Court Opinion

ID: 9940172
Source: CourtListenerOpinion
Date Created: 2024-02-13 17:16:11.39926+00
Date Added: 2024-06-11T13:42:39.335049
License: Public Domain

[EDITORS' NOTE: THIS PAGE CONTAINS HEADNOTES. HEADNOTES ARE NOT AN OFFICIAL PRODUCT OF THE COURT, THEREFORE THEY ARE NOT DISPLAYED.] *Page 552 
[EDITORS' NOTE: THIS PAGE CONTAINS HEADNOTES. HEADNOTES ARE NOT AN OFFICIAL PRODUCT OF THE COURT, THEREFORE THEY ARE NOT DISPLAYED.] *Page 553
OPINION
When a flood control levee fails to retain waters within its design capacity, are plaintiff property owners who suffer damage from the resultant flooding entitled to recover on a theory of inverse condemnation without showing that the damage was caused by unreasonable conduct on the part of the defendant public entities? We conclude that in the case of an unintended breach of a flood control improvement, plaintiffs are not entitled to recover absent proof of such unreasonable conduct.
 PROCEDURAL BACKGROUND
On the morning of February 21, 1980, a flood control levee on the left bank of the San Jacinto River located just downstream from its confluence with Bautista Creek gave way, freeing the river to flood parts of the City of San Jacinto. Several months later, 17 property owners damaged by the flood joined in filing a complaint in inverse condemnation against the Riverside County Flood Control District (District), which owned and operated the levee, as well as the State of California (State). The case was later consolidated with eight other like actions. Five of the individual plaintiffs' cases were selected for trial to the court, the parties stipulating that the judgment in these cases would be binding in all the other actions. Trial was bifurcated, with the issues of inverse condemnation and liability to be tried first, *Page 555 
followed if necessary by trial of the remaining issues of damages and compensation.1
The cases proceeded to trial. At the close of plaintiffs' case, the District moved for judgment pursuant to Code of Civil Procedure section 631.8 (the State elected not to move for judgment under § 631.8). The trial court granted the motion but reserved its statement of decision until completion of the State's case-in-chief. The State put on its defense. The trial court thereafter issued statements of decision and entered judgment in favor of both the State and the District. Plaintiffs appealed.
The Court of Appeal affirmed the judgment on two separate grounds: 1) that there was no evidence the levee was the "proximate cause" of plaintiffs' damages, and 2) that defendants had not "substantially participated" in the design or construction of the levee so as to be subject to inverse condemnation liability. We granted plaintiffs' petition for review to determine the propriety of each facet of the Court of Appeal's decision. We subsequently granted leave to six separate groups representing over one hundred public agencies to file amicus curiae briefs on behalf of defendants.
 FACTUAL BACKGROUND
The evidence adduced at trial as to the factual causes of the flood was relatively straightforward and undisputed. The levee failure followed a series of heavy storms over a period of several days. Expert testimony and a United States Army Corps of Engineers study undertaken after the flood revealed that the breach was caused by the undermining of the levee foundation or "toe" through a process of "scouring," i.e., the removal by water action of the foundation which underlay the levee. The scouring caused the rock-faced revetment on the riverward side of the levee to collapse, exposing the levee's sand foundation to the eroding force of the floodwaters. A breach appeared and water began to escape. Within a relatively short period, the original gap of 20 feet widened to approximately 1,500 feet, or a quarter of a mile, in length.
The scouring process was caused in part by the presence of two other levees in the area, a "Ring" levee on the right bank of Bautista Creek where it meets the San Jacinto River and a Bureau of Indian Affairs levee on the right bank of the San Jacinto River across from the District levee. The configuration of the three levees created a "flow impingement" which forced the channel waters to flow against the District levee at a 25-degree *Page 556 
angle. The flow impingement caused deep scouring which undermined the levee toe and resulted in the failure. Both the Ring levee and the Bureau of Indian Affairs levee were constructed prior to the District levee. Neither was owned or operated by the District.
Plaintiffs never adduced any substantial evidence that defendants had acted unreasonably in the design, construction, operation or maintenance of the levee, or that plaintiffs' damages were caused by any act or failure to act on the part of defendants. Indeed, plaintiffs maintained that they were not required to prove the levee failure was the result of any act or omission of defendants. Plaintiffs asserted that inverse condemnation liability required proof only of the fact that the levee had failed to function within its design capacity, and that this failure caused their damages. In this regard, plaintiffs' evidence showed that the levee was designed and constructed to contain a "standard project storm" or flood discharge of 86,000 cubic feet per second (cfs). The maximum discharge at the time of the breach was approximately 25,000 cfs, well within the levee's design capacity.
