Integrated Water Balance and Water Quality Management Under Future Climate Change and Population Growth: A Case Study of Upper Litani Basin, Lebanon

The impacts of the growing population at Lebanon including Lebanese, Palestinian and Syrian refugees, associated with the changing climate parameters such that the precipitation are putting the Bekaa Valley’s water resources in a stymie situation. The water resources are under significant stress limiting the water availability and deteriorating the water quality at the Upper Litani River Basin (ULRB) within the Bekaa Valley region. These impacts are assessed by Water Evaluation And Planning model to assure the water balance and quality at baseline scenario in 2013, and future scenarios reaching 2095, serving by the Watershed Modeling System to get the flow throughout the Litani River’s ungauged zones. Moreover, a General Circulation Model is used to predict the future climate up to 2100 under several emissions scenarios which shows a critical situation at the high emission scenario where the precipitation will be reduced about 87 mm from 2013 to 2095. The aim of this research is to reduce the water pollution that limits the availability of usable water, and to minimize the gap between the demand and supply of water within the ULRB in order to maintain water resources sustainability, and preserves its quality, even after 80 years. In particular, this may be achieved by removing encroachments on the river, by adding waste water treatment plants, by reducing the amount of lost water in damaged water network, and by avoiding the overconsumption of groundwater.

Simulation for water quality management using system dynamics modeling in the Bedadung Watershed, East Java, Indonesia

The potential for pollution of rivers is influenced by river-water discharge and the distribution of pollution sources. This research aimed to examine recommendations for water quality management in the Bedadung River segment of the Patrang, Sumbersari, and Kaliwates Districts as an urban area of Jember Regency refer to simulations of the total pollution load capacity for 10 years (2016-2026) using a system dynamics modeling. The preparation of a system dynamics modeling used Powersim 5.0 software. It could represent holistic environmental management modeling. The input data were total suspended solid (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and the streamflow of the Bedadung River. The model scenarios were the business of usual, moderate, and optimistic scenarios involving environmental and socio-economic aspects. The medium-term and long-term recommendations for water quality management of the Bedadung River based on system dynamics simulation were respectively moderate scenario and optimistic scenario. The strategies of the moderate scenario were application of the best management practice method in agricultural cultivation, improving sanitation and domestic wastewater treatment, implementing clean production in the field of livestock and industry, as well as waste management on riverbanks. These alternative strategies for river water quality management can be used as consideration for protecting surface water sources in urban areas.

Groundwater Recharge Assessment Using Multi Component Analysis: Case Study at the NW Edge of the Varaždin Alluvial Aquifer, Croatia

Exploring the interaction between precipitation, surface water, and groundwater has been a key subject of many studies dealing with water quality management. The Varaždin aquifer is an example of an area where high nitrate content in groundwater raised public concern, so it is important to understand the aquifer recharge for proper management and preservation of groundwater quality. The NW part of the Varaždin aquifer has been selected for study area, as precipitation, Drava River, accumulation lake, and groundwater interact in this area. In this study, groundwater and surface water levels, water temperature, water isotopes (2H and 18O), and chloride (Cl−) were monitored in precipitation, surface water, and groundwater during the four-year period to estimate groundwater recharge. Head contour maps were constructed based on the groundwater and surface water levels. The results show that aquifer is recharged from both Drava River and accumulation lake for all hydrological conditions–low, mean, and high groundwater levels. The monitoring results of water temperature, chloride content, and stable water isotopes were used as tracers, i.e. as an input to the mixing model for estimation of the contribution ratio from each recharge source. The calculation of mixing proportions showed that surface water is a key mechanism of groundwater recharge in the study area, with a contribution ratio ranging from 55% to 100% depending on the proximity of the observation well to surface water.

Temporal and Spatial Water Quality Assessment for Rivers in Metropolitan Areas Using Multivariate Statistics and Water Quality Indices: A Case Study of the Geumho River, Korea

The Geumho River in South Korea passes through a metropolitan area with a high population density and multiple industrial complexes and, therefore, the water quality of this river is of significance for human health and economic activities. This study aims to assess the water quality of the Geumho River to inform river water quality management and improve pollution control using multivariate statistics and the Korean Water Quality Index (KWQI). Principal component and factor analysis identified those factors related to organic pollutants and metabolism (principal factor 1), and phosphorus and fecal coliform content (principal factor 2). In a cluster analysis, time was considered by distinguishing between seasons (spring, summer, autumn, and winter) and space was considered based on upstream (US), midstream (MS), and downstream (DS) river sections. Seven temporal variables and six spatial variables were extracted from the discriminant analysis (DA) results; the most important water quality variables were high during the spring and summer seasons and in the MS and DS regions. Temporally, the KWQI was highest in winter (70.9) and lowest in spring (59.2), whereas spatially, KWQI values were highest in the US (67.5) and lowest in the MS (56.4) sections. These results indicate that to be most effective, water management interventions in the Geumho River should focus on the urban midstream section and spring seasons.

Investigating the Mechanism Behind the Release of Microcystins in Freshwater Cyanobacteria

<p>The frequency and distribution of toxic cyanobacterial blooms are increasing globally, creating the need for a better understanding of the processes involved in toxic secondary metabolite production. Microcystins (MCs) are potent hepatotoxins produced by a wide range of bloom-forming cyanobacteria genera such as Microcystis and Planktothrix. Although the release of MCs to the extracellular environment has long been considered a by-product of cell lysis and death, several studies suggest the presence of a mechanism that actively transports these toxins outside the cell membrane. The aim of the present study was to find evidence for a link between cell lysis and concentrations of extracellular MCs. A dual-fluorescence cell viability assay using the nucleic acid stain SYTOX Green was optimised for use on Microcystis and Planktothrix. A SYTOX Green concentration of 1 µM, and an incubation time of 30 minutes, yielded a bright and even fluorescent signal that readily identified lysed cells. The improved staining technique, in conjunction with liquid chromatography-mass spectrometry analyses, was employed in a culturing experiment to track the transfer of MCs to the extracellular environment in relation to the amount of cell lysis. For Microcystis, there was a strong and significant positive relationship between cell lysis and the concentration of extracellular MC. When the extracellular MC was predicted according to cell lysis levels and the MC content per cell, lysed cells were a major contributor of MCs to the extracellular environment, although the model overestimated the concentrations. Relationships for Planktothrix were significant but weaker, possibly due to reduced accuracy in the cell enumeration step, which would have altered the calculated MC content per cell. Whilst these findings support the hypothesis that cell lysis is the main contributor of extracellular MCs, the results do not exclude a role of MCs as signalling molecules. The recent finding that programmed cell death may occur in Microcystis under various environmental conditions may explain the commonly observed increase in extracellular MCs. Understanding the mechanisms involved in the transfer of MCs to the extracellular environment will provide further clarification on the function of these secondary metabolites and lead to the improvement of water quality management strategies.</p>