INVITATION TO COMMENT RESPONSE

PROPOSED APPROVAL OF AMENDMENT OF THE LOS ANGELES REGIONAL (BASIN PLAN) TO ESTABLISH AN IMPLEMENTATION PLAN FOR THE MALIBU CREEK NUTRIENTS TMDL AND THE MALIBU CREEK AND LAGOON TMDL FOR SEDIMENTATION AND NUTRIENTS
TO ADDRESS BENTHIC COMMUNITY IMPAIRMENTS

re
GEOMORPHIC AND HYDRODYNAMIC CHARACTERISTICS
of
MALIBU CREEK BENTHOS HABITATS

E.D. Michael, CG 270, EG 157, HG 574
Consulting Geologist
edm@malibuonline.com
April 4, 2017

1.0 INTRODUCTION

This response is based primarily on a preliminary review of reports of the U.S. Environmental Protection Administration, Region IX (USEPA9) and the Los Angeles Regional Water Quality Control Board (LARWQCB). As understood for present purposes, those reports have been generated in response to the Clean Water Act (CWA) Section 303(d) which for California lists, among others, the Malibu Creek main stem and Malibu Lagoon, as two assertedly impaired water bodies in the Malibu Creek drainage area (MCDA).

Accordingly, USEPA9 Staff (2013) have established total maximum daily load (TMDL) standards for nutrients and sedimentation in order to address what are believed to be benthic community impairments of these water bodies, and LARWQCB Staff (2016) present an implementation plan (IP) to assure that those standards are maintained. In dealing with water-body impairments, it appears that the basic EPA approach - its philosophy so to speak - is to assume there exist biologic systems such as benthic communities y that are characterized by behavioral norms which can be defined and hence restored when threatened by stressors, i.e., entities or conditions that have the effect of adversely affecting such norms.

Whether ETA Region IX efforts demonstrate that such an assumption is valid for MCDA nutrients and sedimentation, or are simply postulated and hence remain a work progress, is unclear. To fully address this issue, it is important to recognize that from even a cursory examination of the immediately available data, the work to date has neither carefully examined nor adequately understood the geologic context within which all such systems reside, and that therefore it may be impossible to maintain certain TMDLs. In other words, it is asserted herein that unless the geologic conditions of the MCDA are better understood than as treated in USETA9 Staff (2013), any TMDLs for nutrients and sedimentation assigned are therefore questionable. Furthermore, even though not within the period response for this IP are to be received, it should prove helpful for similar questioned impairments in the MCDA.

1.1 PURPOSE

The purpose of this response is to explain certain aspects of the MCDAs geology that necessarily affect the manner in which nutrients and sedimentation occur in: [i] the main stem and specified major tributaries of Malibu Creek; [ii] the distributary lowermost reach of the creek where it crosses its floodplain; and [iii] an area in the floodplain occupied by the recently completed Malibu Lagoon Restoration and Enhancement Project (MLREP) facility.

This response is limited to considering the appropriateness of the subject IP as applied to the subject EPA-established TMDLs vis-a-vis the MCDAs geomorphic and hydrodynamic character. It does not consider other aspects of the MCDAs geology as treated or as implied by USEPA9 Staff (op.cit.). Its purpose is not to challenge the inclusion in the MCDA something called Malibu Lagoon as a Clean Water Act (CWA) 303(d) per se; rather it questions whether the subject TMDLs reasonably can be regarded as environmentally meaningful based on the USETA Staffs interpretation of the geologic environment within which these water bodies are situated.

1.2 AMBIGUITY

In the interests of accuracy, it is to be noted that the area to which the subject EPA-determined TDMLs are to apply is not limited to the drainage area or watershed of Malibu Creek as those terms commonly are understood. Generally, what is meant by streams drainage area is its tributary area, i.e., the area within which there is a stream to which all other streams within it are either directly or indirectly tributary. Such an area is defined by the watershed boundary traced from a selected stream point in a stream channel. Hence that points elevation is fiducial for the specific drainage area it defines.

In the case at hand, however, rather than a point on a stream, the Malibu Creek floodplain shoreline between the mouths of Malibu Creek and that of the stream in Winter Canyon has been chosen as the fiducial boundary. As such, it includes drainage from an area that is distinct from that of Malibu Creek. In particular, it necessarily includes drainage from Winter Canyon and from intervening slopes between the tributary drainage areas of Winter Canyon and Malibu Creek, and also drainage originating in the creek floodplain. Whether this has been done for the specific purpose of including the recently completed MLREP facility, or perhaps various selected biota and habitat management subareas of the floodplain defined by Ambrose and Lilien (2000, Ch. 8, pp. 8-19 8-43), is uncertain.

Although the distinction between the Malibu Creek tributary area and the area of its floodplain which, while essentially a distributary feature, it is to be understood that herein MCDA refers to both unless otherwise qualified.

1.3 MAPPING ERROR

As noted by USETA9 Staff (op. cit., Sec. 4.4, pp. 4-4 4-6), the Monterey Formation may be a significant source of non-point contamination, thus giving rise to a rather striking error. Specifically, Figure 4-4 (op. cit., p. 4-5), read literally, indicates the entire Malibu Creek Watershed (MCW) be underlain by Monterey/Modelo Formation. This is obviously incorrect and must be due simply to USETA9 staff misunderstanding data provided in referenced geologic reports.

Even casual reference to the geologic maps of Dibblee (1992; 1993) and Dibblee and Ehernspeck (1993) shows that only about 10-15 percent of the MCDA is underlain by that formation. Rather, by the locations of various water bodies, as labeled in the figure, must simply be meant to show those that receive runoff that has passed through the Monterey-Modelo. Nevertheless, those so designated for Stokes Creek and Cold Creek are erroneous. Runoff to Cold Creek does not originate in any area underlain by the Monterey-Modelo, and such a small part of the Stokes Creek drainage area is underlain by it as to be inconsequential.

It is further worthwhile to note in passing that (G)eology in the basin is mostly non-marine in nature, but does include 38 percent Miocene marine sedimentary rock (op. cit., p. 4-4) is clearly erroneous. Most of the MCDA is underlain by Miocene marine formations. This error may be due to the failure to understand that the Topanga Formation and its various equivalents are marine. Aside from Conejo Volcanics and a small area of the Sespe Formation, all bedrock in the MCDA is marine.

1.4 TECHNICALTERMS AND PHRASES

To engage in rational discourse requires some agreement regarding terminology. The character of the MCDA is open to various interpretations because of the inconsistent or improper use of technical terms. Review of the immediately available record indicates that certain terms or phrases applicable to the MCDA discussed below are especially in need of either definition or qualification

. 1.4.1 Technical Terms

aggrading: the process of stream deposition at grade raising its alluvial surface.

bar: a more or less longitudinal and commonly finely sorted mass derived from littoral deposits along a shores the result of wave erosion and longshore drift.

barrier bar: a bar that significantly interrupts hydraulic continuity between separate water masses along a shore.

bed load: unconsolidated granular materials in the bed of a stream.

bitumen: naturally occurring gases, and solid, semi-solid, and fluid hydrocarbons such as tar, pitch, and asphalt, commonly soluble in carbon disulfide; synonymous according to some usages with petroleum.

braided stream pattern: a stream pattern characterized by an upstream channel separates into two or more downstream channels.

closed condition: see Section 1.4.2.5.

cut-and-fill: the process where a stream erodes laterally around an earlier deposited bedload mass blocking a channel.

embayment: any indentation along a shore of such extent as to significantly interrupt the shores more or less linear configuration.

estuary: a type of coastal embayment formed by a relatively large water body entering a terrestrial stream channel of any size - whether a minor creek or a major river - such that there is open and direct contact between the terrestrial and offshore waters; routinely misapplied in public agency documents along the California coast.

floodplain: an expanse of alluvial deposits spread by massive flooding or more commonly by the cut-and-fill process.

geomorphology: the study of landforms.

graded stream: a stream that is neither entraining nor depositing, or alternatively, is entraining and depositing in a manner such that there is no increase nor decrease in bedload volume.

hydrodynamics: the study of forces resulting from fluid movement.

hydrophyte: any plant that is readily observable without the aid of optical magnification and grows in water or on a substrate that is at least periodically deficient in oxygen as the result of excessive water content (Wetland Training Institute, 2002, pp. 102-103).

lagoon: a term applied indiscriminately to various types of water bodies and without qualification simply a term of art lacking scientific significance and commonly used euphemistically.

littoral zone: the area between the highest-high and lowest-low tide lines along a shore.

longshore drift: clastic masses transmitted along the littoral zone due to the kinetic energy of breaking waves.

open condition: see Section 1.4.2.6.

reach: a specific length of a stream

stream bedload: the mass of granular material along the bed of a stream.

wetland: see Section 1.4.2.8.

