LOCKLIN v. CITY OF LAFAYETTE

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Court of Appeal, First District, Division 2, California.

Harry LOCKLIN, et al., Plaintiffs and Appellants, v. CITY OF LAFAYETTE, et al., Defendants and Respondents.

No. A045324.

Decided: November 23, 1992

Philip L. Pillsbury, Jr., Pillsbury, Wilson & Post, Burton J. Goldstein, Goldstein & Goldstein, San Francisco, for plaintiffs and appellants. Timothy J. Ryan, Gordon, DeFraga, Watrous & Pezzaglia, A Law Corp., Martinez, John H. Tallett, John Pound, San Mateo, Gary M. Lepper, Stoddard, Lepper, Falco & Schaefer, Walnut Creek, Joseph A. Montoya, Chief Counsel, Robert J. DeFea, Kenneth G. Nellis, Donald M. Velasco, Lucille Y. Baca, San Francisco, for defendants and respondents.

I

INTRODUCTION

Appellants, property owners or former property owners along the lowest reach of Reliez Creek in Contra Costa County, commenced this lawsuit to recover damages for injury to their real property resulting from erosion and downcutting of the creek's banks.   They joined as defendants the City of Lafayette (City), the County of Contra Costa (County), the Contra Costa County Flood Control District (District), the California Department of Transportation (CalTrans), and the Bay Area Rapid Transit District (BART).1  Claiming that artificially generated excess storm waters resulting from failure of respondents' public storm drainage system and from publicly constructed transportation arteries caused their injuries, appellants proceeded on theories of inverse condemnation, dangerous and defective condition of public property, nuisance and trespass against the respondent public entities.2

The action proceeded to trial.   Following presentation of appellants' evidence, the trial court ruled in favor of respondents CalTrans, BART, County and District on their respective motions seeking judgment pursuant to Code of Civil Procedure sections 581c (nonsuit) and 631.8 (motion for judgment).   Those motions were also granted as to the City, except that the case was permitted to continue to resolution regarding the City's liability arising from the existence of two structures (the “Sizeler outfall” and the “sheet pile structure”) within Reliez Creek.   Directed and special verdicts ultimately were returned in favor of the City on the tort causes of action.   At the conclusion of the evidence in the case against the City, the trial court determined that appellants had failed to prove that either the Sizeler outfall or the sheet pile structure was a substantial concurring cause of damage to any plaintiff's property and, consequently, ruled in the City's favor on the inverse condemnation cause of action.3

On appeal from the judgments, appellants urge trial court error in three respects:  first, because this case involves a public storm drainage system and not a natural watercourse, the trial court should have held respondents strictly liable in inverse condemnation;  second, even if the trial court was correct in applying the “natural watercourse rule,” the trial court wrongly determined the rule to be one of absolute immunity rather than a limited immunity available only if the public entity's conduct was reasonable;  third, appellants having demonstrated each respondent's conduct was a substantial factor in causing their injuries, the trial court erred in requiring appellants to apportion fault among respondents rather than applying the doctrine of joint and several liability to each respondent.   We will affirm and, in doing so, will reject each of these contentions.

II

STATEMENT OF FACTS

Historically, Reliez Creek is a natural watercourse serving to drain a 2,291 acre watershed in Contra Costa County.   The area appellants occupy extends in a generally north to south direction from Condit Road Bridge to Reliez Creek's confluence with Las Trampas Creek, a distance of approximately 1,500 feet.   At the confluence, the waters of Reliez Creek and Las Trampas Creek join and eventually flow into Walnut Creek, ultimately to discharge into Suisun Bay.

Prior to the second world war, the watershed was essentially rural in nature.   After the war, it began to experience significant urban development, a pattern of growth consistent with the experience of most regions within the San Francisco Bay Area.   Expert testimony offered by appellants established watershed development of 15 percent by 1957, 27 percent by 1968, and 33 percent by 1982 (as we shall see, a watermark year in this litigation).4  The BART system occupies 3.5 acres or 0.1 percent of the total watershed;  CalTrans Highway 24 occupies 22.4 acres or approximately 1.0 percent of the total;  respondent City's streets occupy 117.9 acres or approximately 4.8 percent of the total watershed.   No evidence was presented with respect to roadways or other facilities within the watershed area owned and maintained by the County or District after 1968.   There are significant numbers of public and private property owners, not joined as defendants in this lawsuit, whose roads or facilities drain into the natural watercourse of Reliez Creek.   For example, privately owned streets occupy 69 acres;  public streets of the City of Walnut Creek occupy 11 acres;  Acalanes High School occupies over 26 acres, approximately 60 percent of which is impervious.5

The land owned by appellants varies in size from approximately one-half acre to fourteen acres.   The properties occupying this lowest reach of Reliez Creek are approximately one-half mile distant from Highway 24.   Testimony established that Highway 24, at its location within the watershed area, was completed in its present form in 1968.  (Highway 24 at this location consists of two multi-lane roadbeds running generally east and west and separated by the BART right of way and railway facilities.)   A 920–foot culvert, apparently placed within the natural confines of Reliez Creek, serves to collect and drain the surface waters falling on the CalTrans and BART acreage.   This culvert ends well above Condit Road, and, at the point where the waters leave the culvert, there is an engineered structure designed to dissipate the velocity and energy of the emerging water.   Phillip Williams, a hydrologist and one of appellants' expert witnesses, walked up Reliez Creek from Condit Road as far as the culvert sometime in the mid–1980's.   He observed the creek bank in this area was completely different from that below Condit Road, with little evidence of bank failure.6

Among appellants, the Grays owned their property the longest period of time, having purchased in 1965.   The property is located on the west side of Reliez Creek.7  There was no erosion of the creek banks when they acquired their property, which abuts the northern boundary of the Sizeler property.   The first erosion problem experienced by the Grays occurred in 1978 and coincided with the failure of a storm drain outlet owned and maintained initially by the County, then by the City, on an easement existing on the Sizeler property.   Throughout the litigation this area is referred to as the “Sizeler outfall.”

Next in ownership seniority is Locklin who acquired his property in 1968.   In early 1970, a large bay tree sloughed off his property and slid to the bottom of the creek.   At the time the tree fell, Locklin has no recollection of any significant rainfall having occurred.   He further testified the slope of the creek bank maintained itself at its normal approximate 45 degree gradient.   This isolated incident caused Locklin to contact the City and inquire what might be done to prevent bank erosion along the creek.   The City referred Locklin to the County, which provided him with information on how this might be accomplished.   However, no remedial steps were undertaken.   The next time Locklin noticed damage to the banks was in mid-January 1982.

The Sizelers purchased their property in 1977.   It is located on the west side of Reliez Creek and abuts the northern boundary of the Locklin property.   Mr. Sizeler walked Reliez Creek between Condit Road and the Locklin property in 1977 and did not observe erosion to the creek's banks.   At that time, he spoke with the former owners who advised him there had been no previous erosion problems at the site.   However, in 1977, Mr. Sizeler noticed that a drainage pipe carrying storm water runoff from Pleasant Hill Road was leaking and eroding.   This pipe was located on an easement on the northern boundary of his property.   The leaking was causing an erosion of the earth around concrete pedestals that supported piers which carried the drainage pipe to mid-stream of Reliez Creek.   This problem was reported to the City, which in turn contracted with a private company to repair the pipe.   The City, through the testimony of then City Manager Ernest Marriner, acknowledged that while the City had no responsibility to maintain an easement, it did have responsibility to maintain a structure within the easement.  (This storm drainage structure had initially been installed by the County;  it became a City responsibility in 1968 at the time of the City's incorporation.)   In any event, in January 1978, the structure failed and the storm drainage pipe collapsed.   The City, at its own expense, thereafter repaired the storm drainage pipe and constructed an outfall structure.   The next time the Sizelers experienced damage was during the “big storms” of January through March 1982.   Sizeler observed no significant erosion between 1979 and 1982.

The Lins acquired their property on the east side of Reliez Creek in 1978.   The property is located across the creek from the Sizeler property.   Before the Lins purchased, Mr. Lin satisfied himself the creek had not damaged the property.   Along the creek bank he discovered the tracks of an old wagon trail which led from Reliez Creek Station to Orinda, convincing him the bank had been stable for about 100 years.   Shortly after moving onto the property in 1979, the Lins lost a bay tree at the point where the drain from their home and the creek intersect.   They began to experience bank erosion in February 1980.   In April 1980, Mr. Lin wrote Harold Smith Company, which had developed several homes on the east side of the creek, complaining about the loss of three large trees along the bank, two of which were lost due to bad grading or bad drainage by the developer.   At trial, Mr. Lin (who has an engineering background) opined the action of the water cascading down the sill at the Sizeler outfall had undermined his bank.   He also testified the sheet pile structure (which we shall soon refer to), which had been constructed during the winter of 1982–1983, had also caused damage to the creek.   However, Mr. Lin, after experiencing the February 1980 erosion, had constructed a 26–foot long, 8–foot high bulkhead to protect his property from further erosion.

Appellants Edwin Donnell, Lynn Worthington, George Latter and Aaron Johnson were also called to testify.   Each purchased property on the east side of Reliez Creek in the Harold Smith/Century Homes development in 1978.   Mr. Donnell thoroughly investigated the creekside in the summer of 1978 and observed no erosion.   He first observed damage to his property on January 10, 1982, after it had been storming and raining for about a week or so.   It had been raining “[v]ery, very hard ․ [u]nusually hard.”   Between January and March, 1982, severe erosion occurred along the Donnells' creek bank and four large trees were lost.

Mr. Worthington went down to the creek area adjoining his property in the spring of 1978 and detected no signs of erosion.   He first observed damage occurring to his property in January of 1982.   He describes the rains of 1982 as “fairly heavy” and occurring over a four-month period.   Mr. Worthington recalled the “presidential declaration of disaster concerning ․ the damage that occurred [in Contra Costa County] in January, February and March of '82.”

Mr. Latter inspected the creek area behind his property before he purchased and found no sign of erosion in 1978.   He first noticed erosion in early 1982.

Mr. Johnson, whose property abuts the northern boundary of the Lin property, viewed the creek bank in 1978 and found no evidence of erosion.   His first notice of erosion occurred in the winter of 1980 when a large oak tree fell.   He stated that during the winters after 1980 the creek banks would continue to erode.   After the sheet pile structure was installed during the winter of 1982–1983, he continued to experience damage to his property.   However, it is abundantly clear from our review of the record that the major damage to appellants' properties occurred during the January–March storms of 1982, although testimony does indicate some erosion or downcutting occurred thereafter.

The sheet pile structure erected in the Reliez Creek channel from Condit Road Bridge for a distance of 100 feet southerly is an outgrowth of the significant winter storms which occurred during the first three months of 1982 in Contra Costa County.   The project was funded by 80 percent federal money and 20 percent local money.   The latter funding was recouped, at least in part, from the property owners whose land abutted the improvement, i.e., the predecessors in interest to appellants Lykken and Tomassen.   Federal involvement in a creek erosion problem, such as occurred here, is triggered by a declaration of disaster by the Governor of the state seeking federal assistance followed by a request to Washington for a similar disaster declaration by the President.   If both declarations are made, then the Soil Conservation Service (SCS) of the federal government is authorized to participate in what is essentially an emergency repair operation directed to creek bank erosion problems and designed to address dangers to structures and buildings.   Both the Governor of California and the President declared a disaster in Contra Costa County by reason of the winter storms in the early months of 1982.   While the local agencies sought SCS assistance for the entire 1,500–foot reach below Condit Road, the federal agency limited its approval and participation to the 100–foot sheet pile structure.

The abutting property owners provided construction rights of entry, shared in the cost, and agreed to assume full ownership and responsibility for maintaining the structure thereafter.   The agreement between SCS and the District was executed in the summer of 1982 and the work performed and completed during the winter months of 1982–1983.   The City participated in the agreement as an interested property owner, apparently with respect to a culvert at the Condit Road Bridge and/or the structure supporting the bridge.8

Prior to 1968, the political jurisdiction of the area within the Reliez Creek watershed rested in the County.  (Possibly excepting a portion of the City of Walnut Creek which partially occupies the watershed.   The record does not inform us when that incorporation occurred.)   In 1968, the City of Lafayette was incorporated.   When incorporation occurred, the City took over responsibility for roads, storm drains and other facilities which previously had been owned and maintained by the County.   Ernest Marriner, who assumed the job of City Manager at the time of incorporation, testified to a large number of Lafayette citizens, including many of the riparian owners, wanting to retain the creeks in their natural state.   One of the principle objectives of the City's first master plan was to maintain the natural appearance of creeks in the City.   This expression of public attitude was vocalized by citizens at public hearings on the master plan.   Marriner testified to a citizen-circulated petition (apparently originating in response to a rumor that the Army Corps of Engineers was commencing a long range study of creek modification in Lafayette) which sought to preserve the City's creeks in their natural state.   It was Marriner's perception that following the winter storms of 1981–1982 and the severe damage which occurred to creekside property, many riparian owners changed their minds regarding retention of the creeks in their natural state.

