Stream Channelization One threat to Hawaii's wetlands is channelization. Channelization is a method of controlling waters in urban areas as to lessen the chance of flooding. Channels are large ditches with heavy concrete walls. Wetlands have dried up because the natural flow of water has been diverted to other places. This process has reduced the food supply for endangered wetland animals. Channels are unnatural streams which makes them horrible places for our wildlife.

Channelized streams tend to be warmer, run slower and are shallower than the natural streams. These conditions favor introduced species that can tolerate higher water temperatures and lower oxygen levels.

Water Pollution There are many types of pollutants that build up and create siltation. Some pollutants are petroleum products, heavy metals, pesticides and insecticides. They are poisoning the habitat. Silt also can take the form of dirt, leaves, and the plant cuttings. People are thoughtless and throw their rubbish into the lake or down the storm drains. These pollutants and rubbish end up in our watershed!

Nonpoint-source pollution, pollutants such as pesticides, rubbish, and motor oil which originate from unknown sources, is much more of a problem than point pollution such as sewage spillage because we don't know where the pollution is coming from.