Though the trial court issued separate statements of decision as to the State and the District, its findings on the issue of inverse condemnation liability were essentially identical. The trial court found, in pertinent part, as follows: "1. Plaintiffs incurred damage to their property, which was caused by an unintended breach in the project levee on February 21, 1980. [¶] 2. The design capacity of the project levee was a water flow of 86,000 cubic feet per second (CFS). At the time of the breach, the flow in the river channel was approximately 25,000 CFS and the project levee was operating as designed and constructed. [¶] 3. Plaintiffs' damages did not result from an overflow of channel waters in the San Jacinto River. Rather, the losses resulted from a failure in a portion of the project levee, by reason of a breach at a particular point in the levee which allowed the channel waters to escape the river channel and flow onto plaintiffs' property. The channel waters did not overtope [sic] the levee."2
The trial court's findings continued as follows: "[¶] 4. Before construction of the project levee in 1962, the land where plaintiffs' properties are situated were [sic] subject to periodic flooding by waters of the San Jacinto River. Such land is located within the area which is to be protected by the project levee from San Jacinto flood waters flowing at a maximum volume per second, namely 86,000 CFS. [¶] 5. Plaintiffs or their predecessors built businesses, structures, and/or conducted businesses and/or built homes and/or purchased homes and resided on such lands after 1962 and prior to *Page 557 
February 21, 1980. They and their predecessors reasonably relied on the project levee containing the San Jacinto River waters within the river channel, at least to a volume capacity of 86,000 CFS. During such period they reasonably relied on the project levee not failing at any particular point so as to allow river waters to escape and flood their properties. In acting on such reliance, they made substantial expenditures of moneys and other material resources. [¶] 6. The project levee did not increase the risk of damage or impose any easement, servitude, or other burden on plaintiffs' property."
Notwithstanding the trial court's finding that the channel waters had not exceeded the levee's design capacity, the court concluded that the District was "neither a substantial concurring, nor a sole, independent cause of the . . . breach in the project levee . . ." and further concluded that the breach "was not a result of any act, omission or failure to act by the District in carrying out its operation and maintenance responsibilities. . . ." As to the State, the trial court concluded that "no State conduct . . . was a substantial contributing cause of [plaintiffs'] damages and losses."
Based on additional findings relating to defendants' respective participation in the planning, design, funding, construction, operation and maintenance of the levee, the trial court also concluded as a separate basis of decision that neither the District nor the State was a substantial participant in the levee project so as to be subject to inverse condemnation liability for plaintiffs' damages. (See Chatman v. County of Alameda FloodControl etc. Dist. (1986) 183 Cal.App.3d 424, 431-432 [228 Cal.Rptr. 257]; Sheffet v. County of Los Angeles (1970)3 Cal.App.3d 720, 734-735 [84 Cal.Rptr. 11].)
In affirming the judgment in favor of defendants, the Court of Appeal focused on findings (4) and (6) above. The court reasoned as follows: Because plaintiffs' property had been subject to periodic flooding prior to construction of the District levee (finding No. 4), and because the levee had not increased the risk or the extent of the flooding (finding No. 6), then it followed that the levee had not "proximately caused the plaintiffs' damages, i.e., had [not] caused more flooding on plaintiffs' property than there would have been without the levee. . . ."
The Court of Appeal also affirmed the trial court's holding that neither the District nor the State was a substantial participant in the design or construction of the levee so as to be subject to inverse condemnation liability.
As will appear, we conclude that the judgment in favor of defendants was correct, although not for the reasons stated by the Court of Appeal. Accordingly, we shall affirm the judgment. *Page 558
 DISCUSSIONA. Inverse Condemnation Liability and Proximate Cause
Article I, section 19 (formerly § 14) of the California Constitution provides: "Private property may be taken or damaged for public use only when just compensation . . . has first been paid. . . ." In the landmark case of Albers v. County of LosAngeles (1965) 62 Cal.2d 250, 263-264 [42 Cal.Rptr. 89,398 P.2d 129], we construed this provision to mean that, with two exceptions (to be discussed below), "any actual physical injury to real property proximately caused by [a public] improvement as deliberately designed and constructed is compensable under article I, section 14, of our Constitution whether foreseeable or not." As we subsequently explained in Holtz v. Superior Court
(1970) 3 Cal.3d 296 [90 Cal.Rptr. 345, 475 P.2d 441], Albers
fully recognized the fears that an open-ended, absolute liability rule of inverse condemnation could inhibit the construction of beneficial public improvements: "Thus we limited our holding of inverse condemnation liability, absent fault, to `physical injuries of real property' that were `proximately caused' by the improvement as deliberately constructed and planned." (Id. at p. 304.) (1a) In Holtz, we also underscored the fundamental "policy" basis of the constitutional requirement of just compensation: "`The decisive consideration is whether the owner of the damaged property if uncompensated would contribute more than his proper share to the public undertaking.' In other words, the underlying purpose of our constitutional provision in inverse — as well as ordinary — condemnation is `to distribute throughout the community the loss inflicted upon the individual. . . .'" ( 3 Cal. 3d at p. 303.)