Oral and documentary evidence was received regarding the subject of storm drainage easements.   Appellants Locklin and Jackson testified (the latter by stipulation) their respective properties were not encumbered by a dedicated storm drainage easement.   Of those appellants who testified to the existence of a dedicated easement, none, except Sizeler, was able to testify the easement dedication had been accepted by the City or County.   The dedication of storm drainage easements appears to correspond with the submission of subdivision maps for proposed land development.   For example, the official map for Kelly Court, a subdivision located on the east side of Reliez Creek, contains a dedication of storm drainage easements to the City of Lafayette.   However, noteworthy, is the City clerk's certificate attached to the map stating that while the council approved the map it “did not accept or reject on behalf of the public any of the ․ easements shown thereupon as dedicated to public use.”  (Emphasis added.)   Excepting the easement of the Sizeler outfall, appellants have not offered substantial evidence demonstrating acceptance by a public entity of a dedicated storm drainage easement in the area concerned.

On those occasions when trees fell into Reliez Creek, the City undertook their removal.   In 1977, the City engaged the services of a private contractor, RJA Maintenance, to perform maintenance services which had been previously performed by the County under contract with the City.   These services included street repair, cleaning debris from creeks within the City and removing log jam blockages of creek flow.   Tree removal was undertaken to assure the creeks would flow smoothly and efficiently, to avoid any flooding due to log jams, and to abate any threat to downstream public facilities.   Most, if not all, removal of fallen trees from Reliez Creek was in response to requests by the adjoining homeowners.   The winter storms of early 1982, which precipitated considerable erosion and downcutting of creek banks and consequently the loss of a number of large trees, required considerable effort by RJA Maintenance workers over several weeks to remove the fallen trees from Reliez Creek below Condit Road.

Appellants offered expert testimony regarding the effect of the “urbanization” of the watershed area in terms of increasing surface water runoff into Reliez Creek under developed as compared to natural conditions.   Professor David Todd concluded that at the time of his study, which began after he was retained in 1986, 56.6 percent of the watershed had then been developed.   Utilizing a computer program developed by the SCS to calculate runoff from small watersheds under urban and natural conditions, in conjunction with an urbanization study undertaken by Todd's consulting staff, Todd calculated the amount of surface water entering Reliez Creek on a daily basis from 1978 through 1986.   While producing some fairly spectacular gallonage estimates in terms of yearly increases, as well as the cumulative total over the nine-year period studied,9 these calculations in fact had little relevance to the particulars of appellants' damage claims.   Todd, during cross-examination, acknowledged the limited value of his cumulative statistics.   Thus, having testified that 96 million gallons of additional surface water entered Reliez Creek during the 1978 rain year (i.e., 10/1/77—9/30/78), he agreed volume means little “because what really matters is the extent to which that volume is concentrated within limited periods of time.”   Utilizing cumulative calculations of surface water drainage into Reliez Creek over the nine-year study period, Todd concluded the CalTrans/BART development contributed 9.2 percent of the increased volume, which was a “substantial factor” in bringing about the “peak flows” in Reliez Creek causing appellants' damage.

Another expert witness for appellants, Phillip Williams, when asked whether the water flowing off Highway 24 and BART into the culvert beneath was a substantial factor in causing the damage, replied:  “[T]he increase in runoff due to urbanization is—was a substantial factor.  [¶] And the—that runoff from BART and CalTrans is a part of that increase.”   Williams was of the view that the combined contribution of CalTrans/BART to the peak flow in a 100–year storm was less than 1 percent.   Williams did not believe that to be the point, however.   The point, according to Williams, is that total urbanization had caused a substantial increase in flow and velocity, which caused scouring.   The CalTrans/BART component of that was calculated by Williams at 7.2 percent for a two-year flood.   Williams acknowledged his earlier deposition testimony that without the contribution of CalTrans/BART together, the same damage may still have occurred.

III

STATEMENT OF THE CASE

On April 13, 1988, appellants proceeded to trial on issues framed by the second amended complaint, specifically inverse condemnation, nuisance, trespass and dangerous and defective condition of public property.   In each cause of action directed against respondents, Reliez Creek is characterized as part of a storm drainage system, a work of public improvement, owned, operated and maintained by respondents, the failure of which caused appellants' damage.   The tort causes of action were dismissed as to BART due to deficiencies in the tort claims process.   A motion to bifurcate liability issues from damage issues was granted.   Following the close of appellants' case, respondents each moved for judgment pursuant to Code of Civil Procedure section 631.8 on the inverse condemnation cause of action 10 and (except BART) for nonsuit pursuant to Code of Civil Procedure section 581c on the tort causes of action.   Those motions were granted as to respondents CalTrans, BART, County and District;  the motions were also granted as to the City, except as to the City's liability arising from the existence of the Sizeler outfall and the sheet pile structure.

The trial of the action continued against the City as to these two structures.   At the conclusion of the evidence, the trial court and the jury rendered directed and special verdicts in the City's favor on the tort causes of action, and the court found in the City's favor on the inverse condemnation cause of action.

In a well-considered and lengthy statement of decision following its resolution of liability issues in favor of CalTrans, BART, County and District and partially in favor of the City, the trial court concluded:  (1) there was insufficient evidence to support appellants' contention that the Reliez Creek natural watercourse had been transformed into a storm drainage system public improvement;  (2) the natural watercourse rule “․ shield[s] [respondents] from liability for collecting natural surface water drainage and discharging it into a natural channel, even though the volume and velocity increases cause downstream damage”;  (3) appellants failed to prove the BART improvements substantially contributed to appellants' damage;  (4) appellants failed to prove water diverted by CalTrans from the Las Trampas Creek watershed to the Reliez Creek watershed substantially contributed to appellants' damage;  (5) the County could incur no liability because in 1968 it relinquished ownership and control over any public improvements that may have contributed to appellants' damage;  and (6) there was no evidence the District owned or controlled any public improvement within the watershed that may have contributed to appellants' damage.

This timely appeal followed.

IV

DISCUSSIONA.Inverse Condemnation

 Inverse condemnation actions are prosecuted under article I, section 19 of the California Constitution, which provides that “[p]rivate property may be taken or damaged for public use only when just compensation, ascertained by a jury unless waived, has first been paid to, or into court for, the owner.”   This provision is intended “ ‘to afford relief to the landowner in cases in which it is unfair to ask him to bear a burden that should be assumed by society.’ ”  (Holtz v. Superior Court (1970) 3 Cal.3d 296, 303, 90 Cal.Rptr. 345, 475 P.2d 441, quoting Mandelker, Inverse Condemnation:  The Constitutional Limits of Public Responsibility (1966) Wis.L.Rev. 3, 8.)  “[A] public entity may be liable in an inverse condemnation action for any physical injury to real property proximately caused by a public improvement as deliberately designed and constructed, whether or not that injury was foreseeable, and in the absence of fault by the public entity.”  (Souza v. Silver Development Co. (1985) 164 Cal.App.3d 165, 170, 210 Cal.Rptr. 146, citing Holtz v. Superior Court, supra, 3 Cal.3d at pp. 303–304, 90 Cal.Rptr. 345, 475 P.2d 441;  Albers v. County of Los Angeles (1965) 62 Cal.2d 250, 263–264, 42 Cal.Rptr. 89, 398 P.2d 129.)  “[I]n 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.”  (Belair v. Riverside County Flood Control Dist. (1988) 47 Cal.3d 550, 559, 253 Cal.Rptr. 693, 764 P.2d 1070, citations and internal quotation marks omitted, emphasis in original.)  “[P]roximate cause is established where the public improvement constitutes a substantial concurring cause of the injury.”  (Id. at pp. 559–560, 253 Cal.Rptr. 693, 764 P.2d 1070, emphasis in original.)

In ruling on the motion for judgment, the trial court expressly determined that Reliez Creek had not become a work of public improvement that would support a claim for inverse condemnation liability.   On appeal from the granting of a motion for judgment under Code of Civil Procedure section 631.8, the findings of the trial court “ ‘are entitled to the same respect ․ as are any other findings of a trial court, and are not erroneous if supported by substantial evidence.  [Citations.]  Where two or more inferences reasonably can be drawn from the facts, an appellate court is without power to substitute its deductions for those of the trial court.  [Citations.]’ ”  (Rodriguez v. North American Rockwell Corp. (1972) 28 Cal.App.3d 441, 447, 104 Cal.Rptr. 678.)

Appellants introduced various evidence in support of their contention that Reliez Creek had become a “de facto” part of the storm drainage system and, therefore, a work of public improvement.   The court nonetheless determined the evidence was insufficient to show respondents had exercised the kind of control necessary to prove the creek had become part of the drainage system.   For example, the court concluded appellants had failed to prove that (except for the Sizeler outfall and the sheet pile structure) the City ever constructed or maintained any facilities along Reliez Creek.   The court was further persuaded by evidence showing the City intended to leave the creek in its natural state and consistently denied responsibility for erosion damage along the creek's shore.   The court also focused on appellants' failure to show the City or County ever implicitly or explicitly accepted the dedication of storm drainage easements and concluded that occasional use of such easements was insufficient to establish ownership or control.   The court also observed that “[e]mergency tree removal does not make the creek into a work of public improvement.”

The evidence regarding whether the creek had become a public improvement was lengthy.   Keeping in mind that on appeal from a motion for judgment under Code of Civil Procedure section 631.8 we review the evidence in the light most favorable to respondents and affirm the trial court's ruling if supported by substantial evidence (Swanson v. Skiff (1979) 92 Cal.App.3d 805, 810, 155 Cal.Rptr. 280;  Rodriguez v. North American Rockwell Corp., supra, 28 Cal.App.3d at p. 447, 104 Cal.Rptr. 678), we uphold the court's ruling.   Accordingly, none of the respondents could be strictly liable on a theory of inverse condemnation for having converted Reliez Creek into a public improvement.

Appellants' argument to the contrary is largely founded on Souza v. Silver Development Co., supra, 164 Cal.App.3d 165, 210 Cal.Rptr. 146.   In Souza, the plaintiffs, who owned adjoining lots near Pinole Creek, sued both their developers and the City of Pinole for damages sustained in a landslide.   (Id. at p. 168, 210 Cal.Rptr. 146.)   Following a court trial, the court found the creek was part of the city's overall drainage system, and concluded that the creek, functioning as a deliberately included element of the drainage system, was a substantial cause of the landslide.  (Id. at p. 169, 210 Cal.Rptr. 146.)

On appeal, the Souza court rejected the city's argument that the creek was not a public improvement or project.   The court noted that the city had required the developer to construct storm drains and had accepted dedication of those drains.   The city further required the developer to dedicate an easement for drainage along the creek channel and accepted that easement.   The appellate court found this evidence sufficient to support the trial court's conclusion that the creek was in fact a work of public improvement that might subject the city to liability in inverse condemnation.   (164 Cal.App.3d at p. 170, 210 Cal.Rptr. 146.)

In this case, appellants rely on Souza for the proposition that a natural watercourse may be incorporated into a public drainage system.   Respondents assert this case is unlike Souza, because here there was never acceptance of the storm drainage easements that had been dedicated.   The trial court concluded Reliez Creek was not a public improvement because the public entities (1) had not exercised control over the creek;  (2) had not erected structures in the creek (except for the Sizeler outfall and the sheet pile structure, both of which were excluded from the original directed verdict);  and (3) had not accepted the dedicated storm drainage easements.   Substantial evidence supported these conclusions.

B.

The Natural Watercourse Rule

 The trial court found respondents immunized from liability by reason of the natural watercourse rule.   Appellants claim this was error.   We concur in the trial court's view that the natural watercourse rule established by the California Supreme Court continues as established precedent in our state.   By reason of Auto Equity Sales, Inc. v. Superior Court (1962) 57 Cal.2d 450, 456, 20 Cal.Rptr. 321, 369 P.2d 937 [decisions of the Supreme Court are binding upon and must be followed by all lower state courts of California], the trial court was bound, and we are bound, to apply the natural watercourse rule under the facts of this case to immunize respondents from any liability for their having utilized Reliez Creek as a natural drainage channel.

