Using Genetic Algorithms for the optimization of engineering problems has gained popularity within the water resources’ research community. These algorithms based on some biological mechanisms demonstrate robustness and efficiency in finding solutions. However, one of the problems faced by this type of heuristic approach is that the efficiency of the algorithm decreases when applied to real-world problems due to the large space that it must explore to find an optimal solution. For this reason, it is necessary to limit the space that the algorithm must explore to the most promising regions.

This article presents a methodology to rehabilitate urban drainage networks using an iterative procedure to reduce the solutions searching space. The procedure is based on shorten the initially wide search space to one that contains the optimal solution. Through iterative processes, the search space is gradually reduced to define the final region that contains the optimal solution. Once this region is established, a finer discretization is used in the exploration of the space to find the optimal solution. The optimization process includes the replacement of pipelines and the incorporation of storm tanks and hydraulic controls into the network. To achieve this, an optimization model has been developed that uses a Genetic Algorithm as an optimization engine connected to the Storm Water Management Model (SWMM) through a toolkit. The methodology also contemplates the adjustment of certain algorithm operators to improve their efficiency. Finally, this methodology is applied to a real drainage network that needs to be rehabilitated. The obtained results demonstrate the effectiveness of the process of reducing the space for search solutions to face these types of problems.

The middle portion of the St. Johns River is located in East-Central Florida, USA. This region of the St. Johns River is increasingly subject to urbanization and conversion of forest areas to agricultural land. Overall, these changes mean that future flood events in the area could adversely impact local citizens. Therefore, the examination of extreme flood events and resiliency to such events is critically important. The purpose of this preliminary study is to explore a range of practical applications to estimate extreme flood events at locations within the Middle St. Johns River Basin, focusing specifically upon the Wekiva River sub-basin (located just west of Lake Mary, Florida). The current work illustrates the overall technical methodology and provides preliminary estimates of extreme flood events at different return frequencies using two statistical approaches. Future work will also estimate the magnitude of extreme flood events via model simulations utilizing an existing Wekiva River HSPF rainfall-runoff model previously developed by the Saint Johns River Water Management District. Altogether, once fully integrated and complete, the methods will permit prediction of a range of possible flood discharges at any place along the Wekiva watercourse.

A sustainable strategy, involving a combination of physical, chemical and biological methods was proposed as an innovative approach to lake restoration in Poland. We believe that: (i) the interference with the lake shall be limited to the extent that is necessary for the gradual reconstruction of the ecosystem; (ii) attention must be paid to the preservation of biodiversity as an important element affecting the adaptation of the ecosystem in the face of change; and (iii) restoration requires less invasive methods (in comparison with eg. sediment dredging) and nature-based solutions. In the sustainable approach combined methods are used simultaneously, i.e. physical (hypolimnion aeration by means of wind-driven aerator), chemical (phosphorus and ammonium N precipitation with small doses of compounds) and biological methods (supportive stocking with the fry of predatory species). Another innovative method is the direction of spring waters containing high concentrations of nitrates to the deoxygenated bottom of the lake. This method increased the redox potential in the sediment-water interface, preventing the release of phosphorus from the bottom to the water column. It should be stressed that all methods are cost effective compared to other methods of restoration, what is of paramount importance for the local administration, being usually sponsors of lake restoration in Poland.

Long-term studies conducted in several lakes indicated a gradual improvement of water quality by means of: (i) reduction of phosphorus content, (ii) a decrease in chlorophyll-a concentration coupled with an increase of water transparency, (iii) rebuilding the species composition in phytoplankton community (replacement of Cyanobacteria by other groups of algae.

