The Matilija Creek Giant Reed Re-Treatment Project was initiated in Fall 2007 with the goal of eradicating a suite of non-native plant species that heavily infested the floodplain of the main stem of the Ventura River and Matilija Creek. The purpose of the project is to improve habitat quality in the floodplains of these drainages in advance of the future removal of Matilija Dam. Re-treatment of the project area for the same species targeted during the initial treatment began in May 2008 and have continued from one up to three times annually to date. Although complete eradication of the target species throughout the project area is not possible because of constant input of propagules from source populations beyond the boundaries of the project area, the cumulative effect of these re-treatments have transformed floodplain habitats that formerly were infested with invasive, non-native vegetation into native-dominated plant communities where the target species are a minor component.

The Matilija Dam, originally constructed in 1947, has outlived its usefulness. Since construction it has filled with approximately 8 million cubic yards of sediment, and the condition of the dam itself has deteriorated so it no longer serves the purpose of providing water supply and flood protection to the community.

The Matilija Dam Ecosystem Restoration Project has many elements leading up to eventual dam removal, providing many benefits. See webpage for more information: https://www.vcpublicworks.org/wp/mderp/

The SCR-1 levee, constructed in 1961 by the U.S. Army Corps of Engineers (USACE) and owned and maintained by the Watershed Protection District (WP), extends from Highway 101 to South Mountain along the east bank of the Santa Clara River. It protects from flooding parts of the City of Oxnard, the Riverpark development, and unincorporated areas, including the community of El Rio. It has been determined that the levee no longer meets FEMA standards and is in need of rehabilitation.

Link to webpage:  https://www.vcpublicworks.org/wp/santa-clara-river/santaclarariverlevee

Rehabilitation is needed to comply with FEMA levee certification requirements. Phase I (2018) – downstream of UPRR. Raised levee, added rock riprap bank protection, construction of floodway, drainage system, fencing and appurtenances.  

Phase II – SCR-3 Levee Rehab Completion & Habitat Enhancement Project – Coordinated effort of County, City of Oxnard, private development and CA DWR funding. Design and construction of a new levee, flood walls and flood gate downstream of Union Pacific Railroad crossing to meet the Federally mandated levee certification regulations. 

An emergency contract was awarded to take immediate action to mitigate the fast expansion of sinkholes threatening seven residential properties off Foothill Road in the City of Ventura. The uncontrolled expansion of the sinkholes was a result of the recent storm events of late December 2022 and the early weeks of January 2023. The existing 55-year-old metal pipe failed, causing stormwater to undermine the pipe and eroded the soil underneath it. The failed corrugated metal pipe (CMP) was buried in the backyard of seven residential properties. The most clear and imminent threat was a sinkhole that had exposed the reinforced concrete footing of a complex and cascading retaining wall system that supports a swimming pool and a patio area. In addition, storm flows caused significant erosion around and underneath the pipe as they have been naturally redirected underneath the corroded sections of the pipe, thus discharging a large volume of sediment into Arundell Barranca. The contractor mobilized to take immediate action to protect the project site, stabilize the retaining wall and extensive sinkhole, and reestablish the failing CMP storm drain system to a functional state to prevent further dirt/sediment discharge into its receiving channel (Arundell Barranca).

For more information please read: Sinkholes in Ventura backyards require emergency fixes

The finished project will increase public safety by improving access along the Ferro Ditch to the Ferro Debris Basin for maintenance and emergency response during flood events. Additional benefits include increased protection of adjacent agricultural lands, reduced erosion, and channel maintenance costs, and improved water quality in receiving waters including the Mugu Lagoon.

The project consists of the replacement of approximately 1,687 linear feet of earthen and intermittent concreted rock lined sections of trapezoidal channel with 10 linear feet of concrete box culvert, 35 linear feet of RC open rectangular channel, 30 linear feet of concrete transition between the rectangular channel and trapezoidal channel sections,1,507 feet of rock lined trapezoidal channel, 40 linear feet of reinforced concrete flood control wall with floodgates, traffic control, agricultural drainage line relocation, removal and reinstallation of rock in a stilling basin, contour grading and appurtenant work.

This construction project provided repairs and enhancements to the downstream end of the Newbury Park Drain No. 1 from its confluence with the South Branch Arroyo Conejo in Newbury Park to Michael Drive. The channel is located just east of Wendy Drive. Over the years, the corrugated metal pipe (CMP) had deteriorated and the unprotected trapezoidal earth channel experienced significant surface erosion. Without the repairs, the adverse processes will exacerbate the poor condition of the CMP and the trapezoidal channel.

This project consisted of the replacement of existing 8’ diameter corrugated metal pipe culvert with a 12’ wide by 8’ high reinforced concrete box culvert, including reinforced concrete outlet and transition structures, and rock lining of a 62’ long by 38’ wide trapezoidal earth channel.

Drainage Improvements – A 2004 study concluded the dam did not meet current standards and modification or removal was recommended. A 2007 study recommended that removal of the dam could be possible without detrimental downstream effects. The debris basin provided little or no flood protection in 10-, 50- or 100-year events. A dam breach would likely overtop Santa Rosa Road by up to seven feet of water. Built in 1957, the original purpose was as a debris basin.

Removal of existing earthen dam and emergency spillway; demolition and removal of 36-inch reinforced concrete (RC) pipe of primary intake structure, 10-inch corrugated metal (CM) bleeder pipe, 24-inch RC and CM outlet pipes, 20 linear feet (LF) of RC transition structure, and a portion of the concreted rock riprap downdrain; vegetation removal and weed control; construction of 45 LF of 14 feet wide by 6 feet high RC box, 20 LF of RC transition structure, removable bollard fence footing, and concreted rock riprap downdrain structure; resurfacing of existing CMB access road and ramp; installation of erosion control blanket and chain-link fence and gates, and appurtenant work.

Removal was followed by restoration of the environment by planting of native plants, and other improvements.

The purpose of the project was to mitigate repeated inundation of the community of Casitas Springs and State Route (SR) 33 from floodwaters, sediment, and debris originating from the Fresno Canyon Watershed and the related undersized storm drain facilities.

The project encompassed the area between where the Fresno Canyon channel outlets the canyon mouth on the east side of State Route 33 to the Ventura River.

The project components included the installation of a 108-inch reinforced concrete (RC) pipe from Fresno Canyon to the Ventura River utilizing both a jacking method (trenchless) and open trench installation, construction of RC floodwalls, RC masonry retaining walls, RC channel and chute, RC box, RC headwalls, rock riprap, concrete v-ditches, access roads of various materials, and asphalt bike path. The project also included the installation of 60-, 48-, and 18-inch RC pipes, and a 21-inch sewer line, manholes, chain link and wood fencing, chain link and pipe gates, and related appurtenances.

The Casitas Springs Fresno Canyon Diversion Project on Vimeo