Each fall, the water is turned off in the fish ladder to protect the stone structure from the effects of freezing and thawing. Its a real sign of spring each year when April 1 comes around and the gates are opened to let water again flow through the beautiful new fish ladder. Smelts spawn in the lower ladder in early April as the waiting for alewives begins. A few Great Blue Herons have returned and osprey will soon follow. Listen for the sounds of the birds and for water flowing downstream. So begins the vigil for alewives!