Chapter 16.48
DRAINAGE IMPROVEMENTS
Sections:
16.48.010 Construction – Maintenance.
16.48.030 Dedicated easements.
16.48.040 Information to accompany plans.
16.48.060 Drainage within streets.
16.48.090 Adequate drainage outlet.
16.48.010 Construction – Maintenance.
The land divider shall maintain the existing or construct the required drainage facilities for the collection, conveyance, and disposal of all stormwaters that have historically arrived upon the land being divided, or abutting drainage courses in accordance with the City standards. [Ord. 529 § 6.8(A), 1973].
16.48.020 Drainage fees.
In addition to any other fees required by this title, the land divider shall pay a drainage fee to the City prior to approval of the final map in the amount as shown on a schedule established by resolution of the City Council. Said fees shall be deposited in a storm drainage facility fund and shall be used solely for the improvement of the storm drainage system of the City. [Ord. 529 § 6.8(B), 1973].
16.48.030 Dedicated easements.
All drainage facilities and appurtenances shall be installed within streets or easements either existing or to be offered for dedication to the City.
Also, all existing natural drainage courses within the land division which will remain after recordation of the final map shall be delineated on the final map and reserved to the owners as a drainage easement. [Ord. 529 § 6.8(C), 1973].
16.48.040 Information to accompany plans.
A hydrology map showing the location and flow rate of all stormwaters entering upon the land being divided and all hydrology calculations and structural calculations shall be submitted to the City Engineer prior to approval of the drainage improvement plans. [Ord. 529 § 6.8(D), 1973].
16.48.050 Storm frequency.
The storm frequency used for the design of all drainage facilities shall be as follows:
A. Local drainage: 25 years;
B. Sump area: 50 years;
C. Major channels and/or major drainage courses: 100 years. [Ord. 529 § 6.8(E), 1973].
16.48.060 Drainage within streets.
The discharge for a 10-year frequency storm shall be centered between the tops of curbs and that for a 25-year frequency storm shall be centered within the street right-of-way. If either of these conditions is exceeded, additional flood control facilities must be provided. [Ord. 529 § 6.8(F), 1973].
16.48.070 Culverts.
Where any street crosses a natural drainage course and a culvert is required to be constructed to convey the stormwater beneath the street, the culvert shall be designed as follows:
A. For a street having a uniform gradient, the culvert shall be designed to accommodate a 100-year storm with maximum ponding within two feet of the road centerline profile grade, provided diversion of ponded water into another drainage area will not result therefrom.
B. For a street having a dip section, the culvert shall be designed to accommodate a 10-year storm without overtopping the roadway. A 10-year storm may be permitted to overtop the roadway in dip sections where, in the opinion of the City Engineer, topography, soil conditions, adjacent development, and available all-weather routes indicate its feasibility. If permitted, the roadway shall be adequately protected. [Ord. 529 § 6.8(G), 1973].
16.48.080 Inundation.
When any portion of the land within the boundaries of any final map is subject to inundation or flood hazard by stormwaters, such fact and portion shall be clearly shown on the final map by a prominent note on each sheet of such map whereon any such condition exists. [Ord. 529 § 6.8(H), 1973].
16.48.090 Adequate drainage outlet.
When, in the opinion of the City Council, a division of land may cause an unnatural increase or concentration of surface waters onto downstream property, said division of land shall not be approved by the City Council unless drainage outlets, as approved by the City Engineer, are provided which will be adequate to render the City harmless from any dangers therefrom. [Ord. 529 § 6.8(I), 1973].