SR-74 Structures and Railing Project


Caltrans Logo

RIV-74 Replace Structures/Upgrade Railing Project

  • Riverside County, California
  • RIV-74 PM 2.9/3.2 at Morrill Canyon Bridge (Ortega Highway)
  • RIV-74 PM 53.4/53.7 at Strawberry Creek Bridge (Pines-to-Palms Highway)
  • EA: 1G470 /PN: 0816000001

Project Description

The California Department of Transportation (Caltrans) proposes to replace Morrill Canyon Bridge (Bridge No. 56 0169, Post Mile [PM] 3.08 and Strawberry Creek Bridge (Bridge No. 56 0180, PM 53.5) on State Route 74 (SR 74) in Riverside County. Morrill Canyon Bridge is located a few miles east of the Orange County line and west of Lake Elsinore near the community of El Cariso on the Ortega Highway (SR 74), and the Strawberry Creek Bridge is located a few miles east of Hemet and west of Mountain Center on the Pines-to-Palms Highway (SR 74). In May of 2021, the project description was modified to include railing replacement only (i.e. partial demolition), not full bridge replacement, and placement of new precast/prestressed concrete slabs over the existing arches.

Project History and Agency Coordination

Between May of 2019 and March of 2021, Caltrans conducted the environmental review process pursuant to CEQA, NEPA, and other related environmental regulations, including NHPA (National Historic Preservation Act) Section 106. That law requires that Federal Agencies (and/or state agencies using federal funding or permits) to consider the potential effect their projects (Undertakings) may have on Historic Properties. Through the Section 106 process, Caltrans determined that there are three Historic Properties that will be affected by the project: the Morrill Canyon Bridge, the Strawberry Creek Bridge, and the Pines-to-Palms Highway. The consultation, which included coordination with the State Historic Preservation Officer (SHPO),  culminated in the determination that the project would have an adverse effect on historic properties. Caltrans and the SHPO executed a Memorandum of Agreement (MOA) that outlined measures to mitigate the project’s adverse effects on historic properties.

While the project description was modified to allow partial demolition (bridge railing only) instead of full replacement, the project will still result in an adverse effect to the two historic bridges due to the extent of alteration involved. Mitigation outlined in the MOA included: production of Historic American Building Survey (HABS)/Historic American Engineering Recordation (HAER) documentation, development of context-sensitive bridge designs or aesthetic treatments, development of historic context materials to be placed on a project-specific and public-facing website, development of a construction monitoring plan, and other (standard) mitigation measures regarding discovery of human remains or related cultural items and/or artifacts, and late-discovery provisions.

Through the project development process, Caltrans architectural historians, landscape architects, and engineers developed context-sensitive bridge designs which will be implemented for the project. In addition, Caltrans architectural historians worked to develop Historic American Engineering Record (HAER) documentation consisting of large format photographs and written and descriptive text and data for the Morrill Canyon and Strawberry Creek bridges which will be sent to the Library of Congress. Much of the historical and contextual information presented below in fulfillment of Caltrans’ effort to provide a public-facing website for educational purposes, was gleaned from the HAER documentation prepared for the project.

Project Status: Project design has been completed with a Ready-to-List (RTL) date of June 2022 and an award date of December of 2022. 

Construction Duration: Currently estimated to be December 2024 to December 2027.  

Project Location: In Riverside County on Route 74 at two locations; one between PM 2.9 and PM 3.2 at Morrill Canyon Bridge on the Ortega Highway; and the second between PM 53.4 and PM 53.7 at Strawberry Creek Bridge on the Pines-to-Palms Highway. 

Project Cost Estimate:  Project cost estimated at $17.89 million, partially covered by the State Highway Operation and Protection Program (SHOPP) and by Senate Bill 1 (SB-1), along with other state and federal funding programs.

Project Partners: The California Highway Patrol (CHP), the Federal Highway Administration (FHWA), the State Historic Preservation Officer (SHPO), the California Department of Fish and Wildlife (CDFW), the Regional Water Quality Control Board, the US Army Corps of Engineers (USCOE), and the US Fish and Wildlife Service (USFWS).

