Idaho Administrative Code
Title IDAPA 37 - Water Resources, Department of
Rule 37.03.07 - STREAM CHANNEL ALTERATION RULES
Section 37.03.07.010 - DEFINITIONS

01. Alteration. To obstruct, diminish, destroy, alter, modify, relocate or change the natural existing shape of the channel or to change the direction of flow of water of any stream channel within or below the mean high water mark. It includes removal of material from the stream channel and emplacement of material or structures in or across the stream channel where the material or structure has the potential to affect flow in the channel as determined by the director. (3-18-22)

02. Applicant. Any individual, partnership, company, corporation, municipality, county, state or federal agency, their agent, or other entity proposing to alter a stream channel or actually engaged in constructing a channel alteration, whether authorized or not. (3-18-22)

03. Base Food Elevation. The Base Flood (BF) is referred to as the one hundred (100) year flood and is a measure of flood magnitude based on probability. The BF has a one percent chance of occurring or being exceeded in any given year, with the Base Flood Elevation (BFE) being the level of flooding reached during the BF or the one hundred (100) year flood event. (3-18-22)

04. Board. The Idaho Water Resource Board. (3-18-22)

05. Continuously Flowing Water. A sufficient flow of water that could provide for migration and movement of fish, and excludes those reaches of streams which, in their natural state, normally go dry at the location of the proposed alteration. IDWR will assume, subject to information to the contrary, that the USGS quadrangle maps accurately depict whether a stream reach is continuously flowing, at the location of the proposed alteration. Such exclusion does not apply to minor flood channels that are a part of a stream which is continuously flowing in the reach where the alteration is located. Also, such exclusion does not apply to streams which may be dry as a result of upstream diversion or storage of water. (3-18-22)

06. Department. The Idaho Department of Water Resources. (3-18-22)

07. Drop Structures, Sills and Barbs. Physical obstructions placed within a stream channel for the purpose of stabilizing the channel by decreasing stream gradient and velocity and by dissipating stream energy. (3-18-22)

08. Director. The Director of the Idaho Department of Water Resources. (3-18-22)

09. Human Life Support System. Any artificial or natural system that provides all or some of the items (such as oxygen, food, water, control of temperature, or disposition of carbon dioxide) necessary for maintaining human life or health. (3-18-22)

10. Mean High Water Mark. As defined in Idaho Code, § 42-3802(h), the mean high water mark is water level corresponding to the "natural or ordinary high water mark" and is the line which the water impresses on the soil by covering it for sufficient periods of time to deprive the soil of its terrestrial vegetation and destroy its value for commonly accepted agricultural purposes. (3-18-22)

11. Non-Powered Equipment. Equipment which is powered only by human strength. (3-18-22)

12. Plans. Maps, sketches, engineering drawings, photos, work descriptions and specifications sufficient to describe the extent, nature, and location of the proposed stream channel alteration and the proposed method of accomplishing the alteration. (3-18-22)

13. Powered Equipment. Equipment which is powered by means other than human strength such as a gasoline engine or electric motor. (3-18-22)

14. Repair. Any work needed or accomplished, to protect, maintain, or restore any water diversion structure and the associated stream channel upstream and downstream as necessary for the efficient operation of the water diversion structure. (3-18-22)

15. Stream Channel. A natural water course of perceptible extent with definite beds and banks which confines and conducts continuously flowing water. The channel referred to is that which exists at the present time, regardless of where the channel may have been located at any time in the past. For the purposes of these rules only, the beds of lakes and reservoir pool areas are not considered to be stream channels. (3-18-22)