The Cache Creek Improvement Program (CCIP) requires that the Cache Creek Technical Advisory Committee (TAC) produce an annual status report in January of each year for the Yolo County Board of Supervisors. This annual report provides a record of the implementation of the Cache Creek Resources Management Plan (CCRMP) and CCIP for the 2018 Water Year, which spans the period of October 1, 2017 to September 30, 2018. The report is intended to: 1) document the previous year's monitoring results, field observations and any completed in-channel restoration or stabilization projects; 2) provide analysis of data and trends; and 3) identify recommendations and projects for the next year. This report represents a critical component of the adaptive management of lower Cache Creek.
Background
The Cache Creek Area Plan (CCAP) was completed in 1996. The CCAP is comprised of the Off Channel Mining Plan (OCMP) and the Cache Creek Resources Management Plan (CCRMP). The goals of the CCAP effort are protection of groundwater, preservation of agriculture, restoration of Cache Creek, and regulation of commercial mining. Implementation of the CCRMP is discussed further below.
The CCRMP (adopted August 20, 1996, and amended August 15, 2002) is a creek management plan. It eliminated in-channel commercial mining and established an improvement program for implementing on-going projects to improve channel stability and restore habitat along the creek banks. The CCRMP provides a policy framework for the restoration of 14.5 miles of lower Cache Creek and includes specific implementation standards. The Cache Creek Improvement Program (CCIP) is the implementation plan for the CCRMP and identifies specific categories of projects that include: bank stabilization, channel maintenance, re-vegetation and habitat restoration.
The CCIP is overseen by a Technical Advisory Committee (TAC) comprised of three scientists charged with advising the County on implementation of in-channel restoration and stabilization projects. The work of the TAC is, by design, an iterative process driven by on-going monitoring and technical feedback on creek performance. The TAC is comprised of a fluvial geomorphologist, a hydraulic engineer and a riparian biologist.
In January of each year the TAC is required to prepare, and present to the Board of Supervisors, an annual status report for their activities of the previous year. This report fulfills that obligation and provides an opportunity for the TAC, community, and stakeholders to step back and take a larger perspective in looking at both the creek and the CCRMP with a critical eye for improvement.
Program Accomplishments
Four public Cache Creek Technical Advisory Committee (TAC) meetings were held during Water Year 2018: December 5, 2017, March 28, 2018, June 20-22, 2018 (Creek Walk), and August 30, 2018. These meetings were attended by Cache Creek TAC members, County staff, members of various partner agencies, program stakeholders, and the public.
In March 2018, the Natural Resources Division hired Ron Miller as the program’s new mining planner. Ron joins the team after working for the City of Roseville as a senior planner for the previous 12 years. Ron brings a wealth of CEQA and planning knowledge to the County.
The Cache Creek TAC conducted its 2018 Creek Walk on June 20-22, 2018. The Creek Walk is the annual physical inspection of the creek with the main purpose of documenting channel conditions, as required by the CCIP. The entire length of the CCRMP boundary is covered over the three days. Joining the Cache Creek TAC on this year’s Creek Walk was County staff, representatives from the gravel mining industry, program stakeholders, and members of the public. Observations made by the Cache Creek TAC during 2018 Creek Walk are provided as Appendix C within the report. A compilation of miscellaneous photographs captured during the 2018 Creek Walk is provided as Appendix D within the report.
In November 2017, the third year of the required five years of mercury sampling in off-channel mining wet pits (Section 10-5.517, OCMP) was conducted, utilizing the services of Dr. Darrel Slotton. The Year #4 sampling event is scheduled to take place in November 2018. The reports for the Year #1 (2015) and Year #2 (2016) sampling events have been published on the Natural Resources webpage and were attached to the 2016 and 2017 Annual Reports, respectively. The Year #2 (2016) report was finalized in May 2018 and is attached as Appendix E within the report. The Year #3 (2017) report was finalized in December 2018 and is attached as Appendix F.
There was one surface water quality sampling event this Water Year, which occurred on January 10, 2018. The samples from this event were analyzed for a suite of water quality constituents. A detailed discussion of these results is included in Chapter 3.
After substantial public outreach and coordination with program partners, the Natural Resources Division made revisions to the draft proposed updates to the Cache Creek Area Plan, that were released in May 2017, as a part of the 20-Year CCAP Update. These updated revisions were posted on the Natural Resources Division’s website in late September 2018. An environmental impact report for the programmatic update is currently under production with an anticipated release in January 2019. The 20-Year CCAP Update is expected to be completed in early 2019.
