Tuesday, June 11, 2013

Lessons Learned from the Bajadas (Alluvial Fans)

What is a Bajada (or Alluvial Fan) ?
Source:  Structural Geologist Mike Norton

Alluvial fan in the Cirque d'EstaubĂ©, French Pyrenees
Great Definition Source: http://en.wikipedia.org
"An alluvial fan is a fan- or cone-shaped deposit of sediment crossed and built up by streams. If a fan is built up by debris flows it is properly called a debris cone or colluvial fan. These flows come from a single point source at the apex of the fan, and over time move to occupy many positions on the fan surface. Fans are typically found where a canyon draining from mountainous terrain emerges out onto a flatter plain, and especially along fault-bounded mountain fronts. A convergence of neighboring alluvial fans into a single apron of deposits against a slope is called a bajada, or compound alluvial fan."

The above definition by Wiki aptly describes what most around the world, but especially those in drier locations have observed at one time or another with regards geologic features which emerge from most mountain canyons. If you notice the picture above of the alluvial fan in the Pyrennes Mountains which border France and Spain, take note that there is generally one main channel in which the stream or river flows out, and yet, there appears to be a greater historical pattern spread all across this Bajada. In actuality this main channel can oscillate back and forth depending on heavier flow patterns brought about by a wetter than normal rainy period. But there have always been a number of questions that plagued my mind over the years. For the purpose of simplicity (my wife says I write too much text), let's restrict this post to Southern California and in particular Riverside County (although San Bernardino Co fits in nicely as well). There are several Bajada land formations which define most of the inland empire cities from San Bernardino to Los Angeles. Most people don't even realize they are living on many of these alluvial fans or flood plains. Many while commuting never give them any thought or second look. Most river or stream beds have been straightened and channelized for commercial convenience sake. But there are several tree establishment puzzles that took place decades ago which question beg. How did such large examples of old growth Sycamores and Cottonwoods become so well established when they appear to be so far away from the stream bed channel ? From what I always knew of such riparian species, they need generous amounts of water to survive the early years of their life, so what gives with these examples on dry locations ? Cyclic wet periods are extremely key to establishment and should be studied as such and remember not for their destructive potential, but for habitat establishments in the wild.


This next photo below is of a Bajada or Alluvial Fan which emerges from what I thought was once labeled as Portrero Wash or Creek at the bridge on Gilman Hot Springs Rd, but the sign is now removed. It's source is the city regions of Beaumont and Banning CA and in particular the Sun Lakes Country Club and Golf Course. As you may see from this Google Satellite map link Here , the Alluvial Fan was at one time much wider than now. It is restricted by an eastern Earthen barrier or Levee on the east which protects the Scientology Military Compound and the raised easement of Hwy 79 on the western edge. What is left can be seen with several lines of stream channels which fan out at massive flood stages which are characteristic of most alluvial fans, and hence the name. 


Photo Credit: Mine
This photo is looking directly north on Hwy 79 leaving the Hemet/San Jacinto Valley heading north through Lamb's Canyon to it's destination at city of Beaumont. You can see the canyon at top center where the force of water over the years has created this massive Bajada. Not sure why the name of this Portrero creek in the Canyon was removed, but it once had a name on the bridge which crosses over it on Gilman Springs Rd which is actually the old original Hwy 79 before the political realignment. While this alluvial fan is fairly dry looking now, it always wasn't so, especially between the wet years of 1987 thru 1983. Take a look below at some surround city and town historical rain totals. Keep this in mind as it is important.

Image - hvrc.com
Hemet & San Jacinto Valley looking north towards the foothills of the San Bernadino Mountains. Porptrero Creek and the alluvial fan which ran all year would be over on the far right of the photo. 


Hemet California

Historical Annual Rain Totals of a wetter period

1978  -  26.60 inches
1979  -  13.47 inches
1980  -  18.86 inches
1981  -  08.29 inches
1982  -  16.90 inches
1983  -  21.03 inches


Riverside California
Historical Annual Rainfall Totals Same Period
1978  -  12.92 inches
1979  -  12.87 inches
1980  -  15.77 inches
1981  -  08.10 inches
1982  -  15.07 inches
1983  -  22.91 inches



Idyllwild Calfornia

Historical annual Rainfall same period as above

1978  -  46.99 inches
1979  -  29.62 inches
1980  -  45.65 inches
1981  -  15.81 inches
1982  -  49.47 inches
1983  -  56.87 inches
All these figures above are of the rainfall averages for the wetter "El Nino" years. That was an amazing time period of wet. Too bad the officials didn't take advantage of it to rebuild several important ecosystems.


