The main California agency promoting Gov. Jerry Brown’s proposed $16 billion water tunnels gave its expected approval to the project Friday. The move by the Department of Water Resources, which is helping shepherd Brown’s tunnels project over the regulatory and financial hurdles it must clear to break ground, endorsed the tunnels as a sound step environmentally. The Democratic governor wants to remake the state’s water system by tapping two 35-mile tunnels, both of them four-stories high, into Northern California’s Sacramento River, augmenting aging pumps to the south.