St. Joe River Subbasin

In the St. Joe River drainage, 14 of the 17 listed segments are listed for temperature, 11 for sediment, 5 for bacteria, 3 for dissolved oxygen, and 1 segment each for nutrients and habitat alteration. In the St. Maries River drainage, 16 of the 17 listed segments are listed for sediment, 9 for temperature, 8 for habitat alteration, 4 for nutrients, and 1 each for dissolved oxygen and bacteria. Sediment originates in the basin primarily from eroding banks, road crossings, and encroachments. Temperature is most affected by stream shading. Nutrients and bacteria arise from livestock and human wastes, while dissolved oxygen is affected by discharge of oxygen-demanding materials from wastewater treatment facilities and livestock wastes.

Impairment of the cold water beneficial use was assessed using composite scores of fish, macroinvertebrate, and habitat indices. These scores generally indicated full support in most streams assessed in the St. Joe River drainage, but they also indicated use impairment in some tributaries to the St. Joe River. The St. Joe River itself was not listed, nor was it found to be impaired in this assessment. In the St. Maries River drainage, the scores generally indicated full support in the headwaters but revealed use impairment in the downstream reaches of both the tributaries and the river itself.

The assessment resulted in temperature TMDLs for all the segments listed for temperature. Sediment TMDLs were completed for Mica, Fishhook, Bear, and Little Bear Creeks in the St. Joe River drainage; in the St. Maries River drainage, sediment TMDLs were developed for St. Maries River, West Fork St. Maries River, Middle Fork St. Maries River, and Santa, Carpenter, Emerald, Alder, Tyson, Thorn, Renfro, Crystal, Charlie, and John Creeks. Recommendations were also made for delisting certain streams and pollutants.

The US Environmental Protection Agency considers certain unnatural conditions, including habitat alteration, that are not the result of the discharge of a specific pollutant as “pollution.” Since a TMDL is not required for a water body impaired by pollution, but not a specific pollutant, a TMDL was not developed for habitat alteration.