(A) Approved projects that result in the removal of material from channel banks and/or removal of riparian vegetation shall be required to restore the project area consistent with the following standards, and the CCIP:
(1) Native oaks, drought-tolerant shrubs, and drought-tolerant understory species shall be planted on upper slopes, terraces, and other areas where groundwater is deep and soil moisture from flows is minimal.
(2) Shallow terraces may be created along the banks of the low-flow channel from I-505 to the Capay Bridge, with cottonwood and willow pole cuttings planted on the benches. Optional methods include: a) digging short trenches diagonally to the low-flow channel (angled downstream), with pre-rooted willow and cottonwood cuttings planted on the upstream edge of the trench; and b) creating in-channel riparian plots along this reach to trap bed materials to aid in creating the shallow terraces. These measures would allow for the development of a ribbon of vegetation to establish along the low-flow channel in this area, thereby helping to connect the riparian corridor.
(3) Planting shall be conducted immediately after grading, or other site preparation, before invasive vegetation has become established. If undesirable vegetation does become established, it should be removed by mechanical means and approved herbicides, under the supervision of a licensed applicator.
(4) Dense native vegetation shall be emphasized along the streambank to create a distribution of velocities within the channel, with the highest velocities occurring within the low-flow channel. To ensure adequate water supply for new plantings, secure irrigation systems should be installed for revegetation projects within the planning area as needed.
(5) Habitat areas located next to grazing lands shall be fenced in order to prevent vegetation disturbance. Signage shall be installed indicating the area is undergoing habitat restoration.
(6) Fertilizer shall not generally be used because its application favors non-native vegetation. Where appropriate, however, trees and shrubs may be planted with a slow-release fertilizer.
(7) Native seeds, plants and cuttings used for reclamation and restoration activities shall be ecotypes of Cache Creek Watershed genetic origin including areas outside of Yolo County and of Yolo County genetic origin when materials are used that originate from outside of the Cache Creek Watershed. Cottonwood cuttings shall be collected and contract-grown at a nursery with staff experienced in the propagation of native plants. Alternatively, cottonwood and/or willow cuttings can be harvested from vegetation in the project vicinity and planted within the same day. If storage of cuttings is necessary it should occur within the creek or in a bucket of cool water. Other woody riparian species shall be collected and contract-grown from local seed by a qualified native plant nursery. Where revegetation involves such a relatively small area that the requirements for locally-collected and grown material would be infeasible, the seed and plant material to be used in revegetation efforts may be obtained commercially as long as it is of local origin from within Yolo County.
(8) Planting shall be initiated in the fall after the first soaking rains. Container plants shall be planted in holes at least twice as deep and wide as the plant container. The rootball should be thoroughly dampened before planting and the planting holes deeply irrigated prior to planting. After planting, the holes should be backfilled with native substrate material (with no mulch added) and thoroughly tamped to remove air pockets. Willow cuttings may be planted in clusters in planting holes prepared and backfilled in a similar manner. Trees, shrubs, and willow cutting clusters shall be located in randomly spaced, naturally clumped patterns. More regular planting patterns may be considered for larger sites, in order to allow for mechanized equipment used to maintain the site. Herbaceous seed mix (if used) should be planted via broadcast seeding (including raking in), drill seeding (preferred method for flatter areas), or hydroseeded (without hydromulch) over the planting area. If hydroseeding is used, the area shall then be covered with blown rice straw meeting State "weed-free" standards at one ton per acre. Soil stabilizer or tackifier, such as Ecology Controls M-Binder, shall then be included at 150 pounds per acre. Hydromulching is not recommended because of a history of poor results with native seedings. Herbaceous species may also be planted via plugs as appropriate.
(9) Existing hydraulic conditions shall be assumed for all proposed biotic reclamation activities. The County shall work with the Yolo County Flood Control and Water Conservation District to explore opportunities for increasing surface flows during spring and summer. The TAC would be responsible for identifying and implementing new restoration opportunities resulting from the increased water availability. All plantings should be carefully selected based on the existing hydrology and water availability of the reclamation area.
