Here Comes the Flood (Control): Reports of the Board of Engineers on Flood Control to the Los Angeles County Board of Supervisors, July 1915, Part One

by Paul R. Spitzzeri

As we are mired in another severe drought and grappling with the consequences of it and of climate change for our future water supply, this look back over a century ago takes on relevance because of the shifting position we are now in as opposed to how flood control was developed in our area from the mid-1910s onward.

At that time, the concern was what to do to mitigate the occasional heavy flooding that ravaged the region with the response including impounding water with major dams in the San Gabriel Mountains, channelizing the Los Angeles and San Gabriel rivers to efficiently transfer runoff into the Pacific Ocean, and improving creeks and washes to more effective deliver water to those major courses, among other solutions.

Among the pressing questions for the future is whether to rethink the diversion of water into the ocean in favor of capturing it and recharging groundwater supplies, though, of course, most of our consumption comes from water brought from long distances (the Owens Valley, the Sacramento River delta, and the Colorado River) and those supplies are also becoming increasingly smaller.

In April 1914, however, the main object was to establish a flood control board of engineers and have them deliver a comprehensive report to the Board of Supervisors and that document, issued in late July of the following year is tonight’s featured object from the museum’s holdings. The flood control board’s quintet of members, Frank H. Olmsted, Henry Hawgood, Charles T. Leeds, Joseph B. Lippincott, and James W. Reagan, each contributed a section to the report and we’ll focus on those in separate parts.

For this first part, though, we’ll concentrate on the introductory section, which was presented under the signatures of chair Hawgood and Leeds, Lippincott and Olmsted, the latter serving as secretary. Reagan was not a signatory, apparently, because he was appointed the chief’s flood control engineer. First, however, there was an introduction under the name of the Board of Supervisors (a quintet comprised of John J. Hamilton, William E. Hinshaw, Richard H. Norton, Richard W. Pridham, and Frank E. Woodley) and dated 30 August 1915.

It was stated that the formation of the flood control engineers board was “made necessary by the destructive flood of February 1914, and by the certainty that equally great and even greater and more disastrous inundations will occur in the future.” This was, in fact, the case most notably nearly a quarter century later in the flooding of 1938. It was added that “there is a substantial agreement among the five engineers who composed the Board, that the remedial programme indicated by the information herewith published must include four measures . . .”

These included conserving storm water by reforestation and “retarding work” in the mountains; using gravel deposits at canyon mouths at the base of the mountains to spread storm waters; obtaining challens for main streams below these points “and the permanent rectification and protection of these channels;” and diverting water from the Los Angeles and San Gabriel rivers from the harbors at Los Angeles (San Pedro/Wilmington) and Long Beach to Alamitos Bay, where the San Gabriel empties into the Pacific at the intersection of Long Beach and Seal Beach.

There might have been, this piece went on, “varying urgency” about these items, but “all of them are essential in parts of any adequate plan of flood control” and it was all or none with the quartet done at the same time so that they “must be financed and managed as one project” even if raising money, through bonds or other sources, was to be done, as required at any given time.

Moreover, diversion was to be under the auspices of the federal government and through its revenue sources, with plans approved by a national engineering board, while local planning was to be in conformity with federal ones. The state “is expected to contribute liberally to these works, in accordance with the enlightened policy it has purused in other sections of the State.”

Where there was diversion in the aspect of diversion works by the engineers as to location, there were also differences in method for “experimental retarding works constructed in the mountains.” Again, because the feds would be responsible for the decision of the type and locale of these works, this “leaves the Board of Supervisors . . . free to adopt a general plan, unhampered by professional differences as to engineering details.”

When a state law was passed establishing the county’s flood control district, which allowed for tax levies or bond issues for raising funds, the appointment of one or more engineers “to mature a final plan” for the supervisors and then for the public to vote upon, was also called for. The chief engineer, who was Reagan for a dozen years, was to work with the Los Angeles County Flood Control Association, in the development of that final plan.

