3.12 Alignment and Location
a. General.
1) Storm drains shall be laid on a straight alignment between catch basins and between manholes as approved by the City Engineer.
2) Where storm drains are being designed for installation parallel to other utility pipe or conduit lines, the vertical location shall be in such a manner that will permit future side connections of main or lateral storm drains and avoid conflicts with parallel utilities without abrupt changes in vertical grade of main or lateral storm drains.
b. Location in Relation to Water and Sewer Lines and Other Utilities.
1) Public storm drainage lines shall be separated from all other parallel public utilities by a minimum of five (5) feet.
2) Installation of franchise or private utilities in a common trench with storm drain lines shall be prohibited.
c. Location in Street Right-of-Ways.
1) Unless otherwise approved by the City Engineer, storm drain lines shall be located in the street right-of-way within six (6) feet of the face of curb.
d. Location in Public Easements & Easement Widths.
1) Minimum Easement Widths: Unless otherwise specified or authorized by the City, minimum easements widths for storm drains shall be as follows:
|
Storm Drain Diameter |
Depth to Invert | |
≤ 6 feet | ≥ 6 feet | |
10 - 15 inches | 12 feet | 12 feet plus 2 feet for each foot (or fraction thereof) deeper than 6 feet to invert. |
18 - 24 inches | 16 feet | 16 feet plus 2 feet for each foot (or fraction thereof) deeper than 6 feet to invert. |
> 24 inches | 20 feet | 20 feet plus 2 feet for each foot (or fraction thereof) deeper than 6 feet to invert. |
Note: Easements shall be a constant width between manholes or other in-line structures. Easement width shall be based on the deepest portion of the line between such structures.
2) Open channels located outside of public right-of-ways shall be provided with an easement widths as follows:
a) Channel width less than 12 feet at top of banks: Channel width plus 10 feet on one side and 2 feet on the other.
b) Channel width greater than 12 feet at top of banks: Channel width plus 12 feet on both sides.
3) Public storm drains in easements will be allowed only after all reasonable attempts to place the mains in a right-of-way have been exhausted. All easement installations must be approved in writing by the City Engineer on a case-by-case basis.
a) When storm drains in easements are approved by the City, the storm line shall be offset a minimum of 6 feet from any property line or easement boundary, or 1/3 the required easement width, whichever is greater.
b) The conditions of the easement shall be such that the easement
c) shall not be used for any purpose which would interfere with the unrestricted use for storm drain purposes. Under no circumstances shall a building or structure or tree be placed over a storm drain pipe or easement, nor shall any parallel fences be constructed within the easement (access gates acceptable to the City Engineer shall be installed in fences which the City allows to be constructed across City easements). Prohibited structures shall include decks, as well as footings or overhanging portions of structures located outside the easement.
4) Easement locations for public storm drain lines serving a PUD, apartment complex or commercial/industrial development shall be in parking lots, private drives or similar open areas which will permit an unobstructed vehicle access for maintenance by City forces.
5) Common placement in the easement of a sanitary sewer and storm drain line may be allowed by the City Engineer per separation requirements.
6) All public easements must be furnished to the City Engineer for review and approval prior to recording. All recording costs shall be borne by the Developer.
7) Maintenance of the facility easement shall be the responsibility of all parties benefitting from the easement in perpetuity