Beaumont Municipal Code Ch. 16.44 Flood Control and Tract Drainage

Facilities required for the control of tract drainage and floodwaters in Schedules A, B, C, D and E land divisions, set out in Sections 16.40.050 through 16.40.090, are established as follows:

A. The minimum design for facilities which control drainage water generated within a land division or floodwater flowing into or crossing a land division shall be based on a storm having a frequency of once in 100 years. Hydrologic and hydraulic calculations for the design of drainage facilities which control drainage water generated within a land division shall be submitted for approval to the City Engineer. Hydrologic and hydraulic calculations for the design of flood-control facilities to control floodwater flowing into or crossing a land division shall be submitted for approval to the flood-control agency having jurisdiction and to the City Engineer.

B. The use of streets for flood-control and drainage purposes may be prohibited by the City Engineer if the use thereof is not in the interest of the public health, safety and welfare.

C. When the City Engineer permits the use of streets for flood-control and drainage purposes, the ten-year frequency design discharge shall be contained between the tops of curbs, and the 100-year frequency design discharge shall be contained within the street right-of-way. If either of these conditions is exceeded, additional flood control facilities shall be provided.

(Ord. 547 §11.1, 1983)

A. The Flood Control Engineer shall review the hydrologic calculations submitted by the land divider and determine the adequacy of peak discharges of off-site floodwaters impinging upon the land division from which protection must be provided. The land divider may consult and confer with the Flood Control Engineer or his representative as to the adequacy of any flood control facilities proposed.

B. Improvement plans for flood-control facilities to control floodwater flowing into or crossing a land division shall be approved by the Flood Control Agency and the City Engineer.

C. After receipt of an acceptable tentative map, the Flood Control Engineer will recommend conditions to be imposed. He shall also furnish a flood hazard report to the land divider and such governmental agencies as may require the same.

(Ord. 547 §11.2, 1983)

A. Improvement plans for the drainage facilities to control drainage water generated within a land division shall be approved by the City Engineer.

B. In land division where. lot grading is not proposed, the following criteria are established:

1. Where land division streets on sustained gradients cross natural drainage courses, adequate culverts shall be provided to accommodate the 100-year storm with maximum ponding to an elevation of two feet below the road centerline profile grade, provided diversion of ponded water into another drainage area will not result therefrom.

2. Runoff in natural drainage courses exceeding the ten-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 embankment slopes shall be adequately protected.

3. Culverts of adequate size, but not less than eighteen inches in diameter or equal, to prevent the ten year storm from overtopping the roadway shall be provided in dip sections or as approved by the City Engineer.

4. Streets crossing improved channels shall be provided with culverts of adequate size to permit passage of the channel design flow or such other type of crossing as approved by the Flood Control Agency and the City Engineer.

5. Asphalt concrete for lining of channels shall not be permitted.

6. When a land division substantially changes, concentrates or increases the natural flow of surface water onto adjacent property, facilities shall be required to direct the water to an adequate outlet, or the land divider shall obtain a recordable easement or written agreement for drainage purposes across the affected property.

(Ord. 547 §11.3, 1983)