In the report’s introductory section, it was averred that the Board of Supervisors long looked to protect its constituents against flooding, and “the heavy flood damage of 1889 emphasized the need of action.” There was “an unavailing effort” to do something on the San Gabriel River north of El Monte a few years later, followed, in 1898, by a three-person commission for “a suitable flood control location and design” for that watercourse. What followed, however, was a dry spell so that “interest flagged and the need of adequate provision for controlling floods was forgotten.”

In 1911, there was heavy rain in the first quarter and this “awakened the people again to the fact that floods recur” and that was when Olmsted was appointed by the supervisors “to investigate and report on San Gabriel River control,” with his findings submitted to the supervisors in fall 1913. From then, planning continued as “legal limitations to their powers permitted” in only a narrow way, but the new law, taking effect on 8 August 1915, “enlarges these powers” through seven flood control districts. Still, the operation of these and improvements undertaken were “a disappointment” and “have proved inadequate.”

Because of the geographical issues at hand, including the running of water courses through “the most highly improved agricultural and horticultural districts in the United States,” the engineers were focused on preventing and protecting against floods, as well as preserving the harbors. Moreover, it was stated, there were no precedents elswehere in the country to follow when it came to building “small restraining dams in the mountains” to mitigate floods. Instead, “we have to turn to Europe and to India and Japan in order to gain the knowledge that is necessary.”

For the layperson, it was hard “to comprehend the detail and the magnitude of the work” involved, such as establishing a base map on which to lay out the plans and topographic studies were required before trying to get decent plans and estimates. Delays ensued in getting some of these surveys together and “it is essential that further physical investigations should be made in many different localities of the condition of stream flow and rainfall.”

Experiments in what were still called the “Sierra Madre” Mountains with dams on the models found in Switzerland and Germany were also recommended, while looking at conserving water through spreading and looking at channel absorption was to be further analyzed. Because there was still much to be done, the engineers “do not feel justified . . . in making at this time a sweeping recommendation for the general adoption of flood retardation plans in the mountains,” but they did “earnestly advocate that a substantial sum be expended in making exhaustive field demonstrations along these lines.”

One key observation was that, unlike other areas of the country, the local mountain range was close to the ocean “so that the drainage lines of the streams are short.” With “sharp and precipitous gradients” which “change violently,” the problem with the watercourses was that they “are unstable, due, among other causes, to the natural building up of the delta-like fans.” This, in turn, causes “the streams [to] raise themselves above the surrounding country and in flood break their banks and make for themselves new channels.” Major examples involved the redirection, in 1825, of the Los Angeles River from emptying into the ocean where Ballona Creek now ends to its current terminus at Long Beach/Wilmington, while, in 1867, the San Gabriel left its old channel, the Río Hondo as we know it, and followed irrigation ditches and took over the Coyote Creek route where Alamitos Bay is.

While annual rainfall was about fourteen inches a year, “floods respond rapidly to the storms” in the mountains and “they are violent, erratic and usually of short duration, passing by in a few hours. The difference from the Sierra Nevada, of course, is that the latter’s watercourses were mainly from snowmelt, but in the San Gabriels, it is largely runoff from rain. Controlling local floods, then, “is complicated by the large fluctuating volume of the floods, the quantities of debris carried and by the varying gradients.”

As to the history of regional flooding, there is some interesting, if largely anecdotal, material, mainly because official records from the federal weather bureau only went back to 1877, fewer than forty years. In stating that “the frequency of destructive floods is a matter of great moment in considering the justifiable extent of remedial works,” it was noted that a court case from 1897 mentioned the heavy flood years were 1825, 1833, 1862, 1867, 1884, 1886 and 1889, with the latter being the most severe. After that, the official records noted that 1890, 1891, 1905, 1906, 1909, 1911 and 1914 were considered flood years, as well.

With respect to what transpired prior to 1877, there were those who offered that there were major floods in 1842, 1852 and 1874. It has often been stated that the period from late December 1861 to late January 1862 was referred to as “Noah’s Flood,” because it was nearly forty days and estimates for the amount of precipitation range as high as a staggering 50 inches, leaving the enormous Central Valley a massive lake and causing inundations of water throughout the Los Angeles basin.

