| 8. Water - Hydrological Impacts and Water Quality |
Please refer to Appendix A, A-4. Resources Map
Hydrology Impacts are very interconnected with geology and soil issues - it is suggested that this section be referenced to Section 4. Impacts on Geology, Soils. Seismicity, Topographical Impacts.
No hydrology reports are available at this time. Reports done for earlier projects were deemed inadequate, but they, along with community observations, provide the basis for some areas of study:
The "unnamed creek" that flows along the southern portion of the East Parcel drains many hundreds of acres of upland property, including the Johnston Ranch and portions of Quarry Park. Although severely mangled by earlier property owners, the creeks runs quite heavy in the winter and maintains a year round flow through the property, under a highway culvert and through the West Parcel to the ocean. The creek is documented as a significant watercourse in maps dating back to 1894.
This creek waters the riparian habitat at the southwest section of the property, as well as maintains the grove of eucalyptus and cypress at the upper parts. Its overflows contribute to the seasonal wet low lands of the property (see Sections 4.1.b and 4.1.e above), and the main creek feeds the riparian corridor that forms the southern boundary of the West Parcel. This area of the West Parcel is also bordered by several candidate vernal ponds, unique habitats that depend on certain levels of ground water and seasonal flows for their health and maintenance. Flows from this creek, and its sediment load, directly affect the beach formation below the bluffs of the West Parcel, and quite possibly the erosion rate of those bluffs. The West parcel is adjacent to the Monterey Bay National Marine Sanctuary, into which this creek flows.
The EIR should study how this project will affect this water course: current project plans show the creekbed filled in, graded over and presumably channeled under the development. Increased runoff from lack of soil absorption into the riparian area from graded and paved development, additional non-point pollution from residential housing, should be assessed in the EIR for the health of the creek and the habitats it maintains. Sediment carrying capacity should be analyzed to handle whatever uses upstream lands might provide (i.e., logging, quarrying, further development), as well as how the loss of sediment dispersion in lowland flooding will affect habitats, geological and oceanic conditions downstream from the project. See Section 11. Impacts on Biology: Vegetation and Wildlife
The EIR should also consider current flooding problems in the area. This last winter (early 1998) saw extensive flooding from upland areas down through El Granada and through the subject parcel. The 1 acre area designated as a donation to the school was particularly affected with heavy standing water. Concern is expressed that housing development could affect ground water retention, leading to heavier flood flow toward the highway and through the habitats of the West Parcel.
The EIR should assess the project's impact on water quality and availability, from ground and surface water sources. The EIR should also assess cumulative impact of project's potential precedent setting use of low density lands for higher density development on water quality and availability of both ground and surface water throughout the MidCoast area.
| 8.1. Precedents and Consequences |
| 8.2. Mitigation |