1.4.2 Technical Phrases

Public agency reports concerning the MCDA contains various words and phrases which can be confusing. By way of clarification, the following phrases, several of which are necessarily arbitrary, should help to avoid confusion.

1.4.2.1 Malibu Creek Floodplain

The Malibu Creek floodplain (MCF) extends from the creek mouth shore approximately 0.8 miles upstream to its apex at the Cross Creek Mariposa de Oro bridge. Its lateral boundaries are the contacts of floodplain deposits with adjacent older formations.

1.4.2.2 Malibu Creek Mouth

There is no accepted definition of a creek mouth. It is convenient for purposes of discussion to regard the area between the shore and the highway bridge as the mouth of Malibu Creek.

1.4.2.3 Malibu Creek Watershed

The Malibu Creek watershed (MCW) is the area tributary to the creek upstream from the point where it meets the MCF apex.

1.4.2.4 Malibu Lagoon

Malibu Lagoon generally is regarded as an area in the Malibu Creek floodplain in the vicinity of the creek mouth. It has never been geographically defined. Documents either by inference, or directly, offer at least three offhand descriptions: [i] the inundated mouth of Malibu Creek; [ii] the inundated mouth of Malibu Creek extending some unspecified distance upstream; [iii] a wetland, according to USEPA9 Staff (op. cit., Sec. 1.3.2, p. 1-4) of approximately 92 acres either adjacent to or including, a 2/3-mile stretch of creek corridor extending east (north, actually EDM) upstream and extending laterally through the Civic Center area to the Pepperdine property, and which - depending on how one defines lagoon may not exist in the Malibu Creek floodplain.

1.4.2.5 Closed Condition

Closed condition in the present context refers to the mouth of Malibu Creek blocked from flow to the ocean by a sand bar, hence the term barrier bar, generally during the period of April 15 - November 15. Being fed only by ground water and very limited surface flow during that period, inundation in the lowermost reach of the stream channel develops. The inundation level commonly rises to within a foot or so of the barrier bars surface and stabilizes there as the combined rates of ground-water and surface inflow are about equal to the rate of ground-water outflow through the bar. During that period, higher-high tides coincident with sufficiently high surf may result in ocean water overflowing the bar locally into the creek mouth. So far as is known, such inflow has never caused a bar breach.

It is a matter of some interest that on the one occasion of such ocean inflow observed, a school of fish, presumably trout, ranging some 8 - 12 inches in length and estimated to include between fifty and one hundred individuals, collected where the ocean-water inflow was occurring and displayed very active behavior.

Since floodplain ground water to the creek currently is substantially greater than it was prior to extensive development, the closed condition is properly regarded as artificially induced. It persists until on or shortly after November 15 at which time Tapia plant effluent is released into Malibu Creek.

1.4.2.6 Open Condition

Open condition in the present context refers to the Malibu Creek either flowing to the ocean through one or more channels or being capable of such flow if creek water is available for such flow. Upon release of Tapia-plant effluent to the creek, and depending on ground-water levels in the reach between the Tapia plant and the floodplain, within a few hours to perhaps a day, the inundation level rises to a point where overflow occurs, more or less as discussed in Section 2.4.1.2. From then until April 15 or shortly thereafter when Tapia effluent to the creek is curtailed, the open condition prevails.

The open condition is characterized by the exposure of the creek channel bottom locally between the barrier bar and the highway bridge. As commonly observed, the bottom appears as an irregular mudflat with areas of shallow standing water and one or two shallow channels through which flow is occurring to one or more intakes of bar-breaching channels.

Most notably during this period, the crest of the mudflat is a rookery for seagulls and certain other species, a circumstance common there even when the mud flat is a few inches under water. This has been observed for many years and certainly was a pre-historic condition. This situation apparently is due to the presence of benthos. Presumably the lack of such communities is the reason most species ignore the avian islands of the MLREP. Because of the effect of Tapia effluent discharge, the open condition also is properly regarded as artificial.

1.4.2.7 Restoration

With reference to any significantly developed area, restoration - meaning the recreation of a previous condition - is, for practical purposes, impossible. The issue never defined in in environmental discussions is: what previous condition? Nevertheless, the word commonly is when describing environmental projects. Any attempt to recreate an earlier biologic or hydrodynamic condition in an extensively developed area such as the MCDA is necessarily subjective, because the previous condition commonly is only imperfectly known if at all.

1.4.2.8 Wetland

There is no universally accepted definition of a "wetland." That of the Wetland Training Institute (1995, p. 111) should suffice for present purposes:

" Wetlands - Those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas."

As is apparent, the defining criterion is the presence of hydrophytes. Alternatively, the definition of wetland given in CWMW (2012, p. 16), upon which Abramson, et al. (2015, p. 4) rely is:

"Wetlands ..... must have one or more of the following three attributes: (1) at least periodically, the land supports predominantly hydrophytes; (2) the substrate is predominantly undrained hydric soil; (3) the substrate is not a soil and is saturated with water or covered by shallow water at some time during the growing season of the year."

Presumably, (3) assumes some sort of substrate providing, at least periodically, support for hydrophytes. Otherwise, the flooded low area of a paved parking lot, a horse trough, or a gutter would be a wetland.

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2.0 MALIBU CREEK PHYSIOGRAPHIC CHARACTER

Environmental protection concerns organisms the habitats of which are dependent upon physiography, i.e., generally, the physical character of the earth including its geology, topography, and its various dynamic physical processes. Whatever environmental characteristics are to be considered in terms of an areas suitability as a benthos habitat should be consistent with that of the local physiography. Of particular interest in this regard with reference to the MCDA is its geology, especially its geomorphic features, and certain of its hydrodynamic mechanisms.

2.1 PREHISTORIC DEVELOPMENT

The development of the MCDA began with what can be called the Santa Monica Mountains orogeny thought to have begun about a million years before the present (ybp) in mid-Pleistocene time. Then, a broad and more or less featureless plain of geomorphic old age sloped gently southward from an area at least as far north as the Simi Hills to a shore well seaward of that of today. The rate of rise has been so slow that ancestral Malibu Creek, a meandering stream then draining an area of the that mid-Pleistocene plain - conveniently described here as the Las Virgenes surface - was able to maintain its flow to the ocean. No other stream in southern California does this.

That the Las Virgenes surface was one of old age in geomorphic terms is proven by the meandering course of ancestral Malibu Creek. As uplift proceeds, ancestral Malibu Creek continues to incise its bed thus preserving the series of convoluted meanders through the Goat Buttes area. Whatever similar features may have existed downstream have long since been destroyed as the gorge of Malibu Canyon deepened.. However, at the southern base of the range, the channel along the northern, eastern, and southern sides of the Serra Retreat promontory also is an incised meander of ancestral Malibu Creek, except that whereas the Goat Butte meanders are still being incised by modern Malibu Creek, the Serra Retreat meander no longer is because its stream has been captured.

As shown in Figure 1, the Serra Retreat promontory throughout the latter half of the Pleistocene Epoch, as well as most of the Holocene Epoch was a meander spur. According Orme, et al. (2000, Ch. 2, Fig. 1-8; p. 1-16), sediments underlying the Malibu Creek floodplain are terrestrial deposits at least 30 feet thick and probably all deposited during the last 8,000 years. If so, as a matter of speculation, an embayment seaward of the Serra Retreat meander must have first received Pleistocene alluvial deposits that have been replaced or overlain by similar Holocene deposits. In any case, it seems obvious that then, as now, ancestral Malibu Creek just downstream of the meander had been aggrading for thousands of years.

Figure 1. Malibu Creek Floodplain.

The dashed arrow represents the general direction of earlier Holocene flow from the lowermost reach of the Serra Retreat meander. The solid arrow indicates the general direction of modern Malibu Creeks lowermost reach. The dotted lines are roughly the boundaries of creek distributaries initiated during later Holocene time. The meander neck was eliminated as the result of some event not yet understood presumably late in Holocene time. Map base: USGS Malibu Beach quadrangle, 1981 ed.

It is surmised that the Serra Retreat meander neck was in place until fairly late Holocene time, possibly within the last 1,000 - 2,000 years. Perhaps an excessive storm season occurred causing the creek to overflow the neck and thereafter entirely remove it during succeeding periods of erosion. Subsequently, the flow through the gap directly southward captured the meander flow. Thereafter, continued incision of the creek channel has reversed the original flow direction in the Serra Retreat meanders northern reach so it now is tributary to modern Malibu Creek.

