A 15 miles connection between the existing Yakima Freeway at Union Gap and the Zillah freeway was completed on November 24, 1981, and cost $47 million to construct (equivalent to $ in US-GDP dollars).US-GDP The freeway's construction created an embankment between the Yakima River and surrounding areas, which helped to worsen major floods; it also required the digging of several gravel pits nearby, which were later converted into seven trout-stocked ponds that feed a local osprey population.