by Paul R. Spitzzeri
As we continue this series of posts on a crucial early Los Angeles County flood control planning document, it was intended to combine the report by Henry Hawgood on the San Gabriel district with Charles T. Leeds’ investigation into the Coastal Plain section, but there was just too much good material, so here we are treating the latter in its own part.
Leeds became the Los Angeles District engineer for the federal Army Corps of Engineers in 1909. The district (the baseyard of which is at the former Temple School, established by the Temple family and other residents of the Old Mission community near today’s Whittier Narrows Dam) was formed in 1898 after Congress passed legislation for the massive expansion of the port of Los Angeles (San Pedro/Wilmington), followed by development by Long Beach of its own harbor, and so it was obvious that his principal concern would be the protection of the harbor given the tremendous damage from flood-carried silt wrought by the winter 1914 floods that led to the formation of the county Board of Engineers on flood control.
The engineer, asigned to deal with an area south of Ballona Creek, the larger part of the City of Los Angeles, and the Whittier Narrows area noted that “extension of city areas and increasing soil cultivation will cause moderate floods of the past to become serious floods of the future.” He added that, while forest protection, the building of above and below ground reservoirs, levees and dams in the mountains were all very important, “no method is sufficient without channel control in the Coastal Plain.”
This included the use of rip-rap on channel banks for areas with high flow and articulated concrete pavement could also be used in some cases. For lesser flow courses, having 4-foot deepp channels of varying widths and 100-foot wide berms between the main channel and levees were advisable, with cane (bamboo) and willows planted alone levees, as well. It was stated that “history shows that leveeing the channels will not increase the present rate of rise of the river beds.”
As for his main charge, Leeds proclaimed that “the harbor district is one of the greatest asserts of the County” and, as such, “its protection therefore demands first attention.” This could only be achieved fully by diverting the Los Angeles River from Dominguez Hill, near where the 91 Freeway passes through Compton, and carrying flow in a canal to Alamitos Bay, where the San Gabriel River now empties. Beyond this, the river should be redirected from Los Angeles city limits (excepting the recently devised “shoestring” connecting it to the harbor) so that it would be in virtually a straight course, as it was prior to the major flood of 1889, when a sharp southeast channel was created where the City of Vernon is now.
The Río Hondo, exiting the Whittier Narrows, was also changed after the previous year’s inundation and it was recommended that it be returned to the pre-1914 course, terminating at the Los Angeles River just west of the County Farm. What was required for the San Gabriel River (redirected from the Río Hondo after flooding in 1867) was “minor rectifications” below the Narrows, but then, “it should be diverted southwesterly to a junction with the diverted Los Angeles River.” An alternative was to shift the latter to the former further north more cheaply, but “this is not advised . . . as it would lack the safety” recommended by the engineers.
While it was asserted that the combined outfall at Alamitos Bay was designed “as to provide for a leveed channel direct to the beach line,” Leeds suggested “to improve some of the swamp lands down there, by the deposit thereon between levees, of the silt brought down by the combined rivers, then passing the cleared waters to [the] sea.” In fact, much of the South Bay was swamp land before gradually being drained over the years and most of the wetlands along the coast were also “improved,” though some conservation has taken place in recent decades.
For Ballona Creek, there was the concept of concrete storm drains and some check dams in the Santa Monica Mountains canyons to limit runoff. With a leveed channel in the creek, a lesser flow of water would empty into the Ballona Lagoon. In all, the projected cost was not quite $5.5 million, with two-thirds or so devoted to the Los Angeles River, less than 20% to the San Gabriel, under 10% to the Río Hondo and remaining 5% or so for Ballona Creek.
Leeds noted that a provisional report of the Board of Engineers of 3 June 1914 noted that there were eleven major flood years in recorded regional history, these being 1825, 1833, 1862, 1867, 1884, 1886, 1889, 1891, 1906, 1911 and 1914. Federal weather bureau data suggested that others be added to the list, including in 1879, 1887, 1890, 1905, and 1909. For the nearly four decade period between 1878 (official records from the U.S. Weather Bureau [Service] began the prior year), a list of 41 flood events with dates; rainfall levels, flood characterization as light, moderte and heavy; and remarks was provided. He noted what others did about major floods prior to 1877, based on the memory of long-tome locals, though without statistics from which to make meaningful observations.