Traditionally, resolution of liability issues arising out of water damage cases begins by classifying the type of water which has caused the damage.   (Yue v. City of Auburn (1992) 3 Cal.App.4th 751, 758, 4 Cal.Rptr.2d 653.)   In Yue, Justice Marler summarized the process as follows:

“There are causes of action for inverse condemnation due to water damage which differ according to the type of water involved.  (Van Alstyne, Inverse Condemnation:  Unintended Physical Damage (1969) 20 Hastings L.J. 431, 448–465․)  The policy considerations and pleading requirements vary considerably with each type.   Thus, the determination of whether there is a cause of action in inverse condemnation for water damage begins with the traditional analytical approach of finding what type of water caused the damage.

“This categorization process originated in tort cases and is followed in inverse condemnation lawsuits as well.  ‘[I]nverse liability of public agencies is determined in the main by the peculiarities of private law rules governing interference with ‘ “surface waters,” “flood waters,” and “stream waters.” ’   (Van Alstyne, op. cit. supra, 20 Hastings L.J. at pp. 448–449.)   The legal rights and consequences following such categorization of water types have recently been summarized as follows:  ‘ “ ‘ “First, one has no right to obstruct the flow onto his land of what are technically known as surface waters․  Second, one has the right to protect himself against flood waters ․ and for that purpose to obstruct their flow onto his land, and this even though such obstruction causes the water to flow onto the land of another․  Third, one may not obstruct or divert the flow of a natural watercourse.  [Citations.]” ’ ” '  (Weaver v. Bishop (1988) 206 Cal.App.3d 1351, 1353–1354 [254 Cal.Rptr. 425] [private litigants];  italics added.)”   (Yue v. City of Auburn, supra, 3 Cal.App.4th at p. 758, 4 Cal.Rptr.2d 653.)

In Keys v. Romley (1966) 64 Cal.2d 396, 400, 50 Cal.Rptr. 273, 412 P.2d 529, a surface water case, Justice Mosk defined the classifications in the following manner:  “Water diffused over the surface of land, or contained in depressions therein, and resulting from rain, snow, or which rises to the surface in springs, is known as ‘surface water.’   It is thus distinguishable from water flowing in a fixed channel, so as to constitute a watercourse, or water collected in an identifiable body, such as a river or lake.   The extraordinary overflow of rivers and streams is known as ‘flood water.’   (Tiffany on Real Property (3d ed.) § 740;  8 Cal.L.Rev. 197.)”

Here, we are concerned neither with surface nor flood water.   Appellants do not dispute that Reliez Creek is a natural watercourse except to the extent they contend it was converted into a public storm drainage system, a factual issue decided against them.  (See ante at pp. 896–898.)   The waters which damaged their property flowed within a natural channel, with defined bed and banks, which serves to drain a substantial watershed and has done so from time immemorial.

The natural watercourse rule was initially articulated by our Supreme Court in San Gabriel V.C. Club v. Los Angeles (1920) 182 Cal. 392, 188 P. 554.   In San Gabriel V.C. Club, the county had constructed concrete storm drains in the confines of the natural drainage channel thereby accelerating the water flow and causing damage to the land of a lower riparian owner.   The court first noted the “․ civil-law rule, which forbids the gathering together of surface waters and discharging them as a stream upon adjoining lands.”  (Id. at p. 402, 188 P. 554.)   Continuing, the court stated:  “If the surface waters are gathered and discharged into the stream which is their natural means of drainage, so that they come to the land below only as a part of the stream, it is held that no action lies because of their being added.  [Citations.]  Mr. Freeman in his note in 85 Am.St.Rep. 727, reviews very thoroughly the authorities dealing with the right to accelerate or diminish the flow of water, and upon the particular point under discussion says (page 733):  ‘We have just noticed the difference between merely draining on to another's land, and draining into a natural channel or watercourse, which flows across such land.   So far as streams or natural watercourses are concerned, there can be no doubt that on[e] can drain into them, and thereby increase their volume without subjecting himself to liability for any damage suffered by a lower owner.’ ”   (Ibid.;  see also The Weinberg Co. v. Bixby (1921) 185 Cal. 87, 97–98, 196 P. 25.)

Archer v. City of Los Angeles (1941) 19 Cal.2d 19, 119 P.2d 1, is next in the line of Supreme Court authority.   Here, plaintiffs' property was situated near a lagoon which was fed by a natural watercourse.   Public agencies straightened and widened the creek and its tributaries and constructed concrete storm drains to improve drainage.   This accelerated the flow of water into the lagoon.   The outlet from the lagoon into the ocean remained in its natural state.   Heavy rains came, the outlet could not keep up with the accelerated waters, the lagoon overflowed and flooded plaintiffs' property.   Plaintiffs sued in inverse condemnation.

The Archer court, citing San Gabriel V.C. Club, held there was no liability for damage caused by improvements made in the stream for the purpose of draining or protecting the land above, even though the channel is inadequate to accommodate the increased flow of water resulting from the improvements.  (19 Cal.2d at pp. 24–25, 119 P.2d 1.)   The Archer court emphasized the improvements must follow the natural drainage;  water diverted out of its natural channel and discharged into a different channel or upon neighboring land, would subject the diverter to liability.  (Id. at p. 26, 119 P.2d 1.)   However, the court observed, “[t]here is no diversion if surface waters, flowing in no defined channel, are for a reasonable purpose gathered together and discharged into the stream that is their natural means of drainage even though the stream channel is inadequate to accommodate the increased flow.”  (Ibid.;  see also Clement v. State Reclamation Board (1950) 35 Cal.2d 628, 642, 220 P.2d 897.)   It is this statement of the natural watercourse rule which applies to this case under the factual scenario presented by the evidence.

The rationale for the natural watercourse rule stated in both San Gabriel V.C. Club and Archer is two-fold:  (1) avoiding destruction of the possibility of making land available for improvement or settlement and (2) the necessity of permitting the utilization for drainage of the means afforded by nature for the purpose.  (San Gabriel V.C. Club v. Los Angeles, supra, 182 Cal. at p. 401, 188 P. 554;  Archer v. City of Los Angeles, supra, 19 Cal.2d at p. 27, 119 P.2d 1.)   Parenthetically, we suggest yet another rationale, the interest of property owners who develop or acquire developed land in justifiable reliance upon the existence of a natural watercourse as a means of natural drainage.11

In Bauer v. County of Ventura (1955) 45 Cal.2d 276, 289 P.2d 1, the complaint alleged flood control activities by a public entity causing the diversion of waters from a natural watercourse into a ditch adjacent to plaintiffs' property resulting in a reversal of direction of natural flow and damages resulting from flooding.   While Bauer is concerned with the diversion of waters from a natural channel, it cites with approval the natural watercourse rule established by San Gabriel V.C. Club and Archer.   Bauer held:  “Mere improvement within an existing watercourse which accelerates rather than diverts the flow does not give rise to a cause of action when damage results from an overflow.   Straightening, widening or deepening the channel of a stream to improve the drainage or the collection of surface waters for discharge into their natural stream entails no diversion in the event of a resulting overflow.   But to escape liability the improvements thus described must follow the natural drainage of the country or the natural stream.”  (45 Cal.2d at p. 283, 289 P.2d 1, emphasis added.)

In 1966, Justice Mosk authored Keys v. Romley, 64 Cal.2d 396, 50 Cal.Rptr. 273, 412 P.2d 529.  Keys involved two private parties who were adjoining property owners.   The trial court, finding for plaintiff, concluded the defendant had gathered surface waters on his land by artificial means and discharged these waters on plaintiff's lower tenement in a greater volume and in a different manner.   The Supreme Court reversed and remanded to determine the matter on the basis of the reasonableness of the conduct of the parties.   Because, as we shall see, two court of appeal decisions have utilized the reasonable conduct standard of Keys to justify abandonment of the natural watercourse rule, we emphasize the salient distinctions compelling our conclusion that Keys cannot serve as a basis for rejecting the natural watercourse rule as the established law of this state.

At the outset, Keys has nothing to do with the collection of surface waters and their discharge into a natural watercourse.  Keys neither discusses nor in any way considers the natural watercourse rule.   What the Keys court addressed were rights and liabilities of adjoining landowners in California with respect to surface waters traveling onto the land of another.   Inherent in the Keys analysis is (1) real property damaged by the flow of surface water (not water flowing in a natural drainage channel) and (2) one of the adjoining property owners had changed the natural conditions.   Justice Mosk observed:  “Under our [California] civil law rule the owner of an upper, or dominant, estate is entitled to discharge surface water from his land as the water naturally flows.   As a corollary to this, the upper owner is liable for any damage he causes to adjacent property by the discharge of water in an unnatural manner.   In essence, each property owner's duty is to leave the natural flow of surface water undisturbed.”  (64 Cal.2d at pp. 405–406, 50 Cal.Rptr. 273, 412 P.2d 529.)   The Keys decision changed a century old civil law rule regarding surface water disputes to a modified civil law rule.   “No party, whether an upper or 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․  It is equally the duty of any person threatened with injury to his property by the flow of surface waters to take reasonable precautions to avoid or reduce any actual or potential injury.  [¶] If the actions of both the upper and lower landowners are reasonable, necessary, and generally in accord with the foregoing, then the injury must necessarily be borne by the upper landowner who changes a natural system of drainage.”  (Id. at p. 409, 50 Cal.Rptr. 273, 412 P.2d 529, emphasis added.)

The year before Keys was decided, the Supreme Court had occasion to revisit Archer in the landmark decision Albers v. County of Los Angeles, supra, 62 Cal.2d 250, 42 Cal.Rptr. 89, 398 P.2d 129.   There, a unanimous court, joined by Justice Mosk, “shifted the focus in inverse condemnation cases from the common law to the Constitution” (Belair v. Riverside County Flood Control Dist., supra, 47 Cal.3d at p. 562, 253 Cal.Rptr. 693, 764 P.2d 1070) and repudiated a rule announced in Archer that “[i]f 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” (Archer v. City of Los Angeles, supra, 19 Cal.2d at p. 24, 119 P.2d 1).   Thus, Albers “explicitly rejected the notion that there need be a congruence between public and private liability in inverse condemnation actions” (Holtz v. Superior Court, supra, 3 Cal.3d at p. 302, 90 Cal.Rptr. 345, 475 P.2d 441) and held that “any actual physical injury to real property proximately caused by the [public] 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. 263–264, 42 Cal.Rptr. 89, 398 P.2d 129.)

Albers is an inverse condemnation action involving the infamous Palos Verdes Hills landslides and factually does not concern natural watercourses or any other aspect of the “complex and unique province of water law” (see Holtz v. Superior Court, supra, 3 Cal.3d at p. 306, 90 Cal.Rptr. 345, 475 P.2d 441).  Albers did not reject the natural watercourse rule of Archer.   To the contrary, the Albers court reiterated the “fundamental premise” of Archer “that a private riparian owner would have had a right to collect the surface waters on his land and channel them into the stream into which they would naturally drain even though this resulted in a flooding of the lower lands.”  (Albers v. County of Los Angeles, supra, 62 Cal.2d at p. 260, 42 Cal.Rptr. 89, 398 P.2d 129, emphasis in original.)   The court modified Archer only to this extent:  “the [Archer ] court was not required to go further than to hold that article I, section 14, did not require the state to pay for damage which it had a right at common law to cause.”  (Id. at pp. 260–261, 42 Cal.Rptr. 89, 398 P.2d 129, emphasis in original.)

The later decisions of our Supreme Court alluding to the natural watercourse rule are Holtz v. Superior Court, supra, 3 Cal.3d 296, 90 Cal.Rptr. 345, 475 P.2d 441, and Belair v. Riverside County Flood Control Dist., supra, 47 Cal.3d 550, 253 Cal.Rptr. 693, 764 P.2d 1070.   Neither Holtz nor Belair concerns the natural watercourse rule announced in Archer.  Holtz is an inverse condemnation action involving an abutting property owner's loss of subjacent support due to excavation by a public entity.  (3 Cal.3d at p. 299, 90 Cal.Rptr. 345, 475 P.2d 441.)  Belair is also an inverse condemnation action involving the failure of a public improvement, a levee, which gave way during heavy storms.  (47 Cal.3d at p. 555, 253 Cal.Rptr. 693, 764 P.2d 1070.)   Both Holtz and Belair have acknowledged the continuing precedent of the natural watercourse rule.