Resource Significance and Context:

Caltrans identified three historic properties in the project area of potential effect (two bridges and a highway) and assessed the impacts the project will cause to the resources. Both the Morrill Canyon and the Strawberry Creek bridges are historic structures and the latter span is also located on the Pines-to-Palms Highway which is a historic linear resource. The two bridges are significant examples of a rare bridge type in the region; the earth-filled, closed spandrel, masonry arch. While more common in other portions of the country where earlier example can be found, masonry arches and specifically those constructed largely of stone, are rare in California and rarer in Southern California because fewer of them were built here in the first place. Most built in the state were constructed between 1880-1935, with a few exceptions The two bridges at Morrill Canyon (1931) and at Strawberry Creek (1929), were constructed on early rural and mountainous highways built by Riverside County during a period of expanding automobile use that took place just after World War I, which necessitated further highway and bridge construction in the state.   The Pines-to-Palms Highway is significant for the role it played in the development of the mountain areas of Riverside County for travel and recreation during the early years of the 20th century.

Masonry Arch Bridge Context:

Masonry arch bridges are constructed of stone or brick. They are durable and can carry heavy loads as long as the arch is structurally sound.  Pure stone bridges (i.e. those with no concrete components) are one of the oldest vehicular bridge-types used in the United States still likely to be extant due to their durability. It is unknown when the earliest bridge in the world was built, although stone bridge foundations from approximately 4,000 B.C.E. (before common era/B.C.) have recently been excavated in Iraq. China was apparently building stone bridges as early as 3.000 B. C. E., and Greece still boasts the Arkadiko Bridge, built in 1300 B. C. E., which consists of boulders stacked up in an arch form with a triangular-shaped key stone. Masonry arches were a common bridge type during the Roman Empire, as Romans were known for building durable round or semi-circular arch-construction, which they utilized in stream crossings and in the construction of extensive aqueduct systems. The oldest know bridge still in use currently is likely the stone arch Caravan Bridge in Turkey, constructed in 850 B. C. E. The earliest masonry arch bridge still in use in China is the Anji (Safe Passage) Bridge, also known as the Dashi (Big Stone) Bridge, dates to 595-605 C. E. (common era/A.D.). The Romans built the Nimes Aqueduct and famous Pont du Gard viaduct in Italy, which dates to the 1st century C. E. Many Roman bridges remain in Turkey, Italy, Greece, and Spain, as well as Austria, Germany, England, and France. Early examples of masonry bridges also include the Severen Bridge (c. 200 C. E.), and the Karamagara Bridge in Turkey (5th or 6th century C. E.). One Roman masonry arch bridge in Sardinia, the Sant’ Antioco Bridge, was restored during medieval times for reuse.

Masonry arch bridges have a much briefer history in the United States. Many of the earliest vehicular (non-railroad) bridges in the U. S. were made of wood, as this was a readily available material, and are no longer extant. By at least the 17th century, the major population centers of Boston, New York, and Philadelphia had stone bridges. The earliest masonry arch bridge still standing in the United States is the Frankford Avenue Bridge in Philadelphia which was built in 1697. So-called “Post Roads” were constructed along the eastern seaboard to facilitate travel and communication and George Washington toured these important and vital routes in 1789. Construction of the National Road between 1811 and 1834 connecting Cumberland Maryland to Vandalia Illinois, spurred construction of stone arch bridges, culverts, and sign posts (mile markers) in the five states the early highway passed through. In 1806, Congress had authorized funding for construction of this newly proposed trans-Appalachian route, as there was a growing national interest in connecting the colony states with territories located further inland, opening up the “frontier” areas to settlement, commerce, and industry. A fair number of these stone arch bridges are still extant, although the original alignment has been bypassed by US 40. The oldest spans still extant are likely Casselman Bridge (1813) in Maryland and Great Crossings Bridge (1813) in PA, followed by Elm Grove Bridge (1817) in West Virginia. Most of the masonry arch bridges built on the National Road date from the 1820s and 1830s.

