California Code of Regulations › Title 23 - Waters › Division 1 - Central Valley Flood Protection Board › Chapter 1 - Organization, Powers and Standards › Article 8 - Standards › Section 128 - Bridges

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) The
				  standards for construction or modification of bridges within an adopted plan of
				  flood control are as follows:
(1) Any
				  excavation within the levee section or near bridge supports within the floodway
				  must be backfilled in four- (4) inch to six- (6) inch layers with approved
				  material. The levee section must be compacted to a relative compaction of not
				  less than ninety (90) percent per ASTM D1557-91, dated 1991, which is
				  incorporated by reference and above optimum moisture content. Compaction within
				  the floodway must be to the density of the adjacent undisturbed
				  material.
(2) Compaction tests by a
				  certified soils laboratory may be required to verify compaction.
(3) Bridge piers and bents within the
				  floodway must be constructed parallel to the direction of streamflow.
(4) Bridge piers and bents placed within a
				  floodway to support a widened portion of an existing bridge must be constructed
				  in line with existing bents and piers.
(5) Erosion control may be required on the
				  channel banks or levee slopes upstream and downstream of a proposed
				  bridge.
(6) Drainage from a bridge
				  or highway may not be discharged onto a levee section or streambank.
(7) Plans showing all construction facilities
				  (such as temporary staging, coffer dams, and falsework) which will remain in a
				  floodway during flood season, must be submitted to the board for approval prior
				  to installation of these facilities.
(8) All construction facilities (such as
				  temporary staging, coffer dams, and falsework) must be designed to prevent bank
				  erosion during normal flows and to maintain maximum channel capacity during the
				  flood season.
(9) Stockpiled
				  material, temporary buildings, construction equipment, and detours that
				  obstruct streamflows must be removed from floodways prior to the flood
				  season.
(10)
(A) The bottom members (soffit) of a proposed
				  bridge must be at least three (3) feet above the design flood plane. The
				  required clearance may be reduced to two (2) feet on minor streams at sites
				  where significant amounts of stream debris are unlikely.
(B) When an existing bridge being widened
				  does not meet the clearance requirement above the design flood plane, the
				  bottom structural members of the added section may be no lower than the bottom
				  structural members of the existing bridge, except as may be caused by the
				  extension of existing sloped structural members.
(C) When the clearance requirement above
				  design flood plane would result in bridge approach ramp fill in the floodway,
				  the clearance requirement may be reduced to the extent that reasonably balances
				  clearance and fill that would obstruct flow, so as to maintain maximum channel
				  capacity.
(11)
(A) Vehicular access from the roadway to the
				  levee crown may be required at each end of a bridge.
(B) Vehicular access from the levee crown to
				  the floodway and/or the landside levee toe beneath the bridge may be required.
				  Ramps may slope upstream as necessary to provide the access required by this
				  subdivision.
(12)
				  Approved gates must be installed at right angles across the levee crown at all
				  points of access to the levee from each end of a bridge.
(13) Any bridge abandoned or being dismantled
				  must be completely removed, and must be disposed of outside the limits of the
				  levee section and floodway.
(14)
				  Pilings, piers, bents, and abutments of bridges being dismantled must be
				  removed to at least one (1) foot below the natural ground line and at least
				  three (3) feet below the bottom of the low water channel.
(15) Any bridge that is damaged to the extent
				  that it may impair the channel or floodway capacity must be repaired or removed
				  prior to the next flood season.
(16) Replacement railroad bridges must have
				  the soffit members no lower than those of the replaced bridge, but are not
				  required to have a specified amount of clearance above the design flood
				  plane.
(17) Bridge replacements and
				  new bridges shall be built at an elevation so that there is no depression in
				  the crown of the levee.