Memorandum
To: Brian Frus, P.E., Senior Engineer, City of Salinas From: Kate Elliott and The Harris Team
RE: Scope of Work for the Gabilan Creek Restoration Design Date: July 26, 2023
The Harris Team (Harris & Associates, EcoSystems West Consulting Group, Albion Environmental, and Waterways Consulting, Inc.) is pleased to provide this scope of work to assist the City of Salinas (City) with the Gabilan Creek Restoration Design, as part of the Encampment Resolution Grant. The design would include restoration of approximately 3,100 feet between the Creekbridge Village Apartments at Manchester Circle to East Laurel Drive.
The scope of work for the design would include the following elements:
Review of existing studies and surveys/technical studies, where needed, on the hydraulics, jurisdictional delineation, and structural integrity of the creek and levee system, presence of sediment and debris, vegetation characterization, biotic surveys, and presence of invasive plant species.
Update to aquatic resources assessment including characterization of ordinary high water mark and extent of riparian vegetation/habitat, and updates to surveys for amphibians, birds, and other sensitive plant and wildlife species, as determined to be necessary during literature review and surveys.
Based on this assessment of existing conditions, our team will prepare a preliminary design which will address, as needed:
slope repair and levee repair;
silt and debris removal;
tree and plant trimming and removal (to deter encampments and remove invasive plants); and planting of native plants and trees and drought resistant plants to stabilize slopes and compatible with encampment deterrent goals.
Meeting with Project Stakeholders, including the City of Salinas, Habitat Stewardship Project (Return of the Natives), and others (see footnote 1 below) to leverage existing expertise and resources.
Based on a review of the preliminary design and specifications, preparation of the final design, which will include conceptual design plans and planting palette.
Project permitting with regulatory agencies (e.g. US Army Corps of Engineers, Regional Water Quality Control Board, and California Department of Fish and Wildlife).
These tasks are discussed in further detail below.
Task 1. Project Management/Meetings
Task 1.1 – Project Management and Coordination
The Harris Team will work closely with the City to discuss how to meet the City’s needs for the restoration of Gabilan Creek. Our primary goal will be to effectively track Project meetings, tasks, timelines, and schedule to ensure cost effectiveness and efficiency at accomplishing Project goals. Our team will continue to work closely with the City throughout the design process to refine design plans.
Task 1.2 – Meetings with City Staff and Stakeholders
The Harris Team will meet with City Staff to define design goals for Gabilan Creek. Our team will incorporate the City’s existing and future maintenance activities into the project’s design to ensure on-going success of the effort. Current actions may include, but are not limited to, flood management/sediment control, bank stabilization, erosion control, outfall structure maintenance and repair, flood gate maintenance and repair (coordinate with NPDES program), culvert maintenance, repair and replacement, encampment prevention and management, and vegetation management.
Our team will coordinate with relevant organizations and programs, such as the Habitat Stewardship Project (Return of the Natives) to identify opportunities for partnerships and available resources for design planning.
After completion of the technical studies identified below, the Harris Team will meet with the City to determine next steps for the proposed design. Conceptual designs will be prepared under the leadership of the Harris Project Management.
Deliverables
Coordination between Harris Team Members and the City of Salinas (3 Meetings) Coordination between Harris Team Members and Stakeholders, including the Habitat Stewardship Project (Return of the Natives) (up to 3 Meetings) Task 2. Review of Existing Studies, Surveys/Technical Studies Surveys and technical studies will be conducted, as needed for hydrologic, hydraulic, flood capacity analysis, and an assessment of the structural integrity of the levees, as well as of aquatic resources, biological resources, and cultural resources, to provide the scientific basis for the design, and to allow the Harris Team to provide a quantitative impact assessment to the regulatory agencies during permitting. The technical studies also enable us to work with the City to minimize impacts through careful project design.
