Cal. Water Curtailment Cases

Filed 9/29/22 (unmodified opn. attached)

CERTIFIED FOR PUBLICATION

IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA

SIXTH APPELLATE DISTRICT

CALIFORNIA WATER H047270
CURTAILMENT CASES. (Santa Clara County
Super. Ct. No. 1-15-CV285182;
JCCP No. 4838)

ORDER MODIFYING OPINION
AND DENYING PETITION FOR
REHEARING AND REQUEST FOR
JUDICIAL NOTICE
[NO CHANGE IN JUDGMENT]

THE COURT:
It is ordered that the opinion filed on September 12, 2022, be modified as follows:
On page 26, in the second sentence in the last incomplete paragraph replace
“authority” with “authority under section 1052(a)”.
On page 26, in the fifth sentence of the last incomplete paragraph, replace
“nothing in division 2” with “no similar provision in division 2”.
On page 28, in the second full paragraph, add a footnote at the end of the first
sentence that reads: “For purposes of the phase 1 trial and in this appeal, the Board has
not challenged the validity of respondents’ water rights. We have therefore assumed the
validity of respondents’ water rights in deciding this appeal.” Renumber all subsequent
footnotes.
 On page 29, in the first sentence of the last incomplete paragraph, replace “has
long had the authority” with “had the authority in 2015”.
On pages 29 to 30, in the last incomplete paragraph on page 29, in the citation that
continues on to page 30, replace “Stats. 1991, ch. 12, § 3” with “Stats. 2014, ch. 3, § 10;
see also Stats. 1991 Ex. Sess., ch. 12, § 3”.
On page 30, in the second sentence in the last paragraph, replace “held post-1914
appropriative rights,” with “claimed to manage riparian rights and pre-1914 appropriative
rights,”.
There is no change in the judgment. The petition for rehearing is denied.
The request for judicial notice is denied. The materials that are the subject of the
request appear in the record on appeal.

DANNER, J.

GREENWOOD, P.J. WILSON, J.

2
Santa Clara County Superior Court No.: 1-15-CV285182, JCCP No. 4838

Trial Judge: Hon. Brian Walsh

Counsel for Defendant/Appellant, State Water Resources Control Board: Rob Bonta,
Attorney General, Robert W. Byrne, Assistant Attorney General, Tracy L. Winsor,
Allison Goldsmith, Kate D. Fritz, Matthew G. Bullock, Deputy Attorneys General

Counsel for Intervenor/Appellant, Department of Water Resources: Rob Bonta, Attorney
General, Robert W. Byrne, Assistant Attorney General, Laura J. Zuckerman, Russell B.
Hildreth and Carolyn Nelson Rowan, Deputy Attorneys General

Counsel for Amicus Curiae on behalf of Defendant/Appellant, State Water Resources
Control Board: Environmental Law Clinic, Mills Legal Clinic at Stanford Law School,
Deborah A. Sivas, Matthew J. Sanders and Stephanie L. Safdi

Counsel for Plaintiff/Respondent, Byron-Bethany Irrigation District: Somach
Simmons & Dunn, Michael E Vergara, Theresa C. Barfield and Alyson E. Ackerman

Counsel for Plaintiff/Respondent, Central Delta Water Agency: Nomellini Grilli &
McDaniel, Dante John Nomellini, Sr., Dante John Nomellini, Jr., Daniel Allen
McDaniel; Spaletta Law and Jennifer L. Spaletta

Counsel for Plaintiffs/Respondents,
Patterson Irrigation District and Banta Carbona Irrigation District:
Herum\Crabtree\Suntag, Steven A. Herum, Jeanne M. Zolezzi and Lilliana Freeman

Counsel for Plaintiffs/Respondents, San Joaquin Tributaries Authority and South San
Joaquin Irrigation District: Paris, Kincaid & Wasiewski, Valerie C. Kincaid and
Timothy J. Wasiewski

Counsel for Plaintiff/Respondent, South Delta Water Agency: Mohan, Harris, Ruiz,
Wortmann, Perisho & Rubino, S. Dean Ruiz; and John Henry Herrick

Counsel for Plaintiff/Respondent, Oakdale Irrigation District: Tim O’Laughlin

H047270
In re California Water Curtailment Cases
Filed 9/12/22 (unmodified opinion)

CERTIFIED FOR PUBLICATION

IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA

SIXTH APPELLATE DISTRICT

CALIFORNIA WATER H047270
CURTAILMENT CASES. (Santa Clara County
Super. Ct. No. 1-15-CV285182;
JCCP No. 4838)

We decide an appeal arising from the state’s efforts in 2015 to curtail water use in
the Sacramento-San Joaquin River Delta 1 during a severe, multi-year drought.
Appellant State Water Resources Control Board (the Board) appeals from a
judgment issuing preemptory writs of mandate. The Board’s appeal turns on whether it
has the authority to curtail the diversion or use of water by holders of valid pre-1914
appropriative water rights—a group with distinctive rights rooted in the history of
California water law 2—under Water Code section 1052, subdivision (a) 3 (hereafter
section 1052(a)) on the sole ground that there is insufficient water to service their
priorities of right due to drought conditions. The trial court concluded that section

1
We use “the Sacramento-San Joaquin River Delta” and “the Delta”
interchangeably to refer to the Sacramento-San Joaquin River and Delta watersheds.
2
We describe the significance of pre-1914 appropriative water rights and other
fundamental principles of California water law in more detail, post.
3
Unspecified statutory references are to the Water Code.
1052(a) did not authorize the Board to do so and granted relief to respondents, 4 who hold
pre-1914 appropriative water rights.
Section 1052(a), which appears in division 2 of the Water Code, provides: “The
diversion or use of water subject to this division other than as authorized in this division
is a trespass.” (§ 1052(a).) This appeal requires us to construe the language “subject to
this division other than as authorized in this division.” The parties agree that this statute
permits the Board to curtail diversions or uses of water that fall within this definition, but
they disagree about its application to pre-1914 appropriative water rights.
The Board asserts that this language can, under certain conditions, extend to
diversions by all or certain classes of pre-1914 appropriators. In particular, the Board
argues section 1052(a) granted it authority in 2015 to curtail respondents’ diversion or
use of water based on its projection that there would be insufficient water to satisfy a
group of pre-1914 water right holders in the Delta. Respondents counter that “subject to
this division other than as authorized in this division” excludes the diversion or use of
water within the scope of a valid pre-1914 appropriative right, even during times of
limited water supply.
We agree with the Board that section 1052(a) provides the Board authority to
enjoin a diversion or use of water that falls outside the scope of a right held by a pre-1914
appropriative right holder. But we reject its contention that the statute endows the Board
with jurisdiction to curtail diversions based on alleged violations of priorities of right
among valid pre-1914 right holders if it concludes that the water supply is insufficient to

4
Respondents are Banta-Carbona Irrigation District (BCID), Byron-Bethany
Irrigation District (BBID), Patterson Irrigation District, West Side Irrigation District
(WSID), Central Delta Water Agency, South Delta Water Agency, San Joaquin
Tributaries Authority, South San Joaquin Irrigation District, and Oakdale Irrigation
District, which we will refer to collectively as respondents. In September 2020, after the
trial court’s judgment, WSID and BBID consolidated into a single entity called BBID.
We subsequently granted BBID’s request to substitute itself for WSID.
2
satisfy their entitlements. As the latter theory was the sole basis for the Board’s
curtailment notices at issue here, we affirm the trial court’s judgment against the Board.
I. FACTUAL AND PROCEDURAL BACKGROUND
After “one of the driest years in recorded state history,” Governor Brown
proclaimed a state of emergency in January 2014 due to “severe drought conditions.” In
May 2014, the Board notified water right holders in the Sacramento and San Joaquin
River watersheds that the Board had “determined that the existing water supply . . . is
insufficient to meet the needs of all water rights holders.” With respect to pre-1914
appropriative and riparian water right holders, the Board asked them to “conserve water”
and informed them that it might “curtail some pre-1914 and riparian water rights in the
near future.” 5
In January 2015, the Board informed all water right holders in California that,
unless there were significant improvement, it would be notifying those “in critically dry
watersheds of the requirement to limit or stop diversions of water under their water right,
based on their priority.” It warned that “[s]ome more senior riparian and pre-1914 water
right holders can also receive a notice to stop diverting water based on their priority or
limitation of natural flow.”
In February 2015, the Board issued an “informational order,” to take effect on
March 1, 2015. This order stated that the Board “has information that indicates there
may be unlawful diversions of stored water by riparians or pre-1914 appropriative water
right claimants in the Sacramento and San Joaquin River watershed and Delta.” The

5
“Riparian rights are special rights to make use of water in a waterway adjoining
the owner’s property. Overlying rights are special rights to use groundwater under the
owner’s property.” (City of Barstow v. Mojave Water Agency (2000) 23 Cal.4th 1224,
1237, fn. 7 (City of Barstow).) Appropriative rights involve “the diversion of water” and
“ ‘any taking of water for other than riparian or overlying uses.’ ” (People v. Shirokow
(1980) 26 Cal.3d 301, 307 (Shirokow).) Neither riparian nor overlying rights are at issue
in this appeal.

