Carrizo Plain Self-Guided Tour - text version Introduction & History
Hi, I’m Johna Hurl, Carrizo Plain National Monument manager. Follow along with me to explore some of the special places in one of America's newest national monuments. This is a tour that needs to be taken when the roads are dry. Some roads, especially Simmler road, are impassible if it has recently rained. Make sure that you are prepared by having plenty of fuel in your car, food and appropriate clothing before you start. There are also opportunities to hike at the different stops if you wish. The tour includes three stops. Our first stop will be at the Soda Lake Overlook. Next we will venture to the the visitor center and our last stop will be at Wallace Creek along the San Andreas fault.
First, a little history.
Since the mid-1800s, large portions of the grasslands that once spanned California's nearby San Joaquin Valley, have been converted to agricultural, industrial, and urban land uses. Though some of these uses have taken place in the monument years ago. It is now the largest undeveloped remnant of this ecosystem, providing crucial habitat for the long-term conservation of many native plant and animal species that inhabit the area.
In 1984, The Nature Conservancy and the BLM agreed to explore the possibility of acquiring extensive lands in the Carrizo Plain region. This land, to be set aside for preservation and restoration, would function as a single, large "macropreserve" for the rare and endangered San Joaquin Valley species, as well as other vegetation and wildlife.
A steering committee was formed in late 1985 to guide the conceptual development of the project that eventually became the Carrizo Plain Natural Area.
In January 1988, The Nature Conservancy purchased 82,000 acres of the Carrizo Plain from Oppenheimer Industries. BLM received funding from Congress in 1988 and 89 to acquire 51,500 acres. Since then, the monument has grown to a quarter-million acres.
Surface ownership within the monument boundary is a mixture of the BLM, The State Department of Fish and Game, The Nature Conservancy and other private owners. The BLM, the California Department of Fish and Game and the Nature Conservancy are the monument’s managing partners.
On January 17, 2001, the President of the United States signed a proclamation designating the former Carrizo Plain Natural Area, as a National Monument.
Even today, the Carrizo is one of the best kept secrets in California. The monument receives about 30,000 visitors annually, most from December through May. Although it’s only a few hours from Los Angeles, the Carrizo offers visitors a rare chance to be alone with nature. Some visitors say you can “hear the silence.”
While you drive throughout the monument you may see numerous hawks, lizards and other wildlife, and if you are here during the spring, you may be fortunate enough to see a beautiful wild flower display. No matter what the season, the saying: "The closer you look, the more you see" is certainly true.
The monument offers refuge for endangered, threatened, and rare animal species, such as the San Joaquin kit fox, the blunt nosed leopard lizard, and the giant kangaroo rat. In small pools of water, you may be fortunate enough to see: the long horn fairy shrimp, and the vernal pool fairy shrimp. It supports important populations of pronghorn antelope and tule elk, and was the first place in California where these two native species could once begin to roam together. The area is also home to many rare and sensitive plant species, including the California jewelflower, the Hoover's woolly-star, the San Joaquin woolly-threads. Despite past human use, the size, isolation, and relatively undeveloped nature of the area make it ideal for long-term conservation of the dwindling flora and fauna characteristic of the San Joaquin Valley region.
You may ask how did the Carrizo get its name? Well, one speculative story is that when the early Settlers came to the plains they called it, "llano estero" referring to a salt marsh plain. Then later, as others came to the plains, the name changed to "Carrizo Plain." The word "Carrizo" referred to a grass that grew very tall. It was said that the grass touched the bellies of their horses as they rode across that plains. Then as more settlers came the name change once again to Carrisa. "Carrisa Plains" was used up to the time that the managing partners acquired the land. A decision was then made by the partners to return to the earlier name and called it the Carrizo Plain.
Other information about the name and spelling came from the first post office on the Carrizo Plain which was founded in 1882 and was located at the El Saucito Ranch, which is located west of the visitor center a couple of miles. Now let's talk a little bit about the farming and ranching history.
