| September 16, 2002
News Release West Nile virus is in the national news and health experts expect it to arrive in this region soon. National health experts do not believe this will be a health emergency for residents of King County. However, people are rightly asking questions about how best to prepare and protect themselves from West Nile virus. The Department of Natural Resources and Parks is among the King County agencies preparing a response plan. Some citizens have asked specifically about wetlands and county stormwater ponds in relation to the West Nile virus. Here are the answers to some common questions. Why does the county have stormwater ponds? When land is developed to create homes and other improvements, the natural system of trees and dense vegetation over spongy soil is replaced with hard surfaces and lawns over compacted soil. Consequently less of the rainwater that falls is soaked up and more of it runs off at a faster rate. In addition, there are more pollutants in the rainwater runoff due to human activities such as vehicle use and lawn care. Stormwater ponds detain and slow the rate of runoff from developed areas and remove pollutants that are collected in the runoff and are commonly used throughout the United States and the rest of the world. In doing so, the ponds reduce flooding, erosion, landslides, and pollution, all of which are essential to protecting public and private property, public health and safety, and water quality. The ponds are a vital element of the County's program to meet federal and state water quality laws. Is the county going to spray for mosquitoes at stormwater ponds and in wetlands? Widespread chemical controls are not the answer. We are actively researching control options, and are in the process of developing management guidelines for mosquitoes that take advantage of the insects' life cycle and vulnerable stages. The use of pesticides can affect the environment and, ultimately, human health. Why not drain wetlands near homes? Healthy wetlands provide minimal habitat for mosquitoes in that water conditions, water quality, and natural predators deter mosquito use and minimize larval success if egg laying occurs. Predators including other aquatic insects, amphibians, bats and birds heavily feed on any mosquitoes present. Wetlands are a critical element in a healthy ecosystem that benefits people, water quality and wildlife. Wetlands clean and slowly release rainwater and provide flood protection and wildlife habitat. Many wetlands recharge groundwater critical for local drinking water supplies and prevent streams from drying up during the summer. Seventy-percent of Lake Washington wetlands and 99 percent of Duwamish River wetlands have been destroyed by human activities. We will not eliminate mosquitoes by draining wetlands. We could actually increase the mosquito population if their natural predators are destroyed by draining a wetland. Many mosquito species need only a small puddle or depression to breed. Why can't we put goldfish or other fish in ponds, wetlands and creeks with standing water to kill the mosquito larvae? Natural wetlands and creeks do have native fish, amphibians (i.e. frogs, toads, newts and salamanders) and other aquatic invertebrates that are voracious predators of mosquitoes and their larvae. Moreover, it is illegal to deliberately introduce a non-native species into local waters without a permit from the Washington State Department of Fish and Wildlife. Non-native species often create additional problems. They can proliferate forcing out native, beneficial species of fish and other wildlife and often they carry exotic diseases that kill and harm native species. Many ponds and wetlands dry out during the summer and any fish introduced would not survive. I live near a greenbelt or a wetland and worry about my family's personal safety. We will never be able to eliminate all habitats for mosquitoes and not all mosquitoes are carriers of the virus. Greenbelts provide numerous health and quality of life benefits. They clean pollution from air and water and reduce flooding and erosion. Local and federal health experts recommend the best personal protection is to eliminate places where water can stagnate in containers such as buckets, flowerpots and tires. Change water regularly in birdbaths, clean clogged rain gutters, and put mosquito screens on rain barrels. For more information on West Nile virus, visit Public Health - Seattle & King County's West Nile Web page at http://www.metrokc.gov/health/westnile. The Web page will be kept up-to-date as new information becomes available. Related Information |
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