Shorelines face constant erosion, storm damage, and loss of marine habitats due to conventional seawall and riprap structures. In San Diego Bay, a pilot project is testing a different kind of coastal armor that doesn’t just block the sea—it works with it. ECOncrete’s COASTALOCK system interlocking tide-pool units installed at Harbor Island aim to combine structural protection with habitat creation. The results from two years of monitoring show that this nature-inclusive design may offer both engineering resilience and ecological uplift.
What Is COASTALOCK & Why It Matters
COASTALOCK (“CL”) is a patented concrete armor unit designed by ECOncrete to replace standard riprap rock along waterfronts. It’s interlocking and shaped to form tide-pool cavities, overhangs, caves, and water-retaining features. Pantheon Storage+2Pantheon Storage+2
The pilot project installed 74 units across two sites along Harbor Island, San Diego Bay; installation was completed by early 2021. Pantheon Storage+1
Purpose: to provide coastal protection, while enhancing marine biodiversity by mimicking or creating habitats often missing from urbanized shorelines. Pantheon Storage+2Pantheon Storage+2
Design Features & Installation
Interlocking single-layer armor: Rather than loose rocks, the units interlock, increasing stability under wave action. Pantheon Storage+1
Tidal adaptation: The units are arranged in four rows: upper, middle, lower intertidal zones. The top rows mimic tide pools (retain water during low tide), and the lowest row is rotated to create cave-like habitats. Pantheon Storage
Low-carbon concrete: The concrete mix is tailored to the Bay’s marine environment (chemistry, local water conditions), with a formula that supports marine life recruitment. World Port Sustainability Program+1
Installation method: Cast onshore, cured, then transported and installed via barge and crane between October 2020–March 2021. Pantheon Storage
Monitoring & Ecological Impacts
Biological monitoring has taken place at ~8, 14, 20, and 26 months post-deployment (MPD). Pantheon Storage
Results show significantly higher species richness and diversity on the COASTALOCK units than on adjacent control riprap rocks. For example, at 26 MPD, the Armor Units had more algae species (15 vs ~7 on control) and a wider range of sessile invertebrates. Pantheon Storage
The cavities retain water during low tide, creating mini-habitats that support species that can’t survive on exposed rock surfaces. These water-retaining features are key to biodiversity increases. Pantheon Storage
Also measured: organic and inorganic biomass accumulation. The Armor Units showed about double the inorganic content (CaCO₃ etc.) compared to control rocks in many cases. Pantheon Storage
Structural & Practical Performance
Structurally: After 26 months, no visible cracking or chipping on the Armor Units; the units remain stable (no significant displacement). Pantheon Storage
Maintenance requirements have been low; because these are precast concrete units, installation was deliberate, and durability has been promising. Pantheon Storage
The pilot is part of a three-year monitoring program, comparing ecological and structural performance to traditional riprap. Data is being collected every six months. Pantheon Storage+1
Challenges & What Still Needs Work
Long-term durability: While early structural performance is good, wear from storms, potential biofouling, or harsh environmental stress over many years still needs assessment.
Scaling & cost: Precasting, transporting, installing interlocking concrete units is more complex than dumping riprap. Cost implications and logistical challenges are significant.
Regulatory, permitting, and local adaptation: Urban waterfront authorities need to accept new designs; environmental permitting and adapting designs to different tidal zones, wave energy, local marine ecology etc. are nontrivial.
Monitoring timeframe: Ecological succession can take time; some species take longer to colonize; monitoring over multiple seasons is crucial.
Broader Implications & Use Cases
This approach could transform how cities and ports think about coastal armor: from passive protections to active seascapes that support marine life.
Other applications include piers, breakwaters, shoreline promenades, and waterfront redevelopment where environmental enhancement is a goal.
Could help meet regulatory/ environmental mandates for “nature-inclusive infrastructure”, blue economy, climate resilience, and shoreline adaptation.
FAQs
Q1: How much more biodiversity did the Armor Units support vs riprap? By 26 months, many more species of algae, invertebrates, and mobile fauna were found on the COASTALOCK units. Biomass (organic & inorganic) accumulation was also substantially higher. Pantheon Storage
Q2: Do the water-retaining cavities help significantly? Yes. They allow pools of water during low tide, which serve as refuge for many species that can’t survive fully exposed rock surfaces.
Q3: How stable are the units in storms or wave conditions? Early visual inspections (up to 26 MPD) show no major structural damage or displacement; the interlocking design aids stability. Still, long-term performance under extreme weather remains under observation.
Q4: What about carbon emissions? Is this concrete more sustainable? The project uses low-carbon concrete tailored to local conditions; also, the biological buildup (calcium carbonate deposition, etc.) helps sequester carbon. But embodied carbon in concrete is still significant; the ecological benefits help offset, but full life-cycle assessments are needed. Pantheon Storage+1
Conclusion
ECOncrete’s COASTALOCK rock pools in San Diego Bay illustrate a powerful shift in coastal engineering—from static, purely functional shore protection to structures that cherish ecological complexity. Early data shows they provide real habitat value, outperform conventional riprap in biodiversity, and hold up well structurally after over two years.
If the pilot continues to deliver, COASTALOCK and similar nature-inclusive designs may become standard practice in waterfront infrastructure—offering shore protection that isn’t just about resisting the sea, but enhancing it.
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COASTALOCK Rock Pools: Rethinking Seawalls with Biodiversity & Shoreline Armor
Introduction
Shorelines face constant erosion, storm damage, and loss of marine habitats due to conventional seawall and riprap structures. In San Diego Bay, a pilot project is testing a different kind of coastal armor that doesn’t just block the sea—it works with it. ECOncrete’s COASTALOCK system interlocking tide-pool units installed at Harbor Island aim to combine structural protection with habitat creation. The results from two years of monitoring show that this nature-inclusive design may offer both engineering resilience and ecological uplift.
What Is COASTALOCK & Why It Matters
Design Features & Installation
Monitoring & Ecological Impacts
Structural & Practical Performance
Challenges & What Still Needs Work
Broader Implications & Use Cases
FAQs
Q1: How much more biodiversity did the Armor Units support vs riprap?
By 26 months, many more species of algae, invertebrates, and mobile fauna were found on the COASTALOCK units. Biomass (organic & inorganic) accumulation was also substantially higher. Pantheon Storage
Q2: Do the water-retaining cavities help significantly?
Yes. They allow pools of water during low tide, which serve as refuge for many species that can’t survive fully exposed rock surfaces.
Q3: How stable are the units in storms or wave conditions?
Early visual inspections (up to 26 MPD) show no major structural damage or displacement; the interlocking design aids stability. Still, long-term performance under extreme weather remains under observation.
Q4: What about carbon emissions? Is this concrete more sustainable?
The project uses low-carbon concrete tailored to local conditions; also, the biological buildup (calcium carbonate deposition, etc.) helps sequester carbon. But embodied carbon in concrete is still significant; the ecological benefits help offset, but full life-cycle assessments are needed. Pantheon Storage+1
Conclusion
ECOncrete’s COASTALOCK rock pools in San Diego Bay illustrate a powerful shift in coastal engineering—from static, purely functional shore protection to structures that cherish ecological complexity. Early data shows they provide real habitat value, outperform conventional riprap in biodiversity, and hold up well structurally after over two years.
If the pilot continues to deliver, COASTALOCK and similar nature-inclusive designs may become standard practice in waterfront infrastructure—offering shore protection that isn’t just about resisting the sea, but enhancing it.
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