Beyond rainfall, however, the engineer was sure to note that a question of major significance was that
By the growth of cities and towns, with their great areas of roofs and paved streets, by the extension of paved highways and improved watercourses, and by the return water from increasing irrigation (Owens River water is being brought into this county [via the Los Angeles Aqueduct, completed two years prior] from another watershed), the run-off resulting from any given rainfall is steadily increasing, and will change moderate floods of the past into serious floods in the future.
Erosion and silting would also be worsened, because earlier floods “could spread harmlessly over wide areas whose soil was bound down by grass and other vegetation,” those secitons now had streets, embankments and other elements “provoking scour,” while cultivated areas of orchards and sugar beet fields were “easily eroded, only to be deposited at some point nearer the ocean,” including the harbor.
Leeds then briefly reviewed the mitigation efforts of reforestation, impeding or check dams, and reservoirs—all covered in the earlier reports. He returned to the situation in early 1914, which was during a season with rainfall only slight above “normal” (this latter term was devised in a period of several decades of what was likely exceptionally high levels of precipitation, leading to the obvious question of what constitutes a “normal” condition), but with great intensity of flow in short period. During that season, though, about 400,000 cubic yards of silt were deposited at the harbor, so protecting lower lands was as important as working with mountain areas.
Stating the obvious, but for obvious good reason, the engineer observed that “water is such a precious commodity in Southern California, and so vital to its growth, that the greatest possible amount of it should be conserved for beneficial use” and he referred to Olmsted’s report concerning the use of spreading grounds, though silt in heavy floods would limit the effectiveness of percolation into subterranean storage. Moreover, water stored from previous years could fill the grounds so that a major flood season would render the grounds less than useful and “the result would be greater flood damage than formerly.”
So, Leeds went on, “true conservation means the saving of all resources, not only water, but fertile soil and harbor facilities,” the latter comprising “the accompaniment of the greatest communities of the world.” So, storage, the use of impeding dams, levees and other means had to be complemented by “the proper and substantial regulation of the lower river” so that these would “conduct harmlessly to the ocean such flood discharges as are impossible of storage, in order that they may not by their erosive power, wash away the fertile farm lands, and fill up the navigable channels of the harbor.”
The engineer then went into fairly lengthy discusions of surveys; gauging of discharges in watercourses; the cross-section of and protection of the banks of channels (especially narrow but deep ones in high-value areas where cost was a major constraint; the effects of levees on stream beds; the hydraulic elements of courses; sections of levees; protection of banks and the regulation of channels. Much of the discussion dealt with precedents outside the region, highly technical material (including diagrams and a few photos), and other material for the specialist.
As Leeds turned to a description of the Coastal Plain district, he recorded that the area tributary to the Los Angeles and San Gabriel Rivers was 379 square miles (with some of this, about 15%, in Orange and a miniscule amount in San Bernardino counties). He noted that the general gradual slope toward the coast was broken only by a line of low hills including such elements as Dominguez Hill and Signal Hill and that the plain “was probably at one time a broad embayment of the ocean with San Pedro Hill [Palos Verdes] an island off shore.” Geologic uplift and sediments washed down from the mountains reclaimed this area and the looseness of soils also allowed for the fluidity of the channels of the rivers.
He repeated that the Los Angeles River flowed west into Ballona until 1824 (1825, according to most sources) and that for the next sixty-five years it had a near straight southward course, though the 1889 flood caused a redirection east and south. As for the San Gabriel, it “has always flowed through the Whittier Narrows,” where the Mission San Gabriel was originally located and where the Temple family resided in the “Old Mission” community from the early 1850s until just after the report was published, moving in 1917 when oil was found on their land. Notably, he said that “it has from time to time branches into two streams, one being known as the Rio Hondo, and the other as the San Gabriel or New River.”