Significant progress was made on the Cache Creek Parkway Plan. After an initial public outreach effort on the Draft Cache Creek Parkway Plan and Draft Feasibility Study documents that were released in July 2017, Staff made edits to the documents and revised how the Parkway Plan document would be structured. The draft Cache Creek Parkway Plan document has since been bifurcated and will now be comprised of two separate documents, with the associated feasibility study. The first document is the Open Space Inventory and Baseline Improvements (“Baseline Inventory”). This document contains a map and profile of each of the 17 properties and two bridge structures that are already a part or, or negotiated to become, a part of the CCAP open space system, based on executed development agreements. The inventory document is expected to be released in January 2019. The second document, the Master Plan and Parkway Vision (“Master Plan”), contains an overall master plan and vision for future trail connections, identification of gaps and recommendations for future acquisitions, site-specific recreational and open space opportunities, and recommended future improvements, consistent with the goals and aspirations of the CCAP. The Master Plan is expected to be released in early 2019 with an additional public outreach effort. Finally, the draft Feasibility Study is in the process of being updated to accommodate the restructured process.
In September 2018, the Natural Resources Division applied for funding from the State of California Wildlife Conservation Board’s Proposition 1 Stream Flow Enhancement Program. The County’s proposed project would complete planning work critical to the development of feasible, multi-benefit streamflow enhancement alternatives for lower Cache Creek. More information on this proposed project can be found in Section 7.5.1.
In November 2017, the Yolo County Sheriff’s Department generously donated a 2014 Chevrolet Tahoe to the Natural Resources Division. The vehicle, formerly used for law enforcement patrols, has since been retrofitted for field visits to Cache Creek. The Natural Resources Division would like to thank the Sheriff’s Department for their involvement in the stewardship of Yolo County’s natural resources.
In June 2018, the Natural Resources Division purchased its own domain name – www.yolonaturalresoures.org – for quick and easy access to the Division’s website.
Throughout the Fall of 2018, the Natural Resources Division worked closely with the County’s IT Department to migrate the CCAP program’s ArcGIS online organization over to the County’s ArcGIS organization.
In November 2018, the Yolo County Archives kicked off a digitization project of all of historical CCAP program files. This project includes going through the 90+ boxes the program has accumulated over the last 20 years and scanning and sorting relevant files.
The County’s Manager of Natural Resources continues to serve as the Chair of the Water Resources Association (WRA) of Yolo County’s Technical Committee and was made Chair of the Westside Coordinating Committee for a two-year term, highlighting this program’s value in providing watershed monitoring and protection.
Summary of Significant Findings
Hydrologic and Water Quality Findings
The 2018 Water Year was a dry year for Cache Creek, the Sacramento River Valley, and the state of California. There were only two elevated flow events during the water year in contrast from 2017. Water quality sampling data remained within or below the ranges measured in previous years and did not exceed any recommended contaminant limits. Some contaminants continued to be not detected in water year 2018 as in the last several years.
Geomorphology Findings
Water Year 2018 was relatively dry with low magnitude peak flows. This resulted in very limited geomorphic change throughout the CCRMP area. The peak flow was only 1,300 cfs, well below the threshold of about 10,000 cfs where significant geomorphic change begins to occur. Water Year 2018 had the second lowest annual sediment transport since 2005, similar to the previous drought years of 2007, 2009, 2012, and 2014. The only geomorphic change observed during the 2018 Creek Walk was small-scale, local adjustment, with erosion offset by nearby deposition.
Because Water Year 2018 was relatively inconsequential with respect to sediment transport and geomorphic change, the recommendations developed by the Cache Creek TAC after the extremely active Water Year 2017 remained unchanged. Some of the extensive bank erosion and lateral channel migration that occurred in Water Year 2017 did stabilize somewhat due to vegetation growth in 2018, but the net erosional conditions of 2017 and areas of instability remained largely unchanged. The CCRMP should focus on acting on as many recommendations as possible in Water Year 2019 to take advantage of the additional year of observations and understanding related to the highly dynamic Water Year 2017 conditions.
Biological Resources Findings
The condition of biological resources in 2018 was similar to conditions observed in 2017, primarily due to the lack of sustained high flows as occurred in the previous year. The primary observation made during the 2018 Creek Walk was that native vegetation was re-establishing in many locations, especially along the banks of newly-created channels that resulted from 2016–2017 high flows. Two secondary observations were that native vegetation that persisted through the 2016–2017 high flows was still thriving in many locations, and that many formerly vegetated areas that were scoured during 2016–2017 high flows have yet to re-establish. Lastly, native vegetation was again observed to be creating potentially adverse conditions in some locations; however, no actions are yet required other than continued annual monitoring.
Invasive species are still widespread in many locations along lower Cache Creek, although the intensive treatment of arundo, ravennagrass, and tamarisk that has occurred since 2006 with funding from the Wildlife Conservation Board has greatly reduced the extent of these three species. During the 2018 Creek Walk, arundo and tamarisk were observed to be re-establishing in many locations. Many additional invasive species (e.g., Himalayan blackberry, perennial pepperweed, and tree tobacco) remain common along lower Cache Creek, and should be prioritized for treatment and monitoring. After treatment, native species should be planted to enhance habitat and reduce the potential for reinvasion.
