Abstract
A water distribution network in an urban area in Muscat region (capital city of Oman) is assessed for operational performance using the widely accepted methodology proposed by International Water Association (IWA). The technical performance of this network was assessed using global performance index methods after modifying the performance levels as per local guidelines. A total of 37 operational performance indicators for the network were selected to carryout assessment. Overall operational performance showed high scores whereas some indicators showed unacceptable performance values. The network showed very high technical performance considering nodal pressures. The lower performance for pipe velocity may be attributed to the fact that the network is currently being utilized by 70% of the population for which it was designed. The residual chlorine levels were within the acceptable range of the Public Authority for Water (PAW) showing a very good performance by virtue of water quality. This study will be useful for the decision makers to assess the operational, technical and water quality performance of urban networks and take actions for improvements.
This technical note describes a field study investigating the movements of federally endangered Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus (ATS), during the summer and fall of 2017 near a cutterhead dredge working in the James River, Virginia, to provide data addressing the concern about the potential impacts of dredging activities (for example, excavation, transit, disposal, sounds, reduced water quality) on the ATS.
Abstract
The aim of the research was to determine the influence of the substrate and different drainage materials on retention capacity and runoff water quality from three green roof containers. Phosphates were chosen as the water quality indicator based on their potential adverse impact on water quality in urban rainwater collectors. The field experiment was conducted at the Warsaw University of Life Sciences Water Center meteorological station in years 2013–2015. In terms of precipitation, the monitoring period covered a wet (+147.1 mm), average (+42.7 mm) and dry (− 66.3 mm) year. Leakage from the containers was recorded when the substrate moisture exceeded 20% and precipitation exceeded 3.5 mm/d for washed gravel, or 5.0 mm/d for a polypropylene mat and expanded clay. Phosphates were observed in leachates from all containers, with higher values observed in the second year of monitoring. As the result of this study, it can be concluded that the polypropylene mat and aggregates create different conditions for the formation of the leachate, in both volumes and its chemistry. The drainage layer made from a polypropylene mat is the most effective in terms of rainwater retention capacity and the resulting leachate quality.
Operational and technical performance of a water distribution network in Oman
