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Solana Beach Coastal Preservation Association
August 20, 1998
Project No. 1831
Page 2
2
PHYSIOGRAPHY AND GEOLOGY
The Solana Beach coastline extends from the south side of San Elijo Lagoon approximately
1.4 miles south to the projection of Via De La Valle, the southern city limits. The coastal
bluffs extend southerly an additional 0.3 mile to the San Dieguito River valley. This reach
of coastline consists of steep coastal bluffs, except at Fletcher Cove. The bluffs range in
height from approximately 70 feet at Cardiff State Beach, to 90 feet south of Las Brisas.
San Elijo Lagoon is the discharge point for the significant drainage of Escondido Creek
extending 20 miles to the east. The San Dieguito River valley extends approximately 70
miles into the back country to the crest of the Laguna Mountains. The canyon at Fletcher
Cove naturally drains the area of the City between Pacific Coast Highway and the coastal
bluff. A large storm drain also discharges at the Cove. Low altitude oblique aerial
photographs and accompanying topographic maps (Photo and Map Nos. 1 through 8,
respectively) depict the general character of the study area.
Prior to the establishment of extensive residential development along the bluff top, the
drainage divide of the coastal terrace was formed by an ancient beach ridge typically 50
feet back from the contemporary bluff-top, thus limiting over-bluff discharges to very
localized runoff. Southerly of 525 Pacific Avenue, the terrace surface slopes away from the
bluffs, preventing any over bluff discharge. Development has not modified the natural
drainage pattern, except within individual residential lots. With the exception of a few of the
northerly lots, the residences along the bluff are built at elevations above street elevation.
Consequently, drainage from lots is almost entirely to the street. Backyards of a few of the
northerly lots are below the adjacent street level and, at these locations, a small amount of
surface drainage discharges over the bluff to the beach. Similarly, backyards of a few of
the southerly lots appear to have indefinite drainage, suggesting that locally, a small
amount of backyard runoff southerly of 525 Pacific Avenue may also discharge over the
bluff.
Overbluff drainage discharges are minimal at Solana Beach compared to the coastal bluffs
in Encinitas (the adjacent coastal community to the north). In Encinitas, the top of the
ancient beach ridge is upwards of 500 feet east of the bluff top, large areas of ponding and
over-bluff discharge occur, exacerbating subaerial erosion processes in that coastal



 


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