of Gooseberry Creek with Fish Creek. The proposal has met with opposition out of concern for environmental impacts on trout fisheries in the Price River headwaters and the planned diversion of the water impounded by the dam out of the Colorado River basin to supplement the irrigation systems of the Sanpete Valley. As a result of the planned dam the Price River was included on the American Rivers list of the top ten endangered rivers in the United States in 2005. Just downstream of the town of Price, a partnership of the Carbon Canal Company (CCC), The Nature Conservancy (TNC), and the Utah Division of Wildlife Resources (UDWR), is expanding the Olsen Reservoir so that it can capture high spring Price River flows at the end of the Carbon Canal and store it, for agricultural use and to recharge the river in dry seasons and drought years. Tributaries downstream of Price are largely ephemeral. The largest is Grassy Trail Creek which exits the Book Cliffs at East Carbon, Carbon County, and joins the Price River south of Cedar, Emery County. Ecology The headwaters of the Price River harbor Colorado River cutthroat trout ((Oncorhynchus clarki pleuriticus). Distribution and abundance of this cutthroat trout subspecies are now limited to small populations in less than 1% of its historic range in the upper tributaries of the Colorado River watershed. The chief vulnerability of Colorado River cutthroat trout is hybridization with non-native rainbow trout and competitive replacement by non-native brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis). The federally endangered Colorado pikeminnow (Ptychocheilus lucius) is extant in the lower of the Price River. Three other imperiled fishes of the upper Colorado River basin, whose habitat is high desert streams, are the roundtail chub (Gila robusta), the flannelmouth sucker (Catostomus latipinnis), and the bluehead sucker (Catostomus discobolus). All three inhabit or inhabited the lower Price River until the roundtail chub was likely extirpated from the Price River due to low flows in 1977 and 1993, a localized rotenone detoxification problem in 1977, and/or multiple other pollution-caused fish kills. Recreation The Price is a small, shallow river and is normally unnavigable. However, during high springtime flows, the below the Scofield Dam to Castle Gate contain Class I to V whitewater. The river has become increasingly popular with canoeists and kayakers. The tailwater below Scofield Reservoir is sometimes called Lower Fish Creek (although the USGS sets