The Lake News, Lake Cowichan, B.C., Wednesday, January 17, 1990
Riparian Vegetation Important
Stream bank vegetation is a very important component of healthy streams. It provides shade that reduces summer temperature, protects banks and property from erosion, acts as a buffer against sediment from upland runoff, insulates soils from the harmful effects of freezing and thawing and provides cover for fish in the form of root networks. The streamside canopy hosts a large number of insects in various stages of development. Many fall or are blown into streams and constitute an important food source for fish. This is especially so in many smaller creeks during the summer when some streams withdraw to isolated pools and the drifting food supply carried by moving water is no longer available. During this critical period, insects provided by the leaf canopy will make the difference between death and survival for many fish.
Leaves provided by riparian vegetation, especially alders, also contribute to the food budget of streams by providing forage for aquatic insects and contributing valuable nutrients as they decay. These nutrients, along with sunlight, form the base of the food chain in water and are very important in coastal streams which are nutrient poor due to high flushing rates and low nutrient soils.
Aside from biological considerations, streamside vegetation is an important esthetic element of the streamscape.
Most British Columbians are very aware of the values of streamside vegetation and the need to protect it. Logging companies, land developers, farmers, road builders and others are usually required to leave some vegetation along waterways. However, private land owners are usually not restricted and are sometimes tempted to include streams in landscaping projects. Some of these efforts result in complete removal of riparian vegetation. Unwittingly, these projects can damage stream banks and lower stream productivity.
The recently formed Lake Cowichan Village Waterways Committee will be sending a letter to property owners on the Cowichan River that stresses the importance’ of riparian vegetation and the need to protect and enhance it for the benefits of stream ecology and property protection.
The Upper River Riparian Zone is reasonably healthy but can be improved if property owners encourage the growth of natural vegetation like willow and red osier; low growing trees and shrubs with strong root networks that can be cropped if they grow too high or begin to create a jungle. A relatively narrow band is all that is usually necessary in most places and clearing narrow access paths to the river is compatible.
In these times of general decline in environmental quality, a community should do all it can to improve its environmental assets. The Cowichan River is one of our greatest.
A classic Upper Cowichan coho stream
Tags: streamside vegetation