Downstream of the destroyed neck, Malibu Creek has superposed its current distributary character over that of its earlier one. In the process, the floodplain Has widened somewhat farther east through the processes of lateral cutting and filling and accompanying braiding.

Since its inception, orogenic rise of the Santa Monica Mountains has prevailed over that of the sea-level rise, the latter commonly referred to as the Flandrian transgression, believed to have begun with advent of the Holocene interglacial epoch. Consequently, throughout the Holocene, the Malibu Creek floodplain has been aggrading and will continue to do so in the foreseeable future.

2.2 MALIBU CREEK UPPER WATERSHED AREA

The MCW is arbitrarily divided herein as an upper and a lower tributary area. The upper watershed area includes all that tributary to the confluence of Malibu Creek and Cold Creek a short distance upstream from where the creek enters the gorge commonly referred to as Malibu Canyon. It includes in part: [i] a steep incised area of the Santa Monica Mountains northern flank which is drained by several dendritic stream systems tributary to the reach of Malibu Creek in Triunfo Canyon; and [ii] the subdued southward-sloping Las Virgenes surface which is drained by a somewhat trellis-like system of six sub-parallel south-flowing streams 1 2 miles apart.

Streams in the mountain area are ephemeral, and their gradients range up to about 0.24. They are mostly engaged in incision and nowhere near grade. The streams of the Las Virgenes surface have gradients in the range of 0.02 0.04 and are near grade. The overall gradient of Malibu Creek in its upper tributary area is quite low, about 0.005, due partly to its circuitous reach through the Goat Buttes area.

2.3 MALIBU CREEK LOWER WATERSHED AREA

The MCW lower watershed area is that in which all streams are either directly or indirectly tributary to the reach between the confluence of Malibu Creek and Cold Creek and the MCF discussed in Sec. 1.4.2.1. An important characteristic of the lower tributary area is the Rindge dam located about midway downstream from the Cold Creek confluence. Reportedly constructed in 1929, it transformed the creek in that reach to two reaches with significantly different hydrodynamic characteristics. Within a period so far not determined, aggradation completely filled the channel upstream to the top of the dam. The volume of those deposits is estimated to be about 370,000 cubic yards.

Upstream of the dam for about 0.8 miles, the gradient is relatively low due to aggradation. Downstream, based on a more or less uniform channel width, there appears to be little if any aggradation in progress suggesting that reach may be near grade.

2.4 MALIBU CREEK FLOODPLAIN

Although the geologic character of the MCW is well understood, particularly through the work of Dibblee (1992; 1993), Dibblee and Ehernspeck (1993), Campbell, et al. (1996), and Yerkes and Campbell (1980), its floodplain has never been the subject of detailed geologic study. In lieu of a detailed geologic map of the Malibu Creek floodplain (MCF), Figure 2 has been prepared. It serves as a preliminary basis for clarifying the local geologic character as a means of correcting certain gross errors that have crept into the literature over the years. In the figure, only the better known areas of artificial fill have been mapped. Fill thicknesses probably do not exceed about ten feet.

Figure 2. Malibu Creek Floodplain Photogeologic Map.

af: graded artificial fill; Hnb: historic bar sands; Hns: historic braided stream channel; Pns: prehistoric aggraded stream channel deposits; Pnf: prehistoric floodplain alluvium; Pnb: prehistoric bar sands; mf: persistent mudflat . Photobase: Google Earth. This photo is post- 2012 during the open condition, and post-November 2103.

2.4.1 Shore Processes

The geomorphic character of the MCF shore is the result of two interacting hydrodynamic systems: [i] MCF aggradation which advances the littoral zone, and [ii] interacting wave attack and longshore drift. Together, these processes produce a sand bar across the mouth of the creek. When fully developed, it is referred to as the barrier-bar because it prevents creek flow from reaching the ocean.

2.4.1.1 Barrier-bar Destruction and Reconstruction

The mechanical manner in which the bar is constructed is not well understood, but it functions to produce from the longshore drift sand having a narrow range of grain size and composed almost exclusively of feldspar and quartz. Every 10 - 20 years or so, creek flooding removes much, if not all of the barrier bar east of the Malibu Colony. Immediately thereafter, reconstruction of the bar begins progressing from west to east. So far as observed, the bar is completely developed across the creek mouth within a month or so.

Since this mechanism is the result of a dominant northwest wave regime approaching an east-west shore, an easterly longshore drift prevails except for short periods during the summer when a south swell prevails. During especially high northwest swell, sands can be completely removed from beaches; however, during the summer when a south swell prevails, sands offshore are redeposited on the beaches.

2.4.1.2 Bar-breaching Mechanism

No authoritative record regarding breaching of the barrier bar has yet been found. It is understood, anecdotally, that prior to construction of the Tapia plant, in order to avoid stagnant conditions in the barred creek mouth during the summer, the bar was artificially breached to allow trout to reach the ocean, and the breaching done at the western side of the bar, farthest from the Malibu point right-slide surfing break so as to minimize surfers direct contact with the creek outflow waters. Currently, due to the release of Tapia effluent, breaching occurs automatically when the inundated level rises high enough.

As observed November 19, 2013, soon after breaching occurred, a channel about 25 feet wide had been eroded directly through the bar southward to the shoreline, and in a high rate of turbulent flow was occurring. That condition persisted until the inundated level was reduced roughly to about two feet or so below the average elevation of the bars surface. At that time, the rates of inflow primarily from the Tapia plant and breaching-channel outflow approached equilibrium. Figure 3 indicates the complicated interrelationship between geologic and hydrodynamic conditions of the creek mouth during this latter stage open condition.

Figure 3. Malibu Creek Mouth Composite Geologic/Hydrodynamic Conditions.

1: initial breach channel; 2: subsequent breaching channel; 3: tributary channel to either 3 or 4; 4: second breaching due to clogging of channel 1, later captured by channel 5; 5: final position of breaching channel; 6: mudflats exposed upon reduction of inundation level; 7: fine-grained longshore drift; 8: plunging syncline in stratified bedrock; 9: volcanic reef bottom outcrops. Photo base: Google

It is surmised that when the breaching channel outflow reaches a certain rate, the longshore drift mechanism becomes dominant over the power of the breaching channel outflow at the shore. During this process, the breaching channel adopts a generally southeasterly axis diagonally across the bar until, eventually, at the eastern edge of the bar it stabilizes against a rip-rap slope at the base of Vaquero Hill, the site of the Adamson House compound. The breaching channel thereafter maintains that configuration until creek flow terminates due to the end of the authorized Tapia-plant effluent dumping period.

The offshore queried area in Figure 3 appears to be the location of a geologic contact separating a sedimentary section from one of intrusive bedrock. The mudflat within the dotted area is a mudflat where sea gulls and other species are to be found throughout the year. The selective area of wave erosion along the Malibu Colony beach apparently is due to an offshore bottom condition which, depending on wave approach direction, focusses wave energy which interrupts, locally, the longshore drift.

2.4.1.3 Postulated Back-bar Channel Development

From Figure 4, the local stream regimen in most recent prehistoric time can be inferred. The pronounced curve of the creek convex to the west ran through what is now, approximately, the business district north of PCH at its intersection with Cross Creek Road, indicated as MV in the figure. Boundaries of three channels in or adjacent to the approximate location of what is now the MLREP facility also are shown.

Figure 4. Rindge Ranch Map Modified from Doyle and Rindge (2012, p. 61).

Although dated 1931, the base for this map probably was prepared within a few years after the Rindge family obtained title to the Rancho Malibu-Topanga Sequit in 1892. The encircled letters refer to improvements added throughout the 1892 1931 period. The general location of the MLREP facility is encircled. Modified from Doyle and Rindge (2012, p. 68).

All cultural features, indicated by the encircled labels A through F were added to the map after its initial preparation, as well as the pumping plant and tanks many years after 1892 when Frederick Hastings Rindge obtained title to the Topanga-Malibu Sequit It seems likely that the map base was prepared within the period of 1895 1897 and almost certainly prior to 1900.

The configurations of the creek and channels 1, 2, and 3 of Figure 4 numbered in accordance with time of formation, indicate that considerable care was taken in preparation of the map base. The configuration of at the western end of channel 3 suggests either local concentrations of sheet-flow runoff or, conceivably, a series of braided channels fed by an earlier position of the creek. In any case, it appears that terrestrial channel flows suggested by the letters c met the landward base of the existing barrier bar upon part of which the Malibu Colony development was later located. From there, backed-up flows in these channels reached confluence and the combined flow then moved eastward along the base of the bar eventually reaching the creek mouth. In that process, back-bar channel 3 was formed. Earlier similar events had formed channel 2, and channel 1.

