In court, the California Environmental Quality Act is a familiar obstacle to projects large and small — housing developments, solar projects, even bike lanes. It’s also lately become a weapon in the state’s major water conflicts. Last week, the Imperial Irrigation District filed a CEQA lawsuit trying to block a deal among seven states that could lead to further rations of the Colorado River in the near future. Even though environmental law doesn’t apply outside of California, Imperial is the largest holder of Colorado water rights in the country — it has dibs on as much river water as Arizona and Nevada combined — and is suing other California agencies that have agreed to give up water if there’s a shortage.