15.04.140 Storm drainage.
A. Complete drainage systems for the entire subdivision area shall be designed by a professional engineer, licensed in the state of Colorado. At a minimum, the drainage system shall be designed:
1. To permit the unimpeded flow of natural watercourses.
2. To ensure adequate drainage of all low points.
3. To provide for a ten (10) year storm event.
B. The drainage system shall be designed to consider the drainage basin as a whole and shall accommodate not only runoff from the subdivision area but also, where applicable, the system shall be designed to accommodate the runoff from those areas adjacent to and upstream from the subdivision itself, as well as its effects on lands downstream.
C. No subdivision or any part thereof shall be approved if proposed cuts, fills, structures or other features within the proposed subdivision will, individually or collectively, significantly increase flood flows, heights, or damages.
D. Lots and blocks shall be so graded as to eliminate depressions that would accumulate storm water. Grades at building sites shall bear such relationships to roadway and curb grades as to prevent flooding during heavy storms of basement windows or of entryways either to basement or to first floor levels in the absence of basements.
E. All water courses crossed by streets or alleys shall be provided with adequate and permanent culverts of a size, type and material approved by the Town Manager. Culverts on existing streets shall be enlarged wherever necessary by reason of diverted or increased concentration of drainage.
F. Adequate drainage facilities shall be installed prior to construction of any buildings in the subdivision.
G. The drainage system shall be designed and constructed in conformance with the Water Pollution Control Act and the Air Pollution Control Act of the state of Colorado. (Ord. 711 §1 (Exh. A), 2017)