Figure 5. Part of 1903 U.S. Geological Survey Calabasas Quadrangle.

This figure is taken from USETA9 Staff (op. cit., Fig. 6-7, p. 6-8). The Rindge railroad was constructed across the floodplain just north of the northernmost back-bar channel about three years later.

It is reasonable to postulate that this mechanism of back-bar channel development has been in progress for thousands of years possibly beginning almost as soon as creek flows from the Serra Retreat meander, Figure 1, began to develop the floodplain.

2.4.2 UCLA Floodplain Development Interpretation

A report by Ambrose and Orme (2000), commonly called the UCLA study has been the basis for much of the USETA9 staffs analysis of the physiographic development of the Malibu Creek floodplain. While excellent in certain in certain respects, the UCLA study suffers from a fundamental error that of interpreting the creek floodplain throughout its development as largely an area-wide lagoon as shown in Figure 6.

Figure 6. Postulated Lagoonal Conditions, UCLA Study.

From Orme, et al. (2000, Fig. 2-1a, b, p. 2-3).

Such a condition, both in geomorphic and hydrodynamic terms, is impossible to imagine, because it requires the presence of a single area-wide wetland as late as the 1800s to be subsequently buried almost everywhere with the existing substantial thicknesses of stream alluvium by the time the Rindges took possession a period of less than 100 years. Such a process certainly would require thousands of years to accomplish. To be fair, this error in interpretation has little to do with the overall purpose of the UCLA study which considers biological conditions. In fact, seemingly contrary to the idea of a single, area-wide lagoonal expanse over of most the floodplain, Orme (2000, p. 1-17) asserts, somewhat ambivalently, that:

Lower Malibu Creek and its environs have been the focus episodic wetlands throughout the Holocene

Furthermore, a fair reading of the analysis by Orme (op. cit., pp. 1-14 1-17; Fig. 1-8) is the basis for inferring that the Malibu Creek floodplain is advancing seaward sporadically. It is clear that this is due to local tectonic uplift and accompanying Malibu Creek floodplain aggradation during which a series of barrier bars were formed along the seaward advance of the shoreline.

Nevertheless, despite the area-wide lagoonal interpretation of Figure 6 which is clearly inconsistent with this process of episodic seaward aggradation, USEPA9 Staff (op. cit., Sec. 1.3.2, p. 1-4 ) state:

Malibu Lagoon is located in the City of Malibu, Los Angeles County at the mouth of Malibu Creek. The wetland acreage includes 2/3 mile of creek corridor east of the (north EDM) Pacific Coast Highway (PCH) and the wetland habitat acreage is approximately 92 acres. The historic wetland size has been documented and estimated to be several times its present size; the wetland had extended through the Civic Center area to the Pepperdine University property.

It seems clear that this description is based on the interpretation of the lagoonal development in the Malibu Creek floodplain as erroneously postulated in the UCLA study. Further, in failing to distinguish lagoonal acreage from wetland acreage it is unclear if USEPA9 staff regards the two, if not synonymous, at least having no significantly different biological character. This is especially a matter to consider in view of the fact that TMDLs apparently are to be applied to the recently completed Malibu Lagoon Restoration and Enhancement Facility (MLREP) as well as, presumably, elsewhere along the creeks lowermost reach.

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3.0 MALIBU LAGOON RESTORATION AND ENHANCEMENT PROJECT

All wetlands are not lagoons, and not all lagoons are wetlands. Nevertheless, without qualification, USETA9 Staff (op. cit., p. 1-5), in referring to the MLREP state:

Malibu Lagoon is a valuable coastal wetland. In summer 2012, the State of California, Santa Monica Bay Restoration Commission, and CDPR conducted an extensive restoration of Malibu Lagoon Tidal flow and improved water circulation are expected to restore critical habitat for Pacific Flyway migratory birds and threatened wildlife.

In considering the duty of the EPA to define, or have defined, water bodies worthy of protection under the Clean Water Act (CWA), and its authority to define TMDL standards for certain conditions perceived to significantly affect water quality, it is important to understand the character of the MLREP project as a basis for determining whether it is properly regarded as a CWA 303(d) water body.

3.1 MLREP DEVELOPMENT

LARWQCB Staff (op. cit., Table 2, p. 3), in referring to Malibu Lagoon as a feature in existence in 1998, could only have meant the mouth of Malibu Creek, i.e., the inundated lowermost reach of the creek to some point upstream. With completion of the MLREP project, it is clear that it is regarded as part of Malibu Lagoon, as discussed below (Sec. 3.5). Consequently, the proposed subject IP is to consider TMDL standards for the 2014 MLREP facility as well as that of the 1998 Malibu Lagoon. In an attempt to clarify the ETAs conception of lagoonal area(s) and wetland(s) in the Malibu Creek floodplain, it is necessary to consider to some extent the history of the local area.

3.1.1 Beginning Residential and Commercial Development

According to Rockhold (1916, Sh. A3), by about 1914, most of Channel 2 of Figure 4 remained; however, unless simply sketched in by Rockhold, its shape in plan had been significantly modified from that shown in Figure 5. At that time, the Rindge Hueneme Malibu and Southern Railway was still in place, and the land between it and Channel 2 of Figure 4 apparently was not in use either as agricultural or pasture land. By 1929, residential development of the Malibu Colony had progressed significantly, and the area had been entirely filled. That fill may have been materials excavated during construction of the first Pacific Coast Highway in the local area over the railway route west of the MCF. Further use of what is now the MLREP facility area as a disposal site may have occurred during the realignment of present Pacific Coast Highway begun about 1946. In any event, however, it appears that by 1949 all significant grading in the area that was to become the MLREP facility had been completed.

There then ensued a period from about 1950 - 1983 during which a pathway led through the project area to the beach, and for some period, part of the property was used as Little League baseball fields. At that time, the adjacent property to the west, where a private pitch-and-putt course now is located, was simply abandoned farmland.

3.1.2 CDPR Eco-channels

In the early 1980s, title to the 16-acre MLREP area passed from the Rindge family to the State to be administered by the California Department of Parks and Recreation (CDPR). In 1983, for reasons not entirely clear, a system of "eco-channels" was installed. These led to the southeastern corner of the site where it met the mouth of Malibu Creek close to where the western end of the barrier bar and the eastern end of the Malibu Colony meet. Those channels apparently were not based on any formal hydrodynamic design. By the late 1990s, they reportedly had deteriorated primarily as a result of invasive vegetation and sedimentation.

3.2 MLREP DESIGN AND CONSTRUCTION

It appears that research for the MLREP considered no historical data earlier than 1983 and probably was based essentially on conditions as reported in the UCLA study. Initially, presumably sponsored by the CDPR, exploratory planning meetings were undertaken with representatives of various public agencies, a technical advisory committee, a working group, and certain shareholders. So far as the record reflects, there was essential, if not perfect, agreement among all attendees with regard to what needed to be done, if not specifically how to do it. The manner in which such meetings were conducted, and what minutes or documents, if any, were prepared is uncertain.

Initially, however, it was decided to rehabilitate the eco-channels. It seems likely that the theory of a widespread lagoonal condition, as suggested in Figure 6, was the basis for assuming that rehabilitating the eco-channels would require simply clearing them of vegetation and widening and deepening them. Figure 7 may have been the basis for the initial proposal to rehabilitate the eco-channels. Probably, the rejection of the initial eco-channel restoration design in favor of the more straightforward dendritic MLREP design was based on the assumption that the latter would be more efficient with regard to tidal flushing and circulation. Apparently, in the further belief that upon equilibrium, the breaching channel inlet would be close to sea level, the MLREP channel was to be graded to that elevation.

Figure 7. UCLA Study Figure 9-4.

3.3 MLREP OPERATIONAL ISSUES

It is clear from LARWQCB Staff (op. cit., Sec. IV.C. p. 37) that the MLREP facility is regarded as an area where the subject proposed IP is to be applied. However, a review of the first MLREP performance monitoring report prepared for the Bay Foundation by Abramson, et al., (2015), calls into question whether the MLREP facility is an appropriate area for the EPA concern.

Upon completion of the MLREP facility in June 2013, two issues were immediately presented. One is whether the Bay Foundations application of the California Rapid Assessment Method (CRAM) for evaluating wetlands is appropriate. The other is whether the manner in which MLREP algae has occurred is significant.

