California Code of Regulations
Title 23 - Waters
Division 2 - Department of Water Resources
Chapter 1 - Dams and Reservoirs
Article 6 - Inundation Maps
Section 335.10 - Inundation Maps

Universal Citation: 23 CA Code of Regs 335.10

Current through Register 2024 Notice Reg. No. 38, September 20, 2024

(a) An inundation map shall be prepared for each failure scenario as described in section 335.6. Inundation maps must contain the following model outputs as rasters, contours, points, or cross-sections at appropriate time and space intervals displayed over current aerial imagery:

(1) Inundation boundary,

(2) Flood wave arrival time,

(3) Maximum depth, and

(4) Maximum velocity.

(b) If using a raster for items in section 335.10(a), the opacity shall be adjusted to display the underlying aerial imagery.

(c) The inundation boundary shall be displayed as a one-foot maximum depth, except where the flood wave would be confined to a channel or canyon, and where the flood wave no longer poses a threat to life or critical facilities.

(d) General information. Each inundation map sheet shall contain the following information:

(1) The name of the dam, the department's dam number, the national dam ID number, and the county in which the dam is located.

(2) The meteorological loading condition. Identify whether a sunny-day or storm-induced loading condition is depicted. If a storm-induced loading condition is depicted, note the return period of the storm or the term "Probable Maximum Flood," as applicable.

(3) Sediment. If the failure scenario depicts the effects of sediment release, note "Includes reservoir sediment release."

(4) Label identifying the dam.

(5) Symbols and a corresponding legend that identifies all critical facilities in the inundation area and within the mapped extent.

(6) Labels identifying the downstream channels and flood control features within the inundation area, such as dams, levees, canals, rivers, streams, bypasses, weirs, pumps, and control structures.

(7) Boundary delineations identifying the city, county, or other governmental agency jurisdictional boundaries affected by the inundation area.

(8) An arrow indicating north.

(9) An appropriate scale bar and the stated map scale.

(10) Vertical elevation datum specified as NAVD88.

(11) If applicable, an index showing the relationship of the map sheet to the other map sheets.

(12) The preparation date of the map.

(13) The simulation date of the model.

(14) The signature, seal, and license number of the California-licensed professional civil engineer responsible for preparing the map.

(15) A statement that includes:
(A) The information shown is approximate and should be used as a guideline for emergency preparation and response.

(B) Security-sensitive infrastructure may not be shown on this map.

(16) For flood waves that are confined within a channel but not shown within the inundation boundary as allowed by section 335.10(c), a statement indicating high flows may continue beyond the inundation boundary.

(17) Labels identifying low-lying areas where the flood recession is expected to be slow and affect lives or critical facilities.

(e) Map Layout. All inundation maps shall be prepared at a scale and quality that enables a person familiar with the area to clearly comprehend an aerial view of the extent of flooding. A map scale such as that described in Section 11.3.3 of FEMA P-946 may be applied.

1. New section filed 10-19-2017 as a deemed emergency pursuant to Water Code section 6162; operative 10-19-2017 (Register 2017, No. 42). A Certificate of Compliance must be transmitted to OAL by 4-17-2018 or emergency language will be repealed by operation of law on the following day.
2. New section refiled 4-16-2018 as a deemed emergency pursuant to Water Code section 6162, including amendment of subsection (c)(15); operative 4-18-2018 (Register 2018, No. 16). A Certificate of Compliance must be transmitted to OAL by 7-17-2018 or emergency language will be repealed by operation of law on the following day.
3. New section, including amendment of section and NOTE, refiled 7-12-2018 as an emergency pursuant to Water Code section 6162; operative 7-18-2018 (Register 2018, No. 28). A Certificate of Compliance must be transmitted to OAL by 10-16-2018 or emergency language will be repealed by operation of law on the following day.
4. Certificate of Compliance as to 7-12-2018 order, including renumbering of former section 335.10 to section 335.12, renumbering of former section 335.14 to section 335.10 and amendment of section and NOTE, transmitted to OAL 10-16-2018 and filed 11-29-2018; amendments effective 11-29-2018 pursuant to Government Code section 11343.4(b)(3) (Register 2018, No. 48).

Note: Note: Authority cited: Sections 6078 and 6162, Water Code. Reference: Section 8589.5, Government Code; Sections 6160 and 6161, Water Code; and Section 6700, Business and Professions Code.

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