Livestock water tanks are covered under the "Livestock Water Tank Act of Colorado" sections
35-49-101 to 35-49-116, C.R.S. These structures include all reservoirs built after April 17, 1941,
on watercourses which the state engineer has determined to be "normally dry" and having a capacity
of not more than ten acre-feet and a vertical height not exceeding fifteen feet from the bottom of
the channel to the bottom of the spillway. Again, as with erosion control dams, the height is measured
from the lowest point of the upstream toe to the crest of the spillway. No livestock water tanks can
be used for irrigation purposes.
Erosion control dams are governed under Colorado statute (see section 37-87-122, C.R.S. (1990).
These types of structures may be constructed on water courses which have been determined by the
state engineer to be normally dry (which for our purposes is dry more than 80% of the time). Structures
of this type cannot exceed fifteen feet from the bottom of the channel to the bottom of the spillway
and cannot exceed ten acre-feet at the emergency spillway level. The height of the dam is measured
vertically from the lowest point of the upstream toe to the crest of the dam in contrast to those
measured vertically from the centerline pursuant to section 37-87-105, C.R.S. (1990). Note: The
structure can be larger than specified under section 37-87-122, however, it then will be evaluated
and must be constructed pursuant to section 37-87-105.