Credit: Riverside Flood Control 
"Flooding in the vicinity of State Street (Highway 74) and Ramona Expressway,  February 21, 1980, as a result of the breach of the San Jacinto River Levee." 
Again, keep in mind please and burn into your memory if you can, this six year heavier than normal time frame which has valuable learning potential aside from destructive forces which often are the result of human poor planning anyway.

Photo Mine

Major construction of San Jacinto River
bridge on Hwy 79 in Riverside County 1994
I've given some averages here of three locations which give an average perspective of the overall rainfall to western Riverside County. For those folks who remember this wetter rainy period of time, this was during a significant "El Nino" event. For many, it was the first time the term really came to life and had meaning. It was a major time of bridge washouts and road closures. As you can see, the closer to mountains and foothills, rainfall amounts are far more significant, than the interior valleys. Even still, rainfall for all of southern California everywhere was greater than in times past or for that matter ever since. Because of the greater rainfall during these six winters, ground water saturation was at it's greatest and summer monsoonal thunderstorm build up was vastly improved during this period as a result of greater electrical conductivity between the negatively charged ground and positive charged atmosphere. Previously in a couple of earlier posts, I have alluded to the anomalous weather pattern of isolated thunder storm build up in and around Anza which is incredibly easy to spot and observe during periods of less winter rainfall which creates less ground surface conductivity with the exception of specific heavy old growth vegetated areas where good healthy hydraulic lift and redistribution takes place bringing moisture up to the surface from deeper soil layers and for which cloud formation and/or Thunderstorm development is much greater as a result. During these wetter winter periods, because the ground water table is very high and saturation is so complete, such storm development was never an isolated incident. In fact it was so complete that development was common in those days from the deserts all the way to the Ortega Mountains above Lake Elsinore. Now this is where noticeable heavy vegetation increase could be observed in most alluvial fans, but I'll focus here only on the one originating from the mouth of that Portrero Creek for which the drainage came from the higher elevations of Banning and Beaumont California. There were several times when the Gilman Hot Springs Rd had closures. During this heavy rainfall period, water ran completely over the entire alluvial fan all year long in the wettest of these years. Thousands of Willows, Cottonwoods and Sycamore trees created a triangular carpet of bright green all the way to the San Jacinto River main channel to the south from the Gilman Springs Rd bridge.

Photo: Mine
This shot is a closer view from the Bridge. Prior to this greener look above which resulted from this heavier rainfall period, there were only a couple of large Cottonwoods and a single large California Sycamore specimen for which seemed always somehow out of place to me back then because all the rest of the alluvial material was like dry desert wash, there was no riparian green as you see it presently. At the beginning of the change, the entire fan was a complete mass of green as 1000s and 1000s of young riparian seedlings competed for space. Now as you see, natural forces have allowed only the most successful to have made a permanent place in the newer ecosystem. This was more like it was when Juan Bautista de Anza saw and wrote about it , but on a much grander scale than this example which is still greatly restricted as compared to times prior to European settlement.

photo: Mine
This is looking directly to the east on the Hwy 79 bridge looking east towards the actual town of San Jacinto and the mountains beyond which bare the same name. This concrete barrier was created when the Hwy 79 bridge over the San Jacinto River was built in 1994. Traffic was diverted east towards the city of San Jacinto via the Ramona Expressway to State Street and north across a now replaced Iron Truss Bridge to Gilman Hot Springs Rd and then back west again to Hwy 79. In those early days Hwy 79 wash nothing more than a giant flood plain wash and when flooded, closures were common.

Photo: Mine
This shot is on the complete opposite side from the one above it looking west towards a normally dry lake bed called Mystic Lake, so named because of it's often times appearance and then disappearance depending on the amount of water flowing down the San Jacinto River which drains off the San Jacinto Mountains on the eastern side of Hemet Valley. The river itself runs through Lakeview and Nuevo making it's end at Lake Elsinore which also filled completely during this flooding rainfall period between 1978 to 1983. Even Lakeview itself had numerous shallow lakes giving viewers an historical perspective of what this region was as a massive riparian wetlands for which Juan Bautista de Anza first wrote about in his journal or diary. I first encountered this diary from the Riverside County Library as it was recommended to me by a Forester up in Idyllwild in 1981. One passage Anza wrote about was when ascending Bautista Canyon from Anza Valley to the Hemet Valley. He saw a massive bright colouration on the valley floor of solid white and thought it was snow. Mind you, he and his troops had spent all winter in and around Anza before hitting Valle Vista east of Hemet in March the same year. When he arrived on the valley floor at what is now the city of San Jacinto and west to the area of Mystic Lake, he found that the white colour he saw up in the higher elevations were nothing  more than masses of wetland habitat birds of various kinds. Mostly white Snow Geese. Almost hard to believe such great quantities of wildlife once existed. 


