Thursday, April 3, 2014

Sustainable Water for California

from Drought Monitor March 25 2014
Despite recent storms dropping several feet of snow in the mountains, the water content of the snowpack in California was at 32% of normal last Tuesday. The recent rains in northern California have added less than an inch of water; and according to the National Weather Service, the weather is expected to be warm and dry, the rainy season is at an end. After three years of drought, the situation is becoming critical as over a dozen of the small towns with single source water supplies are in danger of running out of water as their wells and reservoirs may go dry before summer’s end. Ninety-nine point eight percent of the state is in a drought from moderate drought through extreme drought to exceptional drought.

The climate of earth has changed over the centuries. The Sahara was not always a desert, once rivers flowed and lakes existed. A 200 year period of drought is believed to have contributed to the collapse of the Mayan civilization. So scientists’ concerns that California and the entire western region will have less precipitation, diminished snow pack and less springtime runoff in the future must be planned for. California must find sustainable water management solutions in the face of a drier future. The drought in California will affect all of us in the cost of food and energy.

California grows $45 billion dollars of food a year, and some nuts and fruits are only grown in California. Without irrigation, crops could never be grown in the arid and semi-arid lands of California where irrigation consumes more than 75% of the water supply. The system of water rights that developed in the west assured for generations the allocation of water to agriculture. The water rights system as conceived and administered in the western states was not designed to conserve water. It was developed in a time when population was still sparse, water supplies were believed to be plentiful and development and growth was to be encouraged. This water rights scheme has resulted in non-sustainable use of groundwater and unsustainable agricultural practices.

Micro-irrigation also known as drip irrigation has the potential to increase yields and decrease water, fertilizer, and labor requirements if managed properly. However, the costs involved in implementing drip irrigation in California can be substantial, not just the $800-$2,000 for the tubing, filters and pumps, but also the irrigation infrastructure that would allow controlled constant delivery of filtered water. On demand water availability for irrigation may be an insurmountable hurdle within the current water infrastructure and  water allocation and rights system in California. This has to change, but the massive water infrastructure of California is not flexible and our political system and human nature have not excelled in the past at sensible choices for the future.

The Pacific Institute an Oakland based NGO is an expert on freshwater issues, especially those in California. They have just launched a new website- California Drought. The website is a central location for tools, research, and information on the drought. The site brings together information on technologies and policies that have been developed to respond to droughts in other parts of the country and world and in previous droughts in California. It is necessary that all communities within California make sure that their water supplies are robust and that they respond to the changes in water availability.

During drought conserving water is the first step. It is the quickest and cheapest way to reduce water demand. Changes in plumbing standards have produced low flow plumbing fixtures that can slash indoor water use. There are tremendous differences in water consumption of appliances and fixtures based on their age and design, according to the Handbook of Water Use and Conservation by A. Vickers.  Before the advent of low flush toilets, flushing was the largest use of water for each person. If you have new toilets and are home all day, your daily water use for flushing would be 8.2 gallons versus 25.5 gallons for an older toilet. That is a significant water savings.

The typical American uses the most water for flushing, showering, washing hands and brushing teeth, and laundry. Buying water efficient appliances and fixtures, maintaining the fixtures and repairing any leaks can significantly reduce our water use. By replacing appliances and fixtures with water efficient fixtures and eliminating outdoor use of water the typical American could reduce their water use to about 38 gallons per person per day without significantly changing their lives. Notice this eliminates outdoor watering. The time for green lawns in California is done. Outdoor watering in the semi-arid climate of California can more than double household water use according the US Geological Survey.

After conservation the next step in changing water use is utilizing all the alternative resources both though soft structure and capital structures. California needs to expand the use of recycled/treated wastewater, eventually eliminating the discharge of treated wastewater into the ocean and capture and treat all storm water. There may also be a role for other strategies, properly managed such as desalinization, the exploitation of groundwater, building additional reservoirs and damns and Governor Brown’s $15 billion plan to bore a pair of 30-mile tunnels east of Sacramento to channel Sierra.

Seawater desalination, by a reverse osmosis process, in which filter sea-water is forced through a fine membrane at up to 1,000 psi to remove salt and other impurities producing freshwater and a highly saline wastewater product referred to as brine is very reliable, but expensive. A relatively small desalination plant, a 50-million gallon a day seawater desalination plant that will supply the San Diego region with approximately 7% of its drinking water needs in Carlsbad, CA cost $1 billion to build and will require 15,000 kilowatt hours of energy for every million gallons of water produced to operate the equipment that is 273,750,000 kW-hours per year. That is extremely expensive water and can only reasonably be used after all conservation and reuse options have been implemented.

A cheaper and just as reliable source of water is to process and treat waste water and storm water. There is no reason that wastewater and water captured in stormwater systems in the cities should be released to the sea. For 30 years Los Angeles County has recycled the water from wastewater treatments plants. This water from both secondary and tertiary treated wastewater is discharged into spreading basins to recharge groundwater. Groundwater recharge can be done by surface spreading or direct injection wells. Recharging an aquifer has lower capital costs than dam and reservoir construction, but requires similar distribution networks and pumping costs tend to be higher. Monitoring water quality and availability are essential.

A private company, Cadiz, wants to tap an aquifer beneath 34,000 acres of the eastern Mojave and sell the water to suburbs and subdivisions in the Los Angeles Basin. Cadiz has proposed pumping 16.3 billion gallons a year from the Mojave to the coast of southern California through a 43-mile pipeline that Cadiz wants to build, and then merge into the Colorado River Aqueduct into Los Angeles. The groundwater took a millennium to seep down from the mountains and is not being recharged at anything approaching that rate. The result will be a drop in groundwater levels and subsidence. It is, however, legal even if it is wrong and unfair. Groundwater in California is complicated. Monitoring water availability and allocations and potential water rights of overlying landowners are not part of the California groundwater ownership and there is no allocation of groundwater the way that surface water rights are allocated.

NASA scientists, university researchers and the California Department of Water Resources water managers are now working together to apply advanced remote sensing and improved forecast modeling to better assess water resources, monitor drought conditions and water supplies, plan for drought response and mitigation, and measure drought impacts. NASA’s Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System to quantify groundwater depletion program will launch the next generation of satellites able to monitor groundwater changes on a weekly basis and be able to interpret the date in a more timely fashion to manage water resources in real time. Our increased knowledge about and ability to monitor water and groundwater and their interactions along with this drought provides California with an opportunity to address longstanding and intensifying water resource concerns. It can be an important turning point in California’s history or the beginning of the end.

No comments:

Post a Comment