By the 1870s, a very few stone bridges had been built in California. According to Caltrans data from 2003, most of the stone arches still extant date from between 1900 to 1909. The majority are in Northern California in Napa and Sonoma counties, with a few distributed among the other counties in Northern and Central California. Compared to other regions of the state, even fewer stone arch bridges were built in Southern California. The 2003 survey included eight masonry arch bridges of note (meaning relatively unaltered) in Southern California; four in Santa Barbara County, two in Riverside County, one in Ventura County, and one in San Luis Obispo County. The oldest stone (highway) bridge in the state appears to be Main Street Bridge in Napa (built in 1860 and rehabilitated in 1985), followed by the Pope Street Bridge in St. Helena built in 1894. The Alvord Lake Bridge in San Francisco (Golden Gate Park) was constructed in 1889 by Ernest Ransome using reinforced concrete, a new material, and shows that in the far west, bridge building technologies of stone and reinforced concrete were both being utilized within a very short time frame, although the use of stone for bridge construction clearly pre-dates reinforced concrete. Both the Morrill Canyon and Strawberry Creek bridges belong to a second period of stone masonry arch construction that took place between approximately 1915 and 1935 and was linked to highway design preferences for roads and highways in rural and mountainous locales. Stone was often chosen as a bridge building material for short spans (100 feet or less) for economical reasons- if the material was sourced locally which cut down the transportation costs, and was an especially important material for public employment programs that took place during the Great Depression as masonry work was labor-intensive and federal and state governments were trying to put as many people as possible to work. Stone masonry was also popular during this same era for aesthetic reasons, as this type of design (masonry arch or combination concrete with masonry) was viewed as a more “natural” and rustic option.    

Morrill Canyon Bridge

The Morrill Canyon Bridge (Bridge No. 56 0169) was constructed in 1931 on the Ortega Highway (SR 74) at PM 3.08 by Riverside County. Riverside County exemplifies the trend of locally built bridges designed by the county surveyor or county engineer. All of the bridge structures in the county dating to the late 1920s and early 1930s likely were designed and built under the supervision of County Surveyor Alexander C. (A. C.) Fulmor, who influenced infrastructure growth in the county from the mid-1910s through the mid-1930s. The as-built drawings for the Morrill Canyon Bridge dated May 13, 1931, carry his signature, although it is not known if he designed the bridge or just certified the final plans. Given the authority for bridge design granted to the county surveyor at that time in California, it is likely that Fulmor designed the bridge. The bridge was originally constructed, owned, and maintained by Riverside County.

Many of the stone highway bridges in California were designed and constructed at the local-government level. Most bridge construction in the state in the late 1880s through the early twentieth century was completed by local governments under the direction of the country surveyor. The state legislature adopted a comprehensive transportation program in 1874, which enabled county governments to establish road commissions and road districts, and to levy property taxes for construction purposes. In 1893, a state law was passed specifically mandating that each county must complete bridge design and construction under the advice and supervision of a county surveyor. In 1907, the Savage Act again empowered counties to incur bonded indebtedness in order to finance the design and construction of roads and bridges, an indication that this was a growing need within the counties at that time. The Morrill Canyon Bridge was originally constructed, owned, and maintained by Riverside County. By April of 1936, the state had conducted the first inspection in a series scheduled to take place every two years, indicating the state had taken over jurisdiction of the highway (and its bridges) by that point.

The Morrill Canyon structure is a significant example of a single-span, closed-spandrel, earth-filled masonry arch bridge. The arch is approximately 30 feet wide (measured parallel to the road) and is about 8 feet high from the streambed up to the arch key (center) stone. The top of the parapet railing is 6.5 feet above the center of the arch, giving the bridge a total height of 14 feet. The bridge consists of a single stone arch covered with a thin layer of concrete, masonry spandrel walls, curved and flared masonry wingwalls, earth fill, roadway deck and pavement, and masonry parapet railings with projecting masonry wheel guards on the inside of the solid parapet railings. Outside of the rustic stone used (which appears to be a local granite, blue-gray in color) and the parapet railing that curves gently downward at each end of the bridge to meet the flared wingwalls, the masonry arch span is devoid of any decoration or other ornamentation. Modern metal beam guardrail has been mounted to the end the railings at the bridge approaches.

Strawberry Creek Bridge

The Strawberry Creek Bridge (Bridge No. 56 0180) was constructed at Post Mile [PM] 53.5 on the Pines-to-Palms Highway portion of Route 74. The bridge was constructed by Riverside County in 1929 under the direction of Alexander (A. C.) Fulmor, who was the county surveyor at that time. Many of the stone highway bridges in California were designed and constructed at the local government level. Most bridge construction in the state in the late 1880s through the early 20th century was completed by local governments under the direction of the country surveyor. In 1874, the state legislature adopted a comprehensive transportation program that enabled county governments to establish road commissions and road districts, and to levy property taxes for the construction of road infrastructure. In 1893, the state passed a law mandating that each county must complete bridge design and construction under the supervision of the county surveyor. In 1907, the Savage Act again empowered counties, allowing them to incur bonded indebtedness to finance the construction of roads and bridges, a general indicator that this was a growing concern in most, if not all, counties in the state. Riverside County exemplifies the trend in locally built bridges designed by the country surveyor. No as-builts for the Strawberry Creek Bridge exist, but a small raised concrete plaque mounted to the top of the south parapet reads “R. C. P. C.” (Riverside County Planning Commission) with the date of construction, clearly indicating the county was involved in the design and construction of the bridge. It is likely that the bridge was designed by, or under the direction of A. C. Fulmor, the county surveyor, who was responsible for construction of bridges in the county. On May 1, 1936, the state conducted the first in a series of bridge inspections that took place from that point on at an interval of every two years, indicating that by that point, the state had already taken over jurisdiction of both the highway and the bridge.   

