Hydrology & Geology

This project, proposed at such an over-the-top scale, has the potential to exacerbate water drainage issues already present on the site, on Water Street hill, and in surrounding neighborhoods.

  • Most properties in the neighborhood already have standing water in the rainy season. That’s because this neighborhood was built on unconsolidated older marine terrace deposits underlaid  by the impermeable mudstone bedrock. During seasonal high intensity rainfall events, the copious amount of water coming down this coastal slope perches along this seam between the consolidated and unconsolidated material. Where will this water go if two levels of underground parking are built? Will the buildings act as a dam and back up yet more water onto adjoining properties? Between the prospects of yet more standing water and lack of solar access during the winter, will the project create health risks for nearby residents and liability for the city?
  • Many homes in the adjoining neighborhood already use sump pumps to remove water from beneath their homes. A home less than 100 yards downhill of the proposed project has had issues with water pooling around the foundation and resultant black mold issues that make it currently uninhabitable. This home was approved seven years ago by both the building department and the planning department. The testing done to determine hydrologic conditions was done during a drought year. We are currently at 48% of our average rainfall at this point in the season. How will an accurate analysis of hydrologic conditions be accomplished under such conditions? The proposed project could very well exacerbate the perched groundwater problems in nearby neighborhoods, and we MUST understand potential negative impacts before proceeding.
  • Also worrisome is the impact that this proposal could have on the hillside that is already potentially unstable between the project site and Water Street. The substrata, viewed from the Water Street road cut, is fractured and continually crumbling in large blocks on the sidewalk, perhaps due to the continual seepage. Such a massive project so close to a steep, potentially unstable slope becomes a mandate for an Environmental Impact Report. This EIR must include at least a slope stability analysis, seismic requirements (831 is within 10 miles of six faults and situated toward the top of a steep slope,) strength of the bedrock to withstand the depth of fracturing needed to support a 6-story building, storm water drainage capacity, soil impermeability study, water runoff parameters.