3
Board ordered “holders claiming riparian and pre-1914 rights in the Sacramento and San
Joaquin River Watershed and Delta” to provide information to the Board about their
diversions and the basis for their rights and to continue to report their diversions to the
Board each month. The Board explained that this information was needed “[t]o
determine whether unauthorized diversions have occurred.” The order noted: “Failure to
comply with this Order subjects the party to enforcement action.”
On April 1, 2015, the Governor issued another executive order continuing the
State of Emergency due to the “severe drought conditions” in the state caused by four
years of drought. The Governor ordered the Board to take various actions, including
requiring “frequent reporting of water diversion and use by water right holders,
conduct[ing] inspections to determine whether illegal diversions or wasteful and
unreasonable use of water are occurring, and bring[ing] enforcement actions against
illegal diverters and those engaging in the wasteful and unreasonable use of water.”
The following day, the Board sent notices to all water right holders informing
them that “[i]f dry conditions persist through the spring, it is anticipated that all holders
of post-1914 and many holders of pre-1914 water rights in certain watersheds will
receive curtailment notices soon.” The Board said it would soon post “estimate[s of] the
timing of curtailments for the various classes of water right holders.”
Three weeks later, the Board sent out another set of notices after it “determined
that the existing water supply in the San Joaquin River watershed is insufficient to meet
the needs of all water rights holders.” These notices told “all holders of post-1914
appropriative water rights within the San Joaquin River watershed . . . to immediately
stop diverting under their post-1914 water rights.” (Underlining omitted.) The notices
also “advised that, if you continue to divert under a claim of pre-1914 right, most or all
pre-1914 rights in the San Joaquin River watershed are likely to be curtailed later this
year due to the extreme dry conditions.” One week later, the Board sent nearly identical
notices to water right holders within the Sacramento River watershed.
4
 On June 12, 2015, the Board sent out another set of notices based on its updated
water supply projections telling those with “pre-1914 claims of right, with a priority date
of 1903 and later for the Sacramento-San Joaquin watersheds and the Delta, that, due to
ongoing drought conditions, there is insufficient water in the system to service their
claims of right.” The notices informed them “of the need to immediately stop diverting
water with the exceptions discussed below . . . until water conditions improve.”
(Underlining omitted.) They stated: “Holders of pre-1914 water right claims with
priority dates equal to or later than 1903 are required to document receipt of this
notice . . . [and] confirm[] your cessation of diversion under the specific pre-1914 claim
of right.” 6
Under the heading “Potential Enforcement,” the notices informed recipients that
“[i]f the State Water Board finds following an adjudicative proceeding that a person or
entity has diverted or used water [] unlawfully, the State Water Board may assess
penalties of $1,000 per day of violation and $2,500 for each acre-foot diverted or used in
excess of a valid water right. (See Water Code, §§ 1052, 1055.) Additionally, if the
State Water Board issues a Cease and Desist Order against an unauthorized diversion,
violation of any such order can result in a fine of $10,000 per day. (See Water Code,
§§ 1831, 1845.)”
On June 16, 2015, the Board sent out a “clarification” to those who claimed both a
pre-1914 appropriative water right and a riparian water right. It stated riparian rights
would not be curtailed but “as of June 12, 2015, there is insufficient water in the system
to meet the needs served by your pre-1914 [appropriative] right.”

6
On June 26, 2015, the Board also sent curtailment notices to Upper San Joaquin
River watershed diverters. Those notices do not appear to be at issue in this appeal.
5
 Shortly thereafter, respondents filed mandate actions challenging on due process
and jurisdictional grounds the Board’s curtailment notices. 7 Respondents asserted that
the Board had violated their due process rights by issuing the curtailment notices without
providing them with an opportunity to be heard. They also contended that the Board had
exceeded its jurisdiction because it “lacks authority to regulate pre-1914 appropriative
water rights.”
Respondents sought a temporary restraining order (TRO) staying the Board’s May
and June 2015 notices, which was heard on July 8, 2015, by the Sacramento County
Superior Court. At the TRO hearing, the Board argued that respondents were not entitled
to due process before the issuance of the curtailment notices but would be entitled to due
process before any enforcement action under section 1052 or section 1831. Respondents
argued that the notices were coercive and requested rescission of language in the notices
requiring them to stop diverting.
The Sacramento County Superior Court (whose order is not directly at issue in this
appeal) agreed with respondents. It found that the coercive language in the June 2015
notices, requiring respondents to stop diverting and to certify that they had stopped
diverting, was improper without a pre-deprivation hearing. The court ordered the
language deleted from the notices. It found that the May and June curtailment notices
violated respondents’ due process rights. The court ordered the Board “to show cause as
to why a preliminary injunction should not issue requiring the Board to issue a revised
letter/notice that is informational in nature.”
On July 15, 2015, the Board issued a “partial rescission” and “clarification” of the
May and June notices. The July 15 notice informed respondents that the Board was
“rescind[ing] the ‘curtailment’ portions of the unavailability notices you received. To the
extent that [those] notices . . . contain language that may be construed as an order

7
The actions were ultimately coordinated in the Santa Clara County Superior
Court.
6
requiring you to stop diversions under your affected water right, that language is hereby
rescinded.”
In the July 15 partial rescission notice, the Board stated “information available to
the State Water Board continues to indicate that there is insufficient water available for
the categories of junior water users identified in the State Water Board’s prior
correspondence, identified above. . . . [¶] Diversion is always subject to water
availability limitations, and diversions under your affected water right may be subject to
enforcement should the State Water Board find such diversions are or were unauthorized.
The State Water Board is continuing its drought-year inspections to determine whether
diverters are using water to which they are not entitled. [¶] . . . Those who are found to
be diverting water beyond what is legally available to them may be subject to
administrative penalties, cease and desist orders, or prosecution in court.”
At a July 30, 2015 hearing, the Sacramento County Superior Court found that the
July 2015 “partial rescission” complied with its order and rejected respondents’ claim
that there continued to be a “constitutional infirmity” in the Board’s notices. The
curtailment notices were later rescinded, and the Board notified water right holders that
water was available for diversion. 8
Before the notices were rescinded, the Board brought enforcement proceedings
against BBID and WSID alleging unauthorized diversions. In 2016, the Board dismissed
those actions after an administrative hearing demonstrated that the prosecution could not
satisfy its burden of proof.