The Río Hondo, which actually was the San Gabriel channel before a redirection in 1867, flowed eighteen miles to empty into the Los Angeles River. Leeds wrote that “the natural course of the [San Gabriel] is into Alamitos Bay, though it has at times followed the present course of the Río Hondo, or flowed westerly between Clearwater and Signal Hill to join the Los Angeles River.” In 1915, “the greater part of the flood of the San Gabriel River finds its way into the harbor through the Rio Hondo and Los Angeles Rivers” and he added that “even the Santa Ana River of Orange County at one time had its mouth in Alamitos Bay.” The low banks, easily eroded, were part of this fluctuating history of stream course so that “almost the whole of this section of the Coastal Plain has been damaged or menaced by these floods in times past.
With respect to protecting the harbor area, Leeds reiterated, though a little more forcefully here, that “Los Angeles Harbor is . . . probably the most vital assert to the growth of this county” and of national significance given its service to interior areas, not to mention expected impacts from the recent completion of the Panama Canal. More than $11 million was spent by the city of Los Angeles and the federal government (not to mention funds expended at Long Beach). Because any solutions for upper portions of the rivers had to conform to federal laws concerning navigable waters, “it is necessary to solve first the problem of protecting the harbor district from flood borne silt deposits, and then to co-ordinate the regulation of the upper rivers therewith.” Federal laws were “very strict and very comprehensive” and he added that allowing silt deposits at the harbor “is a violation thereof and punishable by heavy penalty.” He then provided some detailed legal precedent in support of this.
Getting into some history of the harbor, Leeds wrote that, despite their primitive condition for commerce, “the channels were . . . in their natural condition and had attained a state of fairly stable equilibrium, so that floods had practically no injurious effect upon them, the tidal currents carrying away the greater part of such silt as was brought down by floods.” It was when early improvements were made that the situation changed, so that dredging led to “an enlarged settling basin” where silt was deposited. As the harbor area, and that of Long Beach, grew enormously in last couple of decades, the imperative for protection became more obvious.
There were some interesting quotes from old-timers about the condition of the sloughs that were legion in the Wilmington area, as well as throughout the South Bay area (one, terribly, was called “Nigger Slough” because Joshua Smart, who came to Los Angeles in the late 1850s, bought land on Rancho San Pedro from the Dominguez family, and the slough near his place and north of Wilmington received that racist moniker, though it was changed later to Dominguez Slough—Smart later lived on Los Angeles Street near First.)
Albert A. Polhamus stated that, before 1862, sloughs between what soon became Wilmington and what became Long Beach could not be navigaed by skiffs, which are shallow, flat-bottomed craft. Jotham Bixby, who bought Jonathan Temple’s Rancho Los Cerritos, encompassing Long Beach and nearby areas, in 1866, said that “in the early days the branches of the lagoon at Long Beach were so shallow near Wilmington Lagoon that stock could readily pass over to Terminal (then Rattlesnake) Island for pastures.”
It was added that, prior to 1867 and the rechannelization of the San Gabriel, both the Los Angeles and San Gabriel (Río Hondo) emptied into the ocean near what became Long Beach, but most of the activities with shipping were at San Pedro, so flooding and silting had almost no impact. The shift of the San Gabriel was “extremely fortunate” for both Los Angeles and Long Beach harbors because the silt from that course was deposited further east. In 1910-11, however, flooding including the San Gabriel’s banks breaking so that it linked up more with the older channel, or the Río Hondo, and sent material to the harbor area, and this continued with the 1914 inundations.
Leeds added “as a result the flood of 1913-14, while not as great in run-off as some which have preceded it, was probably the most damaging in the history of this county” as farmed land nerby sent material to the harbors, constituting 2.6 million cubic yards to Los Angeles and some 700,000 to Long Beach, with another roughly 700,000 in areas targeted for future dredging. The recent winter of 1914-15, with “normal” rainfall, still brought up to 600,000 cubic yards. Given that future floods could have more flow, “even greater injury may be expected” because there was also the matter of development and more erosion from cultivated soil and the expansion of the harbors meant more settling basins for silt washed down from inland.
The engineer then cited numerous authorities for the suggestion that the Los Angeles River be diverted southeast and that the Río Hondo/San Gabriel courses also be improved to so that the trio of channels emptied together into a further prepared Alamitos Bay, thereby giving adequate protection to the harbor district. As to those who claimed that dredging the harbors would suffice, Leeds merely pointed out the sheer magnitude of silting.