In Holtz, the public entity sought to limit its exposure to strict liability in inverse condemnation by claiming the statutory protection of Civil Code section 832, which generally allows a private coterminous owner to excavate on his own property without incurring liability so long as he was not negligent.  (3 Cal.3d at p. 302, 90 Cal.Rptr. 345, 475 P.2d 441.)   The defendant contended it therefore had a “ ‘right’ ” to inflict damage, within the meaning of the Archer exception, so long as it was not negligent.  (Id. at p. 306, 90 Cal.Rptr. 345, 475 P.2d 441.)   The Supreme Court rejected this argument.   The court observed that under Albers' interpretation of article I, section 14, plaintiffs should be compensated notwithstanding the limits of Civil Code section 832 “unless the instant case falls within either of two doctrinal categories which were expressly excepted from Alber [s'] generalized strict liability rule.” 12  (Id. at p. 304, 90 Cal.Rptr. 345, 475 P.2d 441, emphasis added.)   Noting that the doctrine of the common law “ ‘right to inflict damage’ ” 13 emanating from the “complex and unique province of water law, has been employed in only a few restricted situations” and recognizing that “[t]he fulfillment of the broad ‘cost spreading’ purpose of the constitutional provision, as clarified in Albers, requires a limited application of the Archer exception” (id. at p. 306, 90 Cal.Rptr. 345, 475 P.2d 441), the court refused to extend the Archer exception because to do so “would so expand the exception as to consume the general Albers rule.”  (Ibid.)  Justice Mosk joined in this unanimous opinion.

In Belair, the Supreme Court dealt with a defective public flood control project and did not address a factual situation involving the natural watercourse rule.   The Belair court's reference to the rule is only in a tangential manner but nevertheless it recognized the Archer exception as one of “two doctrinal categories expressly exempted from Albers's generalized strict liability rule.”  (47 Cal.3d at p. 563, 253 Cal.Rptr. 693, 764 P.2d 1070.)

In summary, the Archer exception providing immunity to an upstream landowner gathering and discharging surface waters into a natural watercourse that serves as their natural means of drainage even though the watercourse is inadequate to accommodate the increased flow, serves as continuing precedent in this state.   The rule has been expressly acknowledged by our Supreme Court in Holtz and Belair as an exception to Albers' generalized rule of strict liability.   The carefully drafted decision in Keys v. Romley, dealing solely with surface waters other than those draining into a natural watercourse, did nothing to modify or repudiate the exception in Archer as stated above.   Important policy considerations dictated the need for this immunity rule in the first instance, and we perceive no compelling reasons for its rejection.   For that matter, it appears the case at bar provides ample and compelling reasons recommending the continuation of its policy.  (See post at pp. 906–908 [discussion of substantial concurring cause].)   Be that as it may, the precedent having been established by our Supreme Court, any repudiation or modification of the immunity exception, under Auto Equity Sales, Inc., v. Superior Court, supra, 57 Cal.2d at page 456, 20 Cal.Rptr. 321, 369 P.2d 937, must come from that source.

The authority of the natural watercourse rule embodied in the Archer exception was recognized and followed by the Fourth District, Division Two, in Deckert v. County of Riverside (1981) 115 Cal.App.3d 885, 895–896, 171 Cal.Rptr. 865.14  Our review of Supreme Court authority as earlier reported convinces us the natural watercourse rule as set forth in Archer exists as controlling authority.   Accordingly, we join with the Deckert court and approve its application by the trial court in the case before us.

We acknowledge views differing from our own announced by the Fourth District, Division One, in Ektelon v. City of San Diego (1988) 200 Cal.App.3d 804, 246 Cal.Rptr. 483 and by our own District, Division Four, in Weaver v. Bishop (1988) 206 Cal.App.3d 1351, 254 Cal.Rptr. 425.   Consequently, we discuss these cases.

With respect to Ektelon,15 we first reject as unfounded its conclusion that “the court in Keys, after an extensive review of water law, postulated a broad rule of reasonableness to be applied to all factual situations, and which should properly be used to modify its holding in Archer.”  (Ektelon v. City of San Diego, supra, 200 Cal.App.3d at p. 808, 246 Cal.Rptr. 483, emphasis added.)   In our view, any fair reading of Keys belies this assertion.   The “extensive review of water law” was essentially directed to the basic rules governing surface waters, and Keys offers no mention or discussion of the natural watercourse rule, a point that Ektelon acknowledges in a parenthetical.  (Ibid.)  Indeed, Keys itself recognized the distinction between “surface waters” and “water flowing in a fixed channel, so as to constitute a watercourse” (Keys v. Romley, supra, 64 Cal.2d at p. 400, 50 Cal.Rptr. 273, 412 P.2d 529), something Ektelon reluctantly acknowledges in a footnote (Ektelon v. City of San Diego, supra, 200 Cal.App.3d at p. 808, fn. 3, 246 Cal.Rptr. 483).  Ektelon's reliance on dicta in Holtz to modify the holding in Archer, 200 Cal.App.3d at pp. 807–808, 246 Cal.Rptr. 483, is similarly misplaced.  Holtz expressly declined to examine the “continued validity” of the natural watercourse rule.   (Holtz v. Superior Court, supra, 3 Cal.3d at p. 307, 90 Cal.Rptr. 345, 475 P.2d 441.)   Until the Supreme Court does so, we are bound to follow the rule as formulated in Archer.  (Auto Equity Sales, Inc. v. Superior Court, supra, 57 Cal.2d at p. 456, 20 Cal.Rptr. 321, 369 P.2d 937.)

We address Ektelon solely for the purpose of disputing its expansive treatment of the Keys decision and its implied rejection of the natural watercourse rule.   Whatever precedential value Ektelon may have in the context of other cases, it provides no guidance here.   Our case is a classic example of the exception set forth in Archer involving the gathering of surface waters for a reasonable purpose and their discharge into a watercourse that serves as their natural means of drainage.  Ektelon, on the other hand, in a manner which cannot be determined from the text of the opinion, involves a natural watercourse and the construction of flood control structures by an upstream landowner.   Where the structures were placed, whether the structures obstructed, diverted or altered the natural flow of the stream or surface waters emptying into it, and what liability role the defendant public entity played are important factors which cannot be discerned from the opinion.   Noteworthy, however, (perhaps even more so than its failure to discuss Deckert;  see fn. 15) is Ektelon's significant reliance on Linvill v. Perello (1987) 189 Cal.App.3d 195, 196–197, 234 Cal.Rptr. 392, a case concerning construction of a levee to control floodwaters and the diversion of those waters onto the property of an adjoining landowner, a case certainly not compelling authority for modification of the natural watercourse rule.

Finally, in Weaver v. Bishop, supra, 206 Cal.App.3d 1351, 254 Cal.Rptr. 425, Division Four of this District approved application of the Keys reasonable use rule in a dispute between private riparian owners of creekside property.   Defendants' placement of riprap (boulders) on the creekside banks allegedly altered the creek's flow causing damage to plaintiffs' property on the opposite bank.  (Id. at p. 1353, 254 Cal.Rptr. 425.)   Whatever dubious value there may be in a rule of law imposing the threat of expensive litigation on every riparian owner attempting to employ time honored methods of protection against the known scouring propensity of a natural watercourse, we need not address here.  Weaver does not involve the collection and discharge of surface waters into their natural means of drainage and, hence, is inapposite to the case at bar.   However, what requires our attention is Weaver's apparent acceptance of Ektelon's expansive treatment of Keys, treating all factual situations under the reasonableness rule.

Weaver postulates its position in this manner:  “However, the nearly unanimous trend has been away from per se rules based on categorical judgments of ‘generally perceived reasonableness,’ and toward fact-based determinations of reasonableness in the particular circumstances of each case.   Thus in Ektelon v. City of San Diego [citation], the court held that an upstream owner who increases drainage into a stream may be liable to downstream owners under ‘ordinary principles of negligence,’ despite Archer v. City of Los Angeles [citation].”  (206 Cal.App.3d at p. 1357, 254 Cal.Rptr. 425.)   Whatever “trend” our colleagues may perceive, it cannot serve as justification for avoiding the obligations of intermediate appellate courts under Auto Equity Sales, Inc. v. Superior Court, supra, 57 Cal.2d at page 456, 20 Cal.Rptr. 321, 369 P.2d 937.   There are compelling policy reasons underlying the announced exception in Archer (providing immunity to an upper landowner who gathers and discharges surface waters into a natural watercourse) which should not be abandoned by an intermediate appellate tribunal bound to observe precedent.

 We conclude that where, as here, a public entity by reason of its improvements has gathered surface waters flowing in no defined channel and discharged those surface waters into a natural means of drainage, the natural watercourse rule precludes imposition of liability even though the natural means of drainage is inadequate to accommodate the increased flow.

C.

Even if the Supreme Court were to determine the natural watercourse rule as defined in Archer v. City of Los Angeles, supra, 19 Cal.2d at pp. 24–25, 119 P.2d 1, no longer affords absolute immunity to a defendant who gathers and discharges surface waters into a natural watercourse, we would nonetheless uphold the judgments in favor of respondents.

1.

Lack of Ownership and Control—County and District

 After determining that the natural watercourse rule completely immunized respondents' conduct, the trial court added that, wholly apart from the rule, the County and District could not be held liable because they had relinquished all ownership and control over the property in question prior to the time the damage occurred.   We agree with the trial court's conclusion that the 1968 incorporation of the City insulates the County and District from liability on any of appellants' claims.

In reaching its decision, the trial court relied primarily on Longfellow v. County of San Luis Obispo (1983) 144 Cal.App.3d 379, 192 Cal.Rptr. 580 and Preston v. Goldman (1986) 42 Cal.3d 108, 227 Cal.Rptr. 817, 720 P.2d 476.   In Longfellow, the plaintiff sued on a dangerous condition theory to recover for damages sustained in a fall.  (144 Cal.App.3d at pp. 382–383, 192 Cal.Rptr. 580.)   The court concluded the County of San Luis Obispo could not be held liable because the City of Atascadero became incorporated and assumed ownership and control of the public property at issue before the injury occurred.  (144 Cal.App.3d at p. 380, 192 Cal.Rptr. 580;  see also Tolan v. State of California ex. rel. Dept. of Transportation (1979) 100 Cal.App.3d 980, 983, 161 Cal.Rptr. 307 [in order to incur liability the defendant must be the owner or be in control of the property at issue at the time of the injury].)

In Preston, our Supreme Court held that a prior landowner, who had constructed a defective pond, could not be liable for injuries sustained in the pond after the property had been sold.   The court explained, “ ‘[a] defendant cannot be held liable for the defective or dangerous condition of property which it did not own, possess, or control.’  ․ [Citation.]”  (42 Cal.3d at p. 119, 227 Cal.Rptr. 817, 720 P.2d 476.)   The court further observed that “generally, we have continued to treat ownership and control as a fundamental requirement for ascribing liability.”  (Ibid.)

Appellants maintain this case is more analogous to Platts v. Sacramento Northern Ry. (1988) 205 Cal.App.3d 1025, 253 Cal.Rptr. 269, which was decided after the trial in this case.   In Platts, the court concluded that a party which had dug a tunnel beneath plaintiff's home could be held liable for later subsidence, despite the fact it had sold the property to the state prior to the damage.   In reaching this conclusion, the court was persuaded by the fact that it was “unreasonable to hold the successor in interest liable for a defect it did not know about and for damages it could not possibly prevent.”  (Id. at p. 1030, 253 Cal.Rptr. 269.)

There are important distinctions between this case and Platts which convince us the rule of Longfellow and Preston should be applied here to terminate the County's and District's liability for the damage that occurred after 1968.   As noted above, the Platts decision was motivated in large part by the fact that the railway tunnel defect was unknown to the state (the subsequent purchaser) and could not have been easily discovered and remedied.   That is not so in this case.   While appellants argue the County and the District should not escape liability because of the incorporation, whatever erosion may have existed along Reliez Creek was patent, not latent, and we see no reason the County and District should remain responsible.   As the court noted in Platts, the responsible party is the one that “controls and supervises the premises and can make the necessary repairs.” 16  (205 Cal.App.3d at p. 1031, 253 Cal.Rptr. 269.)

2.

Immunity for Approving Development—City

 Appellants also seek to hold the City liable for allowing upstream development without providing adequate drainage facilities or insuring they would be provided by the developers.   However, this claim essentially is premised on the City's granting of the permits that allowed the development to take place.   Such governmental activity is clearly immunized under Government Code section 818.4, which provides “[a] public entity is not liable for an injury caused by the issuance, denial, suspension or revocation of, or by the failure or refusal to issue, deny, suspend or revoke, any permit, license, certificate, approval, order, or similar authorization where the public entity or an employee of the public entity is authorized by enactment to determine whether or not such authorization should be issued, denied, suspended or revoked.”

