Coastal Erosion, Flood Risk, Urban Runoff & Recycling Solutions

Coastal Erosion Processes and Hazards

Cliff erosion is a continuing process. Wave refraction causes eroding energy to wrap around jutting headlands, narrowing them and creating tombolos and offshore islands.

Site Selection and Construction Measures

1. Build 5 or more meters above normal high tide.
2. Build in a spot with numerous high dunes between the proposed building and the water.
3. Determine the rate of coastline erosion in the immediate vicinity.

Slope Stabilization Techniques

1. Reduction of slope angle.
2. Terracing.
3. Placement of additional supporting material at the base of the slope.
4. Removal of soil, rock, or artificial structures high on the slope to reduce the mass.

Signs of Slope Failure

1. Doors or windows stick or jam for the first time.
2. New cracks appear in plaster, tile, brick, or foundations.
3. Outside walls, walks, or stairs begin to pull away from the building.
4. Water breaks through the ground surface in new locations.
5. Collapsed pavement, mud, or fallen rocks.

Waste Production and Recycling Challenges

Developed countries produce more waste per capita because they have higher levels of consumption. There are higher proportions of plastics, metals, and paper in municipal solid waste. On the other hand, developing countries produce lower levels of waste per capita with a higher proportion of organic material (biodegradable). Waste management typically represents a higher proportion of municipal expenditure in developed contexts.

Material Composition and Recycling Difficulties

Some products are more composite materials, and it is more difficult to separate them into like components. Source separation is required for effective recycling of many composite items.

Paper, Glass, and Plastic Recycling

For example, paper, unlike some plastics and glass, is easier to decompose and produce again. Glass costs much more to break down (melt) and process, so the procedure is more expensive. It is often cheaper and easier to produce a plastic bottle from scratch than to use recycled plastic.

Urbanization, Runoff and Flooding

Urbanization increases runoff and decreases infiltration.

Example: Via Argentina, El Cangrejo, Panama.

When asphalt and cement replace natural ground cover, increased runoff and decreased infiltration are inevitable.

Flooding will occur without adequate drainage. Adequate drainage comes with a high cost.

Dams: Dams may discharge huge volumes of water very rapidly to safeguard the integrity of the dam during or after heavy precipitation.

Example: Gatun or Alajuela (2010).

Destruction of vegetation: More runoff and reduced root structure also allow soil to be eroded upstream for deposition downstream, which fills up downstream channels and leaves less volume for the stream to carry.

Except when water spills out and over levees, the flood affects downstream floodplains.

Flood Control and Structural Measures

1. Installation of rock berms.
2. Sandbags.
3. Levees.
4. Dikes.
5. Detention basins.
6. Maintaining normal slopes with vegetation.