Appendix E - Geology and Soils Geotechnical Supporting Information COMBINED

LESTER-SHRINER PROPERTY 132-8-2 Page 5 Table 1: Approximate Fault Distances Fault Name Approximate Distance (miles) (kilometers) Calaveras 0.7 1.5 Hayward (Total Length) 6.2 10.0 Greenville 12.2 19.7 Concord-Green Valley 13.3 21.5 A regional fault map is presented as Figure 4, illustrating the relative distances of the site to significant fault zones. SECTION 3: SITE CONDITIONS 3.1 SURFACE DESCRIPTION The site consists of two parcels currently referred to as the Lester parcel and the Shriner parcel. Both adjoining parcels are located south of Dublin Canyon Road and west of Foothill Road. The eastern approximately 22 acres of the Lester parcel and the entire Shriner parcel are being considered for residential development. The site is bordered by mostly undeveloped parcels to the south, east and west. A Jehovah’s Witness Church borders the northeast corner of the site and residential development is located just north of Dublin Canyon Road. Current topographic information indicates the site has approximately 208 feet of topographic relief from the northwest to the southeast. Existing site grades range from approximately Elevation 650 feet at the western edge of the Lester parcel to approximately Elevation 442 feet near the northeastern corner of the site (datum unknown). The prominent topographic features on the site are two saddle ridges along the northern site boundary of the Lester parcel (approximately Elevation 610 and 600 feet). Most of the Lester parcel slopes downward toward Devaney Canyon and the seasonal creek that flows towards the northeast along the southern site boundary. The Shriner parcel is located on the north side of the saddle ridges and drains primarily to the north towards Dublin Canyon Road. Generally, existing hillsides are moderately steep to steep with slopes ranging from 5:1 to 2½:1 (horizontal:vertical). Devaney Creek has side slopes that vary from relatively flat terraces to approximately 2:1. The creek is surrounded by a dense riparian canopy of large trees and bushes. We observed locally steepened stream banks that were near vertical due to erosion and minor slumping. At least three minor drainage swales with locally eroded side slopes appear to flow into the stream from the northwest. The northwest corner of the site drains into a broad ravine that slopes to the north towards the Shriner parcel. The Shriner parcel is comprised of north-facing slopes that range from about 4:1 to 2:1. The western half of the parcel’s slopes are moderately steep and are traversed by two broad drainage swales that sheet flow towards Dublin Canyon Road. The northeastern portion of the Shriner parcel is moderate to steeply sloped and covered with dense trees and brush. The toe of the slope daylights adjacent to Dublin Canyon Road and is buttressed by a retaining wall immediately adjacent to the road. 15! CORNERSTONE EARTH GROUP