Discussion Notes - Climate Change

Desalination in the last few decades has

proven to be the method to produce freshwater out

of salty water with competitive cost compared to

the cost of alternative sources

* Another major concern is climate change. The first to be affected by climate change

impacts will be the old and the poor. It is our responsibility to address the realities of climate

change in our jobs as water planners and managers. Ocean desalination may only use one-third

more energy than water imports, but that is still more energy than is currently being used, which

means increased emissions of greenhouse gases. Reduction of greenhouse gas emissions in other

sectors should not offset more energy-intensive technologies, such as desalination. Instead, they

should offset energy use for more essential processes, such as water treatment. In addition, using

alternative sources of energy (e.g., solar, wind) to power desalination facilities should be

considered. http://ciwr.ucsc.edu/desalplanning/FirstWorkshopSummary_web.pdf

* A proposed desalination plant would:- Cost $115 million, producing 5 million gallons of water a day with the ability to expand to 15 million gallons per day. http://www.marinij.com/marin/ci_7381128

* The San Onofre OTC power generation facility can be used as a case study of

entrainment and impingement impacts. It was found that 4.4 million fish, of 61 different species,

were impinged on the open-water intake screens in 2004. This depressed fish populations within

three kilometers of the facility. The EPA used this case as part of its justification of the new

316(b) rules and did its own case study. They found 57 tons of fish were entrained each year at

the San Onofre facility, which decreased fish populations 60% within one kilometer of the

facility and 35% within three kilometers.

There are several techniques to reduce impingement and entrainment impacts on open

water intakes. The size of the intake pipe can be designed to reduce maximum intake velocity

and thus reduce the possibility of impingement. Wedge wire screens can be installed on existing

open intake towers to prevent entrainment by distributing