Hydropower-based electricity production provides approximately 33% of renewable energy in Greece - an activity, however, associated with adverse environmental effects on watercourses. Therefore, it should be considered as a key factor of water management programs ensuring safety and optimising environmental performance of hydropower facilities in accordance to Greece’s obligations towards European Union (EU) water policy. Water Framework Directive (WFD) was created by the EU in order to help member states to protect and improve the status of water bodies and was incorporated in Greek legislation by Law 3199/2003 . Within the scope of this study, we assessed both Hydroelectric power generation and Water Resources Management in Greece and we recorded the current status of the EU Water Framework Directive implementation in this field. Given that social-ecological systems emphasise the link between people and the ecosphere, we investigated possible conflicts that arise between hydropower-related renewable electricity production and water courses conservation, according to both national and EU legislation. We also studied the tools that WFD provides in order to solve potential problems, maintain economic viability and ensure good ecological status between hydropower utilisation and water protection in the face of increased demands to a more effective and sustainable management of environmental resources.

Polycyclic aromatic hydrocarbons (PAHs) belong to the group of persistent organic pollutants (POPs) which are major environmental pollutants associated with the environment. In this study (preliminary), the concentrations of eighteen (18) PAHs in soil, sediment and fish sample (Clarias anguillaris) of Owan River and agricultural soil samples around the river in Edo State were studied using standard analytical methods. Gas chromatograph equipped with flame ionization detector (GC-FID) was used for the determination of PAHs. The study revealed the presence of the 18 determined PAHs in the soil, sediment and fish (Clarias anguillaris) samples in varying concentrations. The concentrations of PAHs in the soil samples ranged between 0.0000-0.0506 (µg/kg) with total concentrations of ∑0.2390 (µg/kg) and ∑0.2700 (µg/kg) for soil samples from sampling location 1 and 2. The concentrations of the PAHs components in the sediments samples ranged between 0.002092-0.05866 (µg/kg) with total concentration of ∑0.150592 µg/kg and ∑0.0312183 µg/kg for sediment sample from sampling location 1 and 2 respectively. The concentration of PAHs components in the fish sample ranged between 0.0000-0.0746 (µg/kg) with total concentration of ∑0.300 (µg/kg). The concentrations of PAHs were higher in the soil samples than in the sediment samples. Concentrations of the PAHs residues detected in the fish samples were higher than that in the soil and sediment samples. In furtherance of this study, the number of sampling stations shall be increase to cover other communities while data generated will be subjected to more ecological risk assessments.

Due to the current trends of rising numbers of the human population, as well as increasing living standards, wastewater treatment plants are exposed to changes in the quantity and quality of input wastewater. Such changes can affect the efficiency of the operational work of the wastewater treatment plant. There are many input and output parameters of the wastewater quality indicators (Biochemical Oxygen Demand through 5 days, Total Suspended Solids, Chemical Oxygen Demand, etc.), as well as input and output hydraulic parameters (flow of wastewater). There is a need to consider all of these and make decisions about the efficiency of the wastewater treatment plant. Among all the procedures and methods, a multicriteria decision is one that could be applied in this research. The Paper will present the application of the Multi Composite Programming and Promethee method for the real case study of the Parkandabad water treatment plant in Mashhad, Iran.

Abstract

The recent increase of droughts in Sindh, Pakistan has had a large impact on the economy and environment of the province. Continuous change in patterns of rainfall and hydrological cycles due to climate change can potentially accelerate the occurrence of extravagant droughts and affect the availability of water resources in the future. This alarming situation makes it necessary to evaluate and estimate the vulnerability for planning and management of water resources and identify the well-suited and effective mitigation actions to conduct a risk analysis for droughts (drought risk analysis) in the context of climate change. The objective of this research is to identify the change in temporal trends of drought characteristics in Sindh province due to climate change. Initially, at the first stage, the changes in appearance and occurrence of droughts were analyzed by utilizing the Standardized Precipitation Evapotranspiration Index (SPEI) for Climate research unit (CRU) data of Sindh province and were analyzed for the past 30 years (1981 - 2010), and Representative Concentration Pathways (RCP) climate change situations data of year (2011 - 2100). Second, the variation on the temporal trends of drought properties was carried out by utilizing run theory which was used for comparative analysis of drought total period, extent, severity, and significance to allow for quantitative evaluation under previous and approaching climate conditions. These results determine the severe influence of climate change on drought and will contribute to the planning and management of water resources and drought countermeasures (physical control, technical control, administrative and managerial control) to climate change.