8
In September 2015, the Board notified pre-1914 water right holders in the
Sacramento River watershed and Delta, but not the San Joaquin River watershed, that
water was available for their diversions. In November 2015, the Board notified pre-1927
water right holders that water was available in both the Sacramento River watershed and
the Sacramento-San Joaquin Delta. Shortly thereafter, the Board notified post-1914
water right holders that water was available for diversion.
7
 When the Board dismissed the enforcement proceedings, it rejected the claim that
it lacked jurisdiction over pre-1914 appropriative water right holders under section
1052(a). The Board stated, “[BBID and others] object that the Board has no authority to
‘regulate’ pre-1914 or riparian water rights. These enforcement proceedings are not an
effort to regulate the exercise of any valid right. Rather, the enforcement actions seek to
prevent the diversion or use of water that is not authorized by the diverter’s claim of
right. Because the property interest in water is defined, in part, by the priority of the
right, a diversion that is out of priority is a diversion that is outside of the bounds of the
right.” The Board concluded that it “has the authority to take enforcement action
pursuant to Water Code section 1052 against the unauthorized diversion of water under
claim of a pre-1914 water right.”
Although the curtailment notices had been rescinded, respondents maintained their
mandate actions challenging the Board’s May and June 2015 curtailment notices. The
petitions were tried to the court in January 2018 in phase 1 of a trial that was originally
expected to have three phases.
In April 2018, the trial court issued a final statement of decision from phase I in
favor of respondents. In its order, the trial court observed that “the Board does not
dispute that petitioners possess the water rights they claim, and it never purported to
curtail or take enforcement action against petitioners on the ground that their asserted
water rights were invalid.” The court also noted that respondents did not challenge the
Board’s jurisdiction to curtail post-1914 users.
The trial court understood the Board’s jurisdictional argument as limited to its
authority under section 1052(a). The court stated, “the Board does not contend that the
reasonable use doctrine, the public trust doctrine, or any more general authority to
adjudicate or police senior water rights authorized its actions. Further, the Board’s
curtailment efforts were not based on the specific theory that petitioners were taking

8
stored water released by DWR [(Department of Water Resources)], as opposed to water
from any source that was not available under their priority of right.” 9
The trial court decided that “section 1052 does not authorize the Board to ‘curtail’
or take enforcement action against pre-1914 appropriators based on a general lack of
available water under their priority of right, as opposed to a specific trespass against
Division 2 water.” The court observed that the Board was not “wholly without
jurisdiction over these users” and could take certain actions with respect to pre-1914
appropriators under sections 2501 et seq. (comprehensive determination of all water
rights in a stream system) and section 1058.5 (emergency regulations) or “under other
statutory provisions not addressed by the parties.”
After resolving the jurisdictional issue, the trial court went on to find that the
Board’s issuance of the 2015 curtailment notices violated respondents’ due process rights
by failing to provide them with a predeprivation hearing or any other opportunity to
challenge the bases for the notices. The court addressed the due process issue, even
though it was technically moot, as a fundamental issue of broad public interest likely to
recur. 10
Following the trial court’s statement of decision, respondents dismissed their
remaining causes of action that would have been resolved in phase 2 and phase 3.
In June 2019, the court issued a judgment granting respondents writs of mandate.
The Board timely filed notices of appeal from the judgment, as did the Department
of Water Resources, which had intervened in the actions in the trial court. The Board

9
The Board had argued that the presence of stored water in the Delta at the time of
the curtailment notices was relevant to whether the Board had jurisdiction to issue those
notices. However, the court’s statement of decision expressed “no opinion at this time on
the Board’s jurisdiction to bring trespass actions against senior users on the express basis
that they are taking Division 2 water released by DWR” (i.e., stored water), and the court
later noted that it had “not ruled . . . on the stored water issue.”
10
The court subsequently decided that its due process decision applied to “all four
notices,” including the May 2015 notices concerning only post-1914 rights.
9
appeals the trial court’s jurisdictional ruling about the scope of section 1052(a) but does
not challenge the trial court’s decision that the Board had denied respondents due process
of law.
II. WATER RIGHTS UNDER CALIFORNIA LAW
The parties’ competing claims as to the Board’s authority under section 1052(a)
are rooted in the history of California’s complex regulation of water rights.
The California Constitution provides that “because of the conditions prevailing in
this State the general welfare requires that the water resources of the State be put to
beneficial use to the fullest extent of which they are capable, and that the waste or
unreasonable use or unreasonable method of use of water be prevented, and that the
conservation of such waters is to be exercised with a view to the reasonable and
beneficial use thereof in the interest of the people and for the public welfare. The right to
water or to the use or flow of water in or from any natural stream or water course in this
State is and shall be limited to such water as shall be reasonably required for the
beneficial use to be served, and such right does not and shall not extend to the waste or
unreasonable use or unreasonable method of use or unreasonable method of diversion of
water. . . . This section shall be self-executing, and the Legislature may also enact laws
in the furtherance of the policy in this section contained.” (Cal. Const., art. X, § 2.)
“Ownership of California’s water is vested generally in the state’s residents, but
individuals and entities can acquire ‘water rights,’ the right to divert water from its
natural course for public or private use.” (Light v. State Water Resources Control Bd.
(2014) 226 Cal.App.4th 1463, 1477–1478 (Light); § 102.)
“California operates under the so-called dual system of water rights which
recognizes both the appropriation and the riparian doctrines. [Citation.] The riparian
doctrine confers upon the owner of land contiguous to a watercourse the right to the
reasonable and beneficial use of water on his land. The appropriation doctrine
contemplates the diversion of water and applies to ‘any taking of water for other than
10
riparian or overlying uses.’ [Citation.] Both riparian and appropriative rights are
usufructuary only and confer no right of private ownership in the watercourse.”
(Shirokow, supra, 26 Cal.3d at p. 307, fn. omitted.)
In applying this body of law, courts “allocate [] water according to preexisting
legal rights and relationships.” (City of Barstow, supra, 23 Cal.4th at p. 1242.) “Water
right priority has long been the central principle in California water law.” (Id. at
p. 1243.) “In the case of an overdraft, riparian and overlying use is paramount, and the
rights of the appropriator must yield to the rights of the riparian or overlying owner.”
(Ibid.) “As a result, appropriators may be deprived of all use of water when the supply is
short. In turn, senior appropriators—those who acquired their rights first in time—are
entitled to satisfy their reasonable needs, up to their full appropriation, before more junior
appropriators are entitled to any water.” (Millview County Water Dist. v. State Water
Resources Control Bd. (2014) 229 Cal.App.4th 879, 890 (Millview).) Appropriators do
not lose their appropriative rights in times of insufficient water. (Huffner v. Sawday
(1908) 153 Cal. 86, 92.)
“For historical reasons, California [] subdivides appropriators into those whose
water rights were established before and after 1914. Post-1914 appropriators may
possess water rights only through a permit or license issued by the Board, and their rights
are circumscribed by the terms of the permit or license. Riparian users and pre-1914
appropriators need neither a permit nor other governmental authorization to exercise their
water rights.” (Light, supra, 226 Cal.App.4th at p. 1478, fn. omitted.)
Pre-1914 appropriative water rights “originated in the gold rush days when miners
diverted water necessary to work their placer mining claims. The miners adopted among
themselves the priority rule of ‘first in time, first in right,’ and California courts looked to
principles of equity and of real property law to adjudicate conflicting claims. [Citations.]
Thus it was initially the law in this state that a person could appropriate water merely by
diverting it and putting it to use. [¶] The first appropriation statute was enacted in 1872
11
and provided for initiation of the appropriative right by the posting and recordation of
notice. [Citation.] The nonstatutory method [(common law appropriation)] retained its
vitality and appropriative rights were acquired by following either procedure. [Citation.]
[¶] Both methods were superseded by the 1913 enactment of the Water Commission Act
[(the 1913 Act)], which created a Water Commission and provided a procedure for the
appropriation of water for useful and beneficial purposes. The main purpose of the act
was ‘to provide an orderly method for the appropriation of [unappropriated] waters.’ ”
(Shirokow, supra, 26 Cal.3d at pp. 307–308, fns. omitted.) As the 1913 Act did not go
into effect until December 1914, these rights are referred to as pre-1914 appropriative
rights. (Fall River Valley Irrigation District v. Mt. Shasta Power Corp. (1927) 202 Cal.
56, 66.) 11
The 1913 Act created divisions 1 and 2 of the Water Code. (Shirokow, supra, 26
Cal.3d at p. 308.) Section 1052(a) appears in division 2 of the Water Code. Before
turning to our analysis of this provision, we first consider both respondents’ contention
that the Board’s appeal should be dismissed as moot and the pertinent standards of
judicial review.

