Enacted by Stats. 1943, Ch. 368.
Unless the context otherwise requires, the definitions in this chapter govern the construction of this part.
Chapter 1 - Definitions
California Water Code — §§ 6000-6009
Sections (11)
Amended by Stats. 1965, Ch. 1225.
“Dam” means any artificial barrier, together with appurtenant works, which does or may impound or divert water, and which either (a) is or will be 25 feet or more in height from the natural bed of the stream or watercourse at the downstream toe of the barrier, as determined by the department, or from the lowest elevation of the outside limit of the barrier, as determined by the department, if it is not across a stream channel or watercourse, to the maximum possible water storage elevation or (b) has or will have an impounding capacity of 50 acre-feet or more.
Added by Stats. 2017, Ch. 26, Sec. 84. (SB 92) Effective June 27, 2017.
“Critical appurtenant structure” means a water surface barrier or hydraulic control structure that is 25 feet or more in height, that impounds 5,000 acre-feet of water or more, or that the department determines poses a significant downstream hazard potential.
Amended by Stats. 2025, Ch. 617, Sec. 1. (AB 639) Effective January 1, 2026.
(a)Any barrier that is or will be not in excess of six feet in height, regardless of storage capacity, or that has or will have a storage capacity not in excess of 15 acre-feet, regardless of height, shall not be considered a dam.
(b)(1) Any barrier that does not impound water above the top of a levee where maximum storage behind the barrier has a minimum of three feet of freeboard on the levee and is a weir shall not be considered a dam.
(2)This subdivision shall apply only to Peoples Weir, Reynolds Weir, Last Chance Weir, Lemoore Diversion Weir, Island Weir, Crescent Weir, Stinson Weir, Empire Weir No. 1, and Empire Weir No. 2.
(c)For purposes of this section, a “weir” is defined as an agricultural water delivery structure with either mechanically or manually removable flashboards or gates that serves to regulate the flow of water in a stream and that functions as part of a federal flood control system as defined by Part 208 (commencing with Section 208.10) of Chapter II of Title 33 of the Code of Federal Regulations.
Amended by Stats. 2022, Ch. 943, Sec. 1. (AB 1164) Effective January 1, 2023.
(a)An obstruction in a canal used to raise or lower water therein or divert water therefrom, a levee, including, but not limited to, a levee on the bed of a natural lake with the primary purpose to control floodwaters, a railroad fill or structure, a road or highway fill or structure, a circular tank constructed of steel or concrete, or both, a tank elevated above the ground, and a barrier that is not across a stream channel, watercourse, or natural drainage area and that has the principal purpose of impounding water for agricultural use shall not be considered a dam.
(b)An obstruction in the channel of a stream or watercourse that is 15 feet or less in height from the lowest elevation of the obstruction and that has the single purpose of spreading water within the bed of the stream or watercourse upstream from the obstruction for percolation underground shall not be considered a dam.
(c)The levee of an island adjacent to tidal waters in the Sacramento-San Joaquin Delta, as defined in Section 12220, even when used to impound water, shall not be considered a dam and the impoundment shall not be considered a reservoir if the maximum possible water storage elevation of the impounded water does not exceed four feet above mean sea level, as established by the United States Geological Survey 1929 datum.
(d)A noncircular tank, constructed of steel or concrete, or both, that is constructed in a county of the third class by a public agency, under the supervision of a civil engineer registered in the state, that does not exceed 75 acre-feet in capacity or 30 feet in height, and a barrier that is not across a stream channel, watercourse, or natural drainage area and that has the principal use as a sewage sludge drying facility, shall not be considered a dam.
(e)(1) A regulating basin owned or operated by a public entity that is not across a stream channel, watercourse, or natural drainage shall not be considered a dam if all of the following criteria are met:
(A) The barrier constructed to form the regulating basin has
a height of no more than 15 feet from the crest to the lowest downstream elevation where the barrier meets natural ground.
(B) The regulating basin has a storage capacity of no more than 1,500 acre-feet.
(C) The regulating basin, at the time of construction, does not have a downstream hazard classification of “high” or “extremely high,” based upon the department’s criteria for those determinations.
(D) The regulating basin is designed, and its construction is overseen, by a licensed civil engineer.
(E) The regulating basin is compliant with the general plan of the county in which it is located.
(2)In order for a regulating basin to qualify for the exclusion under paragraph (1), the owner
or operator of the regulating basin shall do all of the following:
(A)Before the construction of the regulating basin, submit to the department an inundation map, stamped by a licensed civil engineer, identifying the flow and depth of water from the regulating basin in the event of a failure of a barrier constructed to form the regulating basin.
(B)Undertake an inspection, conducted by a licensed civil engineer, of all barriers and all appurtenant structures of the regulating basin every two years following the regulating basin’s construction, and make the report available on the operating agency’s internet website.
(C)Immediately upon the identification of a failure or the risk of failure of a barrier or works critical to the safe operation of the regulating basin, notify the county sheriff and local emergency
managers of all properties likely to be impacted by a failure, in accordance with the identification of those properties on the map submitted pursuant to subparagraph (A).
(f)For purposes of this section, the following definitions apply:
(1)“Licensed civil engineer” means a civil engineer licensed pursuant to Chapter 7 (commencing with Section 6700) of Division 3 of the Business and Professions Code.
(2)“Natural drainage” means a land area over which seasonal precipitation or natural spring water accumulates and is channelized directly into a stream or watercourse.
(3)“Regulating basin” means a reservoir constructed to impound and manage the inflow and delivery of water for agricultural uses or for the purpose of groundwater recharge or other
actions undertaken to implement the Sustainable Groundwater Management Act (Part 2.74 (commencing with Section 10720) of Division 6).
Added by Stats. 1965, Ch. 1225.
“Reservoir” means any reservoir which contains or will contain the water impounded by a dam.
Amended by Stats. 1965, Ch. 1225.
“Owner” includes any of the following who own, control, operate, maintain, manage, or propose to construct a dam or reservoir:
(a)The state and its departments, institutions, agencies, and political subdivisions.
(b)Every municipal or quasi-municipal corporation.
(c)Every public utility.
(d)Every district.
(e)Every person.
(f)The duly authorized agents, lessees, or trustees of any of the foregoing.
(g)Receivers or trustees appointed by any court for any of the foregoing.
“Owner” does not include the United States.
Amended by Stats. 1965, Ch. 1225.
“Alterations,” “repairs,” or either of them, mean only such alterations or repairs as may affect the safety of the dam or reservoir.
Amended by Stats. 1965, Ch. 1225.
“Enlargement” means any change in or addition to an existing dam or reservoir, which raises or may raise the water storage elevation of the water impounded by the dam or reservoir.
Amended by Stats. 1965, Ch. 1225.
Water storage elevation means that elevation of water surface which could be obtained by the existing dam or reservoir, as previously operated, were there no outflow and were the reservoir full of water.
Added by Stats. 2017, Ch. 26, Sec. 85. (SB 92) Effective June 27, 2017.
“State jurisdictional dam” means a dam not wholly under the control of the federal government.