3.3.1 Questionable CRAM Analysis

As a condition of Coastal Commission approval, periodic physical monitoring of the MLREP facility and application of the California Rapid Assessment Method (CRAM) was required. The fundamental purpose of CRAM analysis is to provide inventories of wetland species and wetland conditions in applicable "assessment areas" (AA). The AA is a wetland sufficiently isolated from its surroundings so as to be reasonably assured that any changes in its physical and biologic characteristics are natural, i.e., unaffected by artificial conditions. In CRAM analysis, various conditions are noted empirically and recorded in special forms to assure temporal and physical consistency. From such form entries, algorithms are used to convert observations to numerical scores by which trends in conditions can be quantified.

Aside from the question of whether the MLREP facility is a wetland, the ostensible CRAM as applied by Abramson, et al. (op. cit., pp. 4 - 7), shown in Figure 8, raises questions regarding both the physical character of the asserted AA and what are referred to as buffer zones.

Figure 8. MLREP Facility CRAM Assessment Area.

The blue area is a CRAM AA according to Abramson, et al. (ibid., Fig. 3, p. 6). The red arrow gives the position and view direction of Photos 1-6.

3.3.1.1 Inappropriate Assessment Area

In Figure 8, the area in blue, presumably defined by Bay Foundation personnel as an AA, includes sections of MLREP channels in which, during open conditions, extensive areas of channel bottoms are exposed. The orange buffer lines are drawn through areas presumed to be buffer zones. In the figure, the red arrow points south-southeast from MLREP facilitys western observation platform just north of the MLREP facilitys bird blind.

Photo 1. Headwater, Southernmost MLREP Facility Channel.

The raised area, left, is part of the MLREP facilitys westernmost avian island. View, ESE; photo: EDM, 01/20/16, 16:03 hrs.

3.3.1.2 Ineffective Buffer Zones

A buffer zone is an area abutting a wetland which, because of its physical character, protects it from external conditions that would interfere with the manner in which it functions naturally. Even if a CRAM-like assessment were applied to the blue area of Figure 8 as a means - other than with regard to hydrophyte development as a means to judge the MLREP facilitys environmental significance in terms of the subject proposed IP TMDLs, the results would be questionable because of the lack of effective buffer zones. Clearly, the arbitrary boundary along the eastern side of the blue area of Figure 8, where there is direct hydraulic continuity with adjacent channel sections, cannot function as a buffer zone.

Aside from this, possible point source of contamination represented by the culvert outlets shown in Photo 2, and the suggestion from Figure 8 that lands adjacent to the MLREP on its northern, western, and southern sides are adequate buffer zones overlooks the fact that ground-water gradients to the MLREP facility from both the north and the south carry in dissolved solid constituents from on-site water-water disposal systems, and similarly, from the pitch-and-putt course to the west, constituents derived from fertilizers all point sources of contamination of some sort.

Photo 2. Asserted CRAM AA, MLREP Facility Southernmost Channel.

Dashed line indicates the approximate boundary, south end of CRAM assessment area of Abramson, et al. (2016). Outlets of two culverts encircled. View east; Photo: EDM, 1/17/17, 13:02 hrs.

Consequently, varying ranges of nutrients and various chemical constituents entering the MLREP facility waters certainly should call into question the significance of the Bay Foundations so-called CRAM scores as reported by Abramson, et al. (op. cit.) and hence their relation to the determination of nutrient TDMLS for the MLREP facility.

3.4 ALGAE OCCURRENCE ISSUE

Unaccountably, Abramson, et al., (op. cit., p. 60) in reporting that:

post-restoration cover data were dominated by wrack, or floating/detached marine kelp species, and after two years, still remained below a 10% total cover range and well within the success criteria recommendations ,

do not mention the astonishingly extensive algal blooms that developed throughout the MLREP facility immediately after its completion. As observed from the west observation platform of the MLREP facility, Photos 3 5 illustrate that condition. The coverage, or "wrack," of those mats was then near 100 percent in some of the channels, and overall, throughout the MLREP facility, such coverage was roughly 60 - 80 percent at times during the summer seasons of 2013 and 2014. However, beginning quite abruptly about the middle of September 2014, as shown in Photos 6a and 6b, the blooms disappeared have not occurred since. The unanswered question is: Why?

One way to prevent algal blooms is to add an algaecide such as copper sulfate. Whether the MLREP facility waters have been treated in some such manner is uncertain, but no other explanation of the current absence of such blooms presents itself at this time. If, indeed, an algaecide is in use, its effect on benthic individuals certainly should be considered. Until it is determined whether the MLREP facility waters are being treated, and if so, the effect on is benthos, it seems premature to assign it any TMDL standard.

Photo 3. Southern Part, MLREP Facility CRAM AA.

This view is taken from roughly from position as that of Photo 2. View, ESE; photo: EDM, 08/06/13, 15:24 hrs.

Photo 4. Algal Mat, MLREP Southern Channel

This view is taken from roughly from the same position as that of Photo 3. View, ESE; photo: EDM, 09/17/13, 11:23 hrs.

Photo 5. Algal Mat, MLREP Southern Channel

This view is taken from roughly from position as that of Photo 3. View, ESE; photo: EDM, 08/14/14, 11:22 hrs.

	a	b

Photos 6ab. Foregrounds, Southern Area of MLREP CRAM AA.

Photo 6a, left. MLREP west observation platform, View E, photo: EDM 09/29/15, 13:26 hrs. Photo 6b, right. MLREP south channel headwaters. View E.; photo: EDM, 09/29/15, 13:27 hrs.

3.5 TMDL APPLICABILITY ISSUE

According to LARWCB Staff, (op. cit., Sec. IV.C. 6), there is a need for TMDL standards for the "Malibu Lagoon Restoration," by which may be meant either the MLREP facility, or the creek mouth, or both. Staff has assumed, in referring to the earlier eco-channels, that the MLREP (op. cit., p. 37) has:

"... re-contoured the western channels to improve water flows and circulation ... (and) ... creating several acres of new wetland."

Clearly, the extent to which TMDLs for nutrients and hence sedimentation should be deemed appropriate rests upon whether this characterization of the MLREP facility is accurate. In fact, it is not.

3.5.1 Absence of Wetlands

Utilizing CWMW, 2012, Abramson, et al. (2015) present the Bay Foundations interpretation of the MLREP AA shown in Figure 8. As shown in Photo 1, it includes a section of MLREP facility channel that is exposed during the open condition. From this evidence alone, according to accepted wetland definitions (Sec. 1.4.2.8), the area to which CRAM analysis has been applied cannot be a wetland, and hence not an AA, because it is devoid of hydrophytes. Photo 1 shows a typical MLREP facility channel bottom condition.

Lacking a definition of "wetlands" in any of the works associated with the design of the MLREP facility, or in the recently completed monitoring report by Abramson, et al. (op. cit.), reference here is to that of the Wetlands Training Institute (1995) as quoted above (Sec. 1.4.2.8). Accordingly, no wetlands have been created by construction of the MLREP facility. This assertion is based on numerous observations during open conditions which invariably show exposed channel bottoms essentially devoid of hydrophytes or any other type of vegetation. This condition has persisted since its completion. Therefore, because the sine qua non of a wetlands is:

"... a prevalence of vegetation typically adapted for life in saturated soil conditions..." (Sec. 1.4.2.8, above),

the lack thereof anywhere in the MLREP facility demonstrates, unequivocally, that it is not a wetland.

Unless for some unspecified reason Abramson, et al. (op. cit.) can show that areas that do not support hydrophytes should nevertheless be considered wetlands, it is difficult to understand how the MLREP facility can considered be a water body suitable for TMDL assignment and hence a subject for the proposed IP.

Since the Bay Foundations asserted CRAM AA lacks hydrophytes and hence, by definition, wetland status, the significance of whatever benthic organisms may reside there is questionable. MLREP facility channel bottom are simply mudflats constructed artificially.

3.5.2 Lack of MLREP Circulation

From the beginning of MLREP planning, a major selling point, so to speak, was that better circulation was necessary to restore the original health of the project area "wetland." Nevertheless, aside from the fact that the project area, per se, was never a wetland, water in the MLREP facility channels, like that in the eco-channels they have replaced, does not circulate.

During the closed condition, the static level in the MLREP channels is the same as that in the impounded creek mouth, and there is no flow because the hydraulic gradient is effectively zero. On the other hand, during the open condition when, several weeks after the breaching channel flow is essentially at grade with flow probably in the range of 30 - 60 gallons per minute, floating objects in the MLREP facility interior remain stationary indicating the absence of current flow except in the immediate vicinity of its boundary with the creek mouth close to the intake of the barrier-bar breaching channel.

It is apparent that drainage from the MLREP facility during the open condition is much like that of tank drainage essentially like that of a bath tub in which the surface simply lowers without lateral translational movement as the volume decreases. In other words, during drainage to reach and maintain open condition equilibrium flow, there is no current flow and hence no circulation over almost the entire expanse of the MLREP facility, because, as with the closed condition, there is no effective hydraulic gradient.