11
We have considered the amicus brief filed by Winnemem Wintu Tribe, Shingle
Springs Band of Miwok Indians, Little Manila Rising, and Restore the Delta. Their
amicus brief traces the “dark and violent historical underpinnings” of pre-1914 water
rights in California. They ask us to consider this history due to the “grave consequences”
of restricting the Board’s jurisdiction over pre-1914 water rights.
We do not question the importance of the issues identified by amici. However, as
the California Supreme Court has observed, “ ‘our resolution of the legal issue[s] before
us does not turn upon our personal views as to the wisdom or morality of the [laws and
policies at issue in this case]. Instead, our task involves . . . question[s] of statutory
interpretation.’ ” (Brennon B. v. Superior Court (2022) 13 Cal.5th 662, 669.) The policy
question of how to treat water rights given their history (as addressed in the amicus brief)
and in the face of decreasing water supplies “ ‘is a decision that only the Legislature can
make. The task before us today is one of statutory interpretation.’ ” (Id. at p. 670.)
12
 III. JUSTICIABILITY AND STANDARDS OF JUDICIAL REVIEW
Respondents argue that the Board’s appeal is moot because it does not challenge
the trial court’s finding that respondents were deprived of due process prior to the
issuance of the curtailment notices and therefore the notices are invalid even if we were
to find error in the trial court’s reading of section 1052(a).
The parties previously took the opposite positions on mootness from those they
advance in this appeal. In the trial court, the Board argued that respondents’ challenges
to the curtailment notices were “moot” because none of those notices remained in effect.
However, the Board noted below: “If it’s taken up on appeal, it would provide guidance
to all of the other parties.”
Respondents conceded below that the curtailment notices “are no longer in effect”
and “no longer in play.” Yet they argued in the trial court that the jurisdictional issue was
not moot because they and the Board continued to have an “actual controversy” about the
Board’s “legal conclusions regarding its jurisdiction over pre-1914 water rights.”
Further, respondents argued that the jurisdictional issue was one of continuing public
importance and so should be addressed even if moot because the case fell within “the
exception to the mootness doctrine” for an “issue of utmost public importance capable of
repetition but [evading] review.”
The trial court rejected the Board’s argument that respondents’ challenge to the
May and June 2015 curtailment notices could not prevail because it was moot after the
lifting of the curtailment notices. The court, citing Young v. State Water Resources
Control Bd. (2013) 219 Cal.App.4th 397 (Young), found that “even if the issue is
technically moot, the Court will reach it under the public interest exception to mootness,
since ‘the jurisdictional question posed is of continuing public interest and importance.’ ”
(See id. at p. 403.)
We similarly decline to dismiss this appeal as moot. While the validity of the
2015 curtailment notices is no longer at issue, the question of whether the Board had the
13
authority to issue the curtailment notices under section 1052(a) remains an important
question affecting the public interest that is capable of repetition yet evading review.
(See NBC Subsidiary (KNBC-TV), Inc. v. Superior Court (1999) 20 Cal.4th 1178, 1190,
fn. 6.) The trial court’s issuance of writs of mandate finding that the Board lacked
jurisdiction under section 1052(a) to issue curtailment notices to pre-1914 appropriators
based solely on drought conditions has the potential, if erroneous, to impede the Board’s
future authority to issue such orders.
Having declined to dismiss the appeal as moot, we will address the merits of the
question before us. Before turning to that task, we consider the standards that guide our
review.
Respondents filed their petitions pursuant to section 1126, subdivision (b), which
provides: “Any party aggrieved by any decision or order [by the Board] may, not later
than 30 days from the date of final action by the board, file a petition for a writ of
mandate for review of the decision or order.” (§ 1126, subd. (b).) Judicial review of the
Board’s action is governed by Code of Civil Procedure section 1094.5. (§ 1126, subd.
(c).) “The inquiry in such a case shall extend to the questions whether the [Board] has
proceeded without, or in excess of, jurisdiction; whether there was a fair trial; and
whether there was any prejudicial abuse of discretion. Abuse of discretion is established
if the [Board] has not proceeded in the manner required by law, the order or decision is
not supported by the findings, or the findings are not supported by the evidence.” (Code
Civ. Proc., § 1094.5, subd. (b).)
The sole issue in this appeal is the proper construction of section 1052(a). “We
review questions of statutory construction de novo.” (California Building Industry Assn.
v. State Water Resources Control Bd. (2018) 4 Cal.5th 1032, 1041.)

14
 IV. THE BOARD’S JURISDICTION UNDER SECTION 1052(A)
A. The Parties’ Contentions
The Board contends that the trial court “fundamentally misread[]” section 1052(a)
by construing it as applying only to “water subject to this division”—excluding water
appropriated by pre-1914 appropriators—rather than reading it as applying to “diversion
or use of water subject to this division.” The Board reads this latter phrase as including
all diversions and uses of water, including the allocation of uses by priorities of right. In
the Board’s view, the trial court improperly focused on whether, at the time of the 2015
curtailment notices, the Delta contained any unappropriated water rather than considering
whether the diversions being made at that time by pre-1914 appropriators were
unauthorized under division 2.
The Board argues that because of the operation of the priority rules, all diversions
by pre-1914 appropriators are potentially subject to division 2 and thus within the scope
of the Board’s authority under section 1052(a). The Board states, “there is no proper
basis to distinguish between the Board’s authority to prevent the diversion or use of water
that is unauthorized because it is in excess of the quantity, place of use, or purpose of use
of a diverter’s valid right, and the diversion or use of water that is unauthorized because it
is in excess of a diverter’s priority of right.”
Respondents maintain that the trial court properly read section 1052(a) as limiting
the Board’s authority to “the diversion of water subject to [d]ivision 2” (italics omitted),
which excludes any water diverted within the valid scope of a pre-1914 appropriative
water right. They contend that sections 1201 and 1202 “define the water subject to
[d]ivision 2” (italics omitted) and do not include within that definition any water diverted
within the valid scope of a pre-1914 appropriative water right. In other words,
respondents assert the Board has no jurisdiction under section 1052(a) over diversions of
water by pre-1914 appropriators within the valid scope of their rights—even where such
diversions might threaten the priority of more senior right holders.
15
 B. Section 1052(a)
1. Statutory Language and Judicial Interpretations
The Board asserts that section 1052(a) provided it with the authority to issue the
2015 notices challenged by respondents.
The pertinent statutory language consists of a single sentence: “The diversion or
use of water subject to this division other than as authorized in this division is a trespass.”
(§ 1052(a).)
The parties agree that “ ‘this division’ ” referenced in section 1052(a) refers to
division 2. The question posed by the Board’s appeal is which water uses are included in
section 1052(a)’s limitation “subject to this division other than as authorized in this
division.” If respondents’ diversions or uses fell within this definition, then the Board
had jurisdiction to act under section 1052(a).
As the California Supreme Court has observed, resolution of the meaning of
section 1052(a) is “not aided by the omission in division 2 of any definition of the water
which is subject to its provisions.” (Shirokow, supra, 26 Cal.3d at p. 306.)
In the absence of such a definition, we apply familiar principles of statutory
construction to answer the question. “ ‘ “ ‘When we interpret a statute, “[o]ur
fundamental task . . . is to determine the Legislature’s intent so as to effectuate the law’s
purpose. We first examine the statutory language, giving it a plain and commonsense
meaning. We do not examine that language in isolation, but in the context of the
statutory framework as a whole in order to determine its scope and purpose and to
harmonize the various parts of the enactment. If the language is clear, courts must
generally follow its plain meaning unless a literal interpretation would result in absurd
consequences the Legislature did not intend. If the statutory language permits more than
one reasonable interpretation, courts may consider other aids, such as the statute’s
purpose, legislative history, and public policy.” [Citation.] “Furthermore, we consider
portions of a statute in the context of the entire statute and the statutory scheme of which
16
it is a part, giving significance to every word, phrase, sentence, and part of an act in
pursuance of the legislative purpose.” ’ ” ’ ” (Smith v. LoanMe, Inc. (2021) 11 Cal.5th
183, 190.) We also are mindful that “ ‘[l]aws providing for the conservation of natural
resources are of great remedial and public importance and thus should be construed
liberally . . .’ [citation] so as to promote the general object sought to be accomplished.”
(Coastside Fishing Club v. California Resources Agency (2008) 158 Cal.App.4th 1183,
1202.)
We first consider the statutory scheme. Section 4 of the Water Code provides:
“No action or proceeding commenced before this code takes effect, and no right accrued,
is affected by this code, but all procedure thereafter taken therein shall conform to the
provisions of this code so far as possible.” (§ 4, italics added.) Section 103 provides:
“In the enactment of this code the Legislature does not intend thereby to effect any
change in the law relating to water rights.” (§ 103.)
Section 1052 appears in chapter 2 of part 1 of division 2 of the Water Code. This
chapter addresses certain aspects of the Board’s authority over water rights. Section 1050
authorizes the Board to enforce division 2 in furtherance of the policy expressed in article
X, section 2 of the California Constitution and for the benefit of the people of this state.
Section 1051 grants the Board the authority to investigate streams and other surface water
sources to determine whether a use or appropriation of water is lawful. Section 1052,
subdivision (b) authorizes the Attorney General to bring an action on behalf of the Board
(or the State) to enjoin use or diversion of water. Section 1052, subdivision (c) identifies
the daily penalties for violations of section 1052(a). Section 1052, subdivision (d)
authorizes the Board to impose administrative civil liability in accordance with the
procedure set forth in section 1055. Section 1058.5 permits the Board to adopt
emergency regulations in response to drought conditions.
As the California Supreme Court has summarized, “Part 2 of the division provides
a comprehensive scheme for the appropriation of water. It defines water subject to
17
appropriation (§§ 1200-1203); declares compliance with the provisions of division 2 to be
the exclusive means of acquiring the right to appropriate or use water subject to
appropriation (§ 1225); authorizes the board to act upon all applications for permits to
appropriate water, to grant permits to take and use water subject to the terms and
conditions of the permit, and to collect fees (§§ 1250-1550); and provides for the
issuance of licenses confirming the right to appropriate such amount of water as has been
beneficially used by the permittees (§§ 1600-1677).” (Shirokow, supra, 26 Cal.3d at
p. 306.) Part 2 also includes section 1831, which authorizes the Board to issue cease and
desist orders in various situations, including where there has been a violation “or
threatened violation” of section 1052(a). (§ 1831, subd. (d).) Chapter 2 of part 2 governs
priorities of right and provides that an “applicant[’s]” priority of right is “as of the date of
the application.” (§ 1450.)
The California Supreme Court has concluded that “[t]he rights not subject to the
statutory appropriation procedures [of division 2] are narrowly circumscribed by the
exception clause of the statute and include only riparian rights and those which have been
otherwise appropriated prior to December 19, 1914, the effective date of the statute.”
(Shirokow, supra, 26 Cal.3d at p. 309, italics added.) This statement, considered in
isolation, would vindicate respondents’ position in this appeal. Nevertheless, subsequent
judicial decisions have concluded that the Board’s authority under division 2 does extend
to some diversions or uses of water by pre-1914 appropriative right holders.
In Young, supra, 219 Cal.App.4th 397, the Court of Appeal considered whether
the Board “lacks jurisdiction to issue a cease-and-desist order [] for an illegal diversion of
water if the diverter claims riparian or pre-1914 appropriative rights.” (Id. at p. 400.)
The Board had asked a diverter “to complete a statement of diversion and use of water
from the Middle River in the Sacramento-San Joaquin River Delta and to provide
evidence to verify the basis of the asserted water right upon which it was diverting water.

