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ENVIRONMENTAL LESSONS
of the
MALIBU LAGOON PROJECT
A Review of the Record
E.D. Michael
March 11, 2014

INTRODUCTION

This review of the Malibu Lagoon project is presented as an object lesson illustrating how an ostensibly well-planned environmental project can fail despite engendering from its inception widespread community approval, ratification of various public agencies mandated to protect or improve the environment, and technical assurances of feasibility. First, it analyzes the record concerning, successively, the project in terms of its prehistoric and historic antecedents, the environmental milieu from which it was conceived, its planning and approval, its construction, and its performance, each followed by comments adding to or modifying that record. Second, it discusses the extent to which the project has failed and the reasons for it. And third, it offers recommendations regarding how failures of similar projects might be avoided.

MALIBU LAGOON PROJECT PURPOSE AND RATIONALE

The announced purpose of the Malibu lagoon project was to "restore" and "enhance" part of the mouth of Malibu Creek, widely regarded as an oceanic coastal lagoon. The creek mouth on its western side had been modified by grading probably for agricultural purposes late in the 19th century, covered with artificial fill during the late 1920s while under private ownership, and after coming under the control of the California Department of Parks and Recreation (DPR), regraded in 1983 with channels on the assumption that this would result in restoring lagoonal conditions and desirable natural habitats. The present lagoon project was undertaken to replace the 1983 channels with others intended to increase circulation thereby greatly reducing or eliminating hypoxia and generally improving habitat conditions.

SCOPE OF REVIEW

This review concerns only physical aspects of the project It remains for others to address its ramifications regarding: [i] its asserted relation to the area's natural ecologic character, especially in terms of so-called endangered species; [ii] its recreational aspects; [iii] the legality of its environmental approval; and [iv] an accounting of funds, all far beyond the abilities of this poor scrivener. Nevertheless, even without attention to such weighty matters, the subject requires a rather lengthy treatment. Hence, it is presented here in six serial installments. These are: Part I - Floodplain Prehistoric Conditions; Part II - Lagoon Project Site History; Part III - Environmental Planning and Approval; Part IV - Lagoon Project Construction; Part V - Lagoon Project Performance; Part VI - Conclusions Although for some readers the serial format can be frustrating, I make no apology. If it was good enough for Sir Arthur Conan Doyle, Henry James, Harriet Beecher Stowe, and Herman Melville, it's good enough for me.

Part I - FLOODPLAIN PREHISTORIC CONDITIONS

The Malibu Lagoon project lies at the south-easternmost part of the Malibu Creek floodplain. The character of the project cannot be fully understood without reference to the floodplain itself and the prehistoric period during which it developed.

ANTECEDENT CONDITIONS

Malibu Creek passes entirely through the Santa Monica Mountains as a superposed stream, i.e., a stream that has maintained its course during a change in the conditions with which it originally was in equilibrium In this respect, it is unique in California. The rise of the Santa Monica Mountains block is believed to have begun about a million years before the present (ybp) during the Pleistocene Epoch considered to have begun about 2.6 million ybp Then, much of the area from which the block began its rise had become an erosional surface of low relief and to some extent an emerged Late Tertiary sea bed. A small part of it was drained by ancestral Malibu Creek - a stream that meandered to the ocean through an area that now includes Thousands Oaks, Calabasas, Agoura Hills, and part of the Simi Hills. The rise was so slow that the creek was able to maintain and deepen its meandering course through the rising block As the block rose, the creek was rejuvenated so that erosion of its thalweg kept pace with increasing elevation Once shallow meanders eventually became the deep gorges now called Goat Buttes and at what is now Serra Retreat In that process, ancestral Malibu Creek lost forever the meander-forming mechanism of stream-bank cutting and filling. Downstream from the Serra Retreat meander, it can only be assumed that similar conditions prevailed. In effect, ancestral Malibu Creek became a youthful stream in response to the steepening mountain block gradient while retaining its old-age configuration to the Pleistocene shore some distance, perhaps a mile or more, farther south than today.

Comment

This condition should have prevailed until the beginning of the Wisconsin glacial episode about 85,000 ybp at which time lowering sea level added additional energy to that due to tectonic uplift. It is inferred that the lowering sea level infused the reach of ancestral Malibu Creek closest to the shore with energy sufficient to introduce locally consequent stream erosion. It is postulated that in the 73,500 years following the beginning of Wisconsin glaciation the area from some point downstream of the Serra Retreat meander was transformed to a youthful terrain Similarly, elsewhere along the Pleistocene Malibu shore, consequent streams developed ancestral to the master streams of today from Topanga Canyon west to Little Sycamore Canyon.

