Catchment to Coast
Introduction
A water catchment is a topographic unit with certain hydrological conditions. All the water in a catchment becomes concentrated within rivers, lakes, reservoirs etc., by which the catchment is drained. Within the topographic boundary or water divide, the catchment comprises a complex of soils landforms, vegetation and land uses. Nowadays, water catchments are becoming more and more a management tool for an integration of environmental, economical and social concerns. The terms catchment, watershed and (river) basin are often used interchangeably. Those catchments which finally drain into the sea are of particular importance for coastal areas.
Importance
About 40% of world population lives within 100 km of the coast. Urban and industrial development, tourism, agriculture, waste dumping and discharges are degrading coastal areas around the world and destroying ecosystems such as wetlands, mangroves, seagrasses and coral reefs. The expansion of agriculture and urbanisation has resulted in the loss of wetland vegetation and further resulted in the loss of retention area for flood water and nutrient fixation. Human activities in catchments have led to remarkable changes in coastal ecosystems. For example:
- massive algal blooms as a result of increased nutrient input mainly caused by agriculture and aquaculture. Algal blooms can be toxic to other organisms and reduce growing conditions for e.g. corals;
- water contamination by pesticides, heavy metals and other dissolved toxins mainly from agriculture and raw sewage can harm flora and fauna in receiving waters and downstream environments;
- turbid waters with increases in sediment delivery due to increased soil erosion (refer to the figure) affect predominantly those coastal environments dependent on good water clarity and high visible depths such as seagrass and corals; and
- decline in biodiversity due to degradation of habitats such as wetlands and mangroves means a reduction of resources; etc.
Catchment management
Catchment management now follows an integrated approach to assess the condition of the catchment and to deduce a sustainable use of the resources. Everybody lives in a catchment. The challenge is to communicate the linkage of people to their catchment.
The ICRAN-Mesoamerican Reef Alliance (ICRAN-MAR) is an example of an integrated approach. It brings together major stakeholders in reef conservation engaging them in activities around three key components: Watershed (Catchment) Management, Sustainable Fisheries, and Sustainable Tourism. The project's primary objectives seek to minimize impacts to the Mesoamerican Reef by improving sustainable business practices in the three areas primarily through capacity building, development of better practices and building partnerships with the private sector.
An example from Europe is the Baltic Sea, which is mainly controlled by the catchment and river nutrient loads. A recent project is the �Research for an Integrated Coastal Zone Management in the German Oder Estuary Region�.
An example of integrated catchment management in Australia is the development of the Reef Water Quality Protection Plan (Reef Plan) for the Great Barrier Reef and the associated catchment area. The goal of the Reef Plan is to �halt and reverse the decline in water quality entering the Reef within 10 years�. Through the Reef Plan, Governments are acting on the potential risk to the Great Barrier Reef from the progressive decline in water quality in waterways entering the Reef, with a focus on diffuse sources of pollutants entering waterways in the Great Barrier Reef Catchment. The Reef Plan identifies strategies and actions to address degraded water quality entering the Great Barrier Reef across several areas of interest including self management, education, economic incentives, planning, regulatory frameworks, research, partnerships, priorities and targets and monitoring.
The ICRAN-Mesoamerican Reef Alliance (ICRAN-MAR) is an example of an integrated approach. It brings together major stakeholders in reef conservation engaging them in activities around three key components: Watershed (Catchment) Management, Sustainable Fisheries, and Sustainable Tourism. The project's primary objectives seek to minimize impacts to the Mesoamerican Reef by improving sustainable business practices in the three areas primarily through capacity building, development of better practices and building partnerships with the private sector.
An example from Europe is the Baltic Sea, which is mainly controlled by the catchment and river nutrient loads. A recent project is the �Research for an Integrated Coastal Zone Management in the German Oder Estuary Region�.
An example of integrated catchment management in Australia is the development of the Reef Water Quality Protection Plan (Reef Plan) for the Great Barrier Reef and the associated catchment area. The goal of the Reef Plan is to �halt and reverse the decline in water quality entering the Reef within 10 years�. Through the Reef Plan, Governments are acting on the potential risk to the Great Barrier Reef from the progressive decline in water quality in waterways entering the Reef, with a focus on diffuse sources of pollutants entering waterways in the Great Barrier Reef Catchment. The Reef Plan identifies strategies and actions to address degraded water quality entering the Great Barrier Reef across several areas of interest including self management, education, economic incentives, planning, regulatory frameworks, research, partnerships, priorities and targets and monitoring.