18
Following an investigation, the Water Board issued a draft [cease-and-desist order]
against [the diverter] for the alleged unauthorized diversion of water.” (Id. at p. 401.)
The diverter sought an administrative hearing, but the hearing officer refused to
allow the diverter’s customers to participate. (Young, supra, 219 Cal.App.4th at p. 401.)
At the hearing, the diverter established that its “riparian or pre-1914 appropriative water
rights” were limited to “no more than 77.7 cubic feet per second (cfs),” and the Board
ordered the diverter “to submit monthly diversion records annually, and before diverting
any water at a rate in excess of 77.7 cfs, . . . to submit additional evidence regarding
water rights and other information to the deputy director of the Water Board.” (Id. at
p. 402.) The diverter’s customers sought reconsideration and judicial review by writ of
mandate. Their mandate petition was based on due process and lack of jurisdiction
grounds. The Board granted reconsideration on due process grounds but maintained that
it had jurisdiction to issue the cease-and-desist order. The trial court issued a writ of
mandate requiring the Board to set aside the cease-and-desist order. (Ibid.)
The Board’s appeal raised the issue of “whether the Water Code gives the Water
Board jurisdiction in enforcement proceedings to determine initially whether a diverter
has either the riparian or pre-1914 appropriative rights it claims.” (Young, supra, 219
Cal.App.4th at p. 404.) The customers argued “that the Water Code does not provide the
authority to the Water Board to adjudicate the validity, the extent, or the forfeiture of
riparian or pre-1914 appropriative rights” and that the Board “had no jurisdiction to do so
before the enactment of Water Code section 1831, and section 1831, subdivision (e)
exempts ‘water not otherwise subject to regulation of the board under this part.’ ” (Id. at
p. 403.) They claimed that “the diverter divests the Water Board of jurisdiction simply
by alleging riparian or pre-1914 appropriative rights.” (Id. at p. 406.)
The Third District Court of Appeal rejected the jurisdictional argument. It first
opined that “essentially the same jurisdictional argument” had been rejected in Temescal
Water Co. v. Department of Public Works (1955) 44 Cal.2d 90. (Young, supra, 219
19
Cal.App.4th at p. 404.) It stated: “The Legislature has granted the Water Board power to
investigate water use and to ascertain whether water is being diverted other than as
authorized in the code. Water Code section 1052 states, in part: ‘The diversion or use of
water subject to this division other than as authorized in this division is a
trespass[,] . . . [¶] . . . [¶] [and the Water Board] shall institute in the superior court in
and for any county wherein the diversion or use is threatened, is occurring, or has
occurred appropriate action. . .’ to have such trespass enjoined.” (Id. at p. 405.)
The Third District decided: “The preamble to section 1831 resolves the
jurisdictional question. It states: ‘When the board determines that any person is
violating, or threatening to violate, any requirement described in subdivision (d), the
board may issue an order to that person to cease and desist from that violation.’ ”
(Young, supra, 219 Cal.App.4th at pp. 405–406.) “The provisions of part 2 of division 2
of the Water Code referred to in Water Code section 1831, subdivision (e) include the
authority to regulate the diversion and use of unappropriated water, including water
claimed under pre-1914 appropriative rights but never perfected, and rights perfected
under a pre-1914 right but lost through nonuse. (Wat. Code, §§ 1201, 1202, subd. (b),
1225.) These provisions also include the authority to regulate water claimed under a
riparian right but either not covered by an existing riparian right or water being diverted
in excess of a valid riparian right.” (Id. at p. 406.) The Third District held that “pursuant
to Water Code section 1831, the Water Board can make a preliminary determination for
purposes of enforcement whether the diverter has either the riparian or pre-1914
appropriative rights it claims without filing a lawsuit.” (Id. at p. 400.) Young, therefore,
stands for the proposition that the Board has the authority under division 2 to adjudicate
the validity, extent, and potential forfeiture of pre-1914 appropriative rights.
In Millview, the First District Court of Appeal agreed with Young’s analysis.
(Millview, supra, 229 Cal.App.4th at p. 885.) The Board’s action in Millview arose from
its investigation of a citizen’s complaint challenging the propriety of Millview’s
20
diversion of water from the Russian River. (Ibid.) This investigation concluded that
Millview’s pre-1914 water right had been “largely forfeited” by “diminished use” for a
20-year period. (Id. at p. 884.) Following an evidentiary hearing, the Board made factual
determinations and issued a cease-and-desist order limiting Millview’s diversion to a
maximum of 1.1 cubic feet per second and a total of 15 acre feet per year. (Id. at pp. 885,
888.) The Board’s cease-and-desist order barred Millview from diverting water beyond
the proper scope of its pre-1914 appropriative right. (Id. at p. 884.) The trial court,
however, overturned the order after finding that “the Board lacks jurisdiction to issue a
[cease-and-desist order] with respect to water diverted pursuant to a pre-1914 right of
appropriation.” (Id. at p. 893.)
The First District rejected the trial court’s jurisdictional conclusion but affirmed
on the ground that the Board’s cease-and-desist order was not supported by sufficient
evidence. (Millview, supra, 229 Cal.App.4th at p. 885.) Relying heavily on the Third
District’s decision in Young, which the First District found “straightforward and
persuasive” (id. at p. 894), the First District decided that the Board had jurisdiction to
determine the proper scope of a pre-1914 appropriative water right and “under Water
Code section 1831 to issue a [cease-and-desist order] precluding excessive diversion”
under that right. (Id. at p. 885, fn. omitted.)
The First District reasoned: “Any other rule would permit a diverter to place his
or her diversion beyond Board regulation merely by claiming to possess, as opposed to
validly possessing, a pre-1914 water right.” (Millview, supra, 229 Cal.App.4th at p. 894.)
It pointed out that the diversion of water that the Board found did not fall within the
proper scope of a pre-1914 water right rendered that diversion an “[u]nauthorized” one.
(Id. at p. 895.) In a footnote, the First District noted that “[p]revention of unauthorized
diversions under section 1052 included the improper diversion of water under asserted
pre-1914 appropriative water rights.” (Id. at p. 896, fn. 12.)

