§ 21-35. Crossing of public drainage channels.

(a)

Generally.

(1)

No public drainage ditch, canal, channel or stream shall be crossed or spanned by temporary or permanent construction of any means except with the prior written approval of the parish police jury.

(2)

Any culvert, pipe, bridge or other method of crossing located within the flow carrying limits of a public drainage channel shall be adequately designed and sized to allow for minimum restricted flow through the point of crossing based on minimum rainfall design frequencies set forth in Section 21-55

(b)

Utility crossings.

(1)

No exposed pipe, conduit, wire, cable or other type of utility line or component shall be placed or installed within the flow carrying limits of a public drainage channel.

(2)

Any utility line or component which crosses a public drainage channel shall be placed or installed:

a.

A minimum of thirty-six (36) inches below the existing flow line or the twenty-five-year design bottom profile of the channel, whichever is lower; or

b.

A minimum of twenty-four (24) inches above the highest known water level or twenty-five-year design flood profile of the channel.

(3)

No utility line or component shall be placed within the right-of-way of a public drainage channel such that it would interfere in any way with the operation or maintenance of said channel.

(4)

Aerial utility line crossings shall be adequately designed and braced so as to provide for a minimum clear span of the public drainage channel between top high banks.

(5)

Subsurface utility line crossings shall be sufficiently anchored to prevent flotation.

(6)

If necessary to maintain the integrity of a utility system, utility line crossings shall be cased or sheathed to protect said line within the public right-of-way.

(7)

Once a utility line or component has been placed or installed across a public drainage channel, it shall be the responsibility of the owner of said line or component to perpetually maintain said line or component and to raise, lower or otherwise modify said line or component at his expense if, for any reason, the cross-section or profile of the channel is thereafter improved or changed by the parish police jury.

(c)

Bridge crossings.

(1)

All bridge crossings shall be designed and constructed in accordance with the requirements and specifications of the parish police jury.

(2)

The lowest level of any bridge deck (super structure) shall be set a minimum of twenty-four (24) inches above the twenty-five-year design flood profile of the channel.

(3)

For piling supported bridges, the pilings shall be arranged and oriented within the channel so as to minimize the restriction of flow and potential accumulation of debris.

(4)

Bulkheads, wing walls, revetment or other means of stabilizing the ends of bridges shall be employed to protect channel banks and flow lines from scour and erosion.

(d)

Private culverts.

(1)

No culvert or drainage pipe shall be placed or installed within a public right-of-way or servitude without the prior written approval of the parish police jury.

(2)

Unless otherwise authorized by the director of public works in writing:

a.

All culverts and drainage pipes placed or installed within a public right-of-way or servitude shall be of a standard shape and cross-sectional area sufficient to allow for the minimum restricted passage of stormwater through the point of installation.

b.

The minimum size of any culvert or drainage pipe shall be eighteen (18) inch diameter or the equivalent sized elliptical pipe or pipe arch.

(Ord. No. 7944, 3-11-85; Ord. No. 8131, 11-21-88)