For the purposes of this chapter, certain terms and words used herein shall be interpreted as follows:
Words used in the present tense include the future tense; the singular number includes the plural, and the plural number includes the singular; words of masculine gender include feminine gender; and words of feminine gender include masculine gender.
The word "includes" or "including" shall not limit the term to the specific example but is intended to extend its meaning to all other instances of like kind and character.
The words "shall" and "must" are mandatory; the words "may" and "should" are permissive.
As used in this chapter, the following terms shall have the meanings indicated:
Each stream segment in Pennsylvania has a designated use, such as cold water fishery or potable water supply, which are listed in Chapter 93. These uses must be protected and maintained, under state regulations.
"Existing uses" are those attained as of November 1975, regardless whether they have been designated in Chapter 93. Regulated earth disturbance activities must be designed to protect and maintain existing uses and maintain the level of water quality necessary to protect those uses in all streams, and to protect and maintain water quality in special protection streams.
Water quality involves the chemical, biological and physical characteristics of surface water bodies. After regulated earth disturbance activities are complete, these characteristics can be impacted by addition of pollutants such as sediment and changes in habitat through increased flow volumes and/or rates as a result of changes in land surface area from those activities. Therefore, permanent discharges to surface waters must be managed to protect the stream bank, streambed and structural integrity of the waterway to prevent these impacts.