Task 2.1 – Hydrologic, Hydraulic, and Flood Capacity Analysis, Assessment of Structural Integrity of the Levee EcoSystems West and Waterways will work with the City to review existing analyses of Gabilan Creek and its levee, to determine if updates or additional study would be required. Waterways has extensive experience designing and engineering projects in surface water environments that have a proven track record of agency approval.
Relevant studies reviewed to date include:
On-going Gabilan Flood Plain Enhancement Project
2022 and 2009 FEMA Flood Maps
2021 Stormwater Development Standards for New and Redevelopment Projects 2019 Storm Water Resource Plan for the Greater Salinas Area (updated 2021) 2019 MS4 Permit for Municipal Storm Water Discharges
2017 FEMA Flood Insurance Study
2017 Storm Water Resource Plan for the Greater Salinas Area 2013 Stormwater Development Standards for New and Redevelopment Projects 2012 WDR Permit for Municipal Storm Water Discharges
2010 Stormwater Development Standards
2006 Stormwater Management Plan
2004 Storm Water Master Plan, as updated
The Harris Team, including Waterways, will meet the City’s Public Works personnel in the field to evaluate the Gabilan Creek, gain an overview of the sediment and debris load currently affecting the creek’s flood capacity, identify locations for sediment, debris, and vegetation removal within the creek (e.g., the reaches where sediment and problematic vegetation and woody debris have accumulated to date). Waterways will assess the embankments of the creek to determine where levee repair is required.
Based on document and data review and on the field visit(s), Waterways will identify proposed actions to minimize future sediment accumulation and to stabilize the levees in Gablian Creek. The study will include identifying and mapping/modeling the Ordinary High Water Mark (OHWM) in Gabilan Creek.
Deliverables
Coordination between Harris Team Members and the City of Salinas (12 meetings; 1 meeting/month) Hydrologic, Hydraulic, and Flood Capacity Analysis/Assessment of Structural Integrity of the Levee Task 2.2 – Jurisdictional Delineation of Aquatic Resources Waters and wetlands (aquatic resources) of the U.S. are protected under the federal Clean Water Act (CWA). An aquatic resources delineation determines the extent of wetlands and waters of the U.S. within the City’s defined Gabilan Creek Restoration area for submittal to the US Army Corps of Engineers (USACE) during permitting. To date, EcoSystems West has conducted reconnaissance surveys of Gablian Creek.
EcoSystems West will map Gabilan Creek and adjacent habitats using ArcGis and resource-grade GPS. Waterways and EcoSystems West will identify the Ordinary High Water Mark (OHWM) of the creek and wetland boundaries, if present, to determine the jurisdiction of the USACE. EcoSystems West will delineate the break in bank and/or boundary of the riparian habitat to determine the jurisdiction of the Regional Board and CDFW. These boundaries will be depicted in ArcGIS shapefiles, geodatabase, and maps.
EcoSystems West will prepare a draft aquatic resources delineation report for Gabilan Creek. This formal jurisdictional aquatic resources delineation of wetlands and “other waters” of the U.S. would be prepared using protocols outlined in the USACE Wetlands Delineation Manual (Environmental Laboratory 1987) and the Regional Supplements to the Corps of Engineers Wetland Delineation Manual: Arid West Region, Version 2.0 (Environmental Laboratory 2008). The USACE defines three criteria to delineate wetlands: (1) hydrophytic vegetation, (2) wetland hydrology, and (3) hydric soils. The OHWM is defined as “that line on the shore established by the fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding areas.” A draft of the delineation report would be submitted to the City for review, comment, and approval prior to submittal to the USACE.