(2a) Plaintiffs here contend that the evidence adduced at trial satisfied the Albers criteria. The undisputed evidence clearly established that plaintiffs incurred actual physical injury to real property. In addition, the trial court found that the breach was "not caused by volume, speeds and heights of the water beyond the design capacity of the levees," i.e., the water flow at the time of the breach was within the range the levee was designed to handle.
However, based upon the trial court's additional findings that plaintiffs' property was subject to flooding prior to construction of the levee and that the levee had not increased the risk of flooding, the Court of Appeal concluded that the element of proximate causation was missing. In so holding the Court of Appeal was mistaken.
After our decision in Albers, Professor Arvo Van Alstyne authored a seminal article on inverse condemnation liability in which he observed that *Page 559 Albers's proximate cause requirement "involves a troublesome conceptual premise." (Van Alstyne, Inverse Condemnation:Unintended Physical Damage (1969) 20 Hastings L.J. 431, 435-438.) Our decision in Albers, supra, 62 Cal.2d 250, contained the seeds of confusion through its combination of "proximate cause" terminology with the elimination of foreseeability as an element of inverse condemnation. Noting this paradox, Professor Van Alstyne suggested that the true measure of proximate cause should be stated in terms of a "`substantial' cause-and-effect relationship which excludes the probability that other forces alone produced the injury." (Van Alstyne, supra,
20 Hastings L.J. at p. 436, italics added.) Although the issue was not raised, we subsequently acknowledged in Holtz "the greater precision, as Professor Van Alstyne contends (id. at p. 436) in restating this element of the Albers test in terms of `substantial' causation." (3 Cal.3d at p. 304, fn. 9.)
Subsequent to Holtz, and in reliance thereon, several Court of Appeal decisions held that inverse condemnation liability may be established where the public improvement constitutes a substantial cause of the damage, albeit only one of several concurrent causes. (See Souza v. Silver Development Co.
(1985) 164 Cal.App.3d 165, 171 [210 Cal.Rptr. 146]; Ingram v.City of Redondo Beach (1975) 45 Cal.App.3d 628, 633-634 [119 Cal.Rptr. 688]; Blau v. City of Los Angeles (1973) 32 Cal.App.3d 77, 84-85 [107 Cal.Rptr. 727].) In Ingram, for example, plaintiffs sued the defendant city for damages incurred when heavy rains caused the earthen wall of a drainage sump to collapse, allowing flood waters to inundate plaintiffs' homes. (45 Cal.App.3d at pp. 630-631.) The trial court rendered judgment for the city, finding that "no damages to plaintiff occurred as a proximate result of any public improvement of defendant. . . ." (Id. at p. 630.)
The Court of Appeal reversed. Relying on our endorsement of the "substantial cause" test in Holtz, the court reasoned as follows: "There is no controversy over the fact that the wall of the sump gave way, releasing a flood onto plaintiffs' properties. This clearly could be a substantial factor in causing the claimed damages. . . . If, however, the damage is caused,solely, by an unforeseen and supervening cause, then liability will not follow." (45 Cal.App.3d at p. 633, italics added.)
(3) Thus, in order to establish a causal connection between the public improvement and the plaintiff's damages, there must be a showing of "`a substantial cause-and-effect relationship excluding the probability that other forces alone produced the injury.' [Citations.]" (Souza v. Silver Development Co.,supra, 164 Cal.App.3d at p. 171, fn. omitted.) (4a) Where independently generated forces not induced by the public flood control improvement — such as a rainstorm — contribute to the injury, proximate cause is established where the public improvement constitutes a substantial *Page 560 concurring cause of the injury, i.e., where the injury occurred in substantial part because the improvement failed to function as it was intended. The public improvement would cease to be a substantial contributing factor, however, where it could be shown that the damage would have occurred even if the project had operated perfectly, i.e., where the storm exceeded the project's design capacity. In conventional terminology, such an extraordinary storm would constitute an intervening cause which supersedes the public improvement in the chain of causation.
(2b) Turning to the case at bar, the record amply supports plaintiffs' claim that the levee was a substantial concurring cause of the damages to their property. Plaintiffs' evidence established, and the trial court expressly found, that the design capacity of the levee was 86,000 cfs, that the maximum flow in the channel at the time of the breach was approximately 25,000 cfs, and that the breach was not caused by volume, speeds or heights of water beyond the design capacity of the levee. Thus, notwithstanding the heavy storms which preceded the breach, plaintiffs demonstrated that the levee's failure to function as intended constituted a substantial concurring — or proximate — cause of the damages.