As to 1889-90, it was noted that there were four separate flood period (23 October, 12 December, Christmas Day and 26 January,) with just one of these “scarce less severe and disastrous than that of 1884, with two causing delays in traffic and three causing some damage at the harbor at San Pedro and Wilmington. The conclusion was that major floods basicaly occurred every few years and more than one flood in a single season also possible.

Discharge and runoff, however, had not been measured at the San Gabriel, while there were a pair of separate estimates for the Los Angeles River during the 1889 inundation. The best assumptions were that the ratio of the floods of 1889 and 1914 were 165 to 100, while the 1884 flood was at 177 to 100. It was cautioned that “perhaps some of the earlier floods which are too remote to furnish information of engineering value” were even greater in ratio, including 1825 and 1862.

The 1914 flood caused an estimated $10 million in damage outside of the harbor area, for which no guess was provided in the report and, interestingly, it was asserted that “the exact amount is immaterial, it is enough, whatever it may be.” By contrast, flood damages in all of Kansas for the first half of 1915 was $15 million and that state is 20 times larger than Los Angeles County.

As to methods used elsewhere, forestation, impeding reservoirs, storage reservoirs, and channel work and levees were discussed with the conclusion that “modern engineering practice includes the combination” of all with the addition of spreading, being “applied to its economic extent to the localities to which best adapted.” There was then a discussion of the seven flood control districts, including the Mountain (San Gabriel, Verdugo, and Santa Monica ranges); the San Fernando Valley; the Arroyo Seco; the Santa Clara River; the San Gabriel Valley; the Western Coastal Plain; and the southeastern coastal plain.

With respect to the Mountain district, it was noted that “it is planed to adopt in general the European practice of attacking the flood problems at their sources in the high mountains.” This included some reforestation due to fire, landslides and erosion due to flooding, so that “re-brushing the slopes were most needed” was to be complemented by “promoting plant life on such canyon floors as have been previously secured against flood flws and mid-summer droughts by the check-dam system.”

In the San Fernando district, which was basically the valley of that name, it was observed that, having a $2.6 million bond issue for irrigating via the Los Angeles Aqueduct, completed just two years prior, “a rapid increase in the population of the valley is expected,” so “the time is opportune for the acquiring of the right of way necessary for purposes of flood protection and conservation.” The biggest need was at the east end where the Big Tujunga and Little Tujunga creeks frequently flooded a large area and it was then asserted that reservoirs in the mountains were not an option because of steep grades, so spreading grounds were the best idea. At the far west, the concept was to create a masonry channel from to the Los Angeles River near Chatsworth, Owensmouth (Canoga Park), and Zelzah (Northridge).

The Arroyo Seco district was along that watercourse through a largely developed area from base of the San Gabriels to the Los Angeles River and “the plans contemplate the construction of a storm channel 150 feet in width protected on both banks by heavy rip-rap with marginal lands to afford access for maintenance, which will also afford opportunity for the whole to be treated as a parkway.” A dam at Devil’s Gate leading into the mountains would include a reservoir, which would supply Pasadena, South Pasadena and Alhambra. The parkway elements “attractive as they are, are not contributary to the actual work of flood control” and so were not included in the planning process as of that time.

For the Santa Clara River, the idea was to build a concrete lined channel less than two miles to carry water past Newhall to a section near the mouth of Placerita Canyon (where gold was discovered in some quantity in 1842). After that protecting the bank was suggested until the channel met the river, for which nearly ten miles to the Ventura County line was to involve remoal of willow trees and other material and to protect banks and the highway (now State Route 126) “at numerous points.”

The San Gabriel District was an areas of 325 square miles all draining to the Whittier Narrows, or Paso de Bartolo, which is two miles in width. Some 100,000 acres of agricultural land was within the district and a little less than half was irrigated, so that “any conservancy of flood waters would increase the ability to bring more lands under irrigation.” For the San Gabriel River and its main tributaries, some 88 miles in length, “flood control works are needed on about sixty per cent” of that area.