FLOODPLAIN DEVELOPMENT

Beginning about 19,000 ybp, the Wisconsin glacial episode began to wane and sea level world-wide began rising due to glacier melting. The resulting landward advance of the sea, called the "Flandrian transgression"[1] caused shoreline streams to begin aggrading.[2] In particular, it is inferred that ancestral Malibu Creek in very late Pleistocene time began this process of aggradation, and that by about 11.5 thousand ybp, at the beginning of the interglacial episode called the Holocene Epoch, it was well advanced Since then - with possible retrograde periods when local tectonic and/or isostatic increments of rise briefly offset sea-level rise - aggradation has continued. Most important for present purposes, this model postulates that the present extent and shape of the Malibu Creek floodplain is entirely in response to the processes of stream clogging and lateral planation that invariably accompanies stream aggradation.[3]
Certainly within the first half of the Holocene Epoch and possibly as early as latest Pleistocene time, flow from ancestral Malibu Creek entered the floodplain from the lowermost reach of the superposed Serra Retreat meander along which Mariposa de Oro in the Serra Retreat area now is located as shown in Figure 1. From near what is now the

Figure 1. Malibu Creek Holocene Floodplain Stream Regimes.

Dashed and solid lines approximate earlier and later creek regimes, respectively. Dotted lines indicate the approximate predevelopment boundaries of the later creek floodplain "Spur" and "Neck" refer to the basic structural characteristics of the Serra Retreat meander. Base: U.S.G.S. 7.5-minute Malibu Beach quadrangle, ed. 1981, as modified.

Cross Creek bridge, just west of the intersection of Mariposa de Oro and Cross Creek Road, the creek flowed on to the aggrading floodplain in a southerly direction along the base of the Malibu Knolls slope and past the mouth of Winter Canyon to the shore near what is now the western end of the Malibu Colony. Probably as late as 1945, the mouth of that stream, blocked by a barrier sand bar, was a body of water that at least as early as 1916 was called "Malibu Lake." Probably it persisted into the early 1940's. A remnant of that feature exists today some 500 to 1,000 feet west of Stuart Ranch Road and just north of the massive highway fill as the only true natural wetland in the Malibu Creek floodplain - excavated depressions in the entirely artificial Legacy Park notwithstanding.

Probably in the latter half of the Holocene Epoch - say 3,000 or 4,000 ybp - ancestral Malibu Creek broke through the neck of the Serra Retreat meander in a manner yet to be understood The resulting isolated spur became the promontory that one day Frederick Rindge (1892, p. 70) was to call "Wunderschön[4] Vista Ridge" and now is the site of Serra Retreat. As a result, Malibu Creek abandoned its southwesterly reach in favor of a direct southerly one. Probably, that event did not change significantly the position of the shore which extended then from Vaquero Point on which the Adamson House now is located to near what is now the western end of the Malibu Colony. Figure 1 illustrates these two stream regimes and their geomorphic origins. It is to be understood that although both occurred in Holocene time, the Serra Retreat meander itself is essentially a superposed Pleistocene feature Although modified to some extent by Holocene stream erosion, it required many thousands of years prior to the Holocene to broaden and deepen it to its basic configuration.

Comment

It is necessary for present purposes to rationalize the available subsurface floodplain data from Bausch, et al. (op.cit.) with what has come to be known as the "UCLA study" by Ambrose and Orme (2000) which, inter alia, interprets the Malibu Creek floodplain during the past 2,000 years as having been mostly a lagoon. Accordingly, (op. cit, pp. 2-1 - 2-2), Figure 2-1a of Figure 2 represents conditions about 2,000 ybp.

Figure 2. UCLA Study Figure 2-1a, b).

Short dashed lines presumably indicate finer-grained lagoonal deposits and dotted areas coarser-grained floodplain deposits. The red circles have been added to indicate the general location of the "Sycamore Grove" - see note (2) below.

To better understand this interpretation, the following quotation (op. cit., p. 2-2) is cited to which has been added numerals for subsequent discussion:

"... The present estuarine lagoon came into existence towards the end of the Flandrian transgression culminating in a reduced but continuing rise of relative sea level of about 1.8 mm per year during late Holocene and, as revealed by tide-gauge records since 1933, historic times A reconstruction of the late Holocene estuarine lagoon some 2,000 years ago, based on field investigations and comparable analogs (1), is presented in Figure 2-a At the time, Malibu Creek spilled from its bedrock narrows upon to a fan delta, at time flooding the entire apex, at other times incising its own deposits to leave a floodplain terrace which survives above the inner margins of the lowland, subject to inundation during unusually high magnitude floods (2). Farther downstream, the creek meandered through its estuarine lagoon (3), but was pushed eastward by the onshore and downdrift construction of a low barrier beach (4). The greater part of the lagoon to the west (5) gradually, if erratically, filled with backwater sediment, occasionally flood deposits, colluvium and alluvial fan deposits from the adjacent hill slopes, and flood-tidal deltas and overwash through and across the still incomplete barrier beach (6). With a larger tidal prism than today, channels through the barrier were maintained for a while by outflowing lagoon waters and the consequent formation of ebb-tidal deltas (7)."