Photo: Mine
This shot is on the same north end of the bridge looking south, not just at traffic, but down into the River bottom. The river itself is channeled as usual, but the bridge extends a mile further south above the flat bottom landscape. This is because when at full flood stage, the earthen channel levees often disintegrate and those fields south of here turn into massive shallow lakes, the type that would have supported huge vast Riparian Cottonwood and Sycamore Forest woodlands which would have successfully even withstood drier periods as the water table here has always been close to the surface. I'll have later posts on that.


Photo: Mine
View looking in the direction of the Scientology Compound and the mature Cottonwood trees well established which had not existed prior to the flooding period. 
Photo Credit: Mine
This view of the Bajada from Hwy 79 eastward is near the Jct of Hwy 79 & Gilman Springs Road. During the massive flooding stages pouring out from points north in Beaumont which has records of over 30+ inches of annual rainfall at times, the mass of water fanned out completely all across the triangular bajada like some giant river delta. Even curving around this direction here. The Trees never really sprouted much on this side away from the main channel, but those that did, didn't linger long, a few years at best and dwarfed or stunted. A small lake did form at the left of this photo, but dried up or percolated into the porous ground in little less than a year. Prior to Hwy 79, water spread out over the entire plain to the west. Such land of course has been consumed by Agricultural Ventures, so any original riparian forests would have been eliminated in favour of what seemed at the time more profitable usage of such valuable nutrient rich landscape. 


Photo Credit: Mine


Photo Credit: Mine

photo: Mine
The top photo here is taken from the Gilman Springs Rd bridge looking north up the throat of the Canyon and Portrero Creek. During the yearly rushing of water through here for a few years, cars were always parked here during the hot summer months and hikers and bathers would make their way up this canyon to pristine water holes and waterfalls. The region was leased up stream by a private country club who always had Security Guards kicking people out or arresting them. There was always controversy about this in the Press Enterprise which is the official Riverside Co newspaper. The bottom photo is of a small tree-like shrub called False Indigo Bush (Amorpha californica), which previously I personally had only seen from Santa Rosa Indian Reservation eastwards through the Santa Rosa Mountain range. The last photo is simply a close up of the compound leaf which is similar to Black & New Mexico  Locust which I have written about before. The flowers that I have seen are almost like an upright lupine flower stalk and dark purple.



Photo Credit: Mine
And finally we have a direct south facing view from the bridge over Portrero Creek on the Gilman Springs Road. It's strange as to why they removed the sign at the bridge identifying the name of the waterway, but here is a link which removes all mystery as to it's historical identity.  The only thing that I can come up with is they wanted to disguise it's identity to hikers and other Nature explorers out from a sensitive area.
http://bridgehunter.com/ca/riverside/56C0523
For the moment, this is what I have and my personal account of what physically took place at this geographical location called Portrero Creek & it's Bajada particularly during the 1980s. This was of course a major part of my work route in commuting for many years. But I did promise to discuss what lessons could be learned from this, so what are they ? Well I always had personal questions in my mind about isolated tree establishments of large solitary trees which existed on dry locations for no apparent logical reasons, especially water loving riparian tree species. Numerous areas like Waterman Canyon in San Bernardino or Cable Wash in Devore or Lytle Creek, all have similar riparian tree establishment puzzles which have clear explanations for their presence if time, observation and experience are taken into account over a period a couple decades. My good fortune was to have seen the Portrero Creek Bajada (alluvial fan) when it was at it's driest barren state and to be observant when the transformation took place especially towards the middle 1980s. 