Nevertheless, defendants contend, as the Court of Appeal expressly concluded, that the District levee was not and could not have been the proximate cause of the damages, because plaintiffs' property was subject to flooding prior to construction of the levee, and because the property would have flooded even in the absence of the levee. There is no merit to this reasoning.
The fact that plaintiffs' property was subject to flooding prior to construction of the levee is not determinative of the question of whether the failure of the levee in this case caused damage to the plaintiffs. As the trial court here found, plaintiffs "reasonably relied on the project levee containing the River waters within the River channel, at least to a volume capacity of 86,000 CFS," and "acting on such reliance . . . made substantial expenditures of moneys and other material resources." By inducing plaintiffs to make substantial improvements in reliance on its providing protection to a flow of 86,000 CFS, and then failing to provide such protection, the levee plainly constituted a "substantial cause" of plaintiffs' damages. (Holtz v. Superior Court, supra, 3 Cal.3d at p. 304, fn. 9.)
Nor is there merit to defendants' contention that proximate cause was not established because plaintiffs failed to demonstrate the improvement increased the risk of flooding, or diverted floodwaters that would not otherwise have crossed plaintiffs' property. (4b) Inverse condemnation liability for failure of flood control projects is not predicated upon proof that the public improvement made a preexisting hazard worse. In this respect, *Page 561 
defendants' reliance on two Court of Appeal decisions, Tri-Chem,Inc. v. Los Angeles County Flood Control Dist. (1976) 60 Cal.App.3d 306
[132 Cal.Rptr. 142] and Shaeffer v. State of California (1972)22 Cal.App.3d 1017 [99 Cal.Rptr. 861], to argue to the contrary is misplaced.
In Tri-Chem, Inc. v. Los Angeles County Flood Control Dist.,supra, 60 Cal.App.3d 306, the plaintiffs sought damages on a theory of inverse condemnation after a drainage system operated by the district overflowed and flooded their property. The jury found in favor of the plaintiffs. On appeal, the District argued that the levee failure "was not a proximate cause of plaintiffs' harm" (id. at p. 310, italics added) since the drainage system had a design capacity of only 550 to 700 cfs, whereas runoff during the storm which resulted in the flood reached approximately 1,096 cfs. (Id. at p. 309.) The Court of Appeal agreed, stating: "All that the record here shows is that a more extensive flood control system might have diverted more water from its natural flow across plaintiffs' properties. There is no evidence that the system did not work as itwas designed to function. . . ." (Id. at pp. 311-312, italics added.)
Shaeffer v. State of California, supra, 22 Cal.App.3d 1017, presents a factually distinct but analytically analogous scenario to Tri-Chem. Plaintiffs sought recovery in inverse condemnation for damages caused by a flood along the Feather River. The evidence showed that the State operated a flood control project along the river which consisted of a levee system and the Oroville Dam. At the time of the flood, however, the dam was only partially completed. Thus, certain property owners were completely protected by the partially completed dam, while others like plaintiffs would have received greater protection had the dam been completed. The trial court concluded that the plaintiffs had sustained no damages attributable to the flood control project of the State.
In affirming the judgment, the Court of Appeal noted that "a public entity is not liable for damages merely because its flood control improvements do not provide the same degree of protection to all property owners in the area." (22 Cal.App.3d at p. 1021.) There was no evidence, the court noted, that the flood control improvements had failed to operate as intended. The mere fact that "other properties receive[d] more benefit than those of plaintiffs because of the phase and stages of the flood control project" was not a sufficient basis of inverse condemnation liability. (Ibid.)
Thus, it is readily apparent that the results in bothTri-Chem and Shaeffer are perfectly consistent with the proximate cause analysis we have outlined. In each case the court concluded that proximate cause was absent — not because the risk of floods preexisted the flood control projects, *Page 562 
nor because the projects had failed to increase the risk or the extent of the floods — but rather because there was no evidencethat the projects failed to function as intended; in both cases the flooding occurred in spite of the flood control improvements, not because of them.
(2c) Here, in contrast, plaintiffs adduced substantial evidence that the District levee failed to function within its design capacity and thus constituted a substantial concurring — or proximate — cause of the damages. The Court of Appeal's holding to the contrary was erroneous.
(5a) Having thus established that the levee failed within its design capacity, and that such failure constituted a substantial cause of their damages, plaintiffs insist that they are entitled to recover as a matter of law on a theory of absolute liability under Albers, supra, 62 Cal.2d 250, without any further showing that the flooding was the result of any unreasonable act or omission attributable to defendants. As explained below, we reject this contention.