(1) - By "field investigations" presumably is meant, primarily, the work of Bausch, et al. (op. cit.), supplemented by three borings for the UCLA study, but whether by "analog" is meant: [i] coastal floodplain depositional conditions elsewhere, or [ii] the presumption of a similar earlier climatic cycle, or both, is uncertain. However, the idea that up until about 200 years ago there had been a period of at least 1,800 years during which there prevailed the low-energy stream condition that a floodplain-wide lagoonal condition requires, is directly controverted by the available evidence, as discussed below.

(2) - If by "floodplain terrace" is meant the surface of deposits exposed after flooding, there are two in the vicinity of the Malibu Creek floodplain. One is at its eastern edge where a mass of alluvium traversed by Serra Road is deposited on a coastal platform at about elevation +80 feet msl carved in the Trancas Formation as mapped by Yerkes and Campbell (1980). Flooding of that area clearly has not occurred during historic time The other is uncertain since the surface at the floodplain's northwestern edge at about +25 feet msl descends more or less uniformly to the northern edge of the barrier bar which, except where breached, defines the southern edge of the floodplain. The earlier stream regime of Figure 1 seems to have been ignored in the UCLA study and suggests that Figures 2-1a and 2-1b of Figure 2, instant, were intended to be essentially diagrammatic. It is to be noted, however, that the protrusion encircled in Figure 2 corresponds to a relatively coarse mass of floodplain alluvium which supports tree growth that Frederick Rindge (1898, pp. 73 - 85) unreservedly admired and enjoyed which he called "The Sycamore Grove."

(3) - There is no evidence of a meandering stream channel in the Malibu Creek floodplain, and the term "estuarine lagoon" in geologic parlance is a non sequitur. An "estuary" is a partly enclosed relatively deep coastal inlet such as a fjord freely open to the sea. Its use to describe a coastal lagoon which is essentially a landlocked feature tributary to the sea only through one or more shallow tidal channels is to be discouraged.

(4) - It is important to understand that the eastward-shifting of the channel breach in the shoreline barrier bar is not "pushed," which implies a direct application of some sort of force. Rather it is the result of the interaction of: [i] more or less continual clogging at the mouth of the breaching channel at its western side, with [ii] east-moving littoral drift, and [iii] the breaching channel flow rate This mechanism is entirely independent of the pattern of flow upstream.

(5) - As previously discussed, the idea of lagoonal conditions over most of the Malibu Creek floodplain in the late Holocene - or at any time - is simply speculation The western side of the floodplain was carved by erosion and lateral planation of the southwesterly directed stream regime There is no evidence that the western side of the floodplain was essentially a lowland subject to filling in late Holocene time.

(6) - The idea of a "still incomplete barrier beach" in late Holocene time is inconsistent with the existence of the postulated widespread lagoon shown in Figure 2-1a, the mere presence of which would require a well developed barrier bar. Barrier bars along the Malibu coast are essentially a function of wave approach and stream deposits at the shore. They are quite common and well- developed at the mouths of the Arroyo Sequit, Trancas Canyon, Zuma Canyon, Corral Canyon, and Topanga Canyon. There is no evidence upon which to postulate an incipient condition of barrier bar formation at the mouth of Malibu Creek 2,000 ybp. Such bar formation is a result of stream aggradation and wave approach along the Malibu coast - a condition that began to develop with advent of the Flandrian transgression and persists today

(7) - The record does not support the idea of a "larger tidal prism" by which presumably is meant a larger volume of lagoonal waters in Holocene time up to 1800 AD as Figure 2-1a of Figure 1 requires Observations such as this and "ebb-tidal deltas" seem to have no purpose other than to support a postulated floodplain-wide lagoonal condition which in the absence of any evidence whatsoever is simply speculative.

