Cal. Water Code § 12899.5

(a) Except as provided by Section 12899.8, if any encroachment exists within the department’s right-of-way, the department may require the removal of the encroachment in the manner provided in this section.
(b) Except as provided in subdivision (e), notice shall be given to the owner, occupant, or person in possession of the encroachment, or to any other person causing or permitting the encroachment to exist, by serving a notice including a demand for the immediate removal of the encroachment from within the right-of-way. The notice shall describe the encroachment with reasonable certainty as to its character and location. In lieu of service upon the person, service of the notice may also be made by registered mail and posting for a period of five days, a copy of the notice on the encroachment described in the notice. In the case of an owner, occupant or person in possession, who is not present in the county, the notice may be given to an agent in lieu of service by mailing and posting.
(c) The department may remove from the State Water Resources Development System any right-of-way encroachment that meets both of the following criteria:
1. (1) Not later than 60 days from the date on which a notice was given pursuant to subdivision (b), the owner, occupant, or person in possession of the encroachment has not asserted a right to be in possession consistent with Section 12899.8 and has not removed, or commenced to remove in a diligent manner, the encroachment.
2. (2) The encroachment obstructs, threatens, or prevents the proper operation, maintenance, or rehabilitation of the State Water Resources Development System.
(d) The department may immediately remove from the State Water Resources Development System any right-of-way encroachment that meets both of the following criteria:
1. (1) Not later than five days from the date on which a notice is given pursuant to subdivision (b), the owner, occupant, or person in possession of the encroachment has not asserted a right to be in possession consistent with Section 12899.8 and has not removed, or commenced to remove in a diligent manner, the encroachment.
2. (2) The encroachment poses an imminent threat to the integrity of one or more features of the State Water Resources Development System.
(e) In the case of an emergency, the department has the authority to take any action necessary to avert, alleviate, repair, or mitigate any threat to the State Water Resources Development System. For the purposes of this chapter, “emergency” means a sudden, unexpected occurrence that poses a clear and imminent danger, requiring immediate action to prevent or mitigate the loss or impairment of life, health, property, or essential public services.
(f) If the department removes any encroachment upon the failure of the owner to comply with the notice pursuant to this section, the department may recover the expense of the removal, costs and expenses of suit, including attorneys fees, and, in addition, the sum of one thousand dollars ($1,000) for each day the encroachment remains after the expiration of the applicable response period described in subdivision (c) or (d).
(g) If the owner, occupant, or person in possession of the encroachment, or person causing or suffering the encroachment to exist, or the agent of any of these parties, disputes or denies the existence of the encroachment, asserts a right to be in possession consistent with Section 12899.8, or refuses to remove or permit the removal of the encroachment, the department may commence, in any court of competent jurisdiction, an action to abate the encroachment as a public nuisance. If judgment is recovered by the department, it may, in addition to having the encroachment adjudged a nuisance and abated, recover one thousand dollars ($1,000) for each day the encroachment remains after the expiration of the applicable response period described in subdivision (c) or (d), and may also recover the expense of that removal, and costs and expenses of the suit, including attorney’s fees.