By Deb Murphy
After five years of drought, the question of what to do with mass quantities of spring runoff is a welcome problem, one that Inyo County Water Commissioner Craig Patten suggested area residents can weigh in on.
“We’re at 244 percent of normal,” Patten said at Wednesday’s Commission meeting. “There could be a million acre-feet of run-off.” While Patten said Los Angeles Department of Water and Power has indicated “they’ll put the water where they can get it when they need it,” this may be the time to store some of it in the Owens Valley.
There was no shortage of suggestions from the Commissioners and County Water Department staff: direct water into some of the old irrigation canals that pre-dated the LA Aqueduct, bring the water table up at Five Bridges and/or Laws, described by Commission Chair Mike Prather as the mitigation orphan. Commissioner Teri Red Owl cited a water spread south of Big Pine years ago. “The water table came up and stayed up for several years afterwards,” she said.
According to Water Department Director Bob Harrington, the department has already opened the Bishop Creek by-pass and diverted water from the Owens River to the McNally Ponds.
Harrington indicated the timing of excess water suggestions could be included in the County’s response to the LADWP’s Annual Operations Plan, in late April.
Patten suggested getting public input, the Commission agreed. Those suggestions should be routed to Bob Harrington firstname.lastname@example.org.
The highlight of Wednesday’s meeting was a presentation by Water Department hydrologist Keith Rainville, providing a hypothesis that could explain West Bishop’s recurring high water table issues.
The County got state assistance through its drought emergency declaration, bringing in Department of Water Resources’ staff to explore a high table that has flooded crawl spaces and seeped out of lawns. The DWR’s report read like a mystery novel that failed to solve the mystery, coming to the same conclusions Harrington did when the problem reared its soggy head in the spring of 2014 and again this past year: seepage from West Bishop’s maze of ditches and ponds after the natural lining of vegetation was cleared out in the winter of 2013-14 when the water was cut off probably caused the problem.
Rainville’s hypothesis started with the last year of a balanced water table when water flowed year-round and seepage flowed evenly from the ditches and ponds to a depth of 40-feet, a level he described as relatively shallow for the Owens Valley’s alluvial fan.
When the water was cut off in the fall of 2013, the water table declined and the older shallow private wells began to run dry. When the water returned the following two springs, the seepage increased faster than the shallow subsurface layer could handle. Instead of all the water flowing down to the groundwater table, some of it spread vertically. With a near average runoff last year, the vertical seepage increased, popping up when the vertical spread met the surface of the gradual slope from west to east.
Rainville’s hypothetical solution: return to the equilibrium of 2013. Residents on Carol Lane may have provided one way to reach that equilibrium.
According to Rainville, the group drained several ponds, refilled them and watched them drain within a day. They repeated the experiment, but lined the ponds with fine-grain sediment. It took three times longer for the water to fully drain out of the ponds.