In Ellison v. City of San Buenaventura, supra, 60 Cal.App.3d 453, 131 Cal.Rptr. 433, the court considered whether the city could be held liable for increased sediment in a natural watercourse that was caused by upstream development approved by the city.   The court concluded Government Code section 818.4 precludes the imposition of liability on a public entity based on its issuance of permits for private development and construction.  (Id. at pp. 458–459, 131 Cal.Rptr. 433.)   Similarly, in this case, the City cannot be held responsible for damage resulting from upstream development where it simply issued permits for private development and never accepted the dedication of any portion of the developments or drainage systems as public property.   Accordingly, under Government Code section 818.4, the City is immunized from liability for having approved upstream development.

3.

Substantial Concurring Cause—CalTrans/BART Facilities

 Appellants' closing brief proclaims “[i]t is important for this Court to realize, that this case is not about ‘urbanization’ or ‘growth.’ ”   (Emphasis in original.)   Certainly, in major part, the record accompanying this appeal belies that assertion.   In fact, the argument is disingenuous.   In the second sentence following the quoted remark, we are told “[i]ndeed, the public entities in this case have authorized and encouraged growth and watershed development in the Reliez watershed, knowing that they were responsible to check the inevitable increase in public drainage, lest the once-natural creek channel collapse from increases in volumes and velocities of public drainage.”   In fact, the entire thrust of appellants' case presented through their expert witnesses related to the effect of “urbanization” on the watershed area in terms of increasing surface water runoff into Reliez Creek under developed as compared to natural conditions.

Expert witness David Todd was retained by appellants in 1986 to investigate what changes had occurred in the flow of Reliez Creek as a result of “urbanization.”   His investigation was the basis upon which appellants sought to establish the CalTrans/BART facilities as a substantial concurring cause of their damages.

The investigation into the effects of “urbanization” on Reliez Creek covered the years 1978–1986.   Thus, the study period begins 10 years after completion of the CalTrans/BART facilities as they presently exist and some 23 years after construction of Highway 24 in its original multi-lane freeway configuration.   Appellants' expert Williams candidly acknowledged “that a good share of the water ․ passing into Reliez Creek has been passing into Reliez Creek from [Highway 24] since [its] original configuration in the mid–1950's.”  (See ante, fn. 6.)   In 1957, according to Williams, only 15 percent of the watershed had been developed.   Again, according to Williams, only 27 percent of the watershed had been developed when the present CalTrans/BART facilities were completed in 1968.   By the winter of 1981–1982, 14 years after completion of the CalTrans/BART facilities (a winter marked by the occasion of storms of such magnitude they initiated a presidential disaster proclamation), only 33 percent of the watershed had been developed.17

While utilizing their closing brief to claim the contrary, in truth the crux of appellants' case against CalTrans/BART is their theory of “urbanization.”   What it proffers is an open-ended theory of causation wherein substantial concurring cause can be measured in perpetuity.   It postulates a never-ending threat of future liability for collection and discharge of surface water into a natural drainage channel no matter how innocuous the collecting and discharging public facility may have been in relation to the downstream environment at the time of its construction.   It pays no heed to the effect of increased contribution of third parties, both public and private, over which the constructing public agency has no authority or control.

This is not idle speculation on our part.   The case at bar is a case on point.   The creekside events prior to the major storms of early 1982 belie any substantial contribution by the CalTrans/BART facilities to claimed property damage suffered by appellants.   The fall of a bay tree on Harry Locklin's property in 1970 was not, according to his own testimony, associated with any disturbance of the normal gradient of the creekside banks adjoining his property or with any significant rainfall.   Locklin suffered no further damage until 1982.   When Stanley Sizeler examined his property in 1977 (nine years after completion of the CalTrans/BART facilities), he observed no significant erosion of the creek's banks and furthermore was advised by his predecessors in ownership that no erosion problem existed at the site.   The events precipitating the collapse of the storm drain pipe structure serving Pleasant Hill Road and eventually resulting in the construction of the Sizeler outfall with its alleged consequences were particularly related to problems associated with that structure.   Mao Lin also examined his abutting creek banks in 1978 and satisfied himself the area had been stable for about 100 years.   The loss of a bay tree in 1979 occurred at a point on his property where the creek intersected a pipe draining water from his property.   When erosion damage occurred in 1980, Mr. Lin directed blame to the Sizeler outfall and the developer of his property.   Edwin Donnell, Lynn Worthington, George Latter and Aaron Johnson investigated their creek banks in 1978 and found no signs of erosion.   William Gray, who had purchased in 1965, first noticed an erosion problem in 1978, an event which coincided with the problem at the Sizeler outfall.   It is also noteworthy that in the mid–1980's when appellants' expert Williams walked the creek north of Condit Road Bridge as far as the CalTrans culvert he observed little evidence of bank failure and noted the creek bank in that area was completely different from that south of the Condit Road Bridge.

 Earlier in this opinion, we noted that a necessary element in the successful prosecution of an inverse condemnation cause of action is proof the public improvement is a “substantial concurring cause” of damage to the plaintiff's property;  that requires “a showing of a substantial cause-and-effect relationship excluding the probability that other forces alone produced the injury.”  (Belair v. Riverside County Flood Control Dist., supra, 47 Cal.3d at p. 559, 253 Cal.Rptr. 693, 764 P.2d 1070, citations and internal quotation marks omitted, emphasis in original.)   No such showing was made in this case.   The testified observations of the property owners residing along the banks of the lowest reach of Reliez Creek belie the contention of a watercourse “out of equilibrium” prior to the calamitous storms of 1982.

Recognizing that the CalTrans/BART facilities had been in place for some 14 years prior to the time appellants suffered damage to their properties in 1982, appellants' experts blamed the damage not on CalTrans and BART but on the “urbanization” of the Reliez Creek watershed generally.   When asked to identify the contribution of CalTrans and BART to the damage, the experts' testimony was considerably more circumspect.   Although Professor Todd responded affirmatively when appellants' counsel asked whether the runoff from Highway 24 was “a substantial factor in causing the damage,” he offered no testimony whatsoever “excluding the probability that other forces alone produced the injury.”  (See ante at p. 907.)   Indeed, the only evidence in the record is to the contrary.   When asked by appellants' counsel whether the CalTrans/BART runoff was “a substantial factor in the damage,” Williams attempted to avoid the question, responding as follows:  “Well, in the—in that—the—the increase in runoff due to urbanization is—was a substantial factor.  [¶] And the—that runoff from BART and CalTrans is a part of that increase, yes.”   On cross-examination, he later admitted the same damage might still have occurred even without the contribution of CalTrans and BART.

Quite apart from the natural watercourse rule, then, appellants have failed to offer any evidence excluding the probability urbanization generally (as opposed to CalTrans and BART specifically) produced their injuries.18  Again, the evidence in the record is to the contrary.   In the words of Williams, “the total effect of the urbanization is what caused the damage.”  (Emphasis added.)   Having failed to establish causation, appellants cannot prevail.

D.

Order Denying Costs

 Following trial, respondents moved for an award of costs under Code of Civil Procedure section 1032.19  BART also requested an award of additional defense costs (including attorneys' fees) under Code of Civil Procedure section 1038, arguing the case against it was not prosecuted in good faith and with reasonable cause.   In response, appellants argued respondents were precluded from receiving an award of costs by Blau v. City of Los Angeles (1973) 32 Cal.App.3d 77, 89, 107 Cal.Rptr. 727, which held that eminent domain or inverse condemnation plaintiffs were “constitutionally entitled” to be free from costs in litigating their claims.

On February 3, 1989, the trial court issued a written statement of decision in which it concluded that although under Blau respondents could not recover costs on the inverse condemnation claims, they could recover costs incurred in connection with the tort causes of action.   It thus requested respondents to submit to the court a list of costs associated solely with the defense of the tort claims.   The court denied BART's request for defense costs under Code of Civil Procedure section 1038.

Respondents thereafter indicated there was no logical way to apportion costs between the inverse condemnation claims and the tort claims and suggested that if apportionment was necessary, 50 percent or 75 percent of the costs should be allocated to the defense of the tort claims.   The court rejected this suggestion, granted appellants' motion to strike respondents' cost memoranda, and denied recovery of all costs.   On appeal, respondents argue decisions after Blau have questioned its holding and reasoning;  they assert Blau should not be relied upon to deny costs in this case.   For the reasons discussed below, we agree.

In Blau, the plaintiffs sued for damage to their property caused by a landslide;  the jury returned a special verdict in favor of the City of Los Angeles.  (32 Cal.App.3d at p. 80, 107 Cal.Rptr. 727.)   On appeal, plaintiffs challenged “the post-judgment orders of the trial court which granted the City's motion to strike plaintiffs' cost bill and denied plaintiffs' motion to tax costs claimed by the City.”  (Id. at p. 88, 107 Cal.Rptr. 727.)   The court observed that generally, in inverse condemnation cases, property owners have “ ‘a constitutional right to recover costs, as otherwise they would be “deprived of the full measure of compensation to which” they were entitled.’ ”  (Id., quoting In re Redevelopment Plan for Bunker Hill (1964) 61 Cal.2d 21, 70, 37 Cal.Rptr. 74, 389 P.2d 538.)   Based on this rule, the court reasoned that although the plaintiffs were unsuccessful at trial, they were “constitutionally entitled to be free of costs in litigating the issue of whether development of a public street caused damages to their real property.”  (32 Cal.App.3d at p. 89, 107 Cal.Rptr. 727, citing Collier v. Merced Irr. Dist. (1931) 213 Cal. 554, 572, 2 P.2d 790.)

Shortly after Blau was decided, the Supreme Court decided City of Los Angeles v. Ricards (1973) 10 Cal.3d 385, 110 Cal.Rptr. 489, 515 P.2d 585.   In Ricards, the plaintiff sued in inverse condemnation for the destruction of a private bridge and won a substantial damage award.  (Id. at pp. 387–388, 110 Cal.Rptr. 489, 515 P.2d 585.)   On appeal, the Supreme Court reversed the award on the ground the evidence failed to support the damages.  (Id. at p. 390, 110 Cal.Rptr. 489, 515 P.2d 585.)   The court then commented “[p]roperty owners are, of course, not constitutionally entitled to costs in inverse condemnation actions if they are unable to prove that there has been a taking or damaging of their property by the defendant governmental entity.  [Citation.]  In such a circumstance the constitutional doctrine of full compensation underlying the award of costs is plainly inapplicable to owners who initiated the unsuccessful litigation.”  (Id. at p. 391, 110 Cal.Rptr. 489, 515 P.2d 585.)   The court ultimately concluded that although the city's replacement of the bridge substantially compensated plaintiff for her loss, because she had suffered some damage to her property, “however minimal,” she was nonetheless entitled to costs.  (Ibid.)

Subsequently, in Smith v. County of Los Angeles (1989) 214 Cal.App.3d 266, 272–273, 262 Cal.Rptr. 754, which was decided after the trial court denied costs in this case, several homeowners sued the County of Los Angeles and the Los Angeles County Waterworks District.   While they prevailed on their claim against the County, judgment was entered in favor of the Waterworks District.  (Ibid.)  On appeal, then appellate court Justice George of the Second District Court of Appeal—the same district which decided Blau—concluded Blau was “wrongly decided” and “contrary to the reasoning expressed in the Supreme Court's opinion in Ricards.”  (Id. at pp. 295, 298, 262 Cal.Rptr. 754.)   The court thus reversed the order denying the Waterworks District its costs and explained, “[t]he constitutional guaranty of full compensation for property taken or damaged for a public use does not apply where a property owner sues a public entity for inverse condemnation but is unable to prove the subject property was taken or damaged by that entity.   In such circumstances, the prevailing party's statutory right to costs applies without constitutional limitation.”  (Id. at p. 297, 262 Cal.Rptr. 754.)

We agree with the well-reasoned opinion in Smith v. County of Los Angeles, supra, 214 Cal.App.3d 266, 262 Cal.Rptr. 754.  Blau, which the trial court relied on to deny costs in this case, was “wrongly decided.”  (Id. at p. 295, 262 Cal.Rptr. 754.)   In a case such as this one, in which appellants have failed to establish that their properties were taken or damaged by respondent public entities, there is no constitutional bar to an assessment of costs.

 With regard to BART's claim for additional costs under Code of Civil Procedure section 1038, BART first argues the trial court misapprehended the appropriate standard for awarding such costs.   In support of its claim, BART focuses on one line in the court's order concluding “it cannot be said that plaintiffs' claim against [BART] was indisputably without merit or pursued in bad faith.”   Under section 1038, the court must determine whether the proceeding was brought in “good faith and with reasonable cause.”   Despite the different language used by the court, it is apparent the court understood its statutory obligation, as it previously noted that BART would be entitled to reasonable defense costs “if the Court finds the action was not brought nor later maintained in good faith and with reasonable cause.”   We thus reject BART's suggestion that the court applied an incorrect standard in ruling on the costs issue.

