Natural and artificial wetlands serve as an important cleaning site of non-point-source water pollution. Wetlands help improve water quality by filtering sediments from the polluted water before it enters the ocean and by using much of the nutrients dissolved in the polluted water for plant growth within the wetlands. High nutrient levels are of particular concern in runoff from golf courses. A good way of helping to mitigate the nutrient problem in the runoff is to direct the water through an artificial wetland before it is allowed to enter a creek or the ocean.