The Strawberry Creek Bridge is a significant example of a single span, earth-filled, masonry arch bridge. The bridge has been identified as a contributor to the Pines-to-Palms Highway, a linear historic resource that is located between Valle Vista (near Hemet) and Palm Desert. While the western section of the highway that parallels the San Jacinto River within the flatter flood plain, was constructed overlapping an earlier roadway, the portion in the vicinity of Strawberry Creek and further east, was on a new alignment. The new so-called “high-gear” road was vital to growing recreational use, tourism and travel in the San Jacinto and Santa Rosa Mountains. The Strawberry Creek Bridge spans a rocky stream channel lined with oaks and sycamore trees. The arch measures almost 38 feet wide at the base, with a height of 12 feet above the creek. The top of the parapet railing is 5 feet above top of the arch, for a total bridge height of 17 feet. The roadway width is approximately 23 feet (measured curb to curb) and the bridge structure is just over 48 feet long, measured along the centerline of the road. Modern metal beam guardrail has been mounted to each of the ends of the parapet railing at the bridge approaches. The main visual element is the curving vertical walls of the masonry parapet railing and adjacent wheel guard (curb). The Strawberry Creek Bridge is devoid of decoration or any other type of ornamentation. The stone used is rounded  and varies in color between a light gray and tan, to a darker brown and reddish brown. It appears to be speckled granite that was likely locally sourced.

Pines-to-Palms Highway

The Morrill Canyon Bridge and the Strawberry Creek Bridge were built on separate sections of Route 74 in mountainous areas of Riverside County. The western portion of Route 74 between Orange County and Lake Elsinore is known as the Ortega Highway, and is within the Cleveland National Forest. The section between Hemet and Palm Desert is known as the Pines-to-Palms Highway, and is within the San Bernardino National Forest, as well as within the Santa Rosa and San Jacinto Mountains National Monument. The Ortega Highway was evaluated for a previous road improvement project in Orange County and was found to be not eligible for listing on the National Register of Historic Places. The Pines-to-Palms Highway was determined to be eligible for listing on the National Register of Historic Places (NRHP) in 2014 in agency coordination for a Caltrans project. The limits of the historic property are from PM 47.23 (east of Hemet) to PM 92.80 which is near Palm Desert. The resource was found eligible under NRHP Criterion A at the local level of significance for its important regional role in  early 20th century tourism and recreational infrastructure development. The linear historic resource is 45.57 miles long and includes multiple contributing features such bridges, masonry culverts and headwalls, (along with the general alignment and physical configuration of the roadway), and a series of masonry curbs and gutters near Palm Desert below the famous Seven Level Grade.