In such circumstances, there arises the question of whether assigning TMDLs is appropriate to an area such as the MLREP facility the hydrodynamic character of which is yet to be understood. Salinity measurement such as those of those of the initial series reported by Abramson, et al. (2015, pp. 24-25) for eight MLREP facility stations, during the period of February 14, 2013 - December, 23, 2014, if made frequently, might be quite useful in this regard.

3.5.3 Black Goo

Almost everywhere in the interior area of the MLREP facility, channel bottoms appear to be covered with a somewhat cohesive and gelatinous organic substance conveniently described here as black goo. It occurs as a distinct stratum overlying saturated inorganic deposits such as clayey silt with which it remains immiscible unless disturbed. Its thickness is about 0.5 1.0 inches close to shores but perhaps more elsewhere. Laboratory specimens have a slight hydrogen sulfide odor. When thoroughly mixed manually and allowed to stand, it does not separate; however, as shown in Photo 7, with slight mixing the separate masses remain immiscible.

The extent of the black goo, as judge by its occurrence in exposed channel bottoms, probably is present everywhere in the MLREP facility channels. This is consistent with the supposition that it is the settled residuum of algae that has been treated with an algaecide. An algaecide such as copper sulfate might explain the goos hydrogen sulfide odor. As a matter of speculation, the goo may the result of the type of enzymatic bacterial organic decomposition believed to be an early-stage reaction forming bitumen.

Most relevant for present purposes is the question of whether the goo is either toxic or otherwise harmful to benthic organisms. Whether or not such, however, its possible effect simply as a physical barrier to overlying waters such that benthic organism exhaust dissolved oxygen seems worthy of investigation. The results of such investigation certainly should precede a determination of whether the MLREP facility is an appropriate ETA water body.

Photo 7. MLREP Black Goo and Clayey Silt.

Sample collected close to shore just west of the south observation point.

* * *

4.0 SEDIMENTATION

Sedimentation as a basis for assigning TMDLs in the MCDA is especially troublesome. The extent to which the biological importance of sedimentation is here left to others. Rather, concern for present purposes is with regard to the physical character of the sedimentation process. A fair reading of USEPA9 Staff (op. cit.) especially Sections 8.1.5, 9.2.1, and 9.23, together with Tables 8-3, 8-4, 8.14, and 8.15, indicates that there is, essentially, a presumption of benthos harm due to sedimentation based on the on a statistically questionable period of 2000 2011 during the latter half of which there was severe drought. However, the treatment of the subject in mechanical terms also raises issues of sedimentation as a significant benthos stressor in the MCDA.

4.1 MCW SEDIMENTATION

The dynamic character of the various MCW streams should be the primary criterion for determining whether sedimentation TDMLs are necessary or, in fact, even possible, let alone feasible. Although many streams in California have similar characteristics permitting reasonable inference concerning similar conditions in different streams that nevertheless affect their benthos communities and their habitats similarly, such is almost certainly not a true of MCDA because of its unique dynamic character. For further consideration in this particular regard, refer to Section 5.2.1, but for now, however, attention is directed to sedimentation with respect to MCW hydrodynamic conditions.

4.1.1 Questionable Presumption of Benthos Habitat Harm

Assumption that sedimentation is an MCW stressor requiring a TMDL standard appears to stem primarily from a series of observations reported by Sikitch, et al. (2013). The organization and illustrations of that report, available on the web, is admirable; however, to consider its significance fully, its appendices, which are not available on the web need to be considered. Contact with Heal the Bay on March 10, 2017 for directions on how to obtain the appendices has so far been unavailing.

However, without regard for statistical aspects of benthos observations, the significance of the bioscores for the California Stream Index and Ratio of Observed and Expected Taxa data reported by USETA9 Staff (2013, Table 8-14), mostly reported by Heal the Bay for some eighteen sites, is suggestive. For the period of 2000 2010, reported bioscore reductions begin in either 2005 or 2006 and continue through that period. The fact that such reductions coincide with the advent of the recent severe drought strongly suggests a relationship between benthos survival and stream surface flow, or ground-water flow, or both.

Nevertheless, USETA9 Staff (op. cit., pp. 10-3 10-8), in support of the asserted need to assign sedimentation TMDLs for the MCDA, state (op. cit., Sec. 10.2):

the excess movement and deposition of sediment is a critical problem in Malibu Creek, its tributaries, and the Lagoon

Similarly, (op. cit., p. 9-31):

(T)he strength of evidence supporting the causal pathway between urban runoff and increased sedimentation is strong ,

Nevertheless, no specific data are offered demonstrating exactly how sedimentation in the MCDA is harming benthos even generally, let alone strongly or critically, or in what specific areas such problems exist. Rather, this seems to be based simply on the idea that sedimentation equals benthos harm, i.e., subjective evaluation rather than documentation.

4.1.2 Questionable Inferred Surface Runoff

In support of the thesis that increased sedimentation in the MCW is due to increased development, USETA9 Staff (op. cit., p. 9-30) state:

Using the Simple method rule (Caraco et al., 1998) the impervious land generates surface runoff relative to pervious land in a ratio 0.95/0.05, impervious surfaces were estimated to yield about 59 percent of the surface runoff in the watershed.

Caraco, et al. (op. cit.) give no such ratio; rather they refer to an give an appendix purporting to apply the Simple Method of Schueler (1987). However, using the impervious area fraction of 0.0695 (USETA9 Staff, ibid.), and a mean annual rainfall of 12 inches, gives an annual runoff of 1.2 inches, whatever that means. To verify the applicability of the 0.95/0.05 rule to the MCW, the calculations of the USETA9 Staff need review.

In any event, brief perusal of the Schuler method as assertedly employed by Caraco, et al. (op. cit.) shows the that the 0.95/0.05 rule has been applied to five local and largely developed test areas of the Atlantic seaboard and immediately adjacent lands having no climatic, geologic, or topographic conditions remotely similar to the MCW. It therefore is difficult to imagine how USETA9 Staff could reasonably regard the 0.95/0.05 as applicable.

4.1.3 Observations of ETA Regional 9 Staff and Staff Scientist Harrington

According to USETA9 Staff (op. cit., Sec. 2.2.1, p. 2-6) Staff Scientist James M. Harrington of the California Department of Fish and Game has stated that in his opinion several major tributaries in the Malibu Creek Watershed show typical signs of ecological impairment due primarily sediment. However, since it also is recognized (op. cit., p. 2-7) that:

(T)here are many other potential causes of the poor IBI scores (including excess nutrients, metals, organics, and exotic species,

the basis for focusing on sedimentation as a causal stressor is not apparent.

Further, in considering the dynamic conditions regarding sedimentation in that:

(M)ost of the sediment mass moving through Malibu Creek leads to filling of natural pools and clogging of substrate, and then moves as bedload during major storm events

(op. cit., p. 10-3), and accepting such observations as accurate locally, it nevertheless, is hardly probative of whether they have any significance, per se, regarding significant benthos harm, if any. For such remarks to be taken as significant with regard to the need for sedimentation TMDLs, the supporting data that were reviewed must be specific in terms of locations and periods observations if they are to be accorded scientific validity. In view of such generalities, is difficult to see any basis whatsoever for concluding, without more, that TMDLs, let along related IPs, in the MCW would be meaningful.

More to the point, flooding great enough to result in channel scouring occurs fairly often in the MCW, say every 10-20 years. Even assuming that sedimentation during the above specified 5-year period is representative the entire MCDA, it cannot have any statistical significance regarding the manner in which sedimentation is expected to occur in the future. Such data have no predictive value whatsoever and clearly cannot be a rational basis for an implementation plan to protect benthos habitats.

Again lacking sufficient observations to determine a representative statistical sedimentation rate for each MCW stream of concern, the fact that it is observed that certain natural pools become filled, and certain substrates become clogged before being scoured away is hardly significant in relation to a TDMLs for other such systems. Nevertheless, it appears that serious consideration is being given to protecting such pools and substrates from excessive sedimentation, all assuming that such features house benthos needing protection.

4.1.4 Comparative Observations Asserting Sediment Accumulation 1983 - 1987

Accepting as accurate the report that for the MCDA:

(M)easurements of sediment in 1987 suggested that the average rate of sedimentation since 1983 was 10 cm/year (and) estimated to be nearly ten times the rate that would have occurred in pre-European settlement periods (op. cit., Sec. 8.2.3, p. 8-60),

it is unclear how such a comparison is relevant to any need for sedimentation TMDLs, in the MCW or anywhere else for that matter.

