The Friant-Kern Canal. File photo.

Friant Water Authority is conducting geotechnical investigations this summer along the outer banks of a 30-mile stretch of the Friant-Kern Canal in southern Tulare County to determine if the soil may support construction of a second canal running parallel to the first.

The reason for the research is the capacity of this key, eastside Valley canal has been reduced by 60% due to recent land subsidence caused by years of vigorous groundwater pumping by nearby farms, homes and businesses.

And that problem worsened during the recent record drought years across California, with the Valley suffering some of the worst effects, escalating the need for groundwater.

While Friant-Kern Canal’s carrying capacity has been compromised by various factors since it began operating in 1951, rapid and severe land subsidence has elevated the problem, particularly in the Corcoran/Tulare Basin. Land elevations measured in 2015 and 2016 revealed the basin had dropped by two feet near Corcoran, inhibiting the movement of water near Deer Creek.

Water managers said there’s no way to operate the canal to eliminate the effects to water users from this much subsidence.

Water in the canal goes not just to farms but provides drinking water to whole communities, many disadvantaged. In wet years, the canal allows farms to replenish groundwater to help manage the subsidence problem.

After some serous study of alternatives, FWA now is focusing on the idea of building a parallel canal east of the existing Friant-Kern Canal near Porterville.

The authority’s chief of external affairs, Johnny Amaral said the organization’s governing board has selected it as the “preferred alternative” to fix the problem.

South Valley water contractor Dan Vink, whose water districts represent 400,000 acres, said the option of building the parallel canal engineered to avoid sinking is superior to building new pumps to move water above the sinking sections of the existing canal.

But a solution won’t come cheap, as Amaral said the estimate to construct the parallel canal is $357 million.

As for how to pay for it, Vink said “multiple sources are the only way,” noting the project is federal and arguably can’t be fixed just with state funds.

“We need locals and farmers, themselves” to help pay, along with federal dollars, he added.

Amaral said, “We are looking at cost sharing among all,” and California congressmen Devin Nunes, R-Visalia, and Kevin McCarthy, R- Bakersfield, and U.S. Sen. Diane Feinstein, a Democrat, all are on board.

And state Sen. Melissa Hurtado, D-Fresno, has authored a $400 million bill that may pay for part of this.

The timetable is short but doable, said Amaral, adding, “We want to be moving dirt by the summer of 2020.”

Vink said that while all eyes are on repairing the Friant Kern Canal, the longstanding effort to build Temperance Flat Dam has taken a back seat, and he’s skeptical that Friant water contractors will be able to afford Temperance Flat water, in any case.