Deliverables
Coordination between Harris Team Members and the City of Salinas (12 meetings; 1 meeting/month) Aquatic Resources Assessment of portions of Natividad Creek (this report will be prepared as an element of the report prepared for the Salinas Creeks and Wetlands Restoration Program) or if determined to be necessary:
Stand Alone Aquatic Resources Assessment of portions of Natividad Creek (Optional Task) Task 2.3 – Biological Assessment
EcoSystems West will conduct a biotic assessment to characterize the biological resources within this reach of Gabilan Creek. To date, the Harris Team reviewed sensitive biological resource data from USFWS, CDFW, California Natural Diversity Database (CNDDB); and other recognized lists of sensitive resources. Additionally, the team has communicated with other local experts about occurrences of sensitive wildlife species that have not been recorded in official databases. Based on this research and these sources, we developed target lists of sensitive plant and wildlife species with potential to occur Gabilan Creek. During the field reconnaissance surveys, we evaluated Gabilan Creek to determine which sensitive resources could occur. A follow-up survey of Gabilan Creek will be conducted. Using ArcGIS, we will map all sensitive habitats adjacent to aquatic features.
Biological resources will be presented in maps.
A biotic assessment letter report will be prepared for Gabilan Creek. The report will include a discussion of existing habitat conditions, documented occurrence of sensitive species in and near the proposed restoration area, potential impacts, and minimization measures to reduce or avoid adverse impacts. A draft of the report will be submitted to the City for review, comment, and approval prior to finalization.
Deliverables
Coordination between Harris Team Members and the City of Salinas (12 Meetings; 1 meeting/month) Biotic Assessment of portions of Gabilan Creek (this report will be an element of the report prepared for the Salinas Creeks and Wetlands Restoration Program) or if determined to be necessary:
Stand Alone Biotic Assessment of portions of Gabilan Creek (Optional Task) Task 2.4 – Cultural and Historical Resources Report
Work within the channel (below the OHWM) of Gabilan Creek falls under the jurisdiction of the USACE and must also must comply with Section 106 of the National Historic Preservation Act (NHPA) through consultation with the State Historic Preservation Officer (SHPO) and Native American tribes.
The Harris Team will identify and map the area(s) of potential effects (APE), on which direct ground disturbance may occur. The APE boundaries defining the limits of additional background research, an updated records search, tribal outreach, and field survey will be established. Albion Environmental will then assess whether any cultural and historic built resources are located directly in or adjacent to the areas of proposed ground disturbance.
Albion’s background research will include conducting a cultural and historic resources records search at the Northwest Information Center (NWIC), requesting information related to Native American resources from the Native American Heritage Commission, and any Native American contacts that are identified by the Commission, reviewing historical maps and documents, and conducting a desktop geoarchaeological review of local soil conditions for evidence of potential buried cultural resources. When possible, the results of these efforts will be used to help guide ground disturbing activities that may impact known cultural resources or refine proposed work in areas that have been identified as sensitive for supporting cultural resources.
A pedestrian field survey will be conducted to identify previously undocumented archaeological and historic built resources visible on the ground surface. The archaeologist will carefully inspect the ground surface to identify artifacts, features, and infrastructure, and assess the local geomorphic context. If resources are identified, the survey team would document them for future study.
A technical report will be prepared describing the results of the records search, historic background research, Native American outreach, and fieldwork, including complete cultural resources inventory forms for all identified resources. It will also provide a determination of potential effects on historic properties and technical recommendations for avoidance, minimization, or additional studies. The technical report will include revised maps of the sensitive areas of the APE, resource locations (as needed), and prominent landscape features.
Deliverables
Coordination between Harris Team Members and the City of Salinas (4 Meetings) Cultural Resources Report (Phase I) for established APE along portions of Natividad Creek (this report will be an element of the report prepared for the Salinas Creeks and Wetlands Restoration Program) or if determined to be necessary:
Stand Alone Cultural Resources Report (Phase I) for established APE along portions of Natividad Creek (Optional Task) As determined to be necessary, depending on Phase I Results and consultation with the US Army Corps of Engineers (USACE) - Extended Phase I/Phase II Reports for established APE along Natividad Creek (This task would be scoped and cost under an amendment) Task 3. CEQA Compliance/Documentation
In compliance with the requirements of the California Environmental Quality Act (CEQA), Harris will prepare the appropriate CEQA documentation for the Project. We anticipate that the use of a Categorical Exemption - Small Habitat Restoration Projects (CEQA Guidelines 15333) from CEQA will be applicable, if the project impact area is less than 5 acres or Categorical Exemption – Existing Facilities (CEQA Guidelines 15333) if the project impact area is greater than 5 acres.
