A multi-dimensional approach to assess water-security risks in river basins

The term water security was launched in 2000. 22 years have passed since then and the world is still experiencing high levels of water insecurity, and vulnerable communities and nations are the receptors of the most devastating consequences of such condition. Climate and socio-economic change can exacerbate water insecurity for all. To contribute to a better understanding of water-security risks in river basins, the authors of this paper present here an approach to assess water-security risks in five dimensions and four scales, and based on systems perspective, hydrocomplexity, risk science, participation of river basin relevant parties, and prioritisation process. Our proposed approach involves six steps: identification of the whole universe of water-security hazards for a specific river basin; qualitative description of the hazard impacts by scales and dimensions; prioritisation of impacts to be fully assessed; full risk assessment of prioritised impacts by analysis of hazards, exposure, vulnerabilities, uncertainties, and the strength of the knowledge; risk visualization; and outlining a risk management plan. We claim this approach could be useful for communities, organisations, academics, and practitioners dealing with or involved in water security. This is an ongoing project, and we are currently developing this approach in two municipalities in Colombia

Effects of water inlet configuration in a service reservoir applying CFD modelling

This study investigated the state of a service reservoir of a drinking water distribution network. Numerical simulation was applied to establish its flow pattern, mixing conditions, and free residual chlorine decay. The influence of the change in the water inlet configuration on these characteristics was evaluated. Four scenarios were established with different water level and flow rate as the differences between the first three scenarios. The fourth scenario was evaluated to assess the influence of the inlet configuration, momentum flow and water level on hydrodynamic conditions within the service reservoir. The distribution of four nozzles of 152.4 mm diameter was identified as a viable measure to preserve the water quality in this type of hydraulic structures

Field assessment of bacterial communities and total trihalomethanes: Implications for drinking water networks

Operation and maintenance (O&M) of drinking water distribution networks (DWDNs) in tropical countries simultaneously face the control of acute and chronic risks due to the presence of microorganisms and disinfection by-products, respectively. In this study, results from a detailed field characterization of microbiological, chemical and infrastructural parameters of a tropical-climate DWDN are presented. Water physicochemical parameters and the characteristics of the network were assessed to evaluate the relationship between abiotic and microbiological factors and their association with the presence of total trihalomethanes (TTHMs). Illumina sequencing of the bacterial 16s rRNA gene revealed significant differences in the composition of biofilm and planktonic communities. The highly diverse biofilm communities showed the presence of methylotrophic bacteria, which suggest the presence of methyl radicals such as THMs within this habitat. Microbiological parameters correlated with water age, pH, temperature and free residual chlorine. The results from this study are necessary to increase the awareness of O&M practices in DWDNs required to reduce biofilm formation and maintain appropriate microbiological and chemical water quality, in relation to biofilm detachment and DBP formation

Identification of Nontuberculous Mycobacteria in Drinking Water in Cali, Colombia

Nontuberculous mycobacteria (NTM) are ubiquitous microorganisms naturally resistant to antibiotics and disinfectants that can colonize drinking water supply systems. Information regarding the spread of NTM in specifically South America and Colombia is limited. We aimed to identify and characterize NTM present in tap water samples from Cali, Colombia. Drinking water samples and faucet biofilm swabs were collected in 18 places, including the city’s three main water treatment plants (WTPs). Filter-trapped material and eluates (0.45 μm) from swab washes were plated in 7H11 agar plates. Suspected colonies were evaluated microscopically, and NTM species were identified based on the rpoB gene. Antibiotic susceptibility testing was also performed. Fifty percent (9/18) of sampling points were positive for NTM (including two WTPs), from which 16 different isolates were identified: Mycobacterium mucogenicum (8/16), M. phocaicum (3/16), M. chelonae (2/16), M. mageritense (2/16), and M. fortuitum (1/16), all rapidly growing mycobacteria. A susceptibility profile was obtained from 68.75% (11/16) of the isolates. M. chelonae was the most resistant species. All NTM isolated are potentially responsible for human diseases; our findings might provide a baseline for exploring NTM transmission dynamics and clinical characterization, as well as potential associations between NTM species found in drinking water and isolates from patients

A multidimensional approach to assess water-security risks in river basins

A conference contribution for the 1st Water-WISER Early Career Researcher Conference, Transdisciplinary Global Perspectives on Water and Waste Services, held at Loughborough University 21 - 23 June 2022.  </p

MUISKA: multidimensional approach for risk assessment of an intermittent water system

Despite its vast reach, the term water security remains challenging to ground into actionable daily water risk scenarios. From its introduction 20 years ago by the ministerial Declaration of The Hague on Water, to its adoption by development actors, water professionals, academia, and governments–various theories, methodologies, and approaches have been published. Failures to advance SDG6 signal a clear need for an approach that includes multiple water-security risks at basin level to improve water and land planning. Here we present MUISKA, MUltidimensional rISK Assessment, an approach to assess and compare multiple water-security risks at basin level. In this paper, we explore the development of the first three steps of this approach by the identification of water service perceptions using surveys in Cajibío, a municipality highly affected by the armed conflict in Colombia. The MUISKA approach allowed us the identification of intermittent water supply as an important and complex water security issue in Cajibío. Based on multiple-actor participation, systems perspective, and notions of hydrocomplexity, MUISKA facilitated the documentation and assessment of complex and competing water-security scenarios