Measuring erosion in vital tidal habitats
Mudflats and tidal areas are highly productive ecosystems that can support large populations of wading birds and act as nurseries for young fish. They are also natural buffers, protecting the coastline from erosion by the sea. However, the tidal region is vulnerable to human activities, such as industry and urban development and potentially threatened by global climate change. The EU-funded TIDE project was set up to help protect Europe's coastal wetlands and tidal environments such as saltmarshes, lagoons and estuaries. The work included the creation of computer models to provide greater insight into processes behind the erosion, distribution and transport of sediments. Project partners St Andrews University, Scotland, developed the cohesive threshold meter (CSM). This device can quickly and easily measure the stability and erosion of intertidal deposits, which are exposed at low tide and covered by water at high tide. The CSM included a water-filled chamber which is secured onto the surface of the sediment. A jet of a water erodes a small area of the sediment surface within the tank. The force used can be systematically increased with each jet of water for a given time period. The level of erosion is determined by measuring the decrease in transmitted infrared light across the chamber as a result of suspended material. Data from erosion experiments is recorded onto the onboard central processing unit and downloaded onto a PC for further analysis at a later date. The results allow changes in sediment stability to be measured over time. Findings by the researchers can be used to create better computer models of tidal areas. Improved simulations will enable more cost-efficient defences to be built for combating coastal erosion and contribute to improved management strategies for the coastal environment.