As you drive through the plain, you may see remnants from the farming and ranching efforts on the plains. One of the first rancing operations took place at the historic El Saucito rance. Ranch tours can be scheduled through the visitor center.
Much of the Carrizo was dryland farmed. Wheat and barley were the two main crops. Occasionally safflower was planted. After the harvest, the "stubble" was grazed mostly by cattle, but also by sheep.
Because of the unpredictable weather and rainfall, some years farmers had great crops but many years crops were marginal. It was often described by the old ranchers as boom or bust!
You'll continue to see cattle and sheep grazing as you drive around the monument. There are still some large, private ranches within the monument boundary that continue to graze cattle and do some limited farming. The managing partners continue to use grazing on public lands as a tool when there is an overabundance of non-native grasses. Grasses and other exotic weeds can choke out some of the sensitive species we have been mandated to manage for.
Stop 1 - Soda Lake Overlook
At our first stop starting here at the Soda Lake Overlook we will make a loop through the northern end of the monument visiting Soda Lake, the Visitor Center, and the San Andreas Fault. This is just a small portion of the monument so you may want to do some more exploring on later visits.
If you walk up he trail to the top of the Soda Lake Overlook, you can see some of the geologic features of the monument.
The Carrizo Plain encompasses two plains: the Elkhorn and the Carrizo. The Elkhorn Plain, nearly 20 miles long and two miles wide, lies at the base of the Temblor Range that you see to the northeast. The elevation of the Elkhorn Plain ranges from 2,300 feet at the southern end and gently rises to 2,500 feet toward the north where it gradually terminates with the San Andreas fault.
Movements of the San Andreas Fault formed the Elkhorn and Panorama Hills that separate the Elkhorn Plain from the Carrizo Plain. The Carrizo Plain, located west of the San Andreas Fault, extends to the eastern base of the Caliente Range. The valley floor is 50 miles long and six miles wide with an average altitude of 2,000 feet.
The Caliente Range, rises to 5,104 feet, is a prominent backdrop to the southwest, while the Temblor Range to the northeast rises to about 4,300 feet. The southern end of the Caliente Range bends east to parallel the Transverse Ranges.
During earlier periods of geologic history, runoff from the Carrizo Plain drained north via the ancestral Salinas River. Since then, uplift at the north end of the Carrizo Plain has cut off this drainage causing all runoff to drain to the lowest part of the plain - Soda Lake.
We’ll explore the geology a little more when we get to Wallace Creek.
Soda Lake is the largest remaining natural, alkali wetland in southern California and the only closed basin within the coastal mountains. Evidence suggests that a river ran through the plains first flowing north to the ancestral Salinas River and then with uplifting from the fault the flow reversed and flowed south. With time and more uplifting outlets were cut off and Soda Lake was formed as an internal basin. As its name suggests, Soda Lake concentrates salts as water is evaporated away, leaving white deposits of sulfates and carbonates that look like baking soda. Sodium sulphate was recovered from Soda Lake beginning in the early 1900s. Brine was pumped into shallow ponds and concentrated by solar evaporation. Salts were then collected and refined on site. A refining plant initially was located on the southwest shore of the lake. In the late 1930s the refining plant was moved north, across the narrow neck on the east end of the lake. Sodium sulphate is used in the manufacture of detergent, kraft paper, textiles and glass. Some remnants of these historic operations is evident today.
Despite this harsh environment, plant and animal species are well adapted to this alkali setting. Birds and insects thrive in the shrubs that surround the lake and when conditions are right, numerous wildflowers bloom in the fields. The lake itself is important to migratory birds. During the winter months the lake may fill with water turning it into a roosting and feeding place for many migratory bird species such as sandhill cranes, American avocets, black-necked stilts and long-billed curlews.
Let's get closer to the lake. There is a parking area closer to the boardwalk or you may walk from the Soda Lake Overlook parking area. Whichever way you go, please stay on existing trails.
