Hydrology and water quality
CV Link could violate water quality standards or waste water discharge requirements. The project will comply with the requirements of the National Pollution Discharge Elimination System (NPDES). As applicable, CV Link construction will follow the CVWD and RCFCWCD standards and guidelines, including to the Riverside County Whitewater River Region Stormwater Quality Best Management Practice (BMP) Design Handbook for Low Impact Development (RCFCWCD, 2014) and the CVWD Development Design Manual (CVWD, 2013). The implementation of BMPs during construction activities will limit erosion and siltation from earthmoving and other construction activities. Exposed soil from excavated areas, stockpiles, and other areas where ground cover is removed will be stabilized to avoid or minimize the inadvertent transport by wind or water. The project is subject to NPDES Construction General Permit requirements. A Stormwater Pollution Prevention Plan (SWPPP) will ensure that erosion, siltation and runoff do not result in flooding on or off the project sites. The SWPPP will identify specific best management practices to ensure that the project meets the requirements of the California State Water Resources Control Board (SWRCB) NPDES Construction General Permit and the Caltrans NPDES Permit. The BMPs will include a) Construction-related erosion and sediment controls, stabilization practices or structural controls, silt fences, earth dikes, drainage swales, sediment traps, check dams, reinforced soil retaining systems, temporary or permanent sediment basins and flow diversion. Temporary erosion and sediment control measures shall be installed during or immediately after initial disturbance of the soil, maintained throughout construction (on a daily basis), and reinstalled until replaced by permanent erosion control structures or restoration of the construction right-of-way. In addition, the following specific actions shall be taken to ensure that impacts are less than significant.
a. CV Link construction shall be avoided within the limits of identified waterways as depicted on the Jurisdictional Delineation Report prepared for this DEIR, except where authorized by federal, state or local permits.
b. Protect inlets and outlets of culverts from construction material intrusions using temporary berms to prevent channel incision, erosion, and sedimentation.
c. Erosion control measures appropriate for on-the-ground conditions, including percent slope, length of slope, and soil type and erosive factor, shall be implemented.
d. Temporary erosion controls such as straw bales and tubes, geotextiles and other appropriate diversion and impounding materials and facilities shall be properly maintained throughout construction (on a daily basis) and reinstalled (such as after backfilling) until replaced with permanent erosion controls or restoration is complete.
e. Where jurisdictional waters are adjacent to the construction right-of-way, the contractor shall install sediment barriers along the edge of the construction right-of-way to contain spoil and sediment within the construction right-of-way.
f. Ensure that all employees and contractors are properly informed and trained on how to properly install and maintain erosion control BMPs. Contractors shall require all employees and contractors responsible for supervising the installation and maintenance of BMPs and those responsible for the actual installation and maintenance to receive training in proper installation and maintenance techniques.
g. Project scheduling will include efficient staging of CV Link construction that minimizes the extent of disturbed and destabilized work area, and reduces the amount of soil exposed and the duration of its exposure to wind, rain, and vehicle tracking.
h. The use of a schedule or flow chart will be incorporated to lay out the construction plan and will allow Link construction to proceed in a manner that keep water quality control measures synchronized with site disturbance, paving and other construction activities.
i. The sequencing and time frame for the initiation and completion of tasks, such as site clearing, grading, excavation, path construction, and reclamation, shall be planned in advance to ensure minimization of potential impacts.
j. Erosion and sediment control BMPs shall be incorporated into travelway construction plans.
To prevent petroleum products from contaminating soils and water bodies, the following BMPs shall be implemented:
a. Construction equipment and vehicles shall be properly maintained to prevent leakage of petroleum products.
b. Herbicides, fertilizers, vehicle maintenance fluids, petroleum products shall be stored, and/or changed in staging areas established at least 100 feet from delineated streams and other drainages. These products must be discarded at disposal sites in accordance with state and federal laws, rules, and regulations.
c. Drip pans and tarps or other containment systems shall be used when changing oil or other vehicle/equipment fluids.
d. Areas where discharge material, overburden, fuel, and equipment are stored shall be designed and established at least 100 vegetated (permeable) feet from the edge of delineated streams.
e. Any contaminated soils or materials will be disposed of off-site in proper receptacles at an approved disposal facility.
f. All erosion control measures shall be inspected and repaired after each rainfall event that results in overland runoff. The project contractor and CVAG shall be prepared year round to deploy and maintain erosion control BMPs associated with CV Link.
g. Existing culverts shall be carefully maintained in place in order to ensure that they function properly. Considerations include: maintenance of inlet and outlet elevations, grade, adequate compacted material cover, and inlet/outlet protection.
Restoration involves restoring the right-of-way to pre-construction conditions by final grading, installation of permanent erosion control measures such as slope breaks and retaining walls at appropriate distances to prevent rill (channel) formation between slope breaks, and re-establishing vegetation where it has been removed to facilitate construction.
a. Cleanup operations shall commence immediately following backfill operations on slopes approaching delineated streams and other drainages.
b. Final grading to restore pre-construction contours shall be completed and soil left in pre-existing condition within 7 days after backfilling the trench.
c. Restoration crew shall follow construction crews as they work systematically from one end to the other end of each Link alignment. If crews cannot work systematically from one end to the other, then erosion control BMPs shall be maintained on all slopes approaching a delineated stream and adjacent to these sensitive areas. If seasonal or other weather related conditions prevent compliance with these time frames, erosion control BMPs shall be maintained until conditions allow completion of cleanup.