4.1.5 Postulated Effective Work Model of Bedload Movement

The concern and hence the need for TMDL standards for pools and substrates, or at least some of them, in some MCW streams, that are being moved by creek flow during a major storm appears to be predicated on the idea that the habitats are somehow transported en masse from one position in a stream reach to another downstream. USETA9 Staff (op. cit., Sec. 10.2.1, p. 10-2), although lacking MCW historical data or data from comparable watershed, nevertheless state:

a reasonable sedimentation rate to protect the health of the Malibu Creek Watershed is determined by evaluating the natural capacity of flow to move sediment the Malibu Creek watershed.

The thought here seems to be that: [i] since excessive sedimentation can adversely affect watershed benthic habitats, and [ii] the natural capacity of a watershed to move its sediment is diminished by excessive sedimentation, therefore, [iii] evaluating that capacity is a measure of watershed health. Without qualification, however, the quoted statement is pointless - nothing more than a truism. Nevertheless, this kind of thinking is offered as the basis for assigning TMDL standards for various streams in the MCW.

Aside from the fact that thus far data are lacking indicating actual MCW habitat harm in any measured degree over a significant period is related to a demonstrated rate of sedimentation for that period are lacking, the natural capacity of flow to move sediment in the Malibu Creek watershed needs discussion. Such a statement seems to assume that for the MCW, habitat harm is a meaningful function of the capacity of the MCW relationship to move sediment.

The idea that sedimentation is a critical problem for benthos habitats in MCW tributaries, as presented by USETA9 Staff appears to be essentially subjective. simply subjective. Nevertheless, in an effort to show how anthropogenic activities exert change in the natural capacity of a stream to move sediment, and hence is significant for MCW benthos communities, USETA9 Staff (op. cit., Sec. 10.2.1, p. 10-3) direct attention to a 1948 paper by Meyer-Peter and Muller - and a modification of it in a 2006 paper by Wong and Parker - that purport to describe an effective work model of bedload mass transport downstream. Presumably the thought is that such a mechanism would be affected by sedimentation, and hence in turn affect, somehow, the health of whatever benthic communities are housed therein, and thereby USETA9 Staff implies, reasonably enough, that the MCW benthos health would be adversely affected. Regardless of the fact that:

(S)ufficient information was not available to complete such an analysis for Malibu Creek watershed , (ibid.)

the question to be addressed here is whether - under any circumstances - an effective work model is relevant to the health of the MCW as is unequivocally asserted, to wit:

the health of the Malibu Creek Watershed is determined by evaluating the natural capacity of flow to move sediment in the Malibu Creek Watershed (op. cit., p. 10-2).

However, no scientific whatsoever is presented to support this statement.

On its face, the idea that effective work applies to stream bedload movement is questionable, because - aside from coherent cobbles and boulders - it requires that a force due to flowing water can be applied, bodily, against a discrete bedload mass. It seems clear that what is postulated is a block of bedload material capable of moving as a unit due to the driving force derived from stream velocity and channel slope together acting in such a manner that it overcomes the resisting critical shear stress (op. cit., Sec. 10.2.1, p. 10-2), i.e., the strength resisting sliding, that must exist between a postulated block and the underlying channel bedrock. Such strength, of course, would be a function of the buoyant weight of the block and the coefficient of friction between the base of the block and the channel bedrock.

Such a model is not even approximately representative of natural stream conditions. A sediment mass in a channel does not present surfaces upon which the water can push no matter how great the flow velocity. Such masses do not move as discrete, coherent blocks but rather as incoherent granular masses with no cohesive strength and very low internal and basal surface shear strength. If fact, it is well established that typical stream bed load masses move more or less according to the Hjuldstrm model.

4.1.6 Hjulstrm Stream-flow Model

Generally, it is well understood that during stream flow of a sufficient velocity rate, grains are entrained or floating in the flow. Similarly, larger grains of a certain size and shape bounce along the bottom in the process referred to as saltation, and still larger grains too heavy to float or be bounced, are being pushed downstream along the surface of either the bed materials or the channel bottom, in the process referred to as traction. Given the seasonal and artificial changes in the flow rate known to occur in the MCW, as well as the range of artificially induced gradients in the various stream reaches, the idea that, somehow, there exists an environmentally meaningful stream capacity for moving bedload downstream, except in the most general, cumulative sense, is not only questionable, but probably impossible as a practical matter to demonstrate. Nor does such a datum seem relevant in terms of benthic habitats considering the fact that periodic flooding strips some stream reaches of all bed load masses and radically disturbs others to such an extent as to destroy all benthic habitats and probably the organisms therein.

Figure 9 is one version of the Hjulstrm stream transport model relating grain size and movement to stream velocity. Even though unrelated to grain mass and shape, the model effectively describes the manner in which a stream functions for a wide range of conditions with regard to its load. There is no reason to believe that this model is inapplicable to the flow regimen of the MCW.

Figure 9. Modified Hjulstrm Diagram.

The Hjulstrm diagram also is useful to explain the cut-and-fill mechanism resulting in the braided stream phenomenon common in such areas as the MCF. With reduction in velocity, saltation is lessened and entrainment of grains of sizes below the fall velocity curve are deposited. The more sudden the reduction in velocity - which can occur almost instantaneously - the greater the mass that is deposited. It is this phenomenon that results in sudden channel clogging followed necessarily by lateral rerouting of the channel during subsequent flows to create the braided streamflow pattern.

4.2 MLREP FACILITY SEDIMENTATION

Given the essentially artificial character of the MLREP facility, its environmental value seems seriously in question physically if not legislatively. As a recreational asset, it certainly has value, but to establish for it some TMDL sedimentation standard - thought to encourage whatever benthic community it may support - seems difficult to justify. At least until the effect of the black goo on benthic organisms is determined, the value of maintaining a certain sedimentation TMDL standard certainly is questionable.

Considering the low surface gradients of areas adjacent to the MLREP, sedimentation rates must be so low that from the recreational point of view, the value of the MLREP facility as an avian refuge requiring little or no maintenance and certainly no sedimentation TMDL standard, or simply as an aesthetic resource, can be maintained by occasional dredging.

* * *

5.0 CONCLUSIONS

It appears that any reduction in an MCDA benthos community is arbitrarily regarded as due to artificial rather than natural stressors, and therefore bad. This the-more-the-merrier approach not only to benthos, but to organisms generally, seems to characterize this aspect of the environmental movement. In effect, it amounts to philosophical rejection of natural selection and predation as environmentally significant coupled with a sort of conceptual nirvana however unrealistic or impossible a restoration to some condition never observed nor actually demonstrated to have existed.

The USETA9 Staff report (op. cit.), despite its valuable format presenting much useful data, is nevertheless to a significant extent erroneous in terms of its physical conception of the MCDA. Until that is better understood, assigning TMDL standards for nutrients and sedimentation is premature, probably meaningless, and certainly wasteful.

5.1 MCDA UNIQUE ENVIRONMENTAL CHARACTER

The MCDA is an absolutely unique hydrodynamic and geomorphic feature in California; as such, TMDLs for it cannot be based reliably on analogy to other drainage areas except possibly as applied to certain very limited processes. Other streams and water bodies along the California coast are due to conditions sufficiently dissimilar to those of the MCDA that to simply assume their benthic community characteristics are comparable is scientifically inappropriate.

For example, in discussion regarding benthos in Malibu Lagoon to be expected in the future USETA9 Staff state (op. cit., Sec. 3.2, p. 3-3):

based on our review of other coastal estuaries, we should expect to see a doubling of the species and taxa richness within a ten year time frame. Our best example and most comparable coastal estuary in size and physical behavior is Los Peasquitos Lagoon

which is clearly inadvisable. Los Peasquitos Lagoon, at the northern side of Torrey Pines State Park in San Diego County, is in the seaward most reach of the Los Peasquitos Creek floodplain. The floodplain is roughly rectangular with an area of about 250 acres, and it exhibits a dendritic drainage pattern. Upstream from its floodplain, locally meandering Los Peasquitos Creek and its upstream extension, Poway Creek, reach northeastward some 15 miles through lowlands, about 80 percent of which is residentially densely developed to its entirely artificially modified headwater area in Poway Mesa.

In contrast, the lowermost 0.8-mile reach of Malibu Creek - and whatever part of that reach, if any, that may be legitimately regarded as lagoonal - is a floodplain of about 50 acres with a distributary drainage pattern. Upstream, the creek passes through about 4 miles of essentially undeveloped mountainous terrain and beyond, about 7 miles of partly mountainous and partly mature topography, only locally developed. Consequently, it is difficult to see how conditions in the two areas are so similar as to be a basis for predicting future benthos conditions in one in any way relevant to those in the other.

