In a historic settlement, the LADWP (Los Angeles Department of Water and Power) and the GBUAPCD (Great Basin Unified Air Pollution Control District) have agreed on terms by which Los Angeles will be able to withdraw significantly more water from the Owens Valley again.
http://www.latimes.com/...
In recent years, the LA Aqueduct water supply which historically has provided the majority of DWP water, has provided much less due to drought and legal restrictions related to a long litany of lawsuits to mitigate the various severe impacts of the water withdrawals. One of these restrictions has related to dust control, which has consumed as much as 75kaf of water in the Owens, reducing diversions by similar amounts.
Great Basin, which is responsible for regulating dust pollution from the huge (110 square mile) dry lake bed created by the draining of Owens Lake after construction of the L.A. Aqueduct, had finally successfully forced LADWP to live up to its obligations to mitigate what has been among the worst particulate pollution in the nation. Progress to-date has resulted in 90% reductions, and continues to improve.
However, the cost, both in financial terms, and in reduced water supply, has been significant. LADWP estimates roughly 1/6th of their ratepayers' bills are devoted to dust control in the Owens. 75kaf of gravity flow water not sent to Los Angeles is about 1/7th of total consumption by DWP customers.
Hence, a solution which promises to cut the cost of dust control to 1/3rd, further improve dust control efficacy, and free up at least half of the water currently used for dust control within 3 years is a godsend for all parties.
The announced settlement promises to do all of that via expanded use of a dust control technique colloquially referred to as tillage. Basically, fine, slightly wetted surface dust is plowed into/under and bound with slightly deeper claybed, and is thus bound for several years before the process must be repeated. The process has been piloted, studied, and deemed a success which can now be more widely deployed in lieu of constant wetting and flooding.
From a 2011 abatement order by Great Basin:
Tillage is commonly used to control wind erosion in agricultural and arid regions around the world. It works by clodding and roughening the soil surface, rendering it more resistant to wind erosion. Surface roughness reduces the wind velocity at the surface, so that windblown soil particles like sand are trapped. The creation of soil clods through appropriate tillage methods forms a stable surface resistant to wind erosion by binding of the available fine-grained loose soil particles.
http://www.gbuapcd.org/...
Given LADWP's prior behavior with respect to this issue, the public might rightly be skeptical of promises in this regard. Great Basin, however, and in particular enforcement officer Ted Schade, have shown themselves worthy of trust on the specific issue of dust control. If Ted Schade says that DWP will not need water currently dedicated for dust control, and that air quality will continue to improve, you can believe him.
Increased withdrawals will begin this year and will ramp up to about half of all dedicated dust control water within just 3 years if all goes as planned. Simultaneously, budgetary demands for dust control and replacement water supply will diminish for Los Angeles ratepayers. Residents of the Owens Valley will maintain their understandable vigilance, but should breathe easier as time goes on.