Irrigation of tree and shrub plantings may be necessary for the first two (2) or three (3) summers in drier sites to allow the roots to develop sufficiently to tap into the summer ground water level. Irrigation may be necessary at least twice per month during dry periods for the first three (3) years. Water requirements of young plantings should be evaluated as part of routine monitoring, with adjustments to the frequency and duration of irrigation made in response to indications of stress.
(10) The site shall be closely monitored for competing nonnative and invasive vegetation, especially priority invasive species on the list maintained by the Cache Creek Conservancy. Nonnative species shall be sprayed or removed by hand as necessary to attain the success criteria, as defined in each site-specific plan. For sites with substantial presence of nonnative species, an additional year of treatment shall be conducted to deplete the seed bank and prepare the site for planting.
(11) All planted sites shall be monitored for native plant establishment and growth for a minimum of three (3) years. Longer monitoring periods are encouraged as relevant to the species. Two (2) years of monitoring following irrigation removal should be considered if merited based on species and site conditions. Monitoring need not be restricted to a contractor obligation and may be partially satisfied through observations conducted during the annual creek walk. If understory species are planted, monitoring shall include standard understory assessments (e.g., percent cover by species at peak standing biomass). Monitoring data shall be made available to the County and the Cache Creek Conservancy, and stored in a centralized database.
(12) The following guidelines shall be followed when developing wetland habitat areas, with refinements and adjustments made based on current professional practice where recommended by a qualified biologist, subject to review by the TAC:
(a) Limit dense stands of aquatic vegetation in shallow areas to lower mosquito harborage and enhance wave action. This will also serve as substrate for mosquito predators.
(b) The banks of areas that retain water after June 1 (the beginning of the optimal mosquito breeding season) shall be steep enough to prevent isolated pooling as the water level recedes, to allow for wave action and to provide access by mosquito predators. Shorelines shall be configured so as not to isolate small channels or shallow ponding areas from the main body of water, to provide continuous access by predators, especially mosquito fish.
(c) Seasonal marshes shall be designed to have at least four (4) months of soil saturation or shallow inundation. Water depths shall not exceed two (2) feet of water.
(d) Marsh species shall be planted every six (6) feet, using plugs salvaged from marshes in the immediate vicinity or obtained from a nursery. Transplanting shall take place within twelve (12) hours after salvage and the root masses shall be kept continuously inundated from the time of transplanting.
(e) Wetland areas shall cover a minimum of one (1) acre. Side slopes shall be no steeper than 3:1 (horizontal:vertical). Small islands and complex shorelines shall be provided to create a diverse environment. Wetland designs shall include provisions for the wetlands to be partially drained periodically, in order to allow for the reseeding of aquatic plants and to promote the decay of built up organic debris.
(f) Pit bottoms shall be recontoured to create areas for waterfowl nesting and depressions to provide a more permanent water feature. Islands should generally be located on the upwind side of the water body to minimize exposure to the prevailing winds. Island slopes above the water level should be no steeper than 2:1 (horizontal: vertical). Emergent vegetation shall be placed around the edges of islands to reduce wave-related erosion. Shrubs shall be widely spaced. Trees and tall shrubs shall not be planted on the islands, since predators perch in them to prey on waterfowl.
(g) Appropriate species and densities for marsh restoration may include the following:
Species (scientific name) | Species (common name) | Density (plugs per acre) |
Species (scientific name) | Species (common name) | Density (plugs per acre) |
Eleocharis radicans | Creeping spikerush | 200 |
Juncus balticus | Baltic rush | 100 |
Schoenoplectus acutus var. occidentalis | Tule | 100 |
Schoenoplectus californicus | Bulrush | 100 |
Schoenoplectus pungens | Three-square | 10 |
Carex rostrata | Beaked sedge | 5 |
Equisetum hyemale | Scouring rush | 5 |
Cephalanthus occidentalis | Buttonbush | 5 |
(13) The following guidelines shall be followed when developing riparian woodland habitat areas, with refinements and adjustments made based on current professional practice where recommended by a qualified biologist, subject to review by the TAC:
(a) Riparian woodland shall be established only where there are coarse slopes containing soil types such as cobbly loam, gravelly loam, or other loamy textures. Where slopes contain significant clay layers, open woodlands (e.g., oak savannas) or grasslands shall be restored instead.
