Fenton Parkway Bridge Geotechnical Investigation
Summary
SCH Number
2023100529
Public Agency
California State University, San Diego
(SDSU)
Document Title
Fenton Parkway Bridge Geotechnical Investigation
Document Type
NOE - Notice of Exemption
Received
Posted
10/19/2023
Document Description
SDSU proposes to undertake a limited geotechnical investigation within the San Diego River in conjunction with the proposed Fenton Parkway bridge. The geotechnical investigation is intended to benefit the City of San Diego, as its purpose is to inform engineering and design specifications required for the proposed bridge. The proposed bridge would be constructed on real property owned by the City of San Diego, and upon the completion of construction, would be owned, operated, and maintained by the City of San Diego.
The geotechnical investigation would involve assessment of subsurface soils at two boring locations (see Figure 1). The boring locations were selected to be near the anticipated proposed bridge pier columns. The borings would be approximately 8 inches in diameter and approximately 150 feet in depth and would not result in removal of existing vegetation. An area of approximately 20 feet by 40 feet around each boring location would be needed to maneuver the equipment associated with conducting the borings (see Figure 1). Additionally, to further avoid permanent disturbances to vegetation, plywood, steel plates, and/or rubber mats would be laid down in these areas and along proposed paths of travel to each area in order to avoid the need for vegetation removal. All spoils and drilling mud would be sealed in drums or stored in a roll-off bin and disposed of off-site. The drums would be temporarily stored in the river channel during the field work and hauled out at the same time the equipment is demobilized. Consistent with County of San Diego Department of Environmental Health guidelines, backfill for the boreholes would include cement-bentonite grout. Up to 5 feet of native soil will be placed at the top of each borehole to resemble the existing conditions prior to drilling.
Equipment that is anticipated for the work in the river channel includes the following: track- or rubber-tired truck-mounted drill rig and associated drill tooling (e.g., augers, drill rods, drill bits, mud pan); four-wheel drive telehandler; tracked skid steer loaders to move supplies and equipment in the river channel; plywood, steel plates, cribbing, prefabricated timber walkways, rubber mats, and/or steel plates to provide access to the drilling locations and support the drilling rig outriggers; 55-gallon drums and/or roll-off bins for storing boring cuttings and drilling mud; large water totes and associated water and grout piping/hoses; and hand tools and equipment for the collection and storage of soil samples. At the end of each workday, all equipment and tools would be turned off and secured within the river channel. Drip pans would be placed under all equipment when not in use or during refueling. All equipment will be demobilized and removed prior to the commencement of rain events significant enough to forecast that the river within or immediately abutting the boring work area will rise above the low flow channel into the area of work. Any equipment stored within the river would be affixed with drip pans to avoid potential fuel leakage exposure to the river environment.
Consistent with the City’s Water Pollution Control Plan requirements (City of San Diego 2023), temporary best management practices (BMPs) would include the use of visqueen and fiber rolls around the work areas, as needed. Implementation of these and other appropriate BMPs would ensure no runoff or siltation resulting from activities would occur in the river channel. All equipment would be stored within the river channel for the duration of the drilling. Any equipment stored within the river would be affixed with drip pans to avoid potential fuel leakage and exposure of the river environment.
Pursuant to the Biology Guidelines of the San Diego Municipal Code’s Land Development Code (2018), a Qualified Biologist would be retained to monitor all geotechnical boring activity to ensure no impacts to biologically sensitive areas occur. Biological monitors will direct work to be performed in locations that will not disturb sensitive environmental resources, as illustrated on Figure 1. The qualified biologist will accompany the drilling team to confirm all staked locations or slightly modify them based on changed conditions to locate worksites consistent with the methodology described above (maximize bare ground, avoid trees and need to remove or trim vegetation). In addition, the work would be heavily monitored by cultural resources (also experienced in paleontological resource monitoring), and hydrology/stormwater resource experts to ensure that sensitive environmental resources are not impacted during the approximately 2- to 3-week investigation period. There is no reason to believe the proposed work could disturb cultural or paleontological resources because there would be no grading, and ground-disturbing work is limited to drilling two 8-inch boreholes on bare land.
A crane will be used to lower the equipment and supplies for the work that cannot be carried by hand into the river channel. Due to the location of the active San Diego River channel, a crane setup is required. It will be located outside of the river channel in an existing construction staging area within the southwest portion of Mission Valley River Park. The crane setup location is devoid of sensitive habitat, as shown in Figure 1, and can swing above the river channel to deliver equipment and supplies into the work area from the air, avoiding the need to traverse sensitive habitat in and around the river channel. A water truck will be staged near the crane location to supply water to the drilling rig with hoses as needed.
