chapter 14 - Drinking Water treatment and Distribution
Impact of Climate Change
The impact of climate change on water quality has been estimated scientifically (Cromwell et al., 2007; IPCC, 2007). Earlier snowmelt and more intense episodes of precipitation will likely increase turbidity in source waters. Increased flooding may lead to sewage overflows, resulting in higher pathogen loading in the source waters. Increased water temperatures and shallower reservoirs may result in more prevalent eutrophic conditions in storage reservoirs, increasing the frequency and locations of cyanobacterial blooms. These potential changes could result in challenges for surface water treatment plants and require additional monitoring to quantify changes in source water quality and better control of finished water quality. Higher sea levels could impact coastal groundwater basins making the protection of groundwater from seawater intrusion more difficult (CUWA, 2007).
Increasing demand on the limited valuable water resources available in California will compound any impact from climate change. The continued growth in the state will continue to stress the availability of the freshwater resources needed for domestic, agricultural, and industrial uses. California coastal water providers have begun evaluating the feasibility of desalination of seawater as an additional supply. Desalinated seawater, although more expensive to develop due to the high energy requirements and planning and permitting costs, has been identified as a reliable drought-proof supply.
As highlighted earlier, Proposition 50 funding of desalination construction and demonstration projects is a critical resource to drive evaluation and implementation of desalination technologies in California.
Efficient Use of Water
The efficient use of water is seen as a viable complement to—and in some instances, a substitute for—investments in long-term water supplies and infrastructure. Water use efficiency is a concept to maximize the use of water or to minimize its waste. Water use efficiency will continue to be a key element of addressing reduced water availability and is seen as a major step to be addressed before turning to more costly water sources such as desalinated seawater. Water efficiency programs and practices may include utility leak detection, water conservation programs, water efficiency pricing and incentives for installing water efficient appliances and landscaping, as well as improvements in water recovery as part of water treatment plants (reducing water used in treatment plant processes for backwash, etc.).
An important aspect of strongly encouraging water conservation is the ability of the water utility to establish an escalating metered rate based on the volume of water used—full cost, conservation or efficiency pricing. Since 1992, California law has required urban water suppliers (those serving more than 3,000 connections or delivering more than 3,000 AF of water per year) to install a water meter on new connections. More recently, AB 2572 established the requirement for retrofitting water meters on pre- existing connections and charging customers for water based on the actual volume of
caLifoRnia WateR PLan | update 2009
iMPRove WateR QuaLitY