What do sea walls prevent

Sea Walls today protect cities and towns on coastlines and keep oceans from damaging businesses from flooding along with saving lives. They are massive structures that are constructed to resist the energy built up from the Ocean. How Do Seawalls work? A Seawall effectively acts as a form of coastal defense by redirecting the energy of a wave made by a storm surge back to the ocean water, protecting the coastline from flooding and reducing erosion of the beach front.

A seawall is a passive structure, which protects the coast against erosion and flooding. Seawalls are often used at locations off exposed city fronts, where good protection are needed and where space is scarce. In the coming years Seawalls will be used on coastlines worldwide in the defense of rising sea levels from Global Warming. The primary purpose of a seawall is protecting residential shorelines from upland erosion and surge flooding.

A seawall acts as an important coastal defense to these types of events. When a wave crashes onto the shore, the seawall redirects a lot of that energy back to the water, protecting the coastline and reduces erosion of the beach front.

It also protects residential areas from flooding. There are many advantages to using retaining walls along coastal beaches and inland shorelines.

The environment can be protected keeping the soil and sand from being eroded and destroyed. They ensure the natural beauty of the coastline and prevent the alternatives that are prevalent like coastal storm surges and when Hurricanes and Tsunamis rear their ugly heads. Other advantages of Seawalls are:. Studies suggest that flooding from rising sea levels will prove more costly than building barriers to protect coastlines. Insurance Companies predict Seawalls will be built all around the world.

In previous years, lots of low lying communities have been allowed to build on properties that were well under sea level.

Add the fact that ocean levels have been rising for decades because of Global Warming and the risk is obvious. A bad storm can create flooding in the coastal areas of New Jersey or New York. Then after the cleanup, comes the higher rates tacked on to premiums before your house is even livable.

A well constructed Sea Wall will have some negative factors attached to it too. Quickly eroding property and reducing the sand supply to their beaches. Seawalls can cause increased damage to adjacent areas of the beach that do not have seawalls.

Wave energy can be reflected from a seawall sideways along the shore, causing coastal bluffs without protection to erode faster. Some other disadvantages of a Seawall are:. Another negative factor in building a Seawall is the maintenance cost. Even well-constructed Seawalls have a maintenance cost.

Some maintenance cost will include:. Depending on local factors, this can cause a wide range of outcomes, including cyclical creation and destruction of islands, inlets, spits, and other coastal features, sometimes over periods of decades or centuries. Long-term erosion can result when winter storms remove the tops of dunes—the damage is irreparable because the summer waves cannot reach high enough to redeposit sand.

So unless they are built according to a coordinated plan, seawalls simply pass along the effects of the waves, which end up eating more violently at the first unprotected spot.

Moreover, walls are effective only on the mainland, not on fragile barrier beaches. We need more and better information, but we can crack the nut if we approach it in an organized manner.

Related Questions Is it possible to make a Batman suit? How long would it take to charge an iPhone with my fidget spinner? This cost includes direct construction costs, direct overheads, costs of associated construction works, minor associated work, temporary works, compensation events and delay costs.

Maintenance costs are another significant and ongoing expense when a hard defence is selected. Continued investment in maintenance is highly recommended to ensure defences continue to provide design levels of protection Linham et al. This is caused by increases in water depth in front of the structure which, in turn cause increased wave heights and wave loadings on the structure. Maintenance costs are also likely to be higher when seawalls are poorly designed or constructed of inappropriate materials.

In many cases, design can be of secondary importance to the availability of raw materials, especially in locations where appropriate construction materials are scare. This was found to be the case in a study of shoreline protection in rural Fiji by Mimura and Nunn Their study highlights the problem that inappropriate design often leads to unfavourable effects, such as wave reflection and toe scour. In the absence of improper design, it is not unusual for designs from one location to be blindly copied at another.

