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 City of Solana Beach
Section 3
Shoreline and Coastal Bluff Management Strategies Draft MEIR
Environmental Impact Analyses
capacity of 4 to 5 inches, and rapid permeability (6.3 to 20 inches per hour). The erosion
hazard is slight to moderate. The rooting depth is more than 60 inches.
Coastal Beaches (Cr) land type occurs as gravelly and sandy beaches along the Pacific Ocean
where the shore is washed and rewashed by ocean waves. Part of this land type is likely to be
covered with water during high tide and stormy periods.
Geologic Setting
The general vicinity of the study area is underlain by the Tertiary sedimentary rocks capped by
the Quaternary marine and non-marine sediments deposited on a series of wave-cut terraces
(Figure 3.1-3).
The Eocene-aged sedimentary rocks of the La Jolla and Poway Groups underlying the study
area and its vicinity were deposited in a continental shelf environment. It is believed that these
rocks were deposited in the subsiding San Diego sedimentary basin, forming a thick
sedimentary sequence (Kennedy, 1975). The rock units of the La Jolla Group exposed in the
study area are the middle Eocene (49 to 47 million years old) Delmar Formation and the Torrey
Sandstone. The Delmar Formation transitions into Torrey Sandstone vertically and laterally.
Four erosional terraces are recognized in the site vicinity area. The three younger terraces are
correlated with the late Pleistocene (120,000 years old) Bay Point Formation, and the oldest
terrace is correlated with the late to early Pleistocene (1,180,000 to 120,000 years old)
Lindavista Formation (Tan and Kennedy, 1996; Kennedy, 1975). In general, three principal
elements are recognized in erosional coastal terraces: a wave-cut platform, an inner edge
(shoreline angle), and a seacliff (Figure 3.1-4). A wave-cut platform has a shallow seaward dip
of 0.01 to 0.02 feet per foot (Ritter and others, 1995; Group Delta, 1998). The modern wave-cut
platform formed as the seacliff retreats stands slightly below water level at the high tide. An
inner edge marks the highest sea level maintained during any glacial/interglacial time. The
older uplifted platforms are overlain by marine and non-marine terrace deposits. The number
and spacing of terraces are determined by the rate of tectonic uplift and the nature of the
coastal processes. The marine terrace deposits in the study area are generally correlated with
the Bay Point Formation.
Coastal Bluff Geology
The on-site materials are described below, from oldest (Delmar Formation) to youngest
(Artificial Fill).
Delmar Formation
The middle Eocene-age (49 to 47 million years old) Delmar Formation of the La Jolla Group
crops out at the northernmost part of Solana Beach, north of 633 Pacific Avenue. It is
composed of yellowish-green sandy claystone interbedded with gray, coarse-grained sandstone
(Kennedy, 1975). In the northern part of Solana Beach, where it is exposed at the base of the
Project No. 323530000
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