From such observation, one can glean from such experience that not only riparian, but even several other plant community ecosystems can become establish anew when these cyclical wetter periods emerge. Although with climate change it is doubtful that such periods will reveal themselves any longer. Still, much can be learned and practical application be created artificially in an urban landscape setting, or habitat restoration project, or with simple home gardening projects. During such unique wetter periods, plants are babied and nurtured during these times of plenty, then gradually the system tapers off in it's generous abundance and allows the earlier established plants to fend for themselves. The stronger plants/trees with the deeper root systems will become the winners, while the weaker ones fail and naturally thin out as the natural program demands. I have used this technique in replication, not only in urban landscape establishment, but in remote habitat restoration and it does indeed prove successful over time. Of course for me, I always inoculate with a good blend of mycorrhizal mix at time of planting. I found myself the last week before I left to come back to Sweden in a disagreement with this inoculating at planting time with a Native Plant nursery person who said that the micro-biological activity is everywhere floating in the atmosphere and it was not necessary. Why yes, there are spores everywhere in the air. But there is also more and more damning evidence that microbiological ecosystems in the ground are suffering some decline just as everything else above the ground. Toxic acid rains and many more chemical and GMO Plant contamination are having an effect on mycorrhizae. I've actually inoculated trees in wild out-plantings and had surrounding Chaparral like Scrub Oak and other trees make drastic improvement through the interconnections, which indicates to me all is not well in the wild. As time goes on, more and more researchers will come to the conclusions that Nature alone cannot function as it normally once did and that some major artificial assistance to speed things up will become necessary. I not only do not like hearing this, but hate having to say it as well. One more important side note about Bajada Basins and Alluvial Plains. Throughout the western North America, they have been huge storage components for water. Many streams or rivers that emerge from mountain canyons will often be seen disappearing deep into the alluvial fan. This is not the result of evaporation, but the looseness of the course rock and sand which allows water to easily filter and percolate deeply into the earth inside these geological forms. The best place to store water is underground, not behind dams or any other surface lake. It's also the best place for the plant world to access water during lean times. (See footnote @ bottom)

Now as far as the urban landscape goes, most ecosystems or plant communities you install should only have surface drip irrigation for the first few years at most. This replicates the cyclic flooding events that in times past made their appearance and created the wild landscapes centuries ago. Now unfortunately while visiting here, I had the opportunity to observe several public and professional landscape systems installed for development utilizing Native plant settings or themes, but employing a method of irrigation that employed large rainbird sprinkling systems which created large surface soil coverage over vast areas which has allowed massive amounts of weeds to grow to 3 or more foot of height and often times out competing the native plants.  The goal is to merely establish the plants are the beginning with just enough regular water for root development and later as I have written about before, installing a method of Deep Irrigation Methods for Training Deeper Rooting networks  and then later updating this with IRRIGATION ISSUES: Why Isn't Nature Replicated more often ? The bottom line is that people just don't get the gist of allowing plants to maintain health and vigor without forcing new growth during hotter months through excessive watering and fertilizing which not only encourages weeds, but attracts all manner of insect pests and fungal diseases and/or other blight. Go out into the wild and you don't see this. This is because they are in maintenance mode by means of sustenance from a deeper underground hydrological system which works well when properly established.

A prime bad Big Brother Government example is of a Cal-Trans Landscaping Project under and around the Interchange on and off ramps of Hwy 52 & Hwy 67 between El Cajon and Santee employing the wrong irrigation techniques of massive Industrial Strength Rainbird displays, though I was happy to see Natives being used. They'll eventually have killed  off what they had set out to accomplish with the utilizing of Native Plants.

In the Rattlesnake Mountain chain far above this Freeway Interchange where the Sky Ranch Development was established, they have followed the same identical flawed pattern as that of the Cal-Trans Native Plant Landscaping Project.  We're talking Mega-Overkill with regards another industrial sized Rainbird Irrigation System which has a double daily watering regimen which has not been changed since the initial installation. The photo to the left here is on the top ridge of the development which buffers between the neighbourhood housing and the wild Conservation No Trespassing protected area. While I applaud the use of Coast Live Oak and other ornamental chaparral shrubs, there are weeds overwhelming the system everywhere, especially in the lower valley near Pepper Drive Elementary School. If they were worried about some naturalized Torrey Pines potentially causing brushfires and insisted they had to be chopped down, then they have almost guaranteed fire disaster by the multiple hectares of weed infested landscape which now encircles this entire Private Rich Folk Community Habitat. The really sad part is when Government, which everyone assumes knows better, pulls blunders like this terrible landscape layout, then to be followed by a large commercial Landscaping firms, what chance is there that your average home and/or land owner will ever get the message ? I'm telling you, this simple basic fundamental stuff about nature needs to be taught long before College or even High School level learning. It should be elementary School teaching.

Photo Credit: Mine
While it is commendable they have established some Coastal Live Oak trees and other native chaparral plants, they will ruin it all if they don't change a flawed irrigation system that has existed for over 8 years now. 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Further Interesting Reading:
Juan Bautista de Anza National Historic Trail Historic Resource Study
I'll have a series of posts dealing with Juan Bautista de Anza's Journal and Natural World documentation experiences and divide them into three or four parts. They are seriously important to what nature once was and how it functioned. They were also detailed in such a way as to report on the local Natural resources which were present and potential money making Ventures for the Empires for who these expeditions were funded for in the first place. Anza's description was almost dead on accurate for the region I'll be relating to between Western Arizona all the way to Riverside California. Keep close watch.
Side note on Alluvial Basin Water Storage: Arizona Geology Blog
Aquifer depletion, Arizona alluvial and Black Mesa basins

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