B. The Requirement of Unreasonable Conduct in Flood Control Cases
Prior to our decision in Albers, supra, 62 Cal.2d 250, it was standard judicial practice to analyze inverse condemnation liability by analogy to tort and property law principles. (See Mandelker, Inverse Condemnation: The Constitutional Limits ofPublic Responsibility (1966) Wis.L.Rev. 3, 6-9; Van Alstyne,supra, 20 Hastings L.J. at pp. 440-442.) This approach was in part predicated on the general understanding that inverse condemnation liability was limited to cases in which a private party would be held liable under like circumstances. (See, e.g.,Archer v. City of Los Angeles (1941) 19 Cal.2d 19, 24 [119 P.2d 1] ["If the property owner would have no cause of action were a private person to inflict the damage, he can have no claim for compensation from the state."]; Clement v. State ReclamationBoard (1950) 35 Cal.2d 628, 637 [220 P.2d 897] ["[P]laintiffs have no right to compensation under article I, section 14, if the injury is one that a private party would have the right to inflict without incurring liability."]; accord Youngblood v. Los Angeles County FloodControl Dist. (1961) 56 Cal.2d 603, 608 [15 Cal.Rptr. 904,364 P.2d 840]; Bauer v. County of Ventura (1955) 45 Cal.2d 276, 282-283 [289 P.2d 1]; Granone v. County of Los Angeles (1965)231 Cal.App.2d 629, 645 [42 Cal.Rptr. 34].)
As earlier noted, however, Albers shifted the focus in inverse condemnation cases from the common law to the Constitution. As we subsequently explained in Holtz v.Superior Court, supra, 3 Cal.3d at page 302: "In Albers v.County of Los Angeles . . . this court explicitly rejected the notion that there need be a congruence between public and private liability in inverse *Page 563 
condemnation actions." The critical issue, we held, was not whether the plaintiff would have a cause of action under tort or property law if the damage were inflicted by a private person, but rather whether the plaintiff should recover "as a matter of interpretation and policy [under] article I, section 14, of the Constitution. . . ." (Albers v. County of Los Angeles, supra,
62 Cal.2d at p. 262; Holtz v. Superior Court, supra, 3 Cal.3d at p. 303.) (1b) As Holtz explained, "In [inverse condemnation cases] the purposes of the constitutional clause, rather than the limits established by a rule of statutory or common law allocating rights and responsibilities between private parties, must fix the extent of a public entity's responsibility." (3 Cal.3d at p. 302.)
Balancing the constitutional purposes of the taking clause with the "competing considerations which caution against an open-ended, `absolute liability' rule of inverse condemnation," we held that "any actual physical injury to real property proximately caused by the improvement as deliberately designed and constructed is compensable under article I, section 14, of our Constitution, whether foreseeable or not." (Albers v.County of Los Angeles, supra, 62 Cal.2d at pp. 261-262; Holtz
v. Superior Court, supra, 3 Cal.3d at pp. 302-304.)
In so holding, however, we also explicitly "identified two strains of decisions in which the urgency or particular importance of the governmental conduct involved was so overriding that considerations of public policy inveighed against a rule rendering the acting public entity liable absent fault." (Holtz
v. Superior Court, supra, 3 Cal.3d at pp. 304-305.) Of the two doctrinal categories expressly exempted from Albers's
generalized strict liability rule, the second, or so-calledArcher exception (Archer v. City of Los Angeles, supra,19 Cal.2d 19), "encompassed those cases in which the state at common law `had the right to inflict the damage.'" (6) (See fn. 3.)
(Holtz v. Superior Court, supra, 3 Cal.3d at p. 305, quoting from Albers v. County of Los Angeles, supra, 62 Cal.2d at p. 262.) (Italics in original.)3
As we later explained in Holtz, the "doctrine of the common law `right to inflict damage,' emanating from the complex and unique province of water *Page 564 
law, has been employed in only a few restricted situations, generally for the purpose of permitting a landowner to takereasonable action to protect his own property from externalhazards such as floodwaters." (3 Cal.3d at p. 306, italics added.) (7a) Frequently referred to as the "common enemy" doctrine, the notion is that the owner of land subject to flooding has the right to erect defensive barriers and that any injury caused thereby to lower landowners as the result of the increased discharge or velocity of water is considered damnumabsque injuria. (See, e.g., Clement v. State ReclamationBoard, supra, 35 Cal.2d at pp. 635-636; The Weinberg Co. v.Bixby (1921) 185 Cal. 87, 95 [196 P. 25]; McDaniel v.Cummings (1890) 83 Cal. 515, 519-521 [23 P. 795].)4 The unique legal privilege which cloaks such protective measures undoubtedly reflects the overriding interest, in a developing economy, of making land freely available for settlement and improvement.5 (Holtz v. Superior Court, supra, 3 Cal.3d at p. 307, fn. 11.)
