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 City of Solana Beach
Section 3
Shoreline and Coastal Bluff Management Strategies Draft MEIR
Environmental Impact Analyses
short-term erosion. The long-term erosional rate of the upper bluffs is thought to be equal to the
long-term rate of the lower seacliffs.
Seacave Plugs and Fills
Effects of Plugs and Fills on Shoreline Erosion and Beaches
There is no evidence that indicates that seacave plugs and fills contribute to shoreline and
beach erosion. Non-erodible and erodible seacave plugs and fills constitute major cost-effective
protective measures, which reduce erosion of the cliff base and improve the overall stability of
the bluffs. Plugs and fills would reduce the need to construct seawalls providing there is
construction access and there are no site constraints such as locations where there is no beach.
Short-term Effects
No short-term effects to geology and soils would result from the plugging or filling of seacaves of
the relatively resistant cliffs in Solana Beach. The plugging or filling of seacaves and notches
with erodible concrete reduces the potential for near-term catastrophic failures, but the erosion
still occurs at the same rate and, with enough passage of time, erodible and non-erodible
concrete would have the same long-term effect. In the short-term, both non-erodible and
erodible plugs and fills would reduce the need of constructing a more intrusive and costlier
protection device such as a seawall.
Long-term Effects
No-long-term effects to geology and soils would result from the plugging or filling of seacaves.
In the long-term (100+ years), both non-erodible and erodible plugs and fills will result in the
ultimate landward erosion of the bluffs. The rate of landward erosion will depend upon varying
factors such as the beach width, cliff strength, and unpredictability of wave and tide conditions.
However, continuation of the Shoreline and Costal Bluff Protection Ordinance reduces the
otherwise seemingly inevitable need for massive seawalls by as much as 50 to 100 years. This
continued reliance on less intrusive structures should allow time for federal and state agencies
to accumulate funds and prepare the necessary studies for sand replenishment programs and
to construct offshore structures if they are deemed appropriate.
Effects of Plugs and Fills on Coastal Upper Bluffs
No negative effects on coastal upper bluffs would result from the plugging or filling of seacaves.
The plugging or filling of seacaves reduces the effects of wave and tide energy on the existing
notches; therefore, reducing the potential failure of the upper bluffs in the short-term. In the
long-term (100+ years), both non-erodible and erodible plugs and fills will result in the ultimate
landward erosion of the bluffs. The rate of landward erosion will depend upon varying factors
such as the beach width, cliff strength, and unpredictability of wave and tide conditions.
Project No. 323530000
Page 3-20
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