BART also asserts appellants had no reasonable basis for proceeding with the inverse condemnation claim against it because it was apparent that BART's contribution to the damage, if any, was minimal.   We disagree.   Appellants argued that under joint and several liability principles, BART could be liable even if it contributed only slightly to the overall damage.   While the trial court ultimately rejected this claim, it expressly noted “[t]here was no decisional law directly [on] point.”   The court thus concluded—and we agree—that appellants pursued a claim which was “arguably correct,” though ultimately unsuccessful.   In light of this conclusion, the court properly refused to award additional defense costs under Code of Civil Procedure section 1038.

V

DISPOSITION

The trial court's order denying costs to respondents under Code of Civil Procedure section 1032 is reversed, and the case is remanded to the trial court for determination of the amount of such costs.   In all other respects, the judgments are affirmed.   Respondents shall recover their costs on appeal from appellants.

APPENDIX

—————

I concur in all portions of the majority opinion except those concluding that:  (1) the natural watercourse rule provides all respondents an absolute immunity from liability;  (2) appellants failed to present evidence establishing CalTrans' liability;  and (3) respondents may recover trial costs under Code of Civil Procedure section 1032, as to which I respectfully dissent.

I.

The granting of immunity under the natural watercourse rule is not, as the majority claims, compelled by the doctrine of stare decisis but violates that salutary principle.   The majority repudiates more than a quarter of a century of California water law embodied in opinions not only of the Supreme Court but our own court and other courts of appeal.   The majority opinion creates confusion in an important area of our law and will obstruct orderly and sensible land use in California.

A.

My colleagues' conclusion that absolute immunity under the natural watercourse rule “continues as established precedent in our state” (Maj. opn. at p. 898) is the product of an unduly constricted reading if not a trivialization of the landmark opinion in Keys v. Romley (1966) 64 Cal.2d 396, 50 Cal.Rptr. 273, 412 P.2d 529.

The importance of Keys lies in the clarified jurisprudential foundation it provides for the determination and application of water doctrine generally.   The purpose of Keys was to clear up “the confusion in [water] law regarding rules and theories ․ caused by a failure to ascertain whether water doctrine arises under property or tort law.”  (Keys, supra, 64 Cal.2d at p. 407, 50 Cal.Rptr. 273, 412 P.2d 529.)  “It has generally been assumed heretofore,” the court observed, “that the rules relative to surface waters are a branch of property law.”  (Ibid.)  Keys repudiates that assumption.   After Keys, liability for water damage to land no longer arises strictly under property law (where the controlling concepts are those of rights, privileges, servitudes, easements, etc.) but tort law, so that concepts of reasonable use or negligence come to bear.  (Id., at pp. 406–410, 50 Cal.Rptr. 273, 412 P.2d 529.)   Emphasizing that “no rule can be applied by a court of justice with utter disregard for the peculiar facts and circumstances of the parties and properties involved,” the Keys court concluded that “[n]o party, whether an upper or lower landowner, may act arbitrarily and unreasonably in his relations with other landowners and still be immunized from all liability.”   (Id., at p. 409, 50 Cal.Rptr. 273, 412 P.2d 529.)

While it is true that Keys did not itself involve water flowing in a fixed channel or watercourse, it is difficult to imagine that the rationale of the opinion was intended to be limited to that particular type of water damage case.

The overarching concern in Keys was that traditional property-based rules were ill-suited to the practicalities of the modern urban community.   The court observed, for example, that the immunity from liability provided by the common enemy doctrine (a variant of the natural watercourse rule) was intended to promote improvement of land and, thus, economic development, without fear of attendant liability for water damage.   Such a rule is largely unnecessary, the court explained, in an area experiencing rapid development.   Similarly, the court noted that the civil law rule, which places liability on the party who has changed the conditions of the land, is not adaptable to the needs of an urban society, where the primary use of land is the erection of structures that are likely to interfere with natural drainage, and engender complaint from adjoining landowners.  (Id., at p. 403, 50 Cal.Rptr. 273, 412 P.2d 529.)   In short, the reason for the shift in the law that Keys represents is that the civil law rule “inhibit[ed] improvement of land” (id., at p. 402, 50 Cal.Rptr. 273, 412 P.2d 529), and was used in this state “when California was primarily a rural society.”  (Id., at p. 406, 50 Cal.Rptr. 273, 412 P.2d 529.)   The urbanization of the state creates the need for “flexible legal relations dependent upon varying circumstances.”  (Id., at p. 408, 50 Cal.Rptr. 273, 412 P.2d 529.)   This conclusion, which arose out of a dispute in Walnut Creek a quarter century ago, applies with far greater force in modern Contra Costa County.

The presence or absence of a riverbed as the vehicle of water transmission is immaterial to the rationale of Keys.   The important fact is the upper landowner's alteration of a natural drainage system;  i.e., the unnatural condition of land that he created relative to the drainage of water from that land, however effectuated.   A riverbed is an element of a “natural system of drainage,” and it may be “unnatural” to materially alter the flow of water in that system so that it damages lower property.   Moreover, Keys makes it clear that the common law rule (that is, the common enemy doctrine that is at the heart of Archer v. City of Los Angeles (1941) 19 Cal.2d 19, 119 P.2d 1), the civil law rule (which, unlike the common law rule gives the upper owner no right to alter the drainage) and the reasonable use rule are all “surface water doctrines.”  (Keys v. Romley, supra, 64 Cal.2d at p. 403, 50 Cal.Rptr. 273, 412 P.2d 529.)   The Keys opinion did not make the distinction between surface water and water in a riverbed, which my colleagues conceive to be the dispositive factor;  nor is there any rational analytical justification for such a distinction.

The rule governing surface waters in California prior to Keys—i.e., the civil law rule that “the lower owner must accept the surface water which drains onto his land but, on the other hand, the upper owner has no right to alter the natural system of drainage so as to increase the burden” (id., at p. 402, 50 Cal.Rptr. 273, 412 P.2d 529)—applied regardless whether the surface water passed through a riverbed on its way to the adjoining property.   Stated differently, the natural watercourse rule is simply one of the many formulations of the general civil law rule repudiated in Keys.   The best illustration of this is that Keys cites Archer—clearly a natural watercourse case—for the proposition that the civil law rule “has been generally recognized as the prevailing law of surface waters in the state [since 1873].”  (Id., at p. 405, 50 Cal.Rptr. 273, 412 P.2d 529, italics added.)

The majority restricts application of the rule of reasonableness established in Keys by a rigid classification of cases involving different types of water, claiming that “[t]he policy considerations and pleading requirements vary considerably with each type.”  (Maj. opn., at p. 898.)   In support of the claim that liability is entirely dependent on the nature of the water causing the harm, the majority relies on the following statement in Yue v. City of Auburn (1992) 3 Cal.App.4th 751 at page 758, 4 Cal.Rptr.2d 653:  “ ‘ “ ‘ “ ‘First, one has no right to obstruct the flow onto his land of what are technically known as surface waters․  Second, one has the right to protect himself against flood waters ․ and for that purpose to obstruct their flow onto his land, and this even though such obstruction causes the water to flow onto the land of another․  Third, one may not obstruct or divert the flow of a natural watercourse.  [Citations.]” ’ ” ' ” '  (Weaver v. Bishop (1988) 206 Cal.App.3d 1351, 1353–1354 [254 Cal.Rptr. 425]․)”  The quoted statement appeared in Horton v. Goodenough (1920) 184 Cal. 451, 453, 194 P. 34, and was reiterated in LeBrun v. Richards (1930) 210 Cal. 308, 314–315, 291 P. 825, both of which were decided long before Keys v. Romley, supra.   Moreover, the statement was not endorsed in Weaver v. Bishop (1988) 206 Cal.App.3d 1351, 254 Cal.Rptr. 425, as is implied in Yue and by the majority in the present case, but rejected as “traditional rules” of strict liability or immunity that are no longer employed.  (Id., at p. 1355, 254 Cal.Rptr. 425.)   As discussed later in more detail (see discussion, post, at pp. 917–918), the opinion in Weaver emphasizes that after the 1966 decision in Keys v. Romley liability is no longer entirely dependent on the nature of the water causing the harm and absolute immunity or strict liability cannot be imposed on that basis.

Professor Van Alstyne's authoritative treatise on inverse condemnation in connection with water damage (Van Alstyne, Inverse Condemnation:  Unintended Physical Damage (1969) 20 Hastings L.J. 431) also makes the point that liability cannot be imposed simply on the basis of the type of water causing the damage and explains why the rule of reasonable use articulated in Keys applies broadly.   He states, preliminarily, that “[t]he noticeable judicial tendency to reject an unqualified application of the ‘common enemy’ rule may be attributed, in part, to the difficulty of making a sharp factual distinction between flood waters and other waters.”  (Van Alstyne, supra, at p. 456.)   Furthermore, “apart from difficulties of classification, the trend also appears to represent a judicial conviction that the ‘common enemy’ rule, unmodified by a test of reasonable conduct, would be an unacceptable basis for arbitrary disruption of rationally grounded expectations of private property owners.   The courts have recognized that the magnitude of governmental projects often far exceeds the scope of flood protection works reasonably to be anticipated at the hands of neighboring private landowners.   A strict and literal assertion of the rule [of absolute immunity], therefore, if applied to government flood control projects, could well be disastrous to private interests.   Accordingly, it has been said, ‘No court has ever so abused the ‘common enemy’ doctrine as to constitute it the common enemy of the riparian owner.'   Finally, the modern approach appears to accept the fact that a rational ordering of duties and liabilities with respect to flood waters is better achieved by the balancing of interests represented in the varying circumstances of individual cases than by a more rigid and inflexible application of narrowly defined property rights.”  (Id., at p. 457, citations, fns. omitted, italics added.)

The majority's theory that the reasonable use rule is limited to surface water cases not involving a riverbed, and that absolute immunity under the “common enemy” doctrine described in Archer is still available in cases in which the surface water is drained into a natural watercourse, is precisely the rigid and inflexible application of a narrowly defined property right that Van Alstyne has condemned and modern courts have abandoned—even in connection with flood control activities that are more highly privileged than those with which we are here concerned.

The arbitrariness of the rigid rule the majority resurrects is illustrated by comparing the result in this case with that in Yue v. City of Auburn, supra, 3 Cal.App.4th 751, 4 Cal.Rptr.2d 653.   In Yue the plaintiffs, who sought damages for the flooding of their restaurant, alleged that the construction of a subdivision increased impervious surfaces which in turn substantially increased storm water runoff onto plaintiffs' property, and that the city had failed to require the developer of the subdivision to mitigate the runoff, and had failed to upgrade its drainage facilities to accommodate the increased flow of water.   The Court of Appeal held that the trial court erred in sustaining the city's demurrer and dismissing the complaint because the rule of reasonableness applied and “this reasonableness doctrine simply presents a question of fact to be determined in each case upon a consideration of all the relevant circumstances.”  (Id., at p. 761, 4 Cal.Rptr.2d 653, citing Keys v. Romley, supra, 64 Cal.2d at p. 410, 50 Cal.Rptr. 273, 412 P.2d 529.)   It is inexplicable why a rule of reasonableness should be applied to assess the liability of a public agency in Yue, where the intervening acts of the private developer were the direct cause of the damage, but not in the present case, where the acts that allegedly caused the increased runoff were entirely those of public agencies.

B.

The absolute immunity allowed by the majority conflicts not only with the logic of Keys but with the subsequent interpretation and application of the rule announced in that case by the Supreme Court and the courts of appeal.

The statement in the majority opinion that “[b]oth Holtz [v. Superior Court (1970) 3 Cal.3d 296, 90 Cal.Rptr. 345, 475 P.2d 441] and Belair [v. Riverside County Flood Control Dist. (1988) 47 Cal.3d 550, 253 Cal.Rptr. 693, 764 P.2d 1070] have acknowledged the continuing precedent of the natural watercourse rule” (Maj. opn., at p. 902) is simply incorrect.   Indeed, the majority opinion cannot be reconciled with Holtz or Belair.

My colleagues' attempt to downplay Holtz does not succeed.1  Their contention that Holtz merely declined to expand the Archer exception but left it otherwise intact ascribes significance to portions of the opinion that are marginally if at all relevant to the question before us (the fact that it is an inverse case, for example), and dismisses language in the opinion specifically pertaining to the reach of the Archer exception that bears directly upon the issue in our case.   As shall be seen, that very language has subsequently been relied upon repeatedly in natural watercourse cases.

