Seawalls Units Herzliya Marina
Herzliya Marina Israel
Product used: Seawall Units
Ports and marinas are an essential part of our coastlines, yet too often these replace rich natural habitats with non-productive concrete based infrastructure. Concrete seawalls are communally used in coastal construction and provide low quality habitat and often promote the dominance of nuisance and invasive species. For the purpose of elevating ecosystem function at Herzliya Marina, ECOncrete® has designed a high texture seawall unit with a bio-enhanced concrete mix that provides suitable environmental conditions for the development of a diverse assemblage of marina flora and fauna while compiling with all the standard seawall requirements for structural performance. Monitoring was performed up to 22 months post-deployment, at which point the ECOncrete® seawall units were covered with a variety of invertebrates, including sponges, oysters, bivalves, bryozoans, and coralline algae, while the control concrete seawall presented the low-diversity assemblage, commonly associated with ports and marinas.
Coastal and marina infrastructure (CMI), often imposes much stress on fauna and flora of natural habitats. Concrete based CMI, provide poor substrates in terms of biological recruitment due to the combined effects of the concrete’s chemistry, featureless surface texture and high inclination compared to natural habitats. Considering the recent growth of world populations and rural development around coastlines, the effect of CMI on the natural environment is catastrophic.
Herzliya Marina, opened to the public in 1995, is the largest and one of the most innovative Marinas in the eastern Mediterranean Sea. The marina provides substantial public boating options for tens of thousands of visitors annually from all over the world. As one of the first marinas in Israel to receive the world renowned eco-label “Blue Flag”, Herzliya Marina put a considerable emphasis on sustainability and elevating ecosystem functionality. For this reason, ECOncrete® has developed a high texture seawall unit composed of bio-enhanced concrete that provides suitable biological and environmental conditions for the development of a rich and diverse assemblage of marina flora and fauna.
ECOncrete® supplies a range of modular, esthetic seawall elements, which functionally integrate into coastal infrastructure. The units can be used to retrofit an existing wall or to provide a fully structural and load bearing wall for new construction. ECOncrete seawalls increase the ability of species to utilize the structure, and can be tailored for specific species of conservational value, without effecting their structural and functional properties.
ECOncrete®’s Seawall defers from standard concrete walls on three levels; concrete chemistry, surface complexity and macro-design. These three elements combined, mimic natural marine environments and decrease the negative effects of concrete based coastal development. The mix is specially designed for the requirements of marine flora and fauna and the surface complexity mimics the one found in natural habitats. In addition, higher level surface elements offer refuge to larger marine life similar to natural habitats.
A direct comparison was made between the ECOncrete® Seawall units and the standard Portland cement comprising the existing seawall infrastructure. Immediately after installation, a baseline survey of the existing conditions on the marina seawall was conducted using a 30×30 cm stainless steel frame (quadrat) to identify the species present. After which, the quadrat area was scraped clean to serve as control for the ECOncrete seawall unit. 22 months post-deployment, the ECOncrete® seawall units were covered with a variety of invertebrates: sponges, oysters, bivalves, bryozoans, sessile tube worms, as well as colonial tunicates and coralline algae. In contrast, the control original marina seawall presented a low-diversity assemblage, which was even lower than the baseline, meaning that in less than two years, the ECOncrete® seawall panels were able to recruit a more diverse and abundant assemblage in comparison to the control and the baseline. The majority of the dominant organisms on the ECOncrete® units were structurally beneficial species that cement their calcitic skeletons onto the structure; thus, contributing to the structural stability and operational life span of the seawall units through the process of biogenic build-up providing bio-protection. In addition, a major part of these species are filter feeders which potentially contribute to the local water quality.
By integrating environmentally sensitive technologies into the design and construction of CMI, ECOncrete® is able to harness natural processes for ecological enhancement and reduce a structure’s ecological footprint. The improved design of the Seawall Units has several implications on the marine environment; such as lowering the ratio between invasive and native species, water purification by filter feeding organisms (e.g. oysters) and more. Apart from its clear ecological significance, biological enhancement also provides structural and socio-economic benefits. Biogenic growth of organisms like oysters, corals or barnacles provides bioprotection; acting to strengthen the structure and add to its stability and longevity. This form of bioprotection can reduce the magnitude and frequency of structural maintenance, which translates into improved ecological stability (reduced anthropogenic intervention), as well as a higher ROI (reduced maintenance costs).