In many delta areas hydraulic structures are key elements in water management strategies for fresh water supply and flood risk management. Adaptation of delta areas to changing climatological and societal conditions will be in pace with the renovation and replacement of these hydraulic structures. Since hydraulic structures are prone to deterioration, their performance diminishes over time. Changes in society, the economy, and the physical environment can also alter the functionality of structures, or have an impact on their performance. Although faced with deterioration and exogenous changes, timing of replacement is essential because replacing too early leads to insufficient use of invested capital, while replacing too late leads to loss of societal benefits. This article explores the timing of replacement using adaptation tipping points. We indicate three drivers – deterioration, biophysical change, and socio-economic change – that determine the moment in time when replacement becomes necessary. Moreover, we conclude that for determining the moment of replacement, at the very least, the objectives, maintenance and operations of hydraulic structures need to be taken into account. This exploration is illustrated with the task of replacing seven hydraulic structures in the River Meuse.
How big is the distributed energy opportunity for water and wastewater utilities?
Energy costs for water utilities are large, and growing Energy is a significant cost for many water utilities, and costs are growing as more energy-intensive forms of water supply, including desalination, are being used. Energy is typically the second-largest utility budget item in developed countries, after labour. In many developing countries, energy can account for 70% or even more, of annual costs. But water and wastewater utilities can generate and export energy – in multiple forms. Water utilities...
Monitoring once through cooling water - Case study
The Situation Power plants and paper mills use service water loops and mill water loops respectively for the cooling of lubricating, hydraulic, turbine and transformer oil. These cooling systems feature large, recirculating volumes of water which are treated with biocides, dispersants, and corrosion inhibitors. By comparison, refineries often useoncethroughcooling water systems. The cooling water is taken from lakes, rivers, or the ocean and circulated once through the plant to cool processes. Large volumes of...
Removing VOCs from Municipal Water Supply - Case Study
QED E-Z Tray® Air Strippers Removing Volatile Compounds in Cheyenne’s Drinking Water The U.S. Army Corps of Engineers (USACE) – Omaha District has funded the design and construction of a new groundwater treatment plant in Cheyenne, Wyoming to treat groundwater from the city’s Borie well field. This important groundwater supply was apparently contaminated with tricholorethene (TCE) in the late 1960s at the Former F.E. Warren Atlas Missile Site 4, several miles southwest and up-gradient of...
Study of hydraulics and mixing in roof tanks used in intermittent water supply
Roof tanks are common in low and middle income countries, due to the intermittent water supply. Their hydraulic and water mixing behaviour has not been studied. This paper presents the results of a study on mixing and water demand in roof tanks, based on physical and numerical models. Tracer tests were carried out on a real scale transparent wall laboratory model of a roof tank, and a three-parameter residence time distribution model was applied, showing that the model that best describes mixing in roof water...
DC Water Taps Into Biodiesel’s Sustainability Benefits
Sustainability is more than a buzzword at DC Water. Ingrained throughout the agency, sustainability is in high gear at DC Water’s fleet division where biodiesel fuel powers all 230-diesel vehicles, and emissions are closely monitored. “Biodiesel just makes sense,” said Timothy Fitzgerald, Director Fleet Management for DC Water. “We switched to biodiesel in 2007 and have never looked back. It can be used in existing diesel engines, reduces emissions, and our drivers notice a big difference...