eight more were identified along the river's course that previously had not been sited in the state of Alabama. This region is most noted for containing numerous species of mollusks and snails. These species feed other aquatic dwelling animals, improve water quality by eating algae, and even indicate environmental issues due to their receptiveness of pollution. Fourteen of the freshwater fish species are non-native species in the Cahaba River. Cahaba lily Among the countless plant species that thrive in and around the Cahaba is Hymenocallis coronaria'', known in Alabama as the Cahaba lily. As a result of its abundant presence here and its threatened status in the three states where it is found, a portion of the Cahaba River near West Blocton has been designated as the Cahaba River National Wildlife Refuge. It is found only in South Carolina, Georgia, and Alabama. While this flower once was present through all of the Southeast, it now exists in about 70 stands with a fourth of the stands in the Cahaba River. The seeds travel with the river's flow, and crevices in the shoals (rocky bars that run across the river) shelter the seeds as they sprout. The Cahaba lilies bloom in early May, and the entire blooming season is through by mid-June. The flowers open in the evening instead of the day due to pollination by sphinx moths, which are active at night. Each flower blooms and lasts only one day before wilting. Tributaries There are numerous small tributaries, including: Buck Creek, northwest of Helena Little Cahaba River (of Shelby County), entering from the southeast, by Cahaba Heights Little Cahaba River (of Bibb County), entering from the east some miles north of Centreville Shades Creek, entering from the northwest after running parallel to the Cahaba for some time Water use The Cahaba flows through heavily populated areas in the Birmingham metropolitan area. It serves as the source of drinking water in the upper course for over 1 million people and is also a popular canoeing destination. Major cities A number of Alabama cities lie on the banks of or in close proximity to the river. They include: Trussville —Cahaba headwaters Birmingham – Cahaba headwaters Hoover – Cahaba runs southwest Helena – Cahaba runs southwest Centreville – Cahaba runs southwest Heiberger – Cahaba turns 90 degrees to southeast Marion – Cahaba runs southeast (east of Marion) Selma – Cahaba runs southeast (west