(b) Native trees and shrubs shall be planted in clusters to create alternate patterns of open and enclosed spaces. Site-specific characteristics may require alternative planting patterns.
(c) Native understory species should be planted whenever possible to reduce soil erosion, resist nonnative species establishment, and to enhance habitat for wildlife and pollinators.
(d) Appropriate species and densities for riparian woodland restoration may include the following:
Species (scientific name) | Species (common name) | Density (number or pounds/acre) |
Species (scientific name) | Species (common name) | Density (number or pounds/acre) |
Rosa californica | Wild rose | 36 |
Quercus lobata | Valley oak | 33 |
Populus fremontii | Fremont cottonwood | 26 |
Salix gooddingii | Black willow | 23 |
Salix laevigata | Red willow | 23 |
Salix lasiolepis | Arroyo willow | 23 |
Salix exigua | Sandbar willow | 23 |
Salix gooddingii | Gooding’s black willow | 23 |
Rubus ursinus | California blackberry | 19 |
Acer negundo | Box elder | 18 |
Vitus californica | Wild grape | 16 |
Cornus sericea | Dogwood | 16 |
Fraxinus latifolia | Oregon ash | 16 |
Platanus racemosa | Western sycamore | 16 |
Sambucus nigra ssp. caerulea | Blue elderberry | 12 |
Ceanothus cuneatus | Buckbrush | 12 |
Artemisia douglasiana | Mugwort | 10 |
Baccharis salicifolia | Mule fat | 6 |
Atriplex lentiformis | Quailbush | 6 |
Elymus glaucus | Blue wildrye | 16 lbs. |
Hordeum brachyantherum | Meadow barley | 16 lbs. |
Elymus triticoides | Creeping wildrye | 16 lbs. |
Additional understory species, especially native forbs that provide pollinator resources (e.g., milkweeds, native clovers, lupines, California poppy) should also be considered.
(14) The following guidelines shall be followed when developing oak woodland habitat areas, with refinements and adjustments made based on current professional practice where recommended by a qualified biologist, subject to review by the TAC:
(a) Oaks should generally be widely spaced (e.g. 50 ft. spacing), and shrubs should generally be planted in mixed-species clusters (e.g. 25 ft. spacing). Native grasses and forbs should be densely planted inbetween woody vegetation.
(b) Appropriate species and densities for oak woodland/savanna restoration may include the following:
Species (scientific name) | Species (common name) | Density (number or pounds/acre) |
Species (scientific name) | Species (common name) | Density (number or pounds/acre) |
Quercus lobata | Valley oak | 20 |
Rosa californica | Wild rose | 15 |
Sambucus nigra ssp. caerulea | Blue elderberry | 10 |
Baccharis pilularis | Coyote brush | 10 |
Heteromeles arbutifolia | Toyon | 10 |
Cercis occidentalis | Redbud | 10 |
Frangula californica | Coffeeberry | 10 |
Rubus ursinus | California blackberry | 8 |
Quercus wislizeni | Interior live oak | 6 |
Aesculus californica | California buckeye | 5 |
Elymus triticoides | Creeping wildrye | 16 lbs. |
Bromus carinatus | California brome | 10 lbs. |
Hordeum brachyantherum ssp. californicum | California barley | 5 lbs. |
Poa secunda | Pine bluegrass | 5 lbs. |
Stipa pulchra | Purple needlegrass | 5 lbs. |
Elymus trachycaulus | Slender wheatgrass | 5 lbs. |
Additional understory species, especially native forbs that provide pollinator resources (e.g., milkweeds, native clovers, lupines, California poppy) should also be considered.
(15) The following guidelines shall be followed when creating habitat areas within previously mined areas outside of the active channel, with refinements and adjustments made based on current professional practice where recommended by a qualified biologist, subject to review by the TAC:
(a) Basins that have floors close to the groundwater level should be restored to seasonal marsh and riparian wetlands. Those that are permeable, dominated by sand and gravel, should promote woodland habitat.
(b) Pit floors shall have sufficient topsoil and overburden to support the proposed habitat. Overburden and soil may be obtained from the diversion of agricultural tailwater, aggregate processing wash fines, of deposition by the creek. Areas to be planted shall be appropriately prepared prior to planting. If necessary, soils may be tested after preparation has occurred in order to determine the need for soil amendments.