All in all, the work concerning the MCDA to date demonstrates the need for a lengthy period of study certainly a period of years - during which the climatic record is reasonably representative of decadal or duodecadal change necessary to determine whether there is significant benthic impairment.

5.2 QUESTIONABLE RELEVANCE OF SEDIMENTATION TMDLS

As presented by USEPA9 Staff, concern about MCDA sedimentation is especially worrisome. It seems to be essentially a solution in search of a problem. There is merely a presumption of habitat harm resulting from sedimentation based on what amounts to preliminary observations rather than firm scientific analysis. Insofar as the record reviewed indicates, neither the necessity, nor the feasibility, of a meaningful TMDL standard for MCW sedimentation has yet been demonstrated. In waters either isolated or otherwise protected from hydrodynamic effects of normal stream flow, sedimentation from point sources probably could usefully be controlled, but it is obvious that the dynamic character of the various MCW streams should be the primary criterion in determining whether sedimentation TDMLs are feasible.

The idea that there exists one or more reaches of Malibu Creek or one of its tributaries where sedimentation conditions are so meaningful as to require a TMDL standard to avoid impairment of benthic communities should be preceded by a survey of such communities during periods the include including flooding and a reasonable range of climatic conditions. The effective-work model of bedload movement, at least as presented thus far, is mechanically impossible. Without more, the extent to which it is inconsistent with the straightforward and readily observable Hjulstrm model, it should be discarded.

5.3 MLREP QUESTIONABLE ENVIRONMENTAL SIGNIFICANCE

It is to be understood that the MCF - particularly with regard to its so-called lagoonal character, generally, and that of the MLREP in particular as discussed in USETA9 Staff (Sec, 1.3.2) is to great extent erroneous. This is primarily because it is based on the UCLA study which postulates a floodplain-wide wetland and/or lagoonal condition, as illustrated in Figure 6, a condition that never existed. Before TMDL standards are applied to the MLREP, the following should be considered regarding whether it is a water body eligible for CWA 303(d) protection.

5.3.1 Fundamental Issue of Environmental Planning

The extent to which the MLREP illustrates a problem in environmental planning is best demonstrated by fact that - beyond sponsoring agencies support - the MLREP facility according to RWQCB Staff (2016, pp. 37-38) it based on the combined efforts of:

Heal the Bay, and California State Department of Parks and Recreation, the Malibu Lagoon Technical Advisory Committee, the Malibu Lagoon Restoration Working Group, as well as numerous other city, county, and state agencies

and as a result, it is asserted that the completed project is a restoration that has:

re-contoured the western channels to improve water flows and circulation creating several areas of new wetlandswhich should help improve the Lagoon conditions for the benthic community. (ibid.)

The extent to which this description of the completed MLREP project is fallacious is of immediate interest.

5.3.2 MLREP Design Defects

Although the open dendritic design of the MLREP facility is a great improvement over that of the 1980s eco-channels, at least in terms of recreational value and apparently conditions for some avian species, it does not perform as advertised, and is in no sense some sort of restoration. The MLREP is based entirely on an erroneous conception of the MCFs hydrodynamic character, and it therefore cannot respond in the manner planned. The question of how such an impressive collection of planning talent could have produced the hydrologically dysfunctional MLREP suggests its greatest value is that of an object lesson in how environmental planning can go awry in the presence of unfettered political correctness.

5.3.2.1 Wetlands Fallacy

The idea that the MLREP area is a restored wetland and should be treated as such is nonsense. It is an entirely artificial facility. However, aside its recreational value, it does seem to serve to some extent as an avian refuge, and it might very well serve as an outdoor laboratory for the study of benthic communities under stress. Since, according to accepted definitions, neither the MLREP facility per se, nor any part of it is a wetland, attempts to apply CRAM analysis to it are meaningless. It is simply a system of artificial of channels which during the closed condition are inundated and during the open condition have partially exposed bottoms best described as mudflats.

5.3.2.2 Lack of Circulation

Waters in the channels of the MLREP facility do not circulate in the accepted sense of the term, i.e., by circuitous flow; rather, they drain and receive waters in a manner involving some sort of mass transfer and replacement that is not understood. Flow in the MLREP only occurs locally at the eastern edge of the project when the barrier bar is breached. Although a change in volume occurs as a result of the change from the closed to the open condition and presumably vice versa flows in the interior of the project do not occur. The lack of circulation represents a condition so unrelated to the natural environment that the character of whatever benthic communities exist there is probably environmentally meaningless.

5.3.2.3 Black Goo

The black goo in the MLREP facility channel bottoms appears to be an unnatural substance the origin and chemical character of which needs to be determined as a first step in assessing the facilitys character as CWA 303(d) water body. In particular, its relationship to the occurrence of algae needs to be determined. Because of the extent and either its physical or chemical effect, the goo present a condition possibly so unnatural that the character the local benthos, however interesting, would seem to be environmentally irrelevant.

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References

Abramson Mark, Karina Johnston, Ivan Medel, Rosi Dagit, Dan Cooper, and Rod Abbott, 2015, Malibu Lagoon Restoration and Enhancement Project Comprehensive Monitoring Report (Year 2): The Bay Foundation rpt. for CA Dept. Parks and Recreation, June 9.

Ambrose, Richard F., and Antony R. Orme, 2000, Lower Malibu Creek and Lagoon Resource Enhancement and Management, Univ. California, Los Angeles final rpt. for California State Coastal Conservancy, May.

Ambrose, Richard F., and Johnathan Lilien, 2000, Ch. 8, Management Alternatives in Ambrose and Orme (2000).

Campbell, Russell, B.A. Blackerby, R.F. Yerkes, J.E. Schoellhamer , P.W. Birkeland, and C.M. Wentworth, 1996, Geologic map of the Point Dume quadrangle, Los Angeles County, California: U.S. Geol. Survey Map GQ-1747.

Caraco, D.J., J. Zielinski, and R. Clayton, 1998, nutrient loading from conventional and innovative development: Chesapeake Research consortium, Center for Watershed Protection, Ellicott City, MD.

CWMW, 2012, California Wetlands Monitoring Workgroup Users Manual, Ver. 6.0, Mar. 94 pp.

Dibblee, Thomas W., Jr., 1992, Geologic map of the Calabasas quadrangle, Los Angeles and Ventura Counties, California: Dibblee Geological Foundation Map #DF-37.

Dibblee, Thomas W., Jr., 1993, Geologic Map of the Malibu Beach Quadrangle, Los Angeles County, California: Dibblee Geological Foundation Map #DF-47.

Dibblee, Thomas W., Jr., and Helmut E. Ehrenspeck, 1993, Geologic Map of the Thousand Oaks Quadrangle, Ventura and Los Angeles Counties, California: Dibblee Geological Foundation Map #DF-49.

Doyle, Thomas W., and Ronald L. Rindge, 2012, Malibu Rails and Roads a Photographic Journey across Rancho Topanga-Malibu-Sequit: Malibu Lagoon Museum, Malibu, CA 100 pp.

LARWQCB Staff, 2016, Implementation plan for Malibu Creek watershed nutrients TMDL (2003) and the Malibu Creek and Lagoon sedimentation and nutrients TMDL to address benthic community impairments: Los Angeles Regional Water Quality Control Board Final Report, December.

Orme, Antony, 2000, Ch. 1, Evolution and historic development in Ambrose and Orme (2000, pp. 1-1 1-37).

Orme, Antony, Kenneth Schwartz, Priya Fennemore, Mark Khulman, and Johannes Feddemma, 2000, Ch. 2, Hydrologic and morphodynamics,1997-98 in Ambrose and Orme (2000, pp. 2-1 - 2-112).

Rockhold, J.E., 1916, Map showing land to be condemned for the opening of the new Malibu Road, Pacific through Coast Hy., Rancho Topanga Malibu Sequit: County Surveyors Map No. 8970, Sh. A3.

Sikich, Sara, Katherine Pease, Sarah Diringer, Mark Abramson, Mark Gold, and Shelley Luce, 2013, Malibu Creek Watershed - Ecosystem on the Brink: Heal the Bay Santa Monica, CA,

USEPA Staff, 2013, Malibu Creek & Lagoon TMDL for sedimentation and nutrients to address benthic community impairments: U.S. Environmental Protection Agency, Region IX, Water Div. rpt., July 2.

Wetlands Training Institute, Inc., 1995, Field Guide for Wetlands Delineation; 1987 Corps of Engineers Manual, Glenwood, NM, WTI20-1, 143 pp.

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

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