State water regulators Tuesday dismissed a record $1.5-million fine against a Northern California irrigation district accused of diverting water last year in violation of a drought order.

The action is the latest twist in the state’s attempts to assert control over water diversions by agricultural districts that hold some of the oldest water rights in California.

The State Water Resources Control Board alleged that the Byron-Bethany Irrigation District in Northern California ignored curtailment orders and took water that it was not entitled to under California’s priority system of water rights.

With the drought slashing flows in the watersheds of the Sacramento and San Joaquin rivers, the board last summer told districts with rights dating back to 1903 to halt diversions, thereby preserving supplies for districts with more senior rights.


Byron-Bethany, which has a 1914 right to withdraw from the southern end of the Sacramento-San Joaquin Delta, continued its diversions for two weeks after the curtailment order was posted, according to the board.

The agency’s enforcement order proposed a $1.5-million fine, which Byron-Bethany protested, arguing that the water board did not have authority over its rights.

After reviewing the state’s case at a March hearing, board officers found weaknesses in the complicated water analysis used to determine the curtailment and recommended dismissal.

The board voted Tuesday to drop the case, while affirming its authority to stop illegal diversions. The board plans to hold a workshop later this year to discuss ways of strengthening its calculations of water availability during a drought.


The board also dismissed an enforcement order – which did not include a fine – against the West Side Irrigation District of Tracy.

bettina.boxall@latimes.com

Twitter: @boxall