Coastal management

Many people live near the sea.

The ocean can wash land away. This is called erosion. We must protect our homes from floods.

Some people build hard walls. These walls are made of rock or concrete. They help stop the water.

Other people use soft ways. They use sand and plants. This helps the beach stay healthy.

Sometimes we let the water in. We move our homes away. This lets the land change naturally.

We work hard to keep our coasts safe.

Many people live near the sea.

Over 1.2 billion people live near a coastline. We must protect these areas from flooding and erosion. Erosion is when the water washes land away.

People use different ways to manage the coast. Some use hard structures. These are called hard engineering.

One example is a groyne. A groyne is a wall built out into the water. It traps sand to make the beach wider. This helps the beach soak up wave power. Another way is a seawall. These are walls made of concrete or stone. They protect towns from big waves.

Other people use soft ways. They use natural parts like sand dunes and plants. This can be better for nature.

Sometimes, people choose managed retreat. This means they let the sea come in. They move homes and buildings away from the water. This lets the land change in a natural way. This is helpful as sea levels rise.

Coastal management is the way people protect land from the sea. This work stops flooding and erosion, which is when water washes land away.

These areas are very important because many people live there. Coastal zones make up less than 15% of the Earth's land. However, they are home to more than 40% of all people. Nearly 1.2 billion people live near a coastline today. By the year 2025, three-quarters of the world's population may live in these zones. As sea levels rise due to climate change, protecting these coasts becomes a very big job.

There are several ways to manage the coast. One way is called "armoring." This uses hard structures like seawalls or groynes.

A groyne is a wall built out into the water. It traps sand to make a beach wider. A wider beach helps soak up the energy from waves. Another way is "managed retreat." This means people allow an area to erode or flood.

This is often done when the land is not worth a lot of money. It creates new homes for nature, like salt marshes. Some people also try to "move seaward" by building new land. Others use "limited intervention" to let natural processes like sand dunes grow.

People have been building things to manage water for a long time. Coastal engineering for harbors likely began before 3500 B.C. The Romans were very good at this work. They built underwater walls and solid breakwaters using Roman concrete.

They even used timber floating caissons to build arched breakwaters. In the Netherlands, Romans were the first to use dredgers at Velsen. Most Roman works disappeared after their empire fell. However, some remains can still be seen under the water today. In Italy, the Venetian Lagoon shows how people used sea walls to protect towns.

Modern methods have changed a lot over the years. Before the 1950s, people mostly used hard structures to stop erosion. In the 1920s and 1930s, local groups built these structures on their own. Sometimes, having too many walls actually caused beaches to disappear. Because of this, engineers began using "soft engineering" in the late 1940s. This means they try to copy natural systems like dunes and beaches. In 1995, a group of specialists started working on coastal protection. In 1999, the European Council issued a special code of conduct for these zones. This helps countries plan how to manage their coasts together.

Managing the coast is a hard job because the sea is always moving. If we build hard walls, the problem might just move to a different beach. This is sometimes called a "coastal squeeze." This happens when natural areas like wetlands cannot move inland because of solid buildings.

When the sea rises, these habitats can get stuck and disappear. Using natural ways, like adding sand to a beach, can help. These soft methods help the coast stay natural and active. Every choice depends on the local land and the cost of the work. It is a balance between protecting people and helping nature.

Coastal management refers to the strategies used to defend against flooding and erosion. It also includes techniques used to claim new lands by stopping erosion. These efforts are increasingly vital because sea levels are rising due to climate change. As sea levels accelerate, tidal energy can disturb coastal sediments. Coastal zones are small, occupying less than 15% of the Earth's land area. However, they are incredibly crowded, hosting more than 40% of the global population. Nearly 1.2 billion people live near a coastline. This population density is three times higher than the global average. By 2025, it is expected that three-quarters of the world's population will live in these coastal zones.

Human history is closely tied to the engineering of coasts. Coastal engineering for harbors likely began before 3500 B.C. with the rise of maritime traffic. The Romans introduced many major innovations in harbor design. They were able to build walls underwater and construct solid breakwaters. To do this, they used a special material called Roman concrete. They also used rubble mounds and arched breakwaters built with timber floating caissons. In the Netherlands, the Romans were the first to use dredgers to maintain the harbor at Velsen. While many Roman structures disappeared after the fall of the Western Roman Empire, some submerged remains are still visible today.

In the Middle Ages, many coastal towns were abandoned due to attacks from the sea. Some harbors were also lost to natural causes like rapid silting or shifting shorelines. The Venetian Lagoon is a unique historical example of continuous prosperity. It provides some of the earliest written reports regarding the use of sea walls to protect settlements. After the Renaissance, there was little improvement in harbor construction until the early 19th century. The advent of the steam engine and the expansion of the British Empire helped revitalize sea trade. This renewed interest led to a massive increase in port works and coastal engineering projects.

Modern coastal management has shifted from "hard" to "soft" engineering. Before the 1950s, the standard practice was to use hard structures. These included seawalls, revetments, and groynes to protect against storm damage. During the 1920s and 1930s, local communities often built these structures on an ad hoc basis. However, these hard structures sometimes caused the loss of beach areas and impeded recreation. In the late 1940s, engineers began a more dynamic approach. They started using artificial beaches and stabilized dunes to replicate natural systems. These soft engineering methods are often more economically viable and environmentally friendly.

There are five general strategies used for coastal defense. The first is managed retreat, which allows an area to erode. This is often used when land is of low value or when sea levels rise. For example, in 1991, a small area at Northey Island in the UK was flooded through managed retreat. The second strategy is armoring, which involves building hard structures like seawalls. The third strategy is to construct defenses seaward of the coast. The fourth is adapting vertically by elevating land and buildings. Finally, limited intervention allows natural processes to take place in areas of low economic importance.

One common hard engineering method is the use of groynes. A groyne is a wall built perpendicular to the coastline. It is designed to trap the sedimentation caused by longshore drift. This process creates a wider beach that absorbs wave energy. Groynes can be made of concrete, rock, wood, or greenharts. While they are cost-effective, they can cause "terminal groyne syndrome." This happens when a groyne prevents sediment from reaching other nearby areas. This has been observed along the Hampshire and Sussex coasts in the UK.

Coastal management must also account for the danger of "coastal squeeze." This occurs when sea levels rise and ecological zones try to move landward. If they encounter solid human structures, they have nowhere to go. This makes wetlands, salt marshes, and mangroves particularly vulnerable. To manage this, the European Council issued the European Code of Conduct for Coastal Zones in 1999. This document helps guide national legislation and promotes integrated management. Effective planning is necessary to balance the needs of growing populations with the protection of fragile coastal ecosystems.