(c) Pits should then be planted and irrigated until the plants have established. Agricultural tailwater is encouraged as an irrigation source. It would provide a valuable source of water for revegetation projects, and would also provide bio-filtering for the sediment and residue pesticides contained within the tailwater.
(d) Pits should be monitored closely for invasive plants species, and invasive species should be removed if found.
(e) Areas that will not be planted may be graded to create steep, barren slopes to provide habitat for the bank swallow.
(f) Except in important recharge areas, levees may be removed, breached at the downstream end, or a culvert installed at the downstream end to allow for dynamic interaction with the variable water level in the creek. Natural flooding will provide additional water, increase the diversity of tree species through colonization, and allow for the accumulation of organic nutrients and sediment.
(g) Habitat plans shall take into account the range of expected water level fluctuations and shall adjust the siting and design of the pit accordingly.
(h) In areas where fluctuating groundwater levels may affect revegetation plots at wet pit sites, consult with the TAC hydrogeologist and biologist to develop a viable, site-specific planting area.
(16) Topsoil and vegetation removed from the streambed shall be salvaged for use in restoration planting within the channel.
(17) Where the low-flow channel is creating excessive bank erosion problems and its relocation becomes necessary, grading within the low-flow channel shall provide topographic conditions that will ensure the safe passage of fish and prevent them from becoming trapped in isolated pockets of water.
(18) Low weirs may be installed, outside of the low-flow channel, to provide shallow pools for encouraging the establishment of riparian vegetation. When establishing shallow pools out of the low-flow channel, but within the floodplain of Cache Creek, the County shall coordinate with the TAC and the California Department of Fish and Wildlife to minimize the potential for native fish species mortality due to potential impediments to fish migrations.
(19) Site-scaled treatment of priority species shall begin within the first year after any ground disturbance using best available methods and optimal timing as appropriate for the species present (e.g., herbicide spraying, cut/stump, mechanical removal). All chemical spraying must be performed by or under the supervision of a Qualified Applicator Licensee and reflect input from a Pest Control Advisor. All cut plants shall either be disposed of or burned to reduce debris and prevent resprouts. All treatments shall be implemented in accordance with the Migratory Bird Treaty Act, the Yolo HCP/NCCP, as other regulations as appropriate. Monitoring of treated areas shall be implemented in order to determine if or when retreatment is necessary to ensure complete removal of the target species.
(20) Where riparian restoration is proposed in streambed areas located outside of the lowflow channel, cottonwood and willow cuttings should be placed within existing swales and other naturally-occurring low-elevation areas in order to provide them with sufficient soil moisture to survive the summer months.
(21) The TAC shall evaluate the vegetative cover within the CCRMP on an annual basis. At a minimum of once every five (5) years, the existing hydraulic model of the Cache Creek channel shall be updated based on current conditions, including topography and estimation of channel roughness based on vegetation conditions. Based on these updates, the TAC shall determine whether changes in topography and vegetation are decreasing channel flood capacity and recommend actions for consideration by landowners and agencies that could alleviate such a loss of capacity if deemed appropriate.
(B) Vegetated buffers comprised of native species should be placed between restored habitat areas and adjoining farmland, in order to minimize the potential for riparian areas to serve as reservoirs for agricultural pests. Said buffers will also reduce the effects of noise, dust, and spraying generated by agricultural operations on wildlife and riparian vegetation.
(C) Native species and water features included in habitat areas should be designed to discourage the proliferation of agricultural pests and weeds that would impair local crops.
(D) Native species shall be selected to encourage the biological control of agricultural and native habitat pests and weeds.
(E) Native trees that are suitable for wildlife perching near agricultural fields dedicated to row crop production should be incorporated into habitat design, in order to provide foraging habitat for Swainson's hawks and other birds of prey.
(F) As an alternative to on-site revegetation where such cannot be feasibly and successfully implemented, habitat restoration or creation at a suitable off-site location and/or non-native removal and other habitat enhancement at a suitable off-site location will be required. (as amended by Ord. 1518, eff. February 13, 2020)