By Deb Murphy
Last summer, a variance was granted allowing less water to be used to control dust off the Owens Lake. For many of the parties, the rationale was water savings in the fourth year of extreme drought.
For the Great Basin Unified Air Pollution Control District, the variance was a test; the end game was a new State Implementation Plan that will be the subject of a public hearing by the district’s board of directors.
“This codifies methods for reducing water usage while still maintaining Best Available Control Methods to maintain legal PM10 (particulate matter less than 10 microns in diameter, roughly 1/7th the thickness of a human hair) limits,” stated Phill Kiddoo, air pollution control officer in a recent e-mail.
Last year’s variance allowed for a late ramp-up of Shallow Flooding on more than 14 square miles of the dry lake. Traditionally, water is spread prior to October 1, the start of the lake’s dust season. The variance allowed that ramp up to reach full compliance by December 1 on 1.12 square miles and by January 16 on the final 13.67 square miles.
The original SIP, drafted in 2008, identified only Shallow Flooding as the Best Available Control Method on 42 square miles of lake bed. The new order allows Tillage and Brine with Shallow Flooding as the back-up measure, carefully defining what areas within that larger area would be appropriate for these options.
Tillage is fairly self-explanatory, deep furrows running east to west, perpendicular to the prevailing winds, in “curving wave patterns,” exposing rougher, heavier soil. Brine Shallow Flooding has been used on Owens Lake since 2013 with the same parameters as Shallow Flooding. The natural salts on the lake bed act as an insulating crust, preventing the finer particular matter beneath it from going air borne. The new board order defines it more specifically requiring lower water content.
The elements of last July’s variance are incorporated in the Dynamic Water Management Plan, allowing later ramp-up and earlier ramp-down on existing Shallow Flooding areas and on Phase 9/10 areas.
The new SIP leaves LADWP little wiggle room, outlining methods, monitoring and compliance requirements in 368 pages of text and maps.
The District Rule, 2016 State Implementation Plan and Environmental Impact Report are available on Great Basin’s website, at the offices on 157 Short St. in Bishop and Inyo County Libraries.
Written comments should be submitted to Phillip Kiddoo at the Bishop office; oral and written comments will be taken at the April 13 meeting, held at LADWP’s Administrative Building Training Room at 111 Sulfate Road, Keeler.