In approving the adoption of a reasonable use standard, the Supreme Court in Holtz re-examined the Archer exception and observed that “the ‘privilege’ recognized by the Archer exception is not necessarily an ‘absolute privilege,’ but in many instances is only a ‘conditional’ one.”   The court thus concluded that “even when a public agency is engaged in such ‘privileged activity’ as the construction of barriers to protect against floodwaters, it must act reasonably and non-negligently.”  (3 Cal.3d at p. 307, fn. 12, 90 Cal.Rptr. 345, 475 P.2d 441, italics added.)   Thus, the Archer exception that survives Keys adopts the rule of reasonableness.

The majority claims Holtz shows the continuing vitality of the natural watercourse rule because of the statement in that opinion that “ ‘fulfillment of the broad “cost spreading” purpose of [article I, section 14 of the California Constitution], as clarified in Albers, requires a limited application of the Archer exception’ ” rather than defendant's proposed expansive one.  (Maj. opn, at p. 903, quoting Holtz, supra, at p. 306, 90 Cal.Rptr. 345, 475 P.2d 441.)   The Holtz court “refused to extend the Archer exception,” my colleagues assert, “because to do so ‘would so expand the exception as to consume the general Albers rule.’ ”   (Ibid., italics in original.)   The majority reasons, in other words, that the refusal to expand the exception is an affirmation of its existence.   The trouble with this analysis is its indifference to the fact that, as Holtz makes clear, the conditional Archer exception that survives Keys incorporates the tort concept of reasonableness that my colleagues refuse to apply.

Just three years ago, in Belair, supra, 47 Cal.3d 550, 253 Cal.Rptr. 693, 764 P.2d 1070, our Supreme Court relied very heavily on Holtz 2 in applying the reasonable use rule in a case involving a natural watercourse (the San Jacinto River) and cited Keys for the by now unremarkable principle that “[t]he 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.”  (Id., at p. 566, 253 Cal.Rptr. 693, 764 P.2d 1070.)  Belair points out that the Archer exception—which, as explained in Holtz, “ ‘encompassed those cases in which the state at common law “had the right to inflict the damage” ’ ” (Belair at p. 563, 253 Cal.Rptr. 693, 764 P.2d 1070, quoting Holtz, 3 Cal.3d at p. 305, 90 Cal.Rptr. 345, 475 P.2d 441, italics in original)—“ ‘has been employed in only a few restricted situations, generally for the purpose of permitting a landowner to take reasonable action to protect his own property from external hazards such as floodwaters.’ ”  (Belair, 47 Cal.3d at p. 564, 253 Cal.Rptr. 693, 764 P.2d 1070, at p. 564, quoting Holtz, 3 Cal.3d at p. 306, 90 Cal.Rptr. 345, 475 P.2d 441, italics omitted.)  Holtz and Belair show that the pure Archer exception (that is, the “absolute” rather than the merely “conditional” immunity) now applies only to private activity.   As stated in Belair, “while we recognized in Albers that strict inverse condemnation liability may not be appropriate in the case of [public] flood control improvements, we emphasized in Holtz that such improvements should not be cloaked with the same immunity as private flood control measures.”   (Belair, 47 Cal.3d at p. 564, 253 Cal.Rptr. 693, 764 P.2d 1070.)   Even though public flood control is a “privileged activity” it should not receive the absolute immunity allowed under Archer's per se rule because “the damage potential of a defective public flood control project is clearly enormous.”   (Belair, 47 Cal.3d at p. 565, 253 Cal.Rptr. 693, 764 P.2d 1070.)   “Therefore,” Belair continues, “as we observed in Holtz, 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, it must [at least] act reasonably and non-negligently.   [Citations.]’  ․ [W]here 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.  [Citations.]”  (Belair, at p. 565, 253 Cal.Rptr. 693, 764 P.2d 1070, italics omitted.)

If a public agency that acted unreasonably in connection with a natural watercourse can be held liable even when involved in flood control, the most highly privileged activity, a fortiori such an agency can be held liable for unreasonable conduct where, as in the present case, the activity is not so highly privileged.

The majority's narrow interpretation of Keys, Holtz and Belair, and its strict and literal application of the Archer exception, conflicts with the overwhelming body of modern case law;  in particular Linvill v. Perello (1987) 189 Cal.App.3d 195, 234 Cal.Rptr. 392;  Ektelon v. City of San Diego (1988) 200 Cal.App.3d 804, 246 Cal.Rptr. 483;  and Weaver v. Bishop, supra, 206 Cal.App.3d 1351, 254 Cal.Rptr. 425.  (See also Ellison v. City of Buenaventura (1976) 60 Cal.App.3d 453, 458, 131 Cal.Rptr. 433 [accepting, arguendo, the view that “the rule of reasonable use [established under Keys ] applies to both surface waters and to natural watercourses.”].)   The majority strains in vain to distinguish these materially indistinguishable cases and is forced in the end to acknowledge its rejection of relevant case law.

In Linvill v. Perello, supra, 189 Cal.App.3d 195, 234 Cal.Rptr. 392 “[a] natural water course (the barranca) flows from north to south in a channel located immediately west of appellants' properties․  The barranca has a history of breaching its banks at an ‘S' curve north of the properties in question during times of flood․  After the floods of 1969, respondents built a levee entirely on their land․”  (Id., at p. 197, 234 Cal.Rptr. 392.)   During a subsequent flood, and as a result of the levee, water in the channel increased in volume and momentum and caused the damage to appellant's land.   Applying the rule of reasonableness articulated in Keys, the court of appeal reversed summary judgment for the plaintiff, explaining that “[w]hether the landowner has acted reasonably is a question of fact to be determined in each case upon a consideration of all the circumstances, including such factors as the amount of harm caused, the foreseeability of harm which results, the purpose or motive with which the landowner acted, and all other relevant matter.”  (Id., at p. 199, 234 Cal.Rptr. 392.)  Linvill v. Perello concludes that Keys v. Romley repudiates the absolute immunity previously provided under the natural watercourse rule.

In Ektelon v. City of San Diego, supra, 200 Cal.App.3d 804, 806, 246 Cal.Rptr. 483, which also involved a natural watercourse, several commercial property owners and tenants sued an upstream developer and the City of San Diego for flood damages.   Having observed that the appeal “involve[d] the continuing validity and interpretation” of the Archer rule, the court reviewed subsequent related cases and, based on Holtz, Keys and Linvill v. Perello, supra, concluded that “[a]n upstream landowner has no absolute right to protect his land from floodwaters by constructing structures which increase the downstream flow of water into its natural watercourse, but is instead governed by the ordinary principles of negligence.”  (200 Cal.App.3d at p. 810, 246 Cal.Rptr. 483.)

The trial court in the present case declined to follow Ektelon because it thought the opinion conceptually flawed 3 and not binding because rendered by a Court of Appeal in another appellate district.   After the trial court ruled, however, Ektelon was approved by the Supreme Court in Belair 47 Cal.3d at pp. 567–568, fn. 9, 253 Cal.Rptr. 693, 764 P.2d 1070 and followed by our own district in Weaver v. Bishop, supra, 206 Cal.App.3d 1351, 1357, 254 Cal.Rptr. 425.

Weaver v. Bishop was an action by landowners against neighbors on the opposite side of a creek for erosion of their property allegedly resulting from defendants alteration of the flow of the creek by placing riprap along its banks in order to prevent the washing away of their own property.   Justice Anderson, speaking for a unanimous court, first established that the facts of the case were analogous to those of Archer v. City of Los Angeles, supra, 19 Cal.2d 19, 119 P.2d 1 and San Gabriel V.C. Club v. Los Angeles (1920) 182 Cal. 392, 188 P. 554.   Nonetheless, the court determined that “the trial court properly concluded that the ‘reasonable use’ doctrine of Keys v. Romley applies․”  (Id., 206 Cal.App.3d at p. 1356, 254 Cal.Rptr. 425.)   Justice Anderson pointed out that, “as Keys acknowledges and illustrates, the general trend in water-damage cases is to replace the rigidities of property law with the more flexible, conduct-oriented principles of tort.  (See 64 Cal.2d at p. 408, 50 Cal.Rptr. 273, 412 P.2d 529.)   Under the latter as expressed in the Second Restatement of Torts, defendants' liability would depend upon a balancing of reasonableness, either by analogy to the rules concerning interference with water use, or under the rules of nuisance and trespass.  [Citations.]  This undoubtedly reflects the emerging state of the law in this field.”  (Id., 206 Cal.App.3d at p. 1358, 254 Cal.Rptr. 425, fn. omitted, italics added.)

The majority's explanation for rejecting the unanimous opinion of another division of our own court in Weaver v. Bishop is as follows:  “There are compelling policy reasons underlying the announced exception in Archer (providing immunity to an upper landowner who gathers and discharges surface waters into a natural watercourse) which should not be abandoned by an intermediate appellate tribunal bound to observe precedent.”  (Maj. opn., at p. 904.)   This rebuke suits its author, not its target.

The policies underlying Archer were not abandoned by Division Four of this court in Weaver, but by the Supreme Court in Keys more than two decades earlier;  an abandonment the high court clarified and reaffirmed in Holtz and Belair and which has been acknowledged by almost every appellate court in this state that has since addressed the question.4  It is my colleagues who are out of step, not everyone else.

California long ago ceased to be the rural outpost it was at the time Archer was decided in 1941.   Given the accelerated development this state has experienced since World War II, the policy arguments advanced in Keys are stronger today than they were at the time the Supreme Court issued that unanimous opinion.   By confining Keys to its narrow facts and ignoring unmistakable language in Holtz and Belair as well as almost all of the intermediate appellate opinions and views of the most authoritative commentators, the majority would turn back the clock.   This should not be done.   The rule of reasonable use which the majority rejects is consistent not only with California cases, as has been seen, but is in accord with decisions across the country.  (Musumeci v. State (1974) 43 A.D.2d 288, 351 N.Y.S.2d 211, 215–216 [state cannot deflect water so as to overburden natural watercourse];  Armstrong v. Francis Corporation (1956) 20 N.J. 320, 120 A.2d 4, 8–10 [adopting rule of reasonable use];  City of Houston v. Renault, Inc. (1968 Tex.) 431 S.W.2d 322 [same];  Weinberg v. Northern Alaska Development Corp. (1963 Alaska) 384 P.2d 450, 452 [same];  Rodrigues v. State (1970 Hawaii) 52 Haw. 156, 283, 472 P.2d 509, 516 [same].)

II.

For the foregoing reasons, I believe the trial court erred in determining that the natural watercourse rule provided absolute immunity against all of appellants' claims.   While I agree with the majority's conclusion that the County, District and City were nonetheless insulated from liability, I do not agree that the evidence failed to establish CalTrans' responsibility for appellants' damage.   In light of the evidence presented, appellants are in my view entitled to a remand for a determination of whether CalTrans acted unreasonably and thus may be liable in tort for using Reliez Creek to drain its land without taking precautions to ensure the creek was not overburdened.

CalTrans argues it cannot be liable under any theory of recovery because the runoff from its property (consisting of Highway 24, which runs through the watershed) was not a substantial contributing factor in appellants' damage.   While the court determined the Archer exception completely immunized CalTrans from liability, to guard against reversal in the event its interpretation of Archer was found erroneous, it also considered whether appellants had established that CalTrans actually contributed to the damage they sustained.   The court concluded causation had not been proven for the inverse condemnation claim, but did not express an opinion whether causation had been established for purposes of the tort claims.5  Thus, there is no ruling to review on this issue and I believe it is inappropriate to engage in an elaborate analysis of the adequacy of the evidence on the question of causation as it relates to the tort claims.   Moreover, I disagree that appellants failed to offer any evidence that respondent public agencies caused their injuries.

Professor Todd testified that the development by BART and CalTrans jointly increased the water runoff by 2 1/212 times what it would have been under natural conditions.   While this increase was attributed to the combined effect of both agencies, a jury might reasonably conclude that CalTrans, which owned 22.4 acres to BART's 3.5 acres, was primarily responsible for this increase.   Furthermore, Dr. Todd stated that although CalTrans and BART only owned a small fraction of the entire watershed (approximately 1.1 percent), because their developments involved largely impervious surfaces they jointly contributed 9.2 percent of the additional water flowing into Reliez Creek.   The record is filled with conflicting evidence concerning the effect of the runoff from CalTrans' property.   Under these circumstances a nonsuit would be inappropriate;  appellants are thus entitled to a trial where they may attempt to prove CalTrans acted unreasonably in its use of Reliez Creek.   If CalTrans can show its contribution was legally insignificant it may avoid liability;  if its contribution was minimal this fact may be used to reduce CalTrans' ultimate liability for the damage.

