Failure to identify substantial alterations to subsurface drainage patterns which could contribute to on-site or off-site flooding.The Proposed Project would substantially alter subsurface drainage patterns through historical tidal sloughs within the project area. These alterations include the installation of the stormwater sewer back-bone along the right-of-way of Mitchell-Mosely Boulevard, Tinker Avenue, Office Park Drive and Fifth Street. These storm sewer laterals would create barriers to shallow groundwater flow which would create surface flooding. The chronic flooding at Main Street and Singelton Avenues adjacent to the project site is a result of a storm sewer lateral constructed across a former tidal slough. The project to address flooding in this location was not completed by the end of 1999 as stated in the EIR, nor is this project expected to completely eliminate the flooding problem in this area.Failure to identify impacts of increased run-off on existing Stormwater System Capacities.
Given the elevation of the project site, grading of the site may cause changes in surface drainage patterns that may overwhelm existing natural and engineered storm drainage systems. The current stormwater sewer system design has approximately 50 percent of the East Housing area draining into the Seaplane Lagoon. The remainder of the East Housing area and the FISC Annex Facility drain towards the Oakland Estuary. The EIR for the Proposed Project does not indicate that these existing drainage patterns will be maintained.
Any increase in the elevation of the East Housing Area and FISC Annex could also alter drainage patterns and contribute to flooding in the surrounding areas. Failure to maintain existing drainage patterns would result in a significant impact. If current grade elevations are not to be maintained within the Project Site, mitigations to address this issue need to be articulated.
Additional Mitigation Required: The EIR needs to identify mitigation measures to eliminate this significant flooding impact of the Proposed Project.Even if the Proposed Project replaces existing stormwater sewers, the replacement sewer would be required to serve other areas in the project vicinity. At the FISC Annex facility, 50 percent of the East Housing area and the Coast Guard Housing Area combine to drain into an outfall in the Oakland Estuary. The proposed new stormwater system would have to be capable of handling the project stormwater flows, together with the drainage from the Coast Guard Housing and the proposed stormwater pump station at Singelton and Main Streets.Mitigation Measure HYD-2 - Stormwater Pollution Prevention Plans Ineffective
The outfall that is to be upgraded in the Seaplane Lagoon currently provides drainage to a large area of Alameda Point. The capacity of any new or modified system must account for stormwater flows from areas outside the project.
Since the neither the system capacities needed to serve existing developed areas, nor the capacities needed to serve the Project are described in the EIR, the EIR fails to analyze or mitigate this potentially significant project.
Additional Information Required: Provide data on the capacities of existing systems and the amount of run-off that the Proposed Project will generate.The Mitigation Measure HYD-2 would be ineffective. The City of Alameda Public Works Department and Bureau of Electricity routinely violate the city?s stormwater pollution prevention ordinance and the prohibitions found in the National Pollutant Discharge Elimination System Permit non-point source permit. There is no evidence that the City enforces the ordinance even in response to citizen complaints. As an example, see the contaminated soils stockpiled adjacent to an unlined drainage ditch at the Alameda Ferry Terminal two years ago by the City of Alameda.Mitigation Measure HYD-2 addresses Construction Related Pollutants (p. 177)
As further example, on December 18, 1999, the California Office of Emergency Services received a report that the City of Alameda had discharged petroleum contaminated stormwater from an underground tank excavation into a tributary to San Francisco Bay.
As further example , on January 19, 2000, the Regional Water Quality Control Board and Alameda County Environmental Health Department received a report that stormwater runoff from this same City owned site was contaminated by petroleum from the underground tank release.
None of the measures required by the City?s stormwater pollution prevention ordinance have been taken at this site or any other city construction site. Given the City?s failure to comply with its Clean Water Act permit, coupled with the City?s failure to enforce its existing Stormwater Pollution Prevention Ordinance, the proposed mitigation HYD-2 will be ineffective in minimizing or eliminating significant stormwater pollution impacts caused by the proposed project.