Here we are at the boardwalk. During the winter, Soda Lake may have enough water to be a shallow lake. The depth of the water varies depending on the amount of rainfall, but averages between 1-3 feet. In one really wet year the water level reached all the way up to Soda Lake Road at the base of the Overlook Hill.
In the dry months, water lies just below the salt crust. Be careful if you walk out there, because you may break through the crust and sink into the mud. We prefer that you stay on the Boardwalk.
The plant community that surrounds the lake is very rare. Plants in this community have adapted to the high levels of salt. The dominant shrub next to the edge of the lake is called Iodine Bush. The next dominant shrub is spiny saltbush. Both of these plants have special features that allow them to survive in the presence of so much salt. Often in the sunlight you can see the salt sparkling on the leaves.
If you are here when there is water on the lake, look out to see if you can spot any of the the migratory birds. Look close. One of the birds that you might see is the sandhill crane. They are most often seen and heard, early in the morning leaving the lake and in the evening returning. They use the lake as a roosting place. This protects them from predators such as coyotes. During the day they go out to feed. Historically they used to feed in the adjacent farming fields. There are still some areas being farmed northwest of the monument that the cranes use to feed in. If there is no water on the lake the birds will not stay on the monument but will travel to other areas such as Pixley and Kern National Wildlife Refuges in the San Joaquin Valley. If you do not see cranes, look for other birds that may be swimming in the lake or foraging in the plants nearby.
Now, instead of looking across the lake, try looking closely down into the water. You may see little, feathery looking things swimming in the lake. These are most likely tiny brine shrimp or artemia that inhabit the lake when it has water. Measuring only 8-10 mm, bring shrimp can live in water that has up to five times the concentration of salts that sea water has! They serve as a food source for some of the birds that visit the lake.
Stop 2 - Visitor Center
Okay now let's head to the Visitor Center. Proceed south on Soda Lake Road approximately 7 miles until you see the sign for the turn off.
Welcome to the Visitor Center. This is where you can sign up for tours to different points of interest as well as get information regarding the monument. Inside the center you will discover many of the significant aspects of the Carrizo.
If you are interested in the native plants of the Carrizo we have a native plant garden here. There is a brochure that you can use to help identify the native plants as you walk around the garden. There are picnic tables available as well under some of the cottonwood trees where you may want to rest or have lunch. As an added bonus, you may be visited by a resident cottontail or a Greater roadrunner while you eat.
Outside toward the back of the visitor center you will also see some of the historic farming equipment used on the plains. That tall, slender structure that you see is the remnant of a grain elevator. The grain was dumped at the base and the elevator lifted the grain up and dispersed it into the tanks that used to be below.
Up the hill to the west you can see Painted Rock. Painted Rock, although vandalized with graffiti when in private ownership, is considered one of the most important Native American pictograph sites in California.
The Painted Rock Trail and vehicle parking area is located less than 3/4 mile from Painted Rock. Painted Rock is monitored for protection and to keep on-going record of the site's condition. It is also closed to the public during the summer solstice to allow Native American use. Public access is restricted to guided tours from March 1 through July 15 to protect sensitive cultural and wildlife resources.
The monument has significant archaeological and historical resources. Human prehistory of the Carrizo Plain probably began near the end of the Pleistocene. This is suggested by the presence of Soda Lake on the Carrizo Plain and the nearby Paleo-Indian Period sites located at Tulare Lake, Buena Vista Lake, and the Tehachapi Mountains dating back to circa 11,000 - 9,000 B.C.. Bedrock mortar milling features and elaborate pictographs show prehistoric occupation of the area. Ethnographic information for this region of California is not well defined, but research indicates that the Carrizo Plain is near the interface of three different cultures, the Chumash, the Southern Valley Yokuts, and the Salinan.