FLOODPLAIN SUBSURFACE CONDITIONS

Figure 3 reproduces Figure 1-8 of Ambrose and Orme (2000, p. 1-16) for the UCLA study. Apparently, it is based largely on data from Bausch, et al. (op. cit., App. B and C) which include the logs of cores from six borings and data from two lines of cone penetrometer tests (CPTs). Their data were supplemented by three additional core logs obtained as part of the UCLA study effort. It is to be noted that the investigation by Bausch, et al. (op, cit.) was for the purpose of determining the extent to which conditions such as faulting, foundation-bearing capacity, and liquefaction might affect development rather than to investigate lagoonal or other environmental conditions.

Figure 3.UCLA Study Figure 1-8, Modified.

This figure is a generalized north-south cross-section through the Malibu Creek floodplain from Anthony and Orme (2000, Fig. 1-8, p. 1-16). "Fluvial gravel" apparently is the "Civic Center gravels" as discussed by Bausch, et al. (1994). The dotted lines in the TEST SECTION bracket a radio-carbon dated interval of 6,500 - 7,850, ybp. Vertical exaggeration: 10X.


Generally, CPT data describe mechanical conditions. They do not provide any direct lithologic information and have value for inferring such only if related to lithologic logs from nearby borings. Of the six cores obtained by Bausch, et al. (op. cit., App B) which range in depth from 43.5 to 55 feet, only LB-4 encountered organic materials that might be indicative of a lagoonal environment, and it was located at the abandoned mouth of the earlier Holocene stream regime shown in Figure 1 This, and data derived from three cores obtained specifically for the UCLA study, apparently provide the only basis for its Figure 1-8, reproduced here as Figure 3 Detailed discussion of these latter three cores (Ambrose and Orme, 2000, pp., 1-15 - 1-20) is essentially an interpretation of alternating fluvial and organic-rich deposits in the range of -1.5 to - 47.7 feet msl supported by reports of scattered plant remains consistent with both fresh and brackish water conditions, and ranging in age from 1,660 - 9,470 ybp From these data, the opinion is offered that they are consistent with Figure 1-8 of Figure 3 as well as another in an east-west direction not reproduced herein. The general locations of relevant data sites regarding subsurface investigations in the Malibu Creek floodplain are shown in Figure 4. Bausch, et al. (op. cit., p. 21) note that from boring B-9 in the "Knapp-Marlin" property, GeoSoils collected two charcoal samples between depths 19.0 and 19.5 feet and 25.0 and 26.5 feet that yielded radiocarbon dates of 6,500 ±130 ybp and 7,850 ±100 ybp, respectively. Although not entirely clear, it appears from Bausch, et al. (op. cit., Pl. 1) that the elevation of the B-9 boring site is at about +23 feet msl.

Figure 4.Subsurface Data Sites - Malibu Creek Floodplain.

LB borings 1 through 6 and GeoSoils boring B-9 are discussed by Bausch, et al. (op. cit., Pl. 1). The dashed line is the approximate northwesterly edge of the floodplain. The coarse dotted lines, not to be confused with the line of houses along Malibu Colony Drive, indicate, diagrammatically, lines of CPTs. A, B, and C are locations of three borings specially drilled for the UCLA study A is very close to LB-1 The location of B is uncertain LPS and CC indicate the locations of the Lagoon project site and Malibu City Hall. Base: USGS 7.5-minute Malibu Beach quadrangle, ed. 1981, as modified.


Ignoring the date error ranges - the averaged 6.5-foot section between the reported depths of 19.0 feet and 26.5 feet in boring B-9 was deposited during a period of about 1,350 years giving a depositional rate of about 1 foot per 208 years. Thus, it would have required 780 years to raise the elevation of the floodplain at B-9 an average distance of 3.75 feet to the present surface at elevation +23 feet msl. Because B-9 is located along the reach of the southwesterly creek regime, this datum indicates that at least as late as 6,500 ybp the southwesterly flow regime of Malibu Creek prevailed. Consequently, taking the period of the Holocene to be 11,500 years, the incision of the meander neck that isolated the Serra Retreat spur must have occurred within the past 5,000 years.

