Analysis Technique (ISODATA) unsupervised classification method. In order to investigate the relationship between fractal dimension and the environmental conditions, also shoreline development index and the environmental conditions, the vegetation conditions in the surrounding of the lagoons were determined using Normalized Difference Vegetation Index (NDVI) algorithm. The result of the study reveals that the relationship between fractal dimension and NDVI is much stronger than the relationship between shoreline development index and NDVI.

The recent floods in the 'God's own Paradise'(Kerala) reminds the Indian Sub-Continent as well as the Global spectators of not just heavy rainfall but also the 'hungry water effect' from deranged desiltation. Laws from the first decade of independence decide the commercial desiltation permits and procedures in most parts of the country with renewed guidelines. The presentation attempts to map the in-river sand mining in all the Indian States, analyze the spatial extent and technology used, resulting degradation of the completely dug-out rivers, alterations in the geomorphology, base flow and river course, conditional water flow into the distributing channels which tend to stand at a higher surface than the further lowered river bed, impact on the continued cultivation in delta regions triggering the contingencies of extreme drought and flood. Poor and delayed adherence to the ecological economic estimates of this evolving nation and the enviro-legal regime can be traced as barriers of environmental restoration. Rampant dredging often with the under and over utilization of mining techniques, reluctant attitude to alternative construction materials raise serious economic & environmental concerns questioning the future livability of the Sub-continent.

Cities at risk of extreme hydro-meteorological events need to be prepared to decrease the extent of the impacts. However, the majority usually reacts to the catastrophe, having failed to proactively prepare against extremes. This can be a result of both absent structural protection measures and problematic governance. While for the first, models exist that can simulate the effect, the effect of the latter is difficult to quantify. This work aims to explore how the different decisions authorities make, regarding for example: whether or not to cooperate with someone; build something; assign funding to something else etc., affect the flood risk management of an area. For that matter, the Institutional Analysis Framework was used to conceptualise the decision-making processes of authorities responsible for flood risk management. Based on this, an Agent Based Modelling tool has been created, enabling the exploration of the system’s behaviour under different decisions and risk scenarios. The tool has used as a case study the responsible authorities for flood protection in the city of Rethymno, Greece. The tool has a user-friendly interface enabling the end-user to explore the drivers of decision-making processes under different conditions.

Uncertainties in hydro-climatic projections are (in part) related to different components of the modeling chain. Although a combination of numerous projections (ensemble) would be needed to characterize the overall uncertainty, in practice a small set of scenario combinations are constructed to provide users with a subset that is manageable for decision-making. The approach is based on a framework, rooted in the information theoretic Maximum Information Minimum Redundancy (MIMR) concept, for identifying a representative subset from an available large ensemble of hydro-climatic projections. We analyze an ensemble of 16 precipitation and temperature projections for Sweden, and use these as inputs to the HBV hydrological model to simulate river discharge until the mid of the 21st century. Representative subsets are judged in terms of different statistical characteristics for precipitation, temperature and discharge and the sensitivity of the identified subset is assessed for different seasons and future periods. Results indicate that a 20-35% subset of the available set of projections can represent a large fraction (more than 80%) of the ensemble range of hydro-climatic changes. We find that the identified representative subsets are sensitive to the regional hydro-climatic characteristics and the choice of variables, seasons and future periods.

A sensing platform for the in situ, real-time analysis of phosphate in natural waters has been realised using a combination of microfluidics, colorimetric reagent chemistries, low-cost LED-based optical detection and wireless communications. Prior to field deployment, the platform was tested in the laboratory where a total of 459 autonomous measurements were performed (153 each of low calibration standard, high calibration standard and sample). The platform was subsequently field-deployed in Dublin Bay at the mouth of the Tolka Estuary, County Dublin, Ireland, to track changes in phosphate continuously at a transitional water body site previously identified as at risk. Initial data from 10/04/19 to 17/04/19 is presented, comprising 168 autonomous measurements (56 each of low calibration standards, high calibration standards and sample).

The rural water supply systems in the countryside necessitate sustainability and security assessment to ensure long-term and safe water supply to target beneficiaries. The study aimed to analyse the hidden threatening factors in water supply system along technical requirements. It also predicts the probability of incidents and security degree of the system. The rural water supply system in typhoon Haiyan affected areas was rehabilitated and constructed through national and international funds. It sampled about 5,921 rural water supply systems constructed and installed in 75 municipalities in Eastern Visayas. The water supply system sampled were: 13 Eastern Samar; 13 from Samar; 12 from Northern Samar; 13 from Leyte; 14 from Southern Leyte; and 1 from the Province of Biliran. The water security was assessed and analyzed according to the following indicators: demand and availability, natural factors affecting safety and quality, and policies and management mechanism. The water criteria was analysed using Analytic Hierarchy Process. The study found out that the natural factors such as floods, drought, eathquake have highest computed possibility values. The water security of the water supply systems in typhoon Haiyan affected areas has to implement control measures to minimize the degree of damange due to natural factors..

In this investigation, we use climatic, water-related indicators to evaluate the impact of climate change on the assimilative capacity of the Asopos River, Central Greece. Indicators were developed and organised under the SWICCA climate service (http://swicca.eu), which aims to develop and showcase a Water Management Information Service for the Copernicus Climate Change Service based, among others, on real case studies and end-users. River flow indicators are the core data for evaluating the assimilative capacity of the Asopos River under different scenarios regarding average flow conditions. Assimilative capacity was evaluated for 6 heavy metals, namely Cr, Cd, Cu, Pb, Ni and Zn. Socioeconomic indicators (GDP and Land Use) were also utilized to incorporate changes of economic activities in the assessment. Climate impact indicators are free of the need for laborious processing. They cannot cover all aspects of local analysis needs but, combined with local information, they are key-data for integrated climate change impact investigations. Results from 226 scenarios of circulation, regional and impact models combinations as well as industrial activity evolution, indicate for the majority of the scenarios, a small impact on the river’s assimilative capacity, associated with climate change, while industrial activity evolution could have a significant effect.