The provision of even, basic design guidance would improve project performance in many cases. Seawall construction is possible on a community scale. There are many examples of ad-hoc construction to protect individual properties and communities. However, ad-hoc seawalls are likely to give much less consideration to the water levels, wave heights and wave loadings during an extreme event. This is largely because these events are hard to foresee without a well-developed science and technology base.

For example, traditional seawall construction methods in Fiji involved poking sticks into the ground to create a fence, behind which logs, sand and refuse would be piled to pose a barrier to the sea. A degree of technical guidance would be of benefit in the design and construction of effective seawalls. This would improve their effectiveness during extreme events and would also help to reduce adverse impacts on adjacent coastlines.

Although it is clearly possible to construct ad-hoc, or traditional, low technology seawalls at a community level, these structures have been shown to afford lower levels of protection against extreme events than designs with a solid science and technology base. They have also been known to exacerbate existing problems. At present, the advice given in developing countries for modern seawall construction appears to be informal, if given at all.

If effective design and construction is to occur, local communities must be given at least basic design guidance. This may come from government or voluntary organisations. Seawall maintenance is likely to be possible at a community level when given appropriate training. This may include educating maintenance engineers on the likely failure mechanisms, how often to survey the structure, what to look for and how to identify weaknesses in the design.

If major weaknesses are found, it may be necessary to employ a professional organisation to repair the structure in the most effective manner. One of the main barriers to the implementation of a well designed seawall is cost.

The design of an effective seawall requires good quality, long-term environmental data such as wave heights and extreme sea levels. This is frequently unavailable in developing countries and can be costly to collect. Secondly, because seawalls are frequently exposed to high wave loadings, their design must be highly robust, requiring good design, significant quantities of raw materials and potentially complicated construction methods.

The availability of experience, materials, labour and specialised machinery for the construction of seawalls may also pose a barrier to the implementation of this technology.

French recommends proactive construction of seawalls at some distance inland. This reduces interference with coastal processes and creates a buffer zone to protect against coastal flooding and erosion. Seawall construction is one of several options available when high value land cannot be protected in other ways. The approach provides a high level of protection to valuable coastal areas although the long-term sustainability of the approach should also be taken into account.

Less technologically advanced designs can be implemented at local levels, utilising local knowledge and craftsmanship. This requires less investment and a reduced need for involvement of large organisational bodies such as national or sub-national government or non-governmental organisations NGOs.

While ad-hoc implementation is possible, technological guidance from expert organisations is desirable to ensure sufficient levels of protection.

Seawalls can also be implemented as part of a wider coastal zone management plan which employs other technologies such as beach nourishment and managed realignment. Placement of seawalls inland, following managed retreat, reduces interference with coastal zone processes and creates a buffer zone to protect against coastal flooding and erosion French, The seawall therefore acts as a last line of defence.

Use of seawalls in conjunction with beach nourishment can also address some of the negative impacts of seawall construction, such as beach lowering and downdrift erosion. Connecting countries to climate technology solutions.

Toggle navigation. Breadcrumb Home. Sea walls Objective:. Coastal zones. Technology group:. Protection hard engineering. Sea walls. The description of this technology originates from Linham and Nicholls What are the Advantages of Seawalls?

What are the Disadvantages of Seawalls? Financial requirements and costs of Seawall Construction A study by Linham et al. Variation in costs between projects is a result of numerous factors, such as: Design height is a major factor affecting costs per unit length of seawall.

Certain design features will increase costs and more robust seawalls will be more costly Construction materials e. Proximity to and availability of raw construction materials Availability and cost of human resources including expertise Maintenance costs are another significant and ongoing expense when a hard defence is selected. Institutional and organisational requirements for Seawall Construction Seawall construction is possible on a community scale.

Seawall Implementation Barriers for Developing Countries One of the main barriers to the implementation of a well designed seawall is cost. Seawall Implementation Opportunities for Developing Countries Seawall construction is one of several options available when high value land cannot be protected in other ways.