It was added that the destruction of 1914 occurred despite the fact that volume was probably 70% less than that of 1889. The idea was to building many small check or impeding dams in the mountains, as well as to spread water, on some 2800 acres to be purchased, over the gravel built up at the mouths of canyons, mainly San Gabriel. Levees would also be required on streams, but the river was to be “a channel of 600 feet in width with boulder faced levees” to Lexington (Rio Hondo) Wash, where a rubble weir, as done in India, was to be constructed before that wash became the Rio Hondo main channel. Below that to near the Narrows the channel was to be 450 feet wide, while the Rio Hondo was to be 330 feet in width, with levees of boulder, if possible, and concrete, if not, but the latter to be a slab at the top and small blocks below and extending into the channel bed. All the washes and creeks entering into these courses were to be “permanently confine[d] to their channels by suitable works.”

The Western Coastal Plain, included Ballona Creek (formerly the last part of the Los Angeles River as noted above), with water feeding into it from the Santa Monica Mountains and run off from the western sections of Los Angeles with some water moving through a spreading effect as well as in washes, but check dams were called for in the mountains. Centinela Creek was a smaller course in the section and empties into the same lagoon at Ballona as the creek of that name, which was to be deepened and have “minor rectification.” City runoff was to be handled through concrete storm drains and those flat lands susceptible to spreading required more surveying. Notably there were private tide gates and a rock jetty at Ballona Lagoon and there was no recommendation to change the situation, but “should the interested property holders desire any other disposition such can easily be arranged” because the creek’s grade was designed to allow for delivery of flod waters to the beach line.

Finally, the southeastern coastal plain covered the area from Inglewood and what became Playa del Rey and Westchester to the San Gabriel River. It was noted that the Los Angeles River flowed directly from Los Angeles to its present terminus at Long Beach from 1825 (it says 1824) to 1889, after which flood year “it changed its course easterly through Vernon rejoinin its old channel near the County Farm [in Downey]” where it mets the Río Hondo. The San Gabriel changed course within this district several times, going as far west as Bouton Lake, in what is now Lakewood.

For this district, “the most vital requirement in the control of these three rivers is the protection of Los Angeles Harbor from the immense amount of silt which these rivers have brought down in time past and which they will continue to bring in increasing measure until properly controlled.” The proposal was to have the federal government, as protector of navigable waters, spent $1.7 million on diversion works and the county bvuilding bridges and maintain the works after they were finished.

More striking, however, was the recommendation to divert all flow of the Los Angeles River, Río Hondo, and San Gabriel River to one outflow at Alamitos Bay. Moreover, it was suggested that the Los Angeles River should be moved west to its pre-1889 channel, with a wide berm covered in cane and willows, as well as rip-rap where needed. South of Compton, perhaps about where the 91 Freeway is now, it was proposed to send the water east to form something like a dam to protect the harbor.

For the Río Hondo, there was a straight grade to Stewart and Gray Road in Downey and it was proposed to continue that straightening to the Los Angeles River, with concrete-faced levees and “a mattress of articulated concrete blocks on the lower part of the slope and extending out onto the bottom of the channel.” The San Gabriel was to be widened and deepened, with similar levees as on the Río Hondo, but its channel was to be moved southwest to follow the channel that went east of Bouton Lake in 1888, which “would eliminate 6 miles of channel . . . and very materially facilitate the harmoizing of the flood planes of the two rivers.”

Finally, at Alamitos Bay, the idea was to level the slopes to the beach line, although, again, it would require federal permission to do anything “below high water mark” with the national government considering “a general diversion plan with outfall at the bay.” The cost estimate for all of the work (check dams, spreading, channelizing and so on) was just north of $16.5 million, with hopes expressed for state and federal assistance, and “a period of about five years should be allowed for its consummation.” The cost was given with the note that the 1914 damage was about 60% of that total and “destructive floods will occur in average intervals of less than five years.”

As we wrap up this first part, Hawgood, Leeds, Lippincott and Olmsted concluded with the warning that “prompt relief from these floods is an urgent public necessity. Supine indifference to this meance is not in accordance with the customs of this community.” Check back tomorrow for part two of this fascinating and important early flood control planning document.

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