Additional Mitigation Required: Provide for additional oversight by the Regional Water Quality Control Board and Alameda County Environmental Health Department to increase the likelihood of effective mitigation.The Mitigation measure HYD-2 addresses potential stormwater pollution by requiring Best Management Practices to prevent construction related pollutants in run-off. The bioaccumulative, toxic, and volatile chemicals found in soils and groundwater at the Project site are not construction related and are therefore not addressed by mitigation HYD-2. As a result, this mitigation would not reduce or eliminate the significant environmental impacts caused by polluted stormwater runoff.Stormwater pollution from Groundwater infiltration
Additional Mitigation Required: Develop mitigation that is not related to construction practices.The EIR indicates that stormwater quality violates current standards for discharge into the Bay due to infiltration of contaminated groundwater into buried sewer laterals. The proposed sewer system is also expected to violate current standards for stormwater discharges to the Bay which represents a significant environmental impact that is not analyzed or mitigated by the project EIR. The EIR should address mitigation of groundwater contamination to ensure that stormwater from the Project site does not exceed numerical water quality standards contained in the San Francisco Bay Water Quality Control Plan.Flooding significance
Additional Mitigation Required: Require the new system to meet the water quality standards established by the San Francisco Bay Water Quality Control Plan.The EIR indicates that a significant flood is one that would damage a proposed structure. The EIR considered the flooding of streets and landscaped areas to be a less than significant impact. The EIR however fails to analyze the environmental effects of flooding when the flood waters contain toxic chemicals. An increase in the elevation of groundwater by flooding, or the release of contaminated groundwater from inundated stormwater inlets, would leave toxic chemical residues in streets and landscaped areas. The significance of periodically distributing toxic chemical throughout a residential area needs to be analyzed, and appropriate mitigations (groundwater cleanup) pursued.Acquisition and Planning
Additional Analysis Required: Reconsider the impact, based on the assumption that flood waters will be contaminated, and mitigate as required.Year one activities would consist of reconstruction of the existing storm drain outfall in the Seaplane Lagoon. The Seaplane Lagoon has been identified as a National Priorities List (NPL) (Superfund) site due to extensive contamination of marine sediments. Cleanup plans for the Seaplane Lagoon, which is part of Operable Unit No. 4 of the Alameda Point Superfund Site, will not be finalized before March 2003. The stormwater sewer between East Housing Area and the Seaplane Lagoon passes through four IR Sites. Cleanup plans required by Superfund have not been developed any of the four IR Sites.Beneficial Uses of Groundwater
The EIR identifies the potential impacts of the stormwater outfall construction as Impact BIO-3. Mitigation Measure BIO-3 includes Mitigation Measure HYD-2. Mitigation Measure HYD-2 addresses polluted stormwater run-off and would be largely irrelevant for dredging activities.
Mitigation Measures BIO-3 may or may not include the discretionary approval of the Army Corps of Engineers, Regional Water Quality Control Board, Department of Fish and Game and/or the US Fish and Wildlife Services. Without determining if the approval of these agencies is required and what conditions would be placed on such approval, the EIR provides an incomplete analysis of environmental impacts of the stormwater outfall installation. The environmental analysis by other agencies of the stormwater outfall will be completed separately from the analysis of other project components. The potential to over-look significant and cumulative environmental impacts is inherent in this type of piecemeal environmental impact analysis.
Additional Analysis Required: Ensure that there will be subsequent environmental review of outfall reconstruction since this document fails to analyze or properly mitigate impacts.The Project EIR indicates that the US Navy has concluded that that shallow groundwater has no designated beneficial uses. The Project EIR notes that the Regional Water Quality Control Board has requested that the Navy evaluate other beneficial uses of groundwater. These beneficial uses will likely include discharge to surface waters used for sensitive ecological habitat, fisheries and contact recreation. Cleanup requirements will be based on these designated beneficial uses.Sewer Abandonment In-place.
The approval of the Proposed Project will significantly increase the costs and time to perform groundwater cleanup necessary to attain numerical water quality standards required to protect beneficial uses. Pumping of contaminated groundwater may cause subsidence beneath proposed structures.
Additional Analysis Required: Analyze the impacts of the Proposed Project on the ecological use of groundwater.The proposal to abandon storm sewers in place by filling with soil or concrete is a significant environmental impact that the EIR fails to analyze or mitigate. The storm sewer at the Project site is known to contain toxic and hazardous materials due to illegal dumping by the US Navy, contaminated stormwater run-off, and infiltration of contaminated groundwater.
The proposal to backfill stormwater drains without removing hazardous wastes, and without proposing long-term monitoring or a deed restrictions to prevent future human exposure will cause significant impacts that need to be addressed.
Additional Analysis Required: Analyze impacts and devise mitigations to prevent unacceptable risk from the abandonment of contaminated storm sewers.
Cover Letter - Project Alternative - Analysis Failures - Deferred Mitigations
Report Organization - Land Use - Population and Housing - Traffic - Air Quality
Public Services - Noise - Drainage and Hydrology - Hazards