The geotechnical boring activities are anticipated to occur over a period of approximately 2 to 3 weeks. Once geotechnical investigations are complete, all equipment would be removed. The drilling start date will depend on the status of environmental, right of access, Department of Environmental Health permits, subcontractor availability, weather, and conditions in the river channel. The drilling would occur between September 16 and January 14 to avoid any potential impacts to nesting and/or special-status bird species. Further, as described above, equipment would be dropped into the work area via crane, which will ensure that existing habitat in and around the river channel would not be affected through the use and maneuvering of equipment (see Figure 1). The aforementioned plywood, steel plates, and/or rubber mats would be used to move equipment from the crane drop location to drilling work areas. Use of these materials would ensure that existing vegetation would not be removed or otherwise destroyed through equipment movement along the temporary access paths in the river channel.
Contact Information
Name
Robert Schulz
Agency Name
San Diego State University
Job Title
University Architect, Associate Vice President, Real Estate, Planning, and Development
Contact Types
Lead/Public Agency
Phone
Email
Location
Cities
San Diego
Counties
San Diego
Regions
Southern California, Statewide
Cross Streets
Fenton Parkway, Mission City Parkway/Camino Del Rio North intersection
Schools
south of the SDSU Mission Valley site development
Waterways
San Diego River
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
Section 15061 (b)(3); Section 15304, Class 4; Section 15306, Class 6
Reasons for Exemption
Categorical Exemption. Section 15061 (b)(3) (common sense exemption); Section 15304, Class 4 (minor alterations to land exemption); and Section 15306, Class 6 (information collection exemption).
The proposed geotechnical evaluation is exempt according to the following CEQA exemptions:
Section 15061 (b)(3) (common sense exemption) states that “Where it can be seen with certainty that there is no possibility that the activity in question may have a significant effect on the environment, the activity is not subject to CEQA.” The geotechnical investigation has been planned to eliminate the potential for impacts to sensitive biological, cultural and aquatic resources through very precise bore hole and work area siting which maximizes avoidance of sensitive biological and aquatic resources and includes program features such as timing of work and contingency planning for temporary demobilization if a substantive rain event is predicted.
Section 15304 (minor alterations to land exemption) states that minor disturbances to land that do not involve removal of healthy, mature, scenic trees are exempt from CEQA. No removal of healthy, mature or scenic trees would occur because all work areas would be devoid of vegetation or would involve laying down mats or plywood on low lying vegetation that could recover its normal growth trajectory once the work has been completed. The work would also be limited to areas outside of the active low flow river channel so as to avoid the potential for effects on water. All equipment will be demobilized prior to the commencement of rain events significant enough to forecast that the river within or immediately abutting the boring work area will rise above the low flow channel into the area of work.
Section 15306 (information collection exemption) states that basic data collection, research, experimental management and resource evaluation activities that do not result in a serious or major disturbance to an environmental resource would be exempt from CEQA. This exemption also clarifies that these activities must be strictly for information gathering purposes or must be part of a study leading to an action that a public agency has not yet approved, adopted or funded. All work would be for the sole purpose of data collection and would not result in a serious or major disturbance to an environmental resource. This data collection effort would be utilized in support of CSU’s (a public agency) efforts to fully study the geotechnical considerations necessary to design a safe and efficient bridge across the San Diego River.
Finally, the proposed geotechnical investigation does not meet any of the exceptions to the use of a categorical exemption under CEQA Guidelines Section 15300.2. Specifically, the work would not: (1) have a significant environmental impact on a particularly sensitive environment; (2) have a significant cumulative impact; (3) have a significant effect on the environment due to unusual circumstances; (4) result in damage to scenic resources; (5) be located on a site included on any hazardous materials list compiled pursuant to state law; and (6) cause a substantial adverse change in the significance of a historical resource.
All supporting documentation is on file with the Lead Agency and is available upon request.
Exempt Status
Statutory Exemption
Type, Section or Code
Section 15262 (feasibility and planning studies)
Reasons for Exemption
The proposed geotechnical evaluation is exempt according to the following CEQA exemptions:
Section 15262 (planning and feasibility studies) stated that “a project involving only feasibility or planning studies for possible future actions which the agency, board or commission has not approved, adopted or funded does not require the preparation of an EIR or Negative Declaration but does require consideration of environmental factors. This section does not apply to the adoption of a plan that will have a legally binding effect on later activities.” The geotechnical investigation is an important information-gathering step to the efficient and appropriate design of a bridge traversing a river corridor that is being proposed by SDSU. The collection of this data by no means binds SDSU or any other entity to proceed with full design, planning, permitting and/or construction of the bridge. Any future bridge would be subject to an independent CEQA document.
Attachments
Notice of Exemption
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