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 City of Solana Beach
Section 2
Shoreline and Coastal Bluff Management Strategies Draft MEIR
Project Description
face is highly erodible. Typical seawalls consist of 24-inch square pre-stressed concrete piles
approximately 45 feet long set and grouted into pre-drilled holes with a height 15 feet above
Mean Lower Low Water (MLLW). Precast wall panels, set behind the row of piles and grout fill,
complete the structure. Depending upon the specific site location, seawalls could vary from 2 to
2.5 feet in thickness, 15 to 40 feet high, and 20 to 600 feet in length. Notches in the bluffs
would be filled with grout behind the wall panels (AMEC 2001).
Shotcrete Walls
Shotcrete walls consist of 6-inch thick reinforced walls, applied directly onto the bluff face, up to
an elevation of 15 feet or higher above MLLW. The design enables a relatively low-cost plan to
armor the seacliff toe, effectively filling in seacaves or notch areas to achieve an overall result of
improving seacliff stability, and arrest further erosion of the bluff base. These areas would be
filled with concrete that has erosion characteristics similar to the adjacent bluff material. These
types of walls are least dependent on construction access as compared to cantilever seawalls.
Depending upon specific site location, shotcrete walls could vary from 15 to 40 feet high and 20
to 600 feet in length (AMEC 2001).
Bluff Tieback Walls
Bluff tieback walls are designed to reduce the blufftop recession process. A typical wall would
consist of a tied-back, free form structural shotcrete skin that can be carved and colored to
increase its natural appearance. The structural face would likely be 15 to 18 inches thick, and
be constructed on a 1:4 (horizontal:vertical) slope extending down from the existing top of bluff.
Depending upon specific site location, tieback walls could range from 30 to 90 feet in height and
20 to hundreds of feet in length (AMEC 2001).
Plugs/Fills
Plugs and fills consist of filling existing seacave notches with textured and colored, erodible or
non-erodible concrete to blend into the existing bluff face and designed to reduce erosion,
further deepening of existing seacaves, and minimizing the effects that could result in a future
need of a more intrusive protection device. Erodible plugs and fills in the short-term keep
seawalls from being built. Short-term is defined as 5 to 30+ years (in areas of faster bluff and
sub-aerial erosion where structures are built close to the top of the bluff) or 50 to 100 + years (in
areas where there is less erosion and there is adequate setback from the top of the bluff). Non-
erodible plugs and fills, in the short-term will do the same. In the long-term, both erodible and
non-erodible plugs and fills will result in the ultimate landward erosion of the bluffs. Wire mesh
or riprap is used with the concrete mixture. Depending upon specific site location, seacave
notches can range from 5 to 400 feet in width, 5 to 20 feet in height, and 2 to 40 feet in depth.
Revetments
Revetments are flexible structures made of placed quarry stone designed to protect bluff toes
from erosion by wave action. The revetment structure is designed for depth limited wave
Project No. 323530000
Page 2-20
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