- Birch Bay Waterslides is located in beautiful Blaine, Washington. With its wide variety of activities and highly trained staff, Birch Bay Waterslides is a waterpark designed and operated for the family. The entire staff at Birch Bay Waterslides takes great pride in making your visit safe and exciting! After you leave the waterpark, head down to Birch Bay and take a walk on the beach and watch ...www.birchbaywaterslides.com