Although, as noted, we expressly excepted the Archer line of decisions from Albers's rule of liability without fault, we also cautioned against the "facile" assumption that an activity which is "privileged" when performed by a private party is equally privileged when undertaken by a public entity. (Holtz
v. Superior Court, supra, 3 Cal.3d at pp. 307-308, fn. 13.) Different policy considerations, we noted, inform the public and the private spheres. While "certain socially beneficial conduct may appropriately be designated `privileged' for private
individuals in order that they will not be deterred from undertaking the activity, the public entity may continue to engage in this same `privileged' activity even if it must bear the loss of resulting damages." (Ibid., italics added.)
(5b) Thus, while we recognized in Albers that strict inverse condemnation liability may not be appropriate in the case of flood control improvements, we emphasized in Holtz that such improvements should not be cloaked with the same immunity as private flood control measures. The *Page 565 
question, therefore, is what standard applies in such cases. We draw the answer from prior case law, public policy and common sense.
On the one hand, a public agency that undertakes to construct or operate a flood control project clearly must not be made the absolute insurer of those lands provided protection. On the other hand, the damage potential of a defective public flood control project is clearly enormous. Therefore, as we observed inHoltz, the courts have consistently held that "even when a public agency is engaged in such `privileged activity' as the construction of barriers to protect against floodwaters, itmust [at least] act reasonably and non-negligently. [Citations.]" (Holtz v. Superior Court, supra, 3 Cal.3d at p. 307, fn. 12, italics added; see also Shaeffer v. State of California, supra, 22 Cal.App.3d at p. 1021.) Contrary to plaintiffs' position, the fact that a dam bursts or a levee fails is not sufficient, standing alone, to impose liability. However, where the public agency's design, construction or maintenance of a flood control project is shown to have posed an unreasonable risk of harm to the plaintiffs, and such unreasonable design, construction or maintenance constituted a substantial cause of the damages, plaintiffs may recover regardless of the fact that the project's purpose is to contain the "common enemy" of floodwaters. (See Bauer v. Ventura County, supra, 45 Cal.2d at pp. 285-286; House v. Los Angeles Flood Control Dist.,supra, 25 Cal.2d at pp. 395-396; San Gabriel V.C. Club v.County of Los Angeles, supra, 182 Cal. at pp. 399-400;Granone v. County of Los Angeles, supra, 231 Cal.App.2d at p. 647.)6
Permitting recovery where the public entity's unreasonable conduct constitutes a substantial cause of damage to property owners negates the apprehension commonly associated with a rule of absolute liability — the discouragement of beneficial flood control improvements — yet properly compensates for losses unfairly incurred. As Professor Van Alstyne observed: "Mindful of the enormous damage-producing potential of defective public flood control projects, the courts have insisted that public agencies must act reasonably in the development of construction and operational plans so as to avoid unnecessary damage to private property. Reasonableness, in this context, is not entirely a matter of negligence, but represents a balancing of *Page 566 
public need against the gravity of private harm." (Van Alstyne,supra, 20 Hastings L.J. at p. 455, fns. omitted.)
The reasonableness of the public agency's conduct must be determined on the facts of each individual case, taking into consideration the public benefit and the private damages in each instance. (See Keys v. Romley (1966) 64 Cal.2d 396, 409-410 [50 Cal.Rptr. 273, 412 P.2d 529].) Inverse condemnation liability ultimately rests on the notion that the private individual should not be required to bear a disproportionate share of the costs of a public improvement. (Holtz v. SuperiorCourt, supra, 3 Cal.3d at p. 303.) Thus, compensation for damages incurred as the result of a flood control agency's unreasonable conduct, measured in light of this balancing test, constitutes no more than a reimbursement to the damaged property owners of their contribution of more than their "proper share [to] the public undertaking." (Ibid.)
Plaintiffs contend that recent Court of Appeal decisions appear, nevertheless, to have applied an absolute liability standard to cases involving flood damages. A review of these decisions reveals that in each case cited the public improvement resulted in a diversion of surface or flood waters from their natural channel or drainage. (See Yee v. City of Sausalito
(1983) 141 Cal.App.3d 917 [190 Cal.Rptr. 595] [storm drainage system which diverted surface waters across plaintiff's property ruptured, allowing water to seep into soil adjacent to plaintiff's property, resulting in massive soil subsidence];Marin v. City of San Rafael (1980) 111 Cal.App.3d 591
[168 Cal.Rptr. 750] [underground drainage pipe which diverted surface waters under plaintiffs' property burst, causing property damage]; Imperial Cattle Co. v. Imperial Irrigation Dist.
