STOCKTON, Calif. – Dozens of Central Valley farmers with their livelihoods on the line packed a courtroom Tuesday as their water provider argued that the state had no right to cut off their supplies.

The case, heard in San Joaquin County Superior Court, was the first to challenge the state's sweeping demand that California's most senior water rights holders stop pumping from rivers and creeks in light of the drought.

Attorneys for the Banta Carbona Irrigation District told Judge Carter Holly that the district's century-old right to draw water from the San Joaquin River predated the state's requirement for permits and cannot be compromised.

Although the argument was made on behalf of just 75 growers near Tracy, the case could affect thousands of farmers, water districts and communities whose supplies hinge on senior water claims. It is viewed as a crucial test of the state's power to manage water use during the drought.

Holly is expected to rule on a request by the State Water Resources Control Board to send the case to a judge outside of San Joaquin County to ensure no partiality as well as a bid by the irrigation district to allow pumping to continue as the case makes its way through the courts.

Those who illegally pump face fines of $1,000 per day plus $2,500 per acre-foot drawn. A

The state water board is contending that there isn't enough water in California's rivers and creeks to meet the demands of all customers. So, per the state's system of seniority, cuts need to be made by those with less senior rights.

Thousands with claims after 1914, the year that California began issuing permits for water draws, have already been told to stop pumping. On June 12, the state water board took the unusual step of extending the directive to senior rights holders with claims back to 1903.

Only once before, during the drought of the late 1970s, has the state reached as deep into the hierarchy of water rights. Those with claims older than 1903 can still draw water.

San Francisco Chronicle