Federal water managers have begun the annual spill of water past hydroelectric dams on the Columbia and Snake rivers to help juvenile salmon and steelhead migrate to the ocean this spring. The spill began April 3 on the lower Snake River and April 10 on the lower Columbia River. Spill for juvenile fish passage helps reduce the proportion of juvenile fish that pass dams through the turbines and helps reduce passage delay at each dam, thereby shortening their travel time through the Snake and Columbia rivers.