21
 These decisions, therefore, establish that the Board has jurisdiction to assess the
scope and validity of pre-1914 water rights and determine whether a right holder has
diverted water in excess of the right holder’s valid right (in which case, the unauthorized
diversion would be subject to division 2). Both Millview and Young, however, examined
the Board’s authority to determine the scope of a specific appropriative right. In
Millview, the Board had concluded that the relevant appropriative right was to divert “a
maximum rate of 1.1 cubic feet per second [] and a total volume of 15 acre-feet per year.”
(Millview, supra, 229 Cal.App.4th at p. 885.) In Young, the Board had determined that
the right holder had the pre-1914 appropriative right “to divert no more than 77.7 cubic
feet per second.” (Young, supra, 219 Cal.App.4th at p. 402.)
Neither decision considered whether the Board has the authority to decide that
section 1052(a) has been violated based on a theory that the diversion violates the priority
rules applicable to pre-1914 appropriative water right holders in a particular region
because of insufficient water availability. The Board contends in this appeal that it does
have such authority; respondents argue it does not. The text of section 1052(a) does not
directly answer this question. Given this ambiguity, it is appropriate for us to consider
the provision’s legislative history.
2. Legislative History
The language of section 1052(a) originated with the Legislature’s 1913 enactment
of the Water Commission Act. (Stats. 1913, ch. 586.) The 1913 Act provided: “The
state water commission is hereby authorized and empowered to investigate for the
purpose of this act all streams, stream systems, portions of stream systems, lakes, or other
bodies of water, and to take testimony in regard to the rights to water or the use of water
thereon or therein, and to ascertain whether or not such water, or any portion thereof, or
the use of said water or any portion thereof, heretofore filed upon or attempted to be
appropriated by any person, firm, association, or corporation, is appropriated under the
laws of this state.” (Stats. 1913, ch. 586, § 10.) The Commission was accorded the
22
“duty” “[u]pon its own initiative” to undertake an “investigation” and to “make an
ascertainment” of the rights of “claimants to the water or the use of water of that stream,
stream system, lake, or other body of water.” (Stats. 1913, ch. 586, § 24.)
The 1913 Act recognized that “[a]ll existing lawful appropriations of water or the
use thereof, shall be and hereby are respected and upheld to [the] extent of the amount of
water appropriated and actually put or in [the] process of being put from the initial date of
the act of appropriation, with due diligence in proportion to the magnitude of the work
necessary properly to utilize the water for the useful or beneficial purpose for which it
was appropriated, or for which it is being used.” (Stats. 1913, ch. 586, § 33.)
Further, “[t]he power to supervise the distribution of water in accordance with the
priorities established under this act, when such supervision does not contravene the
authority vested in the judiciary of the state, is hereby vested in the state water
commission.” (Stats. 1913, ch. 586, § 37.)
The 1913 Act also contained the precursor to section 1052(a). It stated: “The
diversion or use of water subject to the provisions of this act other than as it is in this act
authorized is hereby declared to be a trespass, and the state water commission is hereby
authorized to institute in the superior court . . . appropriate action to have such trespass
enjoined.” (Stats. 1913, ch. 586, § 38.) Like the current statutory scheme, the 1913 Act
provided: “The word ‘water’ in this act shall be construed as embracing the term ‘or use
of water.’ ” (Stats. 1913, ch. 586, § 42; § 1000.)
The Water Code was enacted in 1943. (Stats. 1943, ch. 368.) It provided, “In the
enactment of this code the Legislature does not intend thereby to effect any change in the
law relating to water rights.” (§ 103; Stats. 1943, ch. 368.) Many of the Water Code’s
current statutes have remained unchanged since that date. (See §§ 102, 104, 105; Stats.
1943, ch. 368, §§ 102, 104, 105.) Former section 1052 was part of the 1943 Act, and its
original language is nearly identical to what currently appears in section 1052(a) and very
similar to the language in the 1913 Act: “The diversion or use of water subject to the
23
provisions of this division other than as authorized in this division is a trespass.” (Stats.
1943, ch. 368, § 1052.)
The only subsequent change to this language was a 1987 amendment that changed
“subject to the provisions of this division” to “subject to this division.” (Stats. 1987, ch.
756, § 1.) The language in section 1052(a) has otherwise remained unchanged.
This legislative history demonstrates that the Legislature has always restricted the
Board’s authority over pre-1914 water rights while at the same time granting the Board
broad authority over post-1914 water rights. The precursor to section 1052(a) was part of
the 1913 Act, and it has been a part of California’s water laws ever since. The 1913 Act
itself distinguished between the Board’s power over pre-1914 appropriative rights and
post-1914 appropriative rights. The 1913 Act explicitly provided that “existing lawful
appropriations of water or the use thereof [that is, pre-1914 appropriative rights], shall be
and hereby are respected and upheld to [the] extent of the amount of water
appropriated.” (Stats. 1913, ch. 586, § 33, italics added.) The 1913 Act also provided,
“The power to supervise the distribution of water in accordance with the priorities
established under this act, when such supervision does not contravene the authority
vested in the judiciary of the state, is hereby vested in the state water commission.”
(Stats. 1913, ch. 586, § 37.)
We now turn to the application of section 1052(a) to the facts here.
C. Analysis
We begin with the Board’s contention that the trial court misread section 1052(a)
to apply only to “water subject to” division 2 rather than to “diversion or use of water
subject to” division 2. We agree with the Board that the language of section 1052(a) does
not refer to the corpus of the water but instead to diversions or uses of water. This
construction is the only possible one because the Water Code expressly provides that
“ ‘water’ includes the term ‘use of water.’ ” (§ 1000.)