CV Link will create or contribute runoff water, which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff.
The implementation of BMPs during construction activities shall ensure that erosion and siltation from earthmoving and other construction activities is limited. Exposed soil from excavated areas, stockpiles, and other areas where ground cover is removed shall be stabilized by wetting or other approved means to avoid or minimize the inadvertent transport by wind or water. The project is subject to NPDES Construction General Permit requirements. Project implementation of a Stormwater Pollution Prevention Plan shall be required to ensure that erosion, siltation and runoff do not result in flooding on or off the project sites, and that impacts are less than significant.
A Stormwater Pollution Prevention Plan (SWPPP) shall be prepared and implemented during construction of the Proposed Project. The SWPPP shall identify specific best management practices (BMPs) that will be implemented during project construction. BMPs implemented as a part of the project will ensure that the project meets the requirements of the California State Water Resources Control Board (SWRCB) NPDES Construction General Permit and the Caltrans NPDES Permit. BMPs appropriate for and applicable to the CV Link project include the following.
Construction-related erosion and sediment controls, including any necessary stabilization practices or structural controls, shall be implemented at and in all potentially affected drainages. General structural practices may include, but are not limited to, silt fences, earth dikes, drainage swales, sediment traps, check dams, reinforced soil retaining systems, temporary or permanent sediment basins and flow diversion. Temporary erosion and sediment control measures shall be installed during or immediately after initial disturbance of the soil, maintained throughout construction (on a daily basis), and reinstalled until replaced by permanent erosion control structures or restoration of the construction right-of-way is complete. In addition, the following specific actions shall be taken to ensure that impacts are less than significant.
a. CV Link construction shall be avoided within the limits of identified waterways as depicted on the Jurisdictional Delineation Report prepared for this DEIR, except where authorized by federal, state or local permits.
b. Protect inlets and outlets of culverts from construction material intrusions using temporary berms to prevent channel incision, erosion, and sedimentation.
c. Erosion control measures appropriate for on-the-ground conditions, including percent slope, length of slope, and soil type and erosive factor, shall be implemented.
d. Temporary erosion controls such as straw bales and tubes, geotextiles and other appropriate diversion and impounding materials and facilities shall be properly maintained throughout construction (on a daily basis) and reinstalled (such as after backfilling) until replaced with permanent erosion controls or restoration is complete.
e. Where jurisdictional waters are adjacent to the construction right-of-way, the contractor shall install sediment barriers along the edge of the construction right-of-way to contain spoil and sediment within the construction right-of-way.
f. Ensure that all employees and contractors are properly informed and trained on how to properly install and maintain erosion control BMPs. Contractors shall require all employees and contractors responsible for supervising the installation and maintenance of BMPs and those responsible for the actual installation and maintenance to receive training in proper installation and maintenance techniques.
g. Project scheduling will include efficient staging of CV Link construction that minimizes the extent of disturbed and destabilized work area, and reduces the amount of soil exposed and the duration of its exposure to wind, rain, and vehicle tracking.
h. The use of a schedule or flow chart will be incorporated to lay out the construction plan and will allow Link construction to proceed in a manner that keep water quality control measures synchronized with site disturbance, paving and other construction activities.
i. The sequencing and time frame for the initiation and completion of tasks, such as site clearing, grading, excavation, path construction, and reclamation, shall be planned in advance to ensure minimization of potential impacts.
j. Erosion and sediment control BMPs shall be incorporated into travelway construction plans.
To prevent petroleum products from contaminating soils and water bodies, the following BMPs shall be implemented:
a. Construction equipment and vehicles shall be properly maintained to prevent leakage of petroleum products.
b. Herbicides, fertilizers, vehicle maintenance fluids, petroleum products shall be stored, and/or changed in staging areas established at least 100 feet from delineated streams and other drainages. These products must be discarded at disposal sites in accordance with state and federal laws, rules, and regulations.
c. Drip pans and tarps or other containment systems shall be used when changing oil or other vehicle/equipment fluids.
d. Areas where discharge material, overburden, fuel, and equipment are stored shall be designed and established at least 100 vegetated (permeable) feet from the edge of delineated streams.
e. Any contaminated soils or materials will be disposed of off-site in proper receptacles at an approved disposal facility.
f. All erosion control measures shall be inspected and repaired after each rainfall event that results in overland runoff. The project contractor and CVAG shall be prepared year round to deploy and maintain erosion control BMPs associated with CV Link.
g. Existing culverts shall be carefully maintained in place in order to ensure that they function properly. Considerations include: maintenance of inlet and outlet elevations, grade, adequate compacted material cover, and inlet/outlet protection.
CV Link structures will be within a 100-year flood hazard area, which would impede or redirect flood
flow. CV Link construction will follow the CVWD and RCFCWCD design and development standards and guidelines, including limited to the Riverside County Whitewater River Region Stormwater Quality Best Management Practice Design Handbook for Low Impact Development (RCFCWCD, 2014) and the CVWD Development Design Manual (CVWD, 2013).
CV Link could expose people to a risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam. CV Link construction will follow the CVWD and RCFCWCD design and development standards and guidelines, including limited to the Riverside County Whitewater River Region Stormwater Quality Best Management Practice Design Handbook for Low Impact Development (RCFCWCD, 2014) and the CVWD Development Design Manual (CVWD, 2013).
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