Stream class

Classification of streams based on the present and foreseeable uses made of the water, and the potential effects of on-site changes on downstream uses. Four classes are defined:

1. Class I: Perennial or intermittent streams that provide a source of water for domestic use. Class I streams are used by large numbers of anadromous fish or significant sports fish for spawning, rearing, or migration, or are major tributaries to other Class I streams.
2. Class II: Perennial or intermittent streams that are used by fish for spawning, rearing, or migration. Class II streams may be tributaries to Class I streams or other Class II streams.
3. Class III: All other perennial streams not meeting higher class criteria.

An input stream class is one that delivers data from its source (often the file system as a sequence of bytes. Similarly, an output stream class will write byte-level data. Stream classes should be contrasted with the operation of reader and writer classes.