24
 As the parties acknowledge, water rights do not give anyone ownership of the
corpus of any “water” but only the limited right to divert or use water. Division 2 itself
explicitly provides: “Nothing in this division shall be construed as giving or confirming
any right, title, or interest to or in the corpus of any water.” (§ 1001.) Since water rights
are well-established to be “usufructuary,” they do not grant any right to “water” but only
the right to use water. (Compact Ed. of the Oxford English Dict. (1971) p. 3576
[usufructuary refers to the right to use property of another].) Thus, our construction of
section 1052(a) starts with this understanding of its language.
While we agree with the Board that section 1052(a) extends to diversions and uses
of water subject to division 2, we reject the Board’s contention that this means that
section 1052(a) grants the Board the authority to police the exercise of valid pre-1914
appropriative water rights on the theory that the diverter might have violated the priority
rules applicable to all water right holders.
The Board concentrates on the “subject to” division 2 language and argues that
pre-1914 appropriative rights are “subject to” division 2. It is true that, in certain
respects, pre-1914 appropriative rights are “subject to” division 2. For example, sections
1011, 1011.5, and 1017, which are part of division 2, expressly address pre-1914
appropriative rights. But statutory construction requires us to construe the language of
section 1052(a) as a whole. That means that we must also consider the “authorized in”
division 2 language that follows the “subject to” language in section 1052(a). No pre-
1914 appropriative rights are “authorized in” division 2 because those rights were
acquired before the enactment of the 1913 Act that required authorization for
appropriations of water. Thus, all diversions and uses of water under valid pre-1914
appropriative rights are “other than as authorized in” division 2. (§ 1052(a).)
The Board contends that “diversions that exceed the scope of any existing right are
subject to enforcement by the Board.” This broad assertion of authority by the Board,
however, ignores the justification it asserted in the notices at issue in this appeal. In the
25
June 12, 2015 notice in which the Board announced curtailment of “certain pre-1914
claims of right commenced during or after 1903” (capitalization & boldface omitted), the
Board stated, “the existing water supply in the Sacramento-San Joaquin watersheds and
Delta watersheds is insufficient to meet the needs of some pre-1914 claims of right.” It
told those diverters, “even if there is water physically available at your point of diversion,
that water is necessary to meet more senior water right holders’ needs.”
The accuracy of the Board’s assertion that there would be insufficient water to
meet the needs of some pre-1914 appropriative right holders is not material to this appeal.
That the Board asserted jurisdiction based on this conclusion is the central point.
The Board claims that it has the authority under section 1052(a) to enforce
priorities of right among pre-1914 appropriative right holders due to the lack of sufficient
water to serve all pre-1914 appropriative right holders. Yet nothing in division 2 grants
the Board this authority. “[P]riority of right is important only when the natural or
abandoned flows in a watercourse are insufficient to supply all demands being made on
the watercourse—i.e., during periods of water shortage.” (El Dorado Irrigation Dist. v.
State Water Resources Control Bd. (2006) 142 Cal.App.4th 937, 964.) “As for the
determination of an appropriator’s priority over other appropriators, for appropriations
since 1914 an appropriator’s priority is generally fixed by the date of his or her
application to appropriate the water. (See § 1450.)” (Id. at p. 962, italics added.) While
the Board has the authority under section 1450 (which is in division 2) to police priorities
among post-1914 appropriative right holders, nothing in division 2 gives it that authority
over pre-1914 appropriative right holders. The absence of such a provision is critical
because the Water Code explicitly provides that “no right accrued” “before this code
takes effect . . . is affected by this code.” (§ 4.) And the Legislature expressly stated that
the Water Code was “not intend[ed] [] to effect any change in the law relating to water
rights.” (§ 103.) Since the Board (and its predecessors) had no authority over pre-1914

26
appropriative right holders prior to the enactment of the 1913 Act, it lacks authority under
section 1052(a) to police their priorities of right.
The Board’s proposed reading of section 1052(a) to encompass any water right
holder in a time of drought gives no effect to the provision’s phrase “authorized in this
division.” (§ 1052(a).) In essence, the Board asks us to delete that phrase from the
provision and instead interpret it to read: “The diversion or use of water subject to this
division other than as authorized is a trespass.” But fundamental rules of statutory
interpretation require us to “ ‘giv[e] significance to every word, phrase, sentence, and part
of an act in pursuance of the legislative purpose.’ ” (Sierra Club v. Superior Court
(2013) 57 Cal.4th 157, 166.) We cannot ignore the limits on section 1052(a) imposed by
its restriction to the “diversion or use of water subject to this division other than as
authorized in this division.” (§ 1052(a), italics added.)
As the legislative history recited above indicates, the Legislature took great pains
to preserve existing appropriative rights when it enacted the 1913 Act. In section 33, the
1913 Act stated: “All existing lawful appropriations of water or the use thereof, shall be
and hereby are respected and upheld.” (Stats. 1913, ch. 586, § 33.) In the provision that
is the direct precursor to section 1052(a), the 1913 Act stated: “The diversion or use of
water subject to the provisions of this act other than as it is in this act authorized is hereby
declared to be a trespass.” (Stats. 1913, ch. 586, § 38, italics added.) This language
highlights that the provision did not apply to “existing lawful appropriations of water,”
because those appropriations were not subject to the Act.
The Board points out that other parts of division 2 apply to pre-1914 right holders.
While true, the observation does not assist the Board. For example, the Board points to
its authority over stream systems. (See § 2500 et seq.) Section 2501 provides, “The
board may determine, in the proceedings provided for in this chapter, all rights to water
of a stream system whether based upon appropriation, riparian right, or other basis of
right.” (§ 2501, italics added.) This broad language (which does not appear in section
27
1052(a)) throws into relief the limited scope of section 1052(a). It highlights that the
Legislature knows how to vest the Board with broad authority over all water rights in a
system if it so chooses.
Although the Board asserts it possessed the authority to issue the 2015 notices
under section 1052(a) on the theory that some pre-1914 appropriative right holders might
have infringed the priority of other senior right holders and therefore their diversions
were “unauthorized,” the Board has very limited authority in this regard.
“[N]otwithstanding its power to protect the public interest, the Board plays a limited role
in resolving disputes and enforcing rights of water rights holders, a task mainly left to the
courts.” (United States v. State Water Resources Control Bd. (1986) 182 Cal.App.3d 82,
104, italics omitted.) Whether this approach to water rights in California represents
sound policy in a time of increasing water scarcity is a question for the Legislature.
When we consider section 1052(a) in context, it is clear that it does not apply to
the exercise of what are otherwise valid pre-1914 appropriative rights on a generalized
theory of insufficient water to satisfy the priority rules. If the holder of a post-1914
appropriative right or someone without a valid pre-1914 appropriative right uses or
diverts water, section 1052(a) applies. The same is true where someone claiming a pre-
1914 appropriative right is found to be exceeding the scope of their specific right or the
claimed right is found to be invalid, for example because it has been forfeited.
We reject the Board’s arguments to the contrary. The Board contends that the trial
court erroneously failed to consider whether there was “ ‘stored water’ ” in the Delta at
the time of the 2015 curtailment notices. It argues that because pre-1914 appropriative
water right holders have no right to use or divert “ ‘stored water,’ ” section 1052(a)
authorized the Board to determine that the use or diversion of water by pre-1914 water
right holders was a trespass. The Board claims that “[s]tored and released waters were
present at the time the Board issued the Notices, and their presence was specifically
identified as one basis for the Notices.”
28
 This argument ignores the stated basis for the challenged 2015 curtailment notices.
The notices clearly identified the sole basis for the curtailments as the fact that, “due to
ongoing drought conditions, there is insufficient water in the system to service their
claims of right” “until water conditions improve.” The notices did acknowledge that
stored water might be present in the Delta, but they did not premise the need for
curtailment on that possibility. The notices said only: “Even if there is water physically
available at your point of diversion, that water is necessary to meet more senior water
right holders’ needs or the water may be released previously stored water which must
continue instream to serve its intended beneficial use.” Because the Board did not base
these notices on the presence (or even possible presence) of stored water in the Delta, the
trial court properly concluded that the Board’s authority to act under section 1052(a)
could not be upheld on that basis.
The Board urges us to decide that section 1052(a) permits the Board to find a
trespass “in times of extreme drought” based on projected violations of the priority rules.
(Capitalization & boldface omitted.) It argues: “If the trial court decision is affirmed,
section 1052 in its entirety would be rendered wholly ineffective during severe droughts.
This is not an outcome the Legislature intended.” Nothing in section 1052(a) says
anything about the existence of drought or extreme drought conditions. 12 Moreover, that
section 1052(a) does not apply where the total water supply is projected to be insufficient
to fulfill the appropriative rights of pre-1914 right holders does not leave the Board
without any authority in times of drought.
The Board has long had the authority to adopt “emergency regulation[s]” “to
require curtailment of diversions when water is not available under the diverter’s priority
of right, or in furtherance of any of the foregoing, to require reporting of diversion or use
or the preparation of monitoring reports.” (§ 1058.5, italics added; Stats. 1991, ch. 12,