III.

Finally, I disagree with the majority's conclusion that “there is no constitutional bar to an assessment of costs” against appellants.  (Maj. opn., at p. 909.)   While my colleagues accept the conclusion of Smith v. County of Los Angeles (1989) 214 Cal.App.3d 266, 262 Cal.Rptr. 754, in my opinion, that decision is based on a faulty analysis of City of Los Angeles v. Ricards (1973) 10 Cal.3d 385, 110 Cal.Rptr. 489, 515 P.2d 585, and ought not be followed.

Unlike the instant case (and Smith ), Ricards was concerned with the question of whether an unsuccessful inverse condemnation plaintiff could recover his own costs, not whether an unsuccessful plaintiff could be ordered to pay costs to the prevailing governmental defendant.   Under such circumstances it is understandable the court would conclude the requirement of “full compensation” does not mandate an award of costs to the plaintiff because the plaintiff has no right to any compensation where no taking has been proven.   However, different constitutional policies are implicated when a court attempts to impose upon the losing inverse condemnation plaintiff the duty to pay the defendant's costs.   As this court previously has recognized, the requirement of full compensation is “particularly applicable in inverse condemnation [as compared with direct condemnation (or eminent domain) actions] since the property owner is forced to take on the government's role in initiating the proceedings.”  (Orpheum Bldg. Co. v. San Francisco Bay Area Rapid Transit Dist. (1978) 80 Cal.App.3d 863, 877, 146 Cal.Rptr. 5.)   Although appellants' inverse condemnation claim failed at trial, and we are constrained to uphold that ruling on appeal, it is inappropriate to impose upon appellants the obligation to pay respondents' costs.   A rule permitting large costs awards against losing plaintiffs would undoubtedly inhibit inverse condemnation plaintiffs from bringing potentially meritorious actions and thereby undermine the constitutional safeguard against governmental overreaching.  (See generally, Rose v. State of California (1942) 19 Cal.2d 713, 719–720, 123 P.2d 505.)   Such a result is unacceptable.   Accordingly, I would hold the court properly determined respondents could not constitutionally recover costs incurred in connection with the inverse condemnation claim.   Because respondents insisted it was impossible to apportion the costs between the constitutional and tort claims, I believe the court properly denied all costs under Code of Civil Procedure section 1032.

For the reasons set forth in the majority opinion unrelated to the continuing vitality of the natural watercourse rule, I would affirm that portion of the judgments in favor of BART, the County, the District and the City.   I also would affirm the trial court's denial of respondents' request for costs under Code of Civil Procedure section 1032.   I would reverse the judgment insofar as it is based on an absolute immunity under the natural watercourse rule and remand for trial against CalTrans on the claims for negligence, nuisance, trespass and dangerous condition of public property.

FOOTNOTES

1.   Appellants also sued Century Homes Development Company, the Harold Smith Company and Does 1–50.   Appellants alleged these defendants “failed to use reasonable care in the design, construction, filling, compaction, alteration and forming of [appellants'] real property,” all of which contributed to the landslides on their property.   These defendants are not involved in this appeal.

2.   BART was relieved from defending the tort causes of action due to appellants' failure to perfect their claims pursuant to the Tort Claims Act.   That ruling is not questioned in this appeal.

3.   No appeal is taken from the directed verdict, the special verdicts or the trial court's ruling on inverse condemnation vis-a-vis the Sizeler outfall and the sheet pile structure.

4.   These figures are derived from the testimony of Phillip Williams.   The figures presented by another expert, David Todd, were slightly different but also reflect increasing development of the Reliez Creek watershed.  (See post, fn. 17.)

5.   Except for appellants and the developer of appellants' properties on the east side of Reliez Creek (who is charged with having “negligently constructed, designed, planned, built, maintained, compacted, filled, altered, and otherwise prepared” appellants' real property so that it was unable to withstand erosion from the storm drainage system), no other developer, multi-unit or single family owner who routinely uses the creek as a natural drainage facility for its own property has been joined as a defendant in this lawsuit.

6.   Highway 24 existed in its present location in one form or another for many years prior to 1968.   Dr. Williams acknowledged “a good share of the water that is passing into Reliez Creek has been passing into Reliez Creek from the highway facility since [its] original configuration in the mid–1950's.”

7.   Attached to the reply brief of County and District was an unscaled drawing showing the location and ownership of the various parcels and the location of the Sizeler outfall and the sheet pile structure.   Appellants have not objected to the inclusion of this drawing, and we attach it to this opinion as an appendix solely for the purpose of establishing the geographical relationship of the parcels to each other and to Reliez Creek, as well as the general location of the two structures.

8.   The engineering details of the Sizeler outfall and the sheet pile structure and their impact on Reliez Creek are irrelevant to our factual recitation.   As earlier observed, these two structures were at issue during the trial against the City, the results of which are not being appealed.

9.   For example, Todd estimated an additional 811 million gallons of surface water entered Reliez Creek under developed conditions over the nine-year period.

10.   “[I]n an inverse condemnation proceeding, the parties have a right to a jury trial solely on the issue of compensation.   All other determinations related to the inverse taking, whether purely factual or a mixture of factual and legal, are nonjury questions.”  (Marshall v. Department of Water & Power (1990) 219 Cal.App.3d 1124, 1141, 268 Cal.Rptr. 559.)

11.   Justice Kaufman made reference to this rationale in Belair v. Riverside County Flood Control Dist., supra, 47 Cal.3d at p. 564, fn. 4, 253 Cal.Rptr. 693, 764 P.2d 1070.   While it is unclear whether the comment was directed to the natural watercourse rule or to an exception to the right to erect defensive barriers, there can be no doubt it is a valid consideration as to riparian owners.

12.   The Archer exception is one of the two exceptions.   The other, the Gray exception, involves noncompensable damages inflicted in the proper exercise of the police power.  (Gray v. Reclamation District No. 1500 (1917) 174 Cal. 622, 163 P. 1024.)

13.   Holtz observes that “[i]n some ways the language of the ‘right to inflict damage’ projects a misleading concept” (3 Cal.3d at p. 306, 90 Cal.Rptr. 345, 475 P.2d 441), and that “[i]n recognition of the generally perceived reasonableness of such action [i.e., landowners' efforts to protect their own property from damage] ․ certain types of protective measures were cloaked in a legal ‘privilege.'12  [Citations.]”   (id. at p. 307, 90 Cal.Rptr. 345, 475 P.2d 441).   Footnote 12, in part, states:  “According to Prosser, the ‘privilege’ designation ‘signifies that the defendant has acted to further an interest of such social importance that it is entitled to protection, even at the expense of damage to the plaintiff.   He is allowed freedom of action because his own interests, or those of the public, require it, and social policy will be best served by permitting it.’  (Prosser, Law of Torts (3d ed. 1964) p. 99.)”  (3 Cal.3d at p. 307, fn. 12, 90 Cal.Rptr. 345, 475 P.2d 441, emphasis added.)

14.   Relying on Keys v. Romley, supra, the plaintiffs, in Ellison v. City of San Buenaventura (1976) 60 Cal.App.3d 453, 458, 131 Cal.Rptr. 433, argued the natural watercourse rule had been, or should be, superseded by the Keys rule of reasonable use.   After first observing that Keys had adopted the reasonable use rule as governing liability for diversion of surface waters and had not considered the natural watercourse rule, the Ellison court assumed, arguendo, the reasonable use rule applied to both surface waters and natural watercourses, concluding plaintiffs' complaint failed to state a cause of action under either rule.  (Id. at pp. 458–461, 131 Cal.Rptr. 433;  see also Ullery v. County of Contra Costa (1988) 202 Cal.App.3d 562, 573, fn. 3, 248 Cal.Rptr. 727 [recognizing but having no cause to rule on natural watercourse immunity].)

15.   Inexplicably, Ektelon fails to discuss Deckert v. County of Riverside, supra, 115 Cal.App.3d 885, 171 Cal.Rptr. 865, a Fourth District, Division Two, decision which follows, as it is required to do, our Supreme Court's natural watercourse immunity rule.

16.   While appellants emphasize the fact that the District enforced the City's drainage ordinance and offered advice on remedial measures after the erosion occurred, it did so only at the City's request.

17.   Professor Todd's figures reflected watershed development of 10.7 percent by 1957, 28.6 percent by 1968, and 52.3 percent by 1982.   Although slightly different than Williams' figures, these figures reflect the same trend of increasing urbanization of the Reliez Creek watershed.

18.   The same holds true for the City, County, and District.   There is no evidence the City maintained any structures which were a substantial concurring cause of appellants' damages.   As noted above, appellants have not appealed from the decision as to the Sizeler outfall and the sheet pile structure.  (See ante at p. 891, fn. 3.)   Nor can the City be held liable for approving upstream development.  (See ante at pp. 905–906.)   As to the County and District, there is no evidence they maintained any structures contributing to appellants' damage, having relinquished control to the City in 1968.  (See ante at pp. 904–905.)

19.   Code of Civil Procedure section 1032, subdivision (b) provides “[e]xcept as otherwise expressly provided by statute, a prevailing party is entitled as a matter of right to recover costs in any action or proceeding.”

1.   The majority says Holtz may be disregarded because it was an inverse condemnation case.   This distinction is unimportant, however, because the reasonable use rule also applies in inverse actions alleging water damage.  (See discussion, post, at p. 916, fn. 3.)

2.   The fact that, as the majority emphasizes, Holtz is not a water case obviously did not prevent the Belair court from deferring to the discussion in Holtz of the Archer exception.   The discussion of the Archer exception in Holtz is not only very germane to the issue the court was then addressing but represents one of the most extensive discussions of Archer ever provided by the California Supreme Court.

3.   The trial court believed Ektelon was wrongly decided because it thought it anomalous to apply a reasonable use standard in an inverse condemnation case, which is based on strict liability.   The anomaly does not exist.   Employment of a reasonableness standard instead of the strict liability ordinarily associated with inverse condemnation is a compromise calculated by the common law to rationally accommodate conflicting policy goals.   Thus, in Belair, which, as noted, was also an inverse condemnation action, the Supreme Court quoted the observation of Professor Van Alstyne that the use of a reasonableness standard in certain inverse condemnation actions “ ‘is not entirely a matter of negligence, but represents a balancing of public need against the gravity of private harm.’ ”  (Id., 47 Cal.3d at pp. 565–566, 253 Cal.Rptr. 693, 764 P.2d 1070, citing Van Alstyne, Inverse Condemnation:  Unintended Physical Damage, supra, 20 Hastings L.J. 431, 455.)   Compensation for flood damage incurred as a result of a public entity's unreasonable conduct simply insures that a property owner not bear “a disproportionate share of the costs of a public improvement.”  (Belair v. Riverside County Flood Control District, supra, 47 Cal.3d at p. 566, 253 Cal.Rptr. 693, 764 P.2d 1070, quoting Holtz v. Superior Court, supra, 3 Cal.3d at p. 303, 90 Cal.Rptr. 345, 475 P.2d 441.)   In other words, a plaintiff in an inverse case involving a privileged activity must show (as plaintiffs in other types of inverse cases need not) that the public agency acted unreasonably.   As Van Alstyne has explained at great length (Van Alstyne, Inverse Condemnation:  Unintended Physical Damage, supra ), the use of the reasonable use rule in inverse cases represents a compromise between conflicting goals:  the need to encourage certain types of essential public improvements, such as flood control projects, which justify government immunity, versus the policy of compensating injured persons, which justifies holding government accountable.

4.   The sole exception is Deckert v. County of Riverside (1981) 115 Cal.App.3d 885, 171 Cal.Rptr. 865, where the court interpreted the Archer rule as providing absolute immunity for upper landowners who, through the development of their land, increase the volume of water flowing into a natural watercourse.   The opinion does not even cite Keys or Holtz or any of the other cases explaining the adoption in California of the reasonable use rule and describing the Archer exception as a conditional, not an absolute, privilege.

5.   If the court had determined appellants failed to prove CalTrans caused their damage on the tort claims, as well as the inverse condemnation claim, such a ruling would be reversible.   A nonsuit is improper when, after disregarding conflicting evidence and indulging every legitimate inference in favor of appellants, it is clear that appellants' case provided “ ‘evidence upon which reasonable minds could differ.’ ”   (Baxter v. Alexian Brothers Hospital (1989) 214 Cal.App.3d 722, 725, 262 Cal.Rptr. 867.)   This case provided ample evidence upon which reasonable minds could differ on CalTrans' contribution to appellants' damage.

BENSON, Associate Justice.

PETERSON, J.*, concurs.