(1) The general responsibility to administer and enforce the provision of this act and all rules thereunder shall be carried out by the water RESOURCES DIVISION of the department.

(2) Except where specifically stated, the authority of the department and compliance by the owner of the dam or reservoir to these rules apply to:

(a) dams having a reservoir capacity behind the dam of 50 acre-feet or more measured to the crest of the dam embankment or measured to the maximum water surface that would occur during a probable maximum flood, whichever is less;

(b) reservoirs of 50 acre-feet or more that retain water both as a result of a dam and as an excavation in the impoundment area, measured to the crest of the dam and include the impoundment capacity below the normal land surface; and

(c) multiple or a series of dams erected on a valley, basin, coulee, or ravine where each reservoir is less than 50 acre-feet, but all are operated singly as one reservoir containing more than 50 acre-feet. Whether the series is operated as a single reservoir will be a question of fact in each instance. Factors to consider include:

(i) whether all dams or reservoirs are under the same ownership and control;

(ii) whether all dams or reservoirs operate as a unit, i.e., if one of the dams or reservoirs suffers a change, it will, in most instances, affect one or more of the other dams or reservoirs; or

(iii) whether the dams or reservoirs are physically proximate and on the same valley, basin, coulee, or ravine.

(3) For the purpose of the department's determining the authority or need for an application for hazard classification, construction permit, or operation permit or investigation of a complaint, the department may calculate the reservoir capacity in acre-feet, in absence of detailed data, as 0.4 times the vertical height in feet from the downstream toe of the dam to the crest of the dam times the water surface area at that level in acres.