OVERVIEW

a. Mission

Water resources are high on the agendas of the United Nations and the European Union (Water Framework, Groundwater, and Flood Directives) because they play a major role in the two-way relationship between human activities and the environment. Besides sustaining human life and the environment, water is needed in all economic activities, of which the competing demands (with increasing trend due to climate change) are to be met by this stochastic resource. Water resources must be managed in terms of quality, in terms of geographical distribution (water resources and demand may be remotely located) and in terms of temporal variability (water demand is constant, but water is available only during short periods). Water-resources management is also the means to protect the society from hydrologic extremes regarding prolonged low values (droughts).

b. Research Focus and Main Scientific Directions

The Hydro Group is active in the science and engineering of surface and sub-surface water resources –hydraulics/hydrology/mass transport/resource management– developing and applying analytical and numerical models, deterministic and stochastic, as well as conducting advanced hydrometric work. Along these directions, during 2018-2021, the Hydro Group focused its research activities in the following fields:

Surface hydrology

(i) Establishment and operation of a network of 16 hydrometric stations in Attica and in the Peloponnese. Development of in-house tele-hydrometric stations, at half the price of commercial stations, offering additional features (e.g., connection with camera). Installation of on-line stations with automated data acquisition and transmission. Advanced hydrometrics employing hand-held surface flow velocity radar (SVR) and image velocimetry techniques, along with the development of a maximum entropy flow estimation method. (ii) Development of urban hydrology models and efficient linear regression based sub-hydrological models to simulate hydrological responses. (iii) Water resources management with standard approaches (e.g., dynamic programming, network flow programming and parametric rules) and modern approaches based on straightforward to apply machine-learning algorithms (optimal management policy obtained via plain spreadsheet). (iv) Machine learning models in Hurst-Kolmogorov stochastics. (v) Low computational burden flood models customised for forecasting in small to medium-sized water basins of Greece. Goal providing short-term forecast services.

Subsurface hydrology

(i) Aquifer characterisation – hydraulic parameters: Algebraic estimation of the specific storage from slug tests in confined aquifers in the overdamped case. (ii) Simulation of seawater intrusion in coastal aquifers with variable-density flow models and with an innovative highly efficient decoupled flow and transport model that allows executing multiple runs in Monte Carlo simulations for identifying optimal management strategies and uncertainty.

Ecology

(i) Wetlands as large-scale nature-based solutions: Status and challenges for research, engineering and management. (ii) Linking aquifer recharge, saltwater intrusion and subterranean estuary biogeochem­istry to primary production dynamics of coastal geochemical lagoon dynamics.