The design goals of the developed software are described followed by its architecture, which is presented in detail. The GUI-based interface supports a variety of environmental management problems and can provide best practices in a timely manner. The toolkit is generic and applicable to any scientific field. It was applied on a renewable energy (RE) system's management. The developed model simulates the hydraulic characteristics of a small-scale hydropower (SHP) station. Harmony search algorithm (HSA) toolkit optimized the SHP's operation, without violating the ecological constraints related to environmental flow (EF) regimes. This was equal to maximizing the revenues from SHP's energy production in terms of a hypothetical fluctuating market. Apart from securing the provision of EF regimes, HSA toolkit's outcome provided management practices that increased the total economic gains. Supporting the economic viability of SHPs and their environmental friendliness is needed to strengthen their role in the RE mix.

a b s t r ac tIn this paper, a groundwater management model for which the solution is obtained through a coupled application of simulation and optimization models is analyzed. The most widely used numerical groundwater flow model, MODFLOW, which is a three-dimensional (3-D) model using the finite differences method for solving the governing groundwater flow equations, is used as the flow-simulation model. This model is then connected to the Harmony Search Algorithm, one of the most emerging and successful metaheuristic optimization techniques, which simulates the quest for perfect harmony in music. In this paper, this technique is applied to a classic, theoretical example found in the manual of MODFLOW for comparison purposes, by examining the optimization of its aquifer system in terms of minimizing the pumping cost. For this application, a specially designed computer software programme was developed in MATLAB environment. This software, apart from coupling the simulation and optimization models, provides 2-D and 3-D graphical representations of the results allowing users to have a visual image of the piezometric surface in the whole aquifer system area. More specifically, in the specific management problem, the positions and the total required water demand for the pumping wells from the three aquifers system are pre-defined, while the optimal distribution of the pumping rates is determined through the proposed methodology. The results show that coupling flow-simulation and optimization models could be a very useful procedure when solving complex groundwater management problems.

In this paper, the possibility of installing small hydraulic turbines in existing water-supply networks, which exploit the daily pressure fluctuations in order to produce energy, is examined. For this purpose, a network of five pressure sensors is developed, which is connected to an artificial intelligence system in order to predict the daily pressure values of all nodes of the network. The sensors are placed at the critical nodes of the network. The locations of the critical nodes are implemented by applying graph theory algorithms to the water distribution network. EPANET software is used to generate the artificial intelligence training data with an appropriate external call from a Python script. Then, an improvement model is implemented using the Harmony Search Algorithm in order to calculate the daily pressure program, which can be allocated to the turbines and, consequently, the maximum energy production. The proposed methodology is applied to a benchmark water supply network and the results are presented.