He went to note alternatives to the advocated proposal, including a new mouth between Wilmington and Long Beach, or at one of two locations at the west edge of Long Beach, but there was the asumption that the San Gabriel flow would be redirected further east and, he added, the relative cost of diversion of the Los Angeles River from Dominguez merited that approach. Cost estimates for the desired approach and four alternatives ranged from about $1.437 to $3.7 million, with the diversion to Alamitos Bay, as advocated, being the least expensive, even cheaper than merely improving the old channel between Domingues and the harbor at Long Beach.
The main argument, however, was that “the diversion dike at Dominguez will forever insure the harbors of Los Angeles and Long Beach against flood damage regardless of any possiblt break in either of the rivers higher up.” Moreover, there would be “the perfect reclamation afforded to the rich agricultural lands lying between this proposed dam [dike] and the harbor, [which] will greatly enhance their value.”
As for diverting the rivers, there were two alternatives to the recommended plan noted above, which included the San Gabriel being diverted southeast from what became Bellflower and connecting with the Los Angeles near Bouton Lake in today’s Lakewood, with one having the Los Angeles River rechannelized from Laguna, roughly between Watts and Downey, and then east of Clearwater, now Paramount, to Alamitos Bay and separate from the San Gabriel River (the Río Hondo would still empty into the former). The other would run the Los Angeles from just below downtown as it turned east and south at Vernon and then run it east and south closer to Downey and have it empty into the San Gabriel near Norwalk.
Leeds, though, noted that, while the desired plan was more costly ($5.1 million as opposed to $4.3 and $3.8 million respectively for the others), it was far more safe in protecting the harbor, following more natural contours and grades, be easier to maintain, and not pose problems for riparian water rights and existing underground water supply. Water seeping into the soil above the proposed dike at Dominguez Hill rose back to the surface below it, so this was a net benefit.
Further detailed and technical discussion of suggested improvements to the rivers concerned the improvements of the channel beds, banks, bridges and trestles, addressing concerns of water supply by communities, the creation of the dike and diversion channel on the Los Angeles, and rerouting of the other two, among other aspects. Improvements to Ballona Creek and tributaries, obviously of lesser import compared to the harbor, but still important given the rapid development of the areas west of downtown Los Angeles, were also described, including impeding dams and creek channel clearing in the canyons of the Santa Monica range, the building of storm drains or general improvements along creeks in the plains. It was reiterated that waters would be delivered to the Ballona Lagoon, where private owners had tidal gates to release flood waters and which was outside the purview of the report. Leeds did say that, should they want to dispose of water in a different way, “this modification can be easily arranged without probable increase in cost.”
After providing cost estimates for flood control work, including over $3.6 million for two sections of the Los Angeles River (one to Dominguez and the other in the diversion from there to Alamitos Bay), $534,000 for the Río Hondo, just shy of $1 million for the San Gabriel, and about $318,000 for Ballona Creek (from about where Pico Boulevard meets West Boulevard), Leeds offered his conclusions.
First, was the assertion that flooding occurred at a mean interval of just over three years. Next, “adequate flood protection is entirely feasible and the cost is more than justified.” Third, flood threats and growing costs for rights-of-way “demand the earliest possible action.” Then, all flood control types were important, “although levees afford the only single proved method of completely controlling floods,” so that reforestation and check dams would certainly help with conservation and lowering the cost of works in the plain. Fifth, the diversion of the Los Angeles river was imperative to protect the harbor and “will afford greater benefit to a greater number [a Utilitarian argument] than any other diversion.” Finally, Leeds called for more compliance by the federal government with the recommendations so “that the United States [will] construct the diversion dike and canal because of the protection afforded thereby to the navigable waters of the United States” at the Port of Los Angeles.
We will press on tomorrow with part five, concentrating mainly on the reoprt of James W. Reagan, who later served for a dozen years as the county’s chief flood control engineer, but whose relationship with the others on the Board of Engineers who worked on this report was strained. More on that then!