The river provides groundwater recharge for agricultural water supplies and is free-flowing for 85 percent of its length. Matthews Dam, about one third of the way down the river from its source, forms Ruth Reservoir. The dam is owned by Humboldt Bay Municipal Water District, which provides water from Ranney collectors near Essex for municipal and industrial use in Eureka, Arcata, Blue Lake and numerous unincorporated communities in the Humboldt Bay area. The reservoir can hold of water; and releases power a two megawatt hydro-electric plant generating 5 million kwh during an average water year.