Background: The Vistula River is Poland's longest river, and its section called the Lesser Poland Gorge of the Vistula (Polish: Małopolski Przełom Wisły) belongs to two Natura 2000 Areas. The waters of the Vistula River periodically flood neighbouring areas during winter or summer floods. Among studies on the microbiome of river waters, sanitary analyses to control drinking water dominate. The most frequently determined bacteria are Escherichia coli and Enterobacter, Citrobacter and Klebsiella. In this study we decided to determine the composition of the bacterial community and its metabolic potential in Vistula River water.

Methods: The water was taken from the Vistula River in Janowiec in the Lublin Province. The water was taken from the river flow at a distance of about 27 m from the shore into a 50 L sterile container. In order to analyse the structure of bacterial communities, the next generation V3/V4 16S rDNA region sequencing (NGS) using Miseq (Ilumina) and the community-level physiological profiles (CLPP) method using the Biolog® EcoPlate™ system were applied.

Results: A total of 413 operational taxonomic units (OTU) were obtained, of which 377 could not be classified to type. Among those identified, Arenimonas (2.13%), Brevundimonas (1.44%) and Flavobacterium (1.05%) predominated. Of the OTUs present above 1% in the water, 23 were unclassified, including the dominant Unclassified_CL0182 (5.05%).

The analysis of the metabolic potential of river water community microorganisms showed that they were most active after 120 h incubation of EcoPlate™ plates. The most intensively degraded group of substrates were carbohydrates (30.93%) and the least amines and amides (6.44%).

While searching for bacteria pathogenic to humans, there were a few representatives of Legionella sp. (0.03%) and Rickettsia sp. (0.03 %). Additionally, the presence of bacteria from the genus Brevundimonas (1.44%) and from the family Oxalobacteraceae (0.09%) were detected, which may cause opportunistic infections. The results obtained are surprising, as it is commonly believed that river waters are contaminated with pathogenic microorganisms.

Conclusion: The NGS analysis did not indicate a sanitary risk to humans. A large number of unclassified bacteria indicate a still low level of knowledge and limitations concerning the world of bacteria.

Climate change, along with the high water demand, has increased the groundwater withdrawal and is severely affecting the food-energy-water (FEW) nexus worldwide, especially in the arid and semi-arid regions. In developing countries, like India, lack of awareness and resources for adaptation of advanced technological applications for irrigation has led to inefficient agriculture practices and excessive groundwater withdrawal. In India, more than 89% of extracted groundwater used in the agriculture sector, and at the same time, only 5% of the net irrigated area is drip irrigated. In this study, we aimed to calculate the water use efficiency (WUE) of a flood irrigated orange orchard in central India. The global sensitivity of soil hydraulic parameters also assessed. Thermal Dissipation Probe (TDP-30) sap flow sensor together with HYDRUS 1D model, used to calculate the actual water demand for orange trees and leakage of water below the root zone. The model was satisfactorily able to reproduce the daily sap flow and root water uptake with a Nash–Sutcliffe efficiency (NSE) index of 0.68. The results show that the WUE of flood irrigation is only 25% and 75% of net irrigated water drained below the root zone. The results of global sensitivity analysis (GSA) for the soil hydraulic parameters suggest that the pore-size distribution index and saturated hydraulic conductivity has a significant influence on the leakage below the root zone. Whereas, the air-entry-pressure parameter and saturated hydraulic conductivity have a significant influence on transpiration rates. The study also shows the significance of initial soil moisture condition in optimizing the irrigation schedule. In conclusion, the comprehensive study suggests that flood irrigation is a gravely inefficient irrigation system for the irrigation of orchards, and a sensor-based approach may be more effective in deciding the irrigation patterns.