12
We recognize that section 1052, subdivision (c) provides for higher fines under
certain circumstances when it is “critically dry.” (§ 1052, subd. (c)(1).)
29
§ 3 [original version of § 1058.5].) While each emergency regulation is effective for only
a one-year period, the Board may renew a regulation for additional one-year periods if
the emergency conditions continue to exist. (§ 1058.5, subd. (c).) The Board has utilized
its emergency regulation authority to enact regulations authorizing it to curtail water use
by classes of water right holders during droughts. (Cal. Code Regs., tit. 23, Div. 3, ch. 2,
art. 24, sec. 876.1.) 13 Neither section 1058.5 nor any of these regulations contains the
limits found in section 1052(a).
Section 876.1, which applies specifically to the Delta, provides that “when flows
are determined to be insufficient to support all diversions, [the Board’s designee] may
issue curtailment orders as defined in section 877.1 to water right holders and claimants
in the Delta Watershed in order of water right priority, requiring the curtailment of water
diversion under designated water rights and claims, except as provided in sections 878,
878.1, 878.2 and 879.1 subdivision (b).” 14 (Cal. Code Regs., § 876.1, subd. (b).)
Stanford Vina Ranch Irrigation Co. v. State of California (2020) 50 Cal.App.5th
976 illustrates this authority. In that case, the appellant, who held post-1914
appropriative rights, challenged both emergency regulations adopted by the Board in
2014 and 2015 and the Board’s curtailment orders under those regulations, which barred
all diversions from Deer Creek during certain time periods to protect threatened fish. (Id.
at pp. 983–984, 986–992, 1007.) The Third District Court of Appeal upheld both the
regulations and the curtailment orders because they were within the power granted to the
Board by the Legislature when the Board enacted the emergency regulations. (Id. at
pp. 1005–1008.)

13
Further references to regulations are to this title.
14
California Code of Regulations, section 877.1 defines the Delta and defines
curtailment orders. (Cal. Code Regs., § 877.1, subds. (a), (d).)
30
 We will not speculate about why the Board did not choose to utilize emergency
regulations in 2015 during a four-year drought. Had it done so, the curtailment orders at
issue here might well have been within its authority.
The Board argues that our reading of section 1052(a) conflicts with Young and
Millview and with the decision of the California Supreme Court in Meridian, Ltd., v. San
Francisco (1939) 13 Cal.2d 424. We disagree. Meridian did not involve the Board’s
authority at all or its authority under the precursor to section 1052(a), as the plaintiff in
that case was a private riparian owner and appropriator. (Id. at p. 429.) Furthermore,
nothing the California Supreme Court said in Meridian established that former section 38
or section 1052(a) permits the Board to enjoin as a trespass a diversion or use of water
under a valid pre-1914 appropriative water right.
The Board’s reliance on Young, supra, 219 Cal.App.4th 397 is also misplaced. As
described above, the Board decision challenged in Young was a factual determination—
made after an investigation and an evidentiary hearing—that a particular diverter’s pre-
1914 appropriative right was limited to a specific amount of water. The Board is clearly
authorized to undertake investigations and to make that type of determination—of the
valid scope of a pre-1914 appropriative water right—after an evidentiary hearing.
Even the Water Commission had the authority to make such a determination under
the 1913 Act because it had been specifically granted the authority to undertake an
“investigation” and to “make an ascertainment” of the rights of “claimants to the water or
the use of water of that stream, stream system, lake or other body of water.” (Stats. 1913,
ch. 586, § 24.) This authority has never been withdrawn.
The current statutory scheme provides (as it did at the time of Young): “The board
for the purpose of this division may: [¶] (a) Investigate all streams, stream systems,
portions of stream systems, lakes, or other bodies of water. [¶] (b) Take testimony in
regard to the rights to water or the use of water thereon or therein. [¶] (c) Ascertain
whether or not water heretofore filed upon or attempted to be appropriated is
31
appropriated under the laws of this State.” (§ 1051, italics added.) The Board’s statutory
authority to investigate and determine the validity of appropriative water rights does not
exclude claims of pre-1914 appropriative rights from its scope.
The case before us, unlike Young, does not involve a challenge to a factual
determination by the Board after an investigation and an evidentiary hearing that a
particular pre-1914 appropriative water right is limited to a specific amount of water.
The 2015 curtailment notices at issue were not based on any factual determination
concerning the scope or validity of any particular water rights. The notices curtailed
respondents’ pre-1914 appropriative water rights in their entirety as a class (pre-1914,
post-1903 appropriative water right holders on the Delta) solely due to the Board’s
determination that the Delta lacked sufficient water to satisfy all pre-1914 appropriative
right holders. The trial court here decided only whether these notices were authorized by
section 1052(a). The Third District’s decision in Young is not in conflict with the trial
court’s decision.
The First District’s decision in Millview, supra, 229 Cal.App.4th 879 is similarly
distinguishable. Millview, like Young, did not consider whether the Board has the
authority to curtail a diversion under a pre-1914 appropriative water right claim without
investigating the claim’s scope or validity and without making any factual determination
that the claim is fully or partially invalid.
In sum, while the statutory scheme provides the Board with the power to make a
factual determination that a particular pre-1914 appropriative water right claim is not
valid or that the holder is exceeding the scope of the right, the authority conferred by
section 1052(a) does not include the power to curtail an entire class of pre-1914
appropriative water rights solely on the basis that the Board believes that there will be
insufficient water to serve all pre-1914 appropriative rights.
For these reasons, we agree with the trial court’s conclusion that the Board lacked
authority under section 1052(a) to issue the 2015 curtailment notices to respondents. We
32
emphasize that our decision addresses only the scope of the Board’s authority under
section 1052(a). Nothing we have said in this opinion precludes the Board from properly
exercising its authority over pre-1914 appropriative water right holders under the public
trust doctrine, applicable emergency regulations, or other appropriate authority.
V. DISPOSITION
The trial court’s judgment is affirmed.

33
 ______________________________________
Danner, J.

WE CONCUR:

____________________________________
Greenwood, P.J.

____________________________________
Wilson, J.

H047270
In re California Water Curtailment Cases
Santa Clara County Superior Court No.: 1-15-CV285182, JCCP No. 4838

Trial Judge: Hon. Brian Walsh

Counsel for Defendant/Appellant, State Water Resources Control Board: Rob Bonta,
Attorney General, Robert W. Byrne, Senior Assistant Attorney General, Tracy L. Winsor,
Supervising Deputy Attorney General, Allison Goldsmith, Kate D. Fritz, Matthew G.
Bullock, Deputy Attorneys General

Counsel for Intervenor/Appellant, Department of Water Resources: Rob Bonta, Attorney
General, Robert W. Byrne, Senior Assistant Attorney General, Laura J. Zuckerman,
Russell B. Hildreth, Supervising Deputy Attorneys General, Carolyn Nelson Rowan,
Deputy Attorney General

Counsel for Amicus Curiae on behalf of Defendant/Appellant, State Water Resources
Control Board: Environmental Law Clinic, Mills Legal Clinic at Stanford Law School,
Deborah A. Sivas, Matthew J. Sanders, Stephanie L. Safdi

Counsel for Plaintiff/Respondent, Byron-Bethany Irrigation District: Somach
Simmons & Dunn, Michael E Vergara, Theresa C. Barfield, Alyson E. Ackerman

Counsel for Plaintiff/Respondent, Central Delta Water Agency: Nomellini Grilli &
McDaniel, Dante John Nomellini, Sr., Dante John Nomellini, Jr., Daniel Allen
McDaniel; Spaletta Law PC, Jennifer L. Spaletta

Counsel for Plaintiffs/Respondents,
Patterson Irrigation District and Banta Carbona Irrigation District:
Herum\Crabtree\Suntag, Steven A. Herum, Jeanne M. Zolezzi, Lilliana Freeman

Counsel for Plaintiffs/Respondents, San Joaquin Tributaries Authority and South San
Joaquin Irrigation District: Paris, Kincaid & Wasiewski, LLP, Valerie C. Kincaid,
Timothy J. Wasiewski

Counsel for Plaintiff/Respondent, South Delta Water Agency: Mohan, Harris, Ruiz,
Wortmann, Perisho & Rubino LLP, S. Dean Ruiz; John Henry Herrick

Counsel for Plaintiff/Respondent, Oakdale Irrigation District: Tim O’Laughlin PLC,
Tim O’Laughlin

H047270
In re California Water Curtailment Cases