Now let’s go to Wallace Creek for a look at the San Andreas Fault and talk about the monument’s geology. If you need to use any of the facilities before you leave this would be a good place to do it. Now let’s go to Wallace Creek for a look at the San Andreas Fault and talk about the monument’s geology. You will need to go back to Soda Lack Road and go north (left) approximately 1 mile and turn right on Simmler road. Make sure that it is not wet or you will get stuck. This will take you to Elkhorn Road where you will turn right. Proceed approximately 3 miles to the pullout for Wallace Creek.
Stop 3 - Wallace Creek
Welcome to Wallace Creek. There is a short trail that will takes you up to the Wallace Creek which is an offset drainage created by the fault activity. The geology of the Carrizo Plain is the product of millions of years of erosion, sediment deposition, faulting, volcanism and uplift. From a geological perspective, the mountains and valleys are relatively young. Most of the sediments which consolidated to form the rocks were deposited well after the extinction of dinosaurs.
Marine sedimentary rock predominates in both the Caliente and Temblor Ranges. This
sedimentary rock has both a non-organic and an organic origin. Non-organic sedimentary rock includes sandstone, clay-shale and conglomerate containing boulders and cobbles. Sedimentary rock of an organic origin includes shale composed of the remains of microscopic plants and animals with a varying component of clay. Additionally, sandstones, shales and conglomerate of marine and non-marine origin are interlayered with volcanic flows in the Caliente Range.
The San Emigdio and Sierra Madre Ranges to the south consist of similar rock formations. However, these ranges are orientated east-west compared to the north-south trend of the Temblor and Caliente Ranges.
About nine million years ago, the granitic northern Gabilan Range lay directly west of the
present-day southern Temblor Range. Boulders, cobbles and coarse sand were eroded from this granitic terrain into a near-shore environment. Movement on the San Andreas Fault has since displaced the northern Gabilan Range 120 miles north. The sedimentary rock is exposed in the vicinity of Cochora Ranch in the Temblor Range and is known as the Santa Margarita Formation.
The Carrizo is distinguished for its world-class fossil assemblages (paleontology) and well exposed rock outcrops (stratigraphy).
Several rock formations were first recognized and defined within the Carrizo. Which include: the Paso Robles, Caliente and Morales Formations.
The Caliente Formation contains diverse terrestrial fossil remains interfingered by fossil-bearing marine sedimentary rocks. The formation records continuous deposition during the Miocene Epoch (from 13 million to 25 million years before present) and contains the original type locale for an early horse species.
The San Andreas Fault, 625 miles long, traverses the Carrizo from north to south near the
western base of the Temblor Range. The surface trace of the fault is displayed by creek bed offsets and fault scarps, which are particularly well-preserved in the Carrizo Plain. In part because of the preservation of these physical features, there has been considerable academic research of the fault.
The Fort Tejon earthquake of 1857, with a magnitude over 8.0, was centered in the Carrizo and is probably the strongest earthquake to hit California in historic time. Surface ruptures extended 200 miles and offsets of 30 feet occurred within the Carrizo. Future seismic activity within the Carrizo is highly likely.
Research has been conducted on geological and paleontological aspects of the Carrizo since the 1906 San Francisco earthquake. Recent geophysical investigations measuring natural electrical current present at the earth's surface have been particularly successful due to the Carrizo’s isolation from population centers and lack of electrical interference.
These investigations provide geophysicists a passive method to determine rock types several miles below the surface to help study the geology across the San Andreas Fault.
Low rainfall and sparse vegetation enhance opportunities to map geologic
formations and features. Work within the monument has enabled reconstruction of earthquake events over the last 2,000 years and has improved understanding of the San Andreas Fault, as well as the climatic history that resulted in Soda Lake and its eventual evaporation.
Well, that’s our last stop on our tour. From here you can return to Soda Lake Road via Simmler Road or you can continue your adventures exploring the rest of the monument.
We hope you’ve enjoyed this tour and will come back to the Carrizo Plains soon.