Coast Measures

Coast Measures

1. Laws and Regulations

   • Limit Damaging Activites
     • P: Interrupt functions // E: Banning might be ineffective, thus limit. Limit for balance.// E: Port Phillip Sand dunes// L: Less attractive and no access to all parts of beach
   • Protect Coastal Resources
     • P: Prevent extinction. //E: Fishes, 90% vulnerable.// E: Wakatobi National Park & Goat island. //L: Opposed by fishermen
   • Restrict Development
     • P: Avoid natural disasters. // E: Retreat, Avoidance, Defence. // E: Earthquake Tohoku 2011- 20000 people, destruction of coastal towns and failure of nuclear. // L: Attracted to beaches for resources

2. Soft Engineering Measures

   • Beach Nourishment
     • P: Slows down erosion, replenish the beach. // E: Wider beach - promote eco-tourism, nesting habitat, gently sloping=reduced detrimental impacts of coastal erosion.// E: Cape May Point -360000 cubic yards coast 3.2m. It is most expensive manufactured beaches in the world. // L: Trucking and pipping expensive and time consuming, sand eroded by win and waves, coral reefs die, only 10 years.
   • Planting Vegetation, stabilising dunes
     • P: Planting mangroves and grasses stabilises coastlines. // E: Sand dunes stabilised by planting grasses. Roots anchor and prevent erosion. Plant mangroves bc good intricate roots stabilises by weakening currents and waves. // E: Surdarbans in 2004 Indian Ocean tsunami/ New Zealand ohama Beach // L: Grow slowly, young mangrove fragile, building fences cost incurred.
   • Encourage coral reef growth
     • P: Corals growing by shallow sea w environmental conditions enhances their growth of living. // E: Corals weaken wave energy and serve as breeding ground. // E: 1996 man dives, sculpture.// L: not easy to encourage growth as sites need to be surveyed, danger of siltation and slow growth.

3. Hard Engineering Measures

   • Seawalls
     • P: Constructed to protect coastlines against wave attack by absorbing waves. // E: Most seawalls made of concrete, serve as flood barriers, weaken wave energy, protect cliffs from undercutting. // E" Seawall Pondicherry. //L: Costly to build and maintain, where beach materials deposited alter longshore drift - increased erosion downdrift from structure, aesthetically unappealing.
   • Gabion
     • Gabion are wire cages usually filled with crushed rocks. // They are built along the shore/behind the beach to reduce erosion as they absorb wave energy as they have gaps to allow water to filter through. // Gabions in sg reclaimed land but vandalised so removed. // Ugly - fall in tourism, easily destroyed, destroyed corroded trampled, regular maintenance, lifespan 5-10y.
   • Breakwaters
     • Break force of oncoming waves. // Structures composed of concrete or boulders build parallel to coast. Constructed offshore, they create a zone of calm waters as they break force. - allow accretion and stabilisation behind them. // Portland Habour, England/ Semaphore Park. // Ugly, costly, protect unevenly.
   • Gryones
     • Constructed right ankle to shore to retain sediments// Absorb and reduce energy of waves and cause material to be deposited on updraft side. Slows down beach drifting and encourage development of wide beach, prevent reduce erosion, sustain extend beach areas, do not affect access, last 20-30 years. // Holderness Coast// Ugly, costly to build and maintain, unable keep beach intact and aligned.
   • Tetrapods
     • 4-pronged concrete surfaces that dissipate wave energy. // Stacked offshore in interlocking position. Allow water pass around them. Reduce possibility being damaged by waves. Pre-casted - case final shape before being positioned. Placed quickly. // E: Crescent City// Ugly, expensive, dangerous to swimmers surfers boaters.