CONTRACT MONITORING FOR COAST PROTECTION

Shore lines are the most sensitive protective zones of marine environments. We all live on continents. Many of us close to or at the coast directly. Since we have realized that the climate is changing we are focused that the land mass on earth is shrinking. Glaciers and the ice on the Northand South Pole are melting. It results in rising water levels. It is also obvious that higher temperature differences will run into more wind dynamics and evaporation. This has an impact on the coast directly, worldwide. High waves and currents can destroy dikes and shoreline stabilization. Constructions have to be reinforced and enlarged. Argus Gesellschaft für Umweltmesstechnik mbH is one of the leading companies in Germany for precise high frequency wave measurements for more than 15 years. Argus provides a simple, low cost and high effective system to help scientists and hydrographers to calculate the parameters needed to build protective constructions or to protect natural habitats.

Another impact on shore lines and river banks is manmade and created by ships. Ships are getting bigger and bigger. To be competitive we go faster and faster. Time is money. The combination of bigger ships and higher traffic speeds will affect the devastation of human habitats. Natural grown river banks and shore lines can hold the soil up to a certain wave and current activity. This natural resource must be protected. To prevent wash outs ship speeds must be limited. Bigger ships create more down drafts, wave heights and currents, resulting in even more impact. Human settlements are endangered. The ARGUS AWG system provides real time data and processed wave spectra to regulate traffics and set speed limits.

The combined ARGUS wave-current monitoring system can be erected in about 2 hours on existing posts or constructions close to the shore. The data can be sampled with 20 Hz (up to 100 Hz) and send to the server via GPRS, UHF or WIFI radio modem. A processing program carries out the calculation for wave spectra and currents. The resolution of such a system is less than 10 mm wave height at high frequency. Different current meters can be combined with the ARGUS WAVE GAUGE (AWG). The AWG itself is a very robust system and measures the wave heights using a simple wire. The 3 mm compensated stainless steel alloy wire can withstand waves up to 4 m waves and survives heavy physical impacts. An AWG network can be synchronized and controlled by a data server.

The spar buoy wave detector provides a monitoring system for small wave measurements. Scientists may be interested in this system. Small high frequency waves sometimes have more impact on beaches and habitats than high energy waves. It has something to do with the resonance between the wave frequency and the materials on shore. For example if impacts from tall waves hit a sandbank it will more or less stay as it was.

High frequency waves with a period of 1 second or less will destroy the sandbank shortly. High frequent activities will force the sand particles to get closer and closer and will push the water out of the gaps between them. This effect will also take a major volume of sand with it and at the end this effect removes the natural coast protection.

This instrument can be deployed without any additional support structure. The spar buoy will be constructed based on the oscillation and wave lengths at the location. The buoy will not follow waves 50% shorter than the calculated frequency.

As for all spar buoys the major part stays under water. The submerged part contains the AWG electronic, a pressure transducer, battery packs, a data logger, a radio modem and controls. An on board tilt sensor will help calculating the actual wave height from the raw data if the buoy is getting out of the vertical. At the top a GPS, a radio antenna and a traffic identifier are mounted on.