Many common and special-status species of wildlife, invertebrates, and fish were again observed by the Cache Creek TAC and volunteer observers during the annual Creek Walk. Special-status species observed included Swainson’s hawk (State threatened), riparian bank swallow (State threatened), and Western pond turtle (State species of special concern). Additional species of note included American dipper, lesser nighthawk, red-tailed hawk, red-shouldered hawk, and Sacramento pikeminnow.
Significant opportunities for habitat enhancement and restoration were again noted in 2018, including the PG&E “Palisades” site (river mile [RM] 26.8), Capay Open Space Park (RM 26.3), the Hayes “Bow-Tie” property (RM 20.0), the Millsap property (RM 18.5), the Wild Wings Open Space Park (RM 17.0), and the Correll-Rodgers properties (RM 13.7). Based on 2017 and 2018 Creek Walk observations, the long-term resilience of revegetation and restoration projects within or adjacent to the active channel should be carefully considered prior to implementation, since such projects can be negatively impacted or completely removed by high flows. Passive restoration (e.g., streamflow enhancement) may be a more cost-effective approach for in-channel or near-channel locations subject to high flows.
Summary of 2018 Recommendations
Hydrologic and Water Quality Recommendations
The Cache Creek TAC Hydraulic Engineer recommends the following:
Capay Dam – Remedies to prevent future damage of the dam and movement of the dam’s concrete pads into the channel should be undertaken.
PG&E Palisades – The erosion control blanket and all associated infrastructure be removed and the palisades either be removed entirely or cut at or below ground level and revegetation/natural stabilization project be implemented. PG&E is working on design plans to implement this as of early 2018.
Erosion sites identified (Jensen Bend, Granite Esparto, Esparto Bridge, Woodland Reiff, south bank of RM 23.3, Teichert Esparto, and Payne Property) should continue to be monitored in the future.
Longitudinal profiles of water surface elevations should be performed in the future, similar to the efforts on January 9, 2017 (more information is described in Section 3.3), to assist in calibrating the hydraulic model of Cache Creek developed in 2016. The Cache Creek TAC Hydraulic Engineer recommends mobilizing for survey for a predicted flow in excess of 30,000 cfs if observed in the winter of 2018-2019.
Geomorphology Recommendations
As in previous years, geomorphology recommendations for Water Year 2018 are in three general categories: monitoring, evaluation, and implementation. The Cache Creek TAC Geomorphologist recommends that all of the 2017 recommendations be carried into 2018, as follows:
Accelerate voluntary implementation of previously recommended bar skimming projects at RM 25 and RM 20.
Evaluate the potential for additional bar skimming at RM 21 and RM 22.
Complete removal of the PG&E Palisades infrastructure from Cache Creek.
Notify bridge owners that conditions from 201 remain largely unchanged and some additional vegetation encroachment has occurred in 2018, necessitating continued monitoring at all bridges.
Complete detailed monitoring and assessment of channel treatments at locations of 2017 channel migration and erosion (RM 26, 25.5, 23.5, 22, 21.5, and 18).
Continue detailed monitoring of fine sediment deposition at Huff's Corner and complete an evaluation of the need to remove deposited fine sediment.
Finally, as in Water Year 2017, the Cache Creek TAC Geomorphologist recommends that that Cache Creek TAC and County work together to develop a comprehensive invasive species removal, ecoystem restoration, flood management and water supply bundle of projects based on prior Cache Creek TAC recommendations and submit additional Proposition 1 (and other) grant proposals to fund such projects in Water Year 2019.
Biological Resources Recommendations
Recommendations regarding biological resources, prepared by the Cache Creek TAC Riparian Biologist, are grouped into four general categories: native vegetation monitoring and management (Section 5.1.5), habitat restoration (Section 5.2.3), invasive species monitoring and management (Section 5.3.2), and special-status species (Section 5.4.2).
Recommendations regarding native vegetation focus on monitoring approaches intended to understand changes in native vegetation, as well as management actions required (if any) to maintain desirable flow conditions.
Recommendations regarding habitat restoration highlight high-priority potential projects, the importance of including native understory species, the need for post-implementation monitoring, the importance of planting native species on invasive species treatment sites, and the potential for increased surface flows and strategic channel maintenance projects to accelerate native habitat recovery.
Recommendations regarding invasive species monitoring and management include expanding the list of priority species and the areas in which treatments are implemented, the importance of a formal monitoring program to track invasive species, the need to remove treated biomass from the CCRMP area, the importance of planting native species on invasive species treatment sites, and the ongoing need to leverage invasive species treatment within the CCRMP area to support additional mapping and treatment upstream of Capay Dam.
Recommendations regarding special-status species focus on the need for additional monitoring and documentation of both rare and common species, documentation of observations, and the potential for increased surface flows to benefit Western pond turtles and other native species. |