The Pines-to-Palms Highway corridor has a complex development history. The current route crosses the ancestral homeland of the Cahuilla Indians. Indigenous peoples developed a network of trails in the area that dates back thousands of years. These trails connected the desert to upland hunting and gathering locations via trails up Palm Canyon and into the Pinon Flats area by way of Carrizo Creek, and these trails have a long tradition of use. Outside of the ancient trail system, early wagon (toll) roads were built into the area beginning in the 1870s from the direction of Hemet. These early roads lead into the mining area around Rayneta on upper Strawberry Creek, various timber stands that were being logged in and around at Dutch Flat, and a cluster of campgrounds and tourist hotels in Strawberry and Fern valleys that would later become known as Idyllwild. In 1891, the Lake Hemet Water Company began construction of a masonry dam southwest of Mountain Center at the headwaters of the South Fork of the San Jacinto River to provide water to San Jacinto Valley (Hemet and San Jacinto vicinity). Hauling equipment and supplies into the upper Garner Valley for the dam required construction of a road wide enough for freight wagons and the six-mule teams that pulled them. By at least 1911-12, the county had constructed a road up the San Jacinto River canyon as far as the toll road at Oak Flats, a mile or so west of where Strawberry Creek joins the San Jacinto River. By the 1910s, most of the toll roads leading into the area had been converted to public “control” roads. Due to the growing number of automobiles trying to use the mountain roads, safety concerns and limited road capacity required set hours of one-way traffic. The new highway route that was laid-out starting in 1928 up the San Jacinto River Valley overlapped portions of the earlier toll roads and a twisting county route that had suffered many washouts, most of the road was placed on an entirely new alignment, The new and improved alignment eliminated some of the drainage and flooding problems that had plagued the earlier roads and included relocation and realignment of the San Jacinto River itself within the lower canyon area. From Dry Creek (just east of Strawberry Creek) the highway struck out in a new direction, leading due west up a steep ridge and around White Post Turn (named for the white post markers that were along the outside of the turn), then east to Mountain Center and into the Idyllwild area. From the junction in Mountain Center, the new highway lead southeast to Garner Valley, then east through Vandeventer Flats, descending through a rocky ridgeline and into Ribbonwood. From there the roadway straightens out and cuts across a plateau south of Asbestos Mountain, losing elevation gradually approaching Pinon Pines where the Nightingale campground was later built, past the prominent visual landmark of Sugarloaf Mountain, curving through towering boulder stacks and craggy rock formations at Black Hill, then skirts along the edge of Deep Canyon and past Haystack Mountain. From there the highway passes through a gap in the ridge above the desert and down the dramatic and looping Seven Level Grade to Palm Desert. The section between Hemet and Mountain Center was built as Forest Highway (FH) 72, while the section east from Mountain Center to Palm Desert it was built as FH 70.      

While the Ortega Highway was an early highway route into the mountains, it was located in an area already served by a series of north-south roads popular for automobile tourists. In contrast, the Pines-to-Palms Highway opened up a much larger area, especially the area between the lower Garner Valley and Palm Desert where there had been virtually no highway access previously. The road was heavily lobbied for by two main groups; those trying to expand the state park system in the San Jacinto Mountains, and a group of businessmen in Indo and surrounding desert towns in order to provide residents with access to higher and cooler elevations. (This was especially important during summer months as air-conditioning was not common at the time.) Construction of the Pines-to-Palms Highway involved Riverside County which provided the labor and hired contractors for the construction of the road using funds provided by the county initially, and later by the federal government, as the proposed route passed through Forest Service land and would provide reliable access for fire suppression and control purposes. Records indicate the eastern section starting at “Mile 22” (of FS 72) which would be at about Sugarloaf Mountain, then northeast to Palm Desert, was located with  direction proved by the United States Bureau of Public Roads- at the time located within the US Department of Agriculture- because the rugged topography presented so many engineering challenges. The portion of the highway between Hemet and Mountain Center, which presented less of an engineering challenge, was surveyed and constructed first and was complete by April of 1930. Construction of the highway between Mountain Center (just south of Idyllwild) and Palm Desert began in January of 1930, but was delayed for months when the alignment through the Santa Rosa Mountains was debated. The eastern section of the highway between Mountain Center and Palm Desert was completed in late July of 1932. By 1934, the full length of the Pines-to-Palms Highway between Hemet and Palm Desert had been officially adopted as a state route. The Pines-to-Palms Highway also carries both a California Scenic Highway (1971) and a National Forest Scenic Byway (1993) designation.


Federal Highways Administration (FHWA), Back in Time: The National Road (

Ham, Stacie, Survey and Evaluation of Masonry Arch Bridges (Sacramento, California: Division of Environmental Analysis, California Department of Transportation, 2003)

McMorris, Christopher, Report and Figures, Vol. 1 of Caltrans Historic Bridge Inventory Update: Concrete Arch Bridges (Davis, California, JRP Historical Consulting, 2004)

Parsons Brinckerhoff and Engineering and Industrial Heritage, A Context for Common Historic Bridge Types, NCHRP Project 25-25, Task 15 (for the National Cooperative Highway Research Program, the Transportation Research Council, and the National Research Council, 2005)

Smith, Mary K. and Steven Holm, Finding of Effect for RIV 74 Rail Upgrade/Bridge Replacement Project (San Bernardino, California, California Department of Transportation, 2020)

State of California Department of Transportation, 1936 Bridge Reports, Bridge No. 56-169 (Morrill Canyon) and Bridge No. 56-180 (Strawberry Creek), on file, California Department of Transportation, Division of Maintenance, Structure Maintenance and Investigation, Bridge Inspection Records Information System (BIRIS), Los Angeles.