Deliverables
Coordination between Harris Team Members and the City of Salinas (4 Meetings) Draft and Final Categorical Exemption (this documentation will be an element of the document prepared for the Salinas Creeks and Wetlands Restoration Program) or if determined to be necessary:
Stand Alone Draft and Final Categorical Exemption (Optional Task) Task 4. Preliminary and Final Design Plans
The Harris Team will continue to work with the City to develop Natividad Creek Restoration Conceptual Design Plans. Conceptual Design Plans will be based on the results of the technical studies, beginning with the structural integrity of the levee and any necessary repairs to the levee or structural stabilization of the slopes of the creek. Sediment and debris removal will be addressed, including anticipated on-going maintenance actions.
A Conceptual Design Plan that identifies trees which are recommended for removal or trimming will be included as well as a planting palette for native shrubs, plants, and seed mix suitable to the area and compatible with restoration goals of deterring encampments and having low maintenance requirements. The planting palette developed as part of the 2023 Salinas Urban Forest Management Plan will be used to select suitable trees for the project. This type of plan would typically include native trees that provide shade and stabilize the embankments but are limbed up to allow a clear line of site under the trees. In addition, low growing native forbs and wildflowers can be planted as an understory to the tree canopy. Conceptual Design Plans would include the planting palette, plant spacing, recommendations for planting, irrigation, weeding, and other maintenance, as needed. The Harris Team will work with the City and stakeholders, as applicable, to develop preliminary and final plans.
Deliverables:
Coordination between Harris Team Members and the City of Salinas (4 Meetings) Coordination between Harris Team Members and the Habitat Stewardship Project (Return of the Natives) (2 Meetings) Conceptual Design Plan (this plan will be an element of the CMP prepared for the Salinas Creeks and Wetlands Restoration Program) or if determined to be necessary:
Stand Alone Draft Conceptual Design Plan (Optional Task) Task 4. Regulatory Compliance/Permitting
We anticipate that the regulatory compliance/permitting task includes preparing permit application packages for USACE, the Regional Board, and CDFW for work with the respective jurisdictions of these agencies. EcoSystems will utilize hydrologic, hydraulic, and flood capacity studies to identify impacts associated with sediment and debris removal in this reach of Gabilan Creek, as well as repairs to the levee and slope stabilization. A component of these activities can likely be permitted with USACE under Nationwide Permit 27 – Aquatic Habitat Restoration and Nationwide Permit 13 – Bank Stabilization. A Section 401 Water Quality Certification will be required from the Regional Board and a Lake and Streambed Alteration Agreement from CDFW. We anticipate that the project will be self-mitigating through habitat restoration and enhancement.
Deliverables:
Prepare Draft and Final Permit Applications for:
USACE
Regional Board
California Department of Fish and Wildlife
(Permit applications for Gabilan Creek Restoration will be a component of the permit applications prepared for the Salinas Creeks and Wetlands Restoration Program) or if determined to be necessary:
Prepare Draft and Final Stand Alone Permit Applications (Optional Task) Task 5. Preconstruction Surveys for Plan Implementation EcoSystems West will provide preconstruction surveys for plan implementation, as needed. Preconstruction surveys for sensitive amphibians and reptiles, breeding birds, bats and woodrats may be required. This task will be performed under an amended scope once preconstruction survey needs have been determined.
Deliverables:
Environmental Training (prepare materials and provide training to all personnel) Preconstruction Surveys for sensitive resources
Biological Monitoring, as determined to be necessary based on presence of sensitive resources and condition in permits. 2 3
2 Scope of Work for the Gabilan Creek Restoration Design