Comment

Neither the data from Bausch, et al. (op. cit.) nor the cores for the UCLA study provides a sufficient basis for the lithologic detail of Figure 3 That the subsurface data are considered "consistent" by Ambrose and Orme (op. cit., p. 1-20) with the figure can mean nothing more than that it depicts one of an infinite number of ways that subsurface conditions might exist in the floodplain; in fact, it is simply an artistic rendering Furthermore, the data support neither the contact of "Fluvial gravels" vis-a-vis the overlying "Fluvial sand," etc., nor their horizontal and vertical distributions. In other words, whatever the GeoSoils logs of borings may show, those of Bausch, et al. (op. cit., App. B) demonstrate simply that the mass called the "Civic Center gravels" has a preponderance of sandy gravels recognizable at certain locations below a depth of about 50 feet, but by no means do they demonstrate the lateral or vertical lithologic continuity shown in Figure 2. Furthermore, although the depths of LB-1 through LB-6 ranged between 43.5 and 51.5 feet, only the log of LB-4, drilled in the wetland of what was once "Malibu Lake" reports significant organic material Most likely, the transition of the Civic Center gravel mass to the overlying "estuarine materials ... deposited beginning approximately 15,000 years ago and continuing to about 2,000 years ago..." as asserted by Bausch, et al. (op. cit. , Sec. 5.1.4, p. 21), is the result of a decreasing rate of sea-level rise during the later stage of the Flandrian transgression Furthermore, disparate occurrences of "estuarine" materials at depth lacking any evidence of lateral continuity provide no basis whatsoever for postulating a lagoonal condition over the floodplain during the Holocene epoch nor at any other time.[5]

CONCLUSIONS

The available subsurface data are insufficient to demonstrate that actual lagoonal conditions persisted over most of the floodplain as late as 1,800 ybp during which low-energy stream conditions would have to have prevailed. If that were true, it would mean that somehow, since 1800 AD, the local area suddenly became the site of its present high-energy stream depositional character to account for alluviums with upper surfaces now in the range of +10 - +20 feet msl, well above the surface elevation of any tidal lagoon postulated to have existed a mere 200 hundred years previously Consequently, such a postulate cannot be seriously considered. While an opinion of "... episodic wetlands throughout the Holocene..." (op. cit., p. 1-19) seems justified, the data do not support the idea of an area-wide lagoon in the Malibu Creek floodplain at any time. The floodplain-wide lagoonal thesis of the UCLA study may have been presented simply in support of the study's primary purpose which was to investigate existing conditions in order to "... understand better the natural system and human impacts on this system, and to develop strategies for the long-term management of the lower watershed ..." (op. cit, p. iv) To that end, the UCLA study has much to offer With regard to planning, however, renderings such as Figures 2 and 3, per se, could have played a significant role in the minds of Malibu Lagoon project planners as ostensibly confirming the idea of a lagoon at the mouth of Malibu Creek suitable for restoration. To the extent that today's community of environmental shakers and movers regard restoration as very important, if not the sine qua non, of project funding, it is a matter of significant concern that the Malibu Lagoon project came to be implemented even though it has no such antecedent character.

References

Ambrose, Richard F., and Anthony R. Orme, 2000, Lower Malibu Creek and lagoon resource enhancement and management: Univ. Calif. Los Angeles, special study for California Coastal Conservancy.

Bausch, Doug, Gan Mukhodhyay, and Eldon M. Garth, 1994, Report of geotechnical studies for planning purposes in the Civic Center area, City of Malibu, California: Leighton and Assoc., Inc. rpt., Project No. 2920647-01 for Malibu Village Civic Association, March 18.

Rindge, Frederick Hastings, 1898, Happy Days in Southern California: The Riverside Press, Cambridge, Massachusetts and Los Angeles, California, reprinted by KNI, Inc., Anaheim, CA, 1984.

Yerkes, R.F., and R.H. Campbell, 1980, Geologic map of the east-central Santa Monica Mountains, Los Angeles, County, California; U.S. Geol. Survey Misc. Inv. Series Map I-1146

* * *


[1] Meaning of "Flandrian transgression" varies. Some authors use it simply to refer to sea-level rise since glacial melting began near the end of the Wisconsin glacial episode and has continued into the Holocene interglacial episode Others limit it to the period of about 19,000 - 6,000 ybp after which the rate of sea-level rise has become measurably less.

[2] Aggrading refers to the rise of a depositional surface in response to its rising base level.

[3] Any serious attempt to understand the natural character of the Malibu creek floodplain must begin with the installation of a weather station and the preparation of a detailed topographic map, a contour map of the underlying bedrock surface, and subsurface exploration to determine possible sections with textures sufficiently uniform to consider their possible performance as aquifers.

[4] German for "simply beautiful."

[5] Parenthetically, the idea that the Civic Center gravels occur in a confined, laterally continuous zone through which effluent can be safely pumped offshore from the presently proposed waste-water treatment facility to serve the Civic Center area - which the City currently assumes, based on a study investment of something like $2 million, will answer the demands of the Regional Water Quality Control Board - is misguided. The Civic Center gravels are unconfined; injection in them will certainly raise local floodplain equilibrium levels possibly to such an extent as to introduce wetland conditions, particularly in the area between Malibu Road and the barrier bar underlying the Colony.