(1985) 167 Cal.App.3d 263 [213 Cal.Rptr. 622] [irrigation system overflowed, diverting surface waters onto plaintiff's property]; McMahan's of Santa Monica v. City of Santa Monica
(1983) 146 Cal.App.3d 683 [194 Cal.Rptr. 582] [water main which diverted waters under plaintiff's building ruptured, damaging the building].)
As earlier noted,7 the "common enemy" doctrine did not confer the right to divert or obstruct waters from their natural channels or drainages, and several pre- as well as post-Albers
decisions, relying on this principle, appear to have endorsed a rule of inverse liability without fault where such diversions were present. (See, e.g., Youngblood v. Los Angeles CountyFlood Control Dist., supra, 56 Cal.2d at p. 607 ["[W]hen waters are diverted by a public improvement from a natural watercourse onto adjoining lands the agency is liable for the damage . . . even though no negligence could be *Page 567 
attributed to the installation of the improvement."]; see alsoYee v. City of Sausalito, supra, 141 Cal.App.3d at pp. 920-923.)
We need not examine the validity of these decisions here, for there was no evidence presented that the District levee affirmatively diverted or burdened plaintiffs' property with floodwaters in excess of those which would have escaped in the absence of the levee.8 It is doubtful, however, whether evidence of an unintended "diversion" — an elusive concept to begin with (see Van Alstyne, supra, 20 Hastings L.J. at pp. 460-461) — would elevate the test of inverse condemnation liability to absolute liability, rather than a reasonableness standard. As earlier discussed, the purposes of the Constitution, rather than the rules "emanating from the complex and unique province of water law," must fix the extent of a public entity's responsibility. (Holtz v. Superior Court, supra, 3 Cal.3d at p. 306.) It is sufficient for our purposes here to hold that when a public flood control improvement fails to function as intended, and properties historically subject to flooding are damaged as a proximate result thereof, plaintiffs' recovery in inverse condemnation requires proof that the failure was attributable to some unreasonable conduct on the part of the defendant public entities.
Defendants contend that inverse condemnation damages should not be available even where the public entity's conduct is unreasonable unless plaintiffs can establish that the improvement affirmatively diverted floodwaters onto property that would not otherwise have been affected. There is no merit to this contention. As noted above, Albers explicitly rejected the notion that public and private liability principles are necessarily coextensive. (Albers v. County of Los Angeles,supra, 62 Cal.2d at pp. 260-262.) Those historical policy considerations which conditioned private water law actions on an affirmative diversion or obstruction of stream, surface or floodwaters do not necessarily apply to claims for "just compensation" against the government. (Holtz v. SuperiorCourt, supra, 3 Cal.3d at pp. 306-307.) (7b) (See fn. 9.),(5c) When a public agency erects improvements to protect against floodwaters, it must, at a minimum, act reasonably; its liability for unreasonable acts or omissions does not require proof that the public agency affirmatively diverted waters where they would not otherwise have flowed.9 *Page 568
 CONCLUSION (8) There is perhaps no rule of review more firmly established than the principle that a ruling or decision correct in law will not be disturbed on appeal merely because it was given for the wrong reason. If correct upon any theory of law applicable to the case, the judgment will be sustained regardless of the considerations that moved the lower court to its conclusion. (Green v. Superior Court
(1985) 40 Cal.3d 126, 138 [219 Cal.Rptr. 186, 707 P.2d 248]; D'Amico
v. Board of Medical Examiners (1974) 11 Cal.3d 1, 19 [112 Cal.Rptr. 786,520 P.2d 10].) (9) Accordingly, notwithstanding the Court of Appeal's error in concluding that plaintiffs failed to establish proximate cause, the decision must be upheld because plaintiffs did not proceed on a negligence theory, and with respect to their inverse condemnation claim adduced no substantial evidence that the flooding was the result of any unreasonable act or omission attributable to defendants. The judgment in favor of defendants was correct as a matter of law.
The judgment of the Court of Appeal is affirmed.10
Lucas, C.J., Broussard, J., Panelli, J., Arguelles, J., and Eagleson, J., concurred.
1 Prior to trial, plaintiffs expressly waived all causes of action against the defendant public entities except inverse condemnation.
2 In this connection, the trial court had earlier granted summary adjudication as to the following issue: "That the breaks in the levee were not caused by volume, speeds and heights of the water beyond the design capacity of the levees."
