Gov. Jerry Brown wants to build two 35-mile underground tunnels to keep water coming south through the Sacramento-San Joaquin Bay Delta. The San Diego County Water Authority used to pine for such a plan. But now, emboldened by its drought-proofing projects and wary of shocking ratepayers, the agency is aggressively questioned Brown’s delta tunnels. For over 50 years, the San Diego County Water Authority championed projects that bring water to Southern California from Northern California. But no more.