The Eklutna River (/iːˈkluːtnə/) is approximately 11.8 miles (19 km) long and is located in the Southcentral region of the U.S. state of Alaska. A portion of the river flows through a canyon up to 400 feet (122 m) deep, emptying into the Knik Arm of Cook Inlet approximately 17 miles (27 km) northeast of Anchorage. This degraded anadromous stream historically originated from Eklutna Lake, which itself is fed by Eklutna Glacier. Eklutna River is now fed primarily by groundwater before being joined by Thunderbird Creek. Thunderbird Creek, which enters the south bank about 1 km (0.6 mi) upstream from where the river exits the canyon and forms an alluvial fan. Due to water impoundments on the Eklutna River for power generation, Thunderbird Creek is currently the main source of water in the lowe