3 The other exception recognized in Albers, the so-calledGray exception (Gray v. Reclamation District No. 1500
(1917) 174 Cal. 622 [163 P. 1024]) holds certain physical injuries to property to be noncompensable if inflicted pursuant to the proper exercise of the government's "police power." This doctrine of noncompensable damages applies "only under `emergency' conditions; i.e., when damage to private property is inflicted by government `under the pressure of public necessity and to avert impending peril.'" (Holtz v. Superior Court,supra, 3 Cal.3d at p. 305, quoting House v. L.A. County FloodControl Dist. (1944) 25 Cal.2d 384, 391 [153 P.2d 950]; seeAlbers v. County of Los Angeles, supra, 62 Cal.2d at pp. 256-261.) "Instances of this character are the demolition of all or parts of buildings to prevent the spread of conflagration, or the destruction of diseased animals, of rotten fruit, or infected trees where life or health is jeopardized." (House v. L.A.County Flood Control Dist., supra, 25 Cal.2d at p. 391; Holtz
v. Superior Court, supra, 3 Cal.3d at p. 305, fn. 10.)
4 The common law privilege, however, does not permit a property owner to obstruct or divert a stream from its natural channel (Clement v. State Reclamation Board, supra, 35 Cal.2d at pp. 635-636; The Weinberg Co. v. Bixby, supra, 185 Cal. at p. 95), or to collect and discharge surface waters so as to increase the natural servitude. (Shaw v. Sebastopol (1911)159 Cal. 623, 624 [115 P. 213]; Granone v. County of LosAngeles, supra, 231 Cal.App.2d at p. 646; Farrell v. City ofOntario (1919) 39 Cal.App. 351, 358-395 [178 P. 740].) One scholar has suggested that the development of this exception to the "common enemy" doctrine reflects the countervailing interest of property owners who develop land "in justifiable reliance upon the continuance of existing watercourses as means of natural drainage." (Van Alstyne, supra, 20 Hastings L.J. at p. 458.)
5 See, e.g., San Gabriel V.C. Club v. Los Angeles (1920)182 Cal. 392, 401 [188 P. 554, 9 A.L.R. 1200] ("Not to permit an upper land owner to protect his land against the stream would be in many instances to destroy the possibility of making the land available for improvement or settlement and condemn it to sterility and vacancy. Such a rule would seriously interfere with the development of the country.").
6 The dissenting opinion in this matter purports to share our concern that strict inverse condemnation liability in these particular circumstances may "deter future public works," but nevertheless would require compensation for injuries "whether foreseeable or not . . . unless the public entity can demonstrate that [the] interest in compensation is outweighed by the risk that such compensation will unreasonably inflate the cost of the project in a manner likely to deter . . . future construction. . . ." (Dis. opn. at p. 574.) This amorphous hindsight test of liability appears to us unworkable. In addition, it is inconsistent with the purpose of avoiding deterrence of beneficial projects, because the decision to build or not build a project is necessarily determined on the basis of foresight, not hindsight.
7 See footnote 4, ante, at page 564.
8 There appears to be no merit to the dissenting opinion's suggestion that this could "plausibly" be characterized as a diversion case. The trial court expressly found, as the evidence amply demonstrated, that plaintiffs were subject to periodic flooding before the levee was constructed, and that the levee did not "increase the risk of damage or impose any easement, servitude, or other burdens on plaintiffs' property."
9 Indeed, it is not even accurate to state that the "diversion" principle applies any longer in private water-law actions. In Keys v. Romley, supra, 64 Cal.2d 396, this court reviewed the historical development of the law governing surface waters, noting that the rule had been that an upper landowner was entitled to discharge surface waters from his land as the water naturally flows, but was liable for damage caused by any disturbance of the natural drainage. (Id. at pp. 405-406.) InKeys, however, we modified this rule by inserting a requirement of reasonableness in every action by adjacent landowners: "No party, whether an upper or a lower landowner, may act arbitrarily and unreasonably in his relations with other landowners and still be immunized from all liability. [¶] It is therefore incumbent upon every person to take reasonable care in using his property to avoid injury to adjacent property through the flow of surface waters." (Id. at p. 409.) Relying on Keys, several recent Court of Appeal decisions have made similar modifications to the rules pertaining to flood and stream waters in actions between private landowners. (See Linvill v. Perello (1987) 189 Cal.App.3d 195
[234 Cal.Rptr. 392], holding that the rule of reasonableness was applicable even where defendant's flood endangered or lost, the officials are nevertheless required to make only one control levee had not interfered with the natural channel of a stream or diverted the natural flow of the waters in such channel; Ektelon v. City ofSan Diego (1988) 200 Cal.App.3d 804, 810 [246 Cal.Rptr. 483], holding that an upstream landowner does not have an absolute right to protect his land from floodwaters by erecting structures which merely increase the downstream flow of water in its natural watercourse, but rather is governed by ordinary principles of negligence.)
10 Our holding renders it unnecessary to reach the second issue raised in plaintiffs' petition relating to whether the State or the District was a "substantial participant" in the levee project so as to be subject to inverse condemnation liability.