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Moses Lake Water Quality

Frequently Asked Questions

Moses Lake and the surrounding watershed are susceptible to blue-green algae blooms. Blue-green algae is actually a bacterium called cyanobacteria that have similar qualities to forms of algae. Some blue-green algae produce toxins that are harmful to humans and animals. Blooms occur in the summer, when higher temperatures and elevated nutrient levels combine to create a thriving environment for blue-green algae. Whether or not blooms are toxic, they diminish the economic and recreational opportunities in Moses Lake and the surrounding region. 

  • What is toxic algae?
    Toxic algae refers to a particular type of algae found in lakes and ponds called blue-green algae or cyanobacteria. This type of algae is a natural part of lakes, but sometimes it can grow rapidly or bloom. Lakes experiencing a bloom will look cloudy. The algae will begin to accumulate as a surface scum and often resembles blue or green paint. A handful of blue-green algae species sometimes produce toxins during blue green blooms.
  • Should I be concerned about toxic algae?
    When blue-green algae is producing toxins, high levels can cause serious illness in humans and animals who play in or ingest affected waters. Toxic algae exposure can kill pets, waterfowl, and other animals. Pets who drink lake water are particularly at risk. Smaller children that may ingest water when swimming are also at higher risk. For current advisories and additional information visit the Grant County Heath District.
  • What do I do if I see a blue-green algae bloom?
    As soon as you see a bloom or possible signs of poisoning: 1. Avoid all contact with the water. 2. Keep pets and livestock away from the water. 3. Call the Grant County Health District at 509-766-7960 and report the location.
  • Can I eat fish from the lake when a toxic bloom is present?
    One type of toxin, microcystin, can accumulate in fish tissues, especially in the organs (liver, kidneys, etc.). Concentrations in the tissues would depend on the bloom severity where the fish was caught. Take caution when considering consumption of fish caught in a water body where major algae blooms occur. Before eating, remove the internal organs, which may contain more of the algae/toxin.
  • What is causing the toxic algae blooms?
    Blue-green algae is a normal part of the lake system and is always there in low numbers. Blue green algae blooms often occur in late summer and early fall. While temperature and sunlight play a role in blooms, often times excessive nutrients - particularly phosphorus, are the primary factors leading to blooms. Frequent toxic algae blooms are one symptom of excessive phosphorus pollution and a sign of declining water quality. Phosphorus pollution flows into the lake from the surrounding areas.
  • What can I do to help prevent toxic algae?
    The best way to help prevent future toxic algae blooms is to reduce phosphorus coming into the lake. Even small reductions in phosphorus can make a big difference. According to Washington State Depatment of Health (see brochure), here are 5 ways we can help reduce nutrient loading: 1. Maintain or restore native plants around lake shorelines and streams that feed the lake. Native wetland plants help filter water and do not require pesticides or fertilizers for maintenance. 2. Be cautious with lawn and plant fertilizers and pesticides. Do not over-water, overfertilize, or use more than the recommended amount of pesticides. 3. Use proper care and maintain your septic system. Damaged septic systems are a source of nutrient loading into nearby water. Have your system pumped and inspected every 3–4 years. Learn more from the Grant County Health District here. 4. Prevent surface water runoff from agricultural and livestock areas. Do not allow livestock to drink or defecate in streams or lakes. Do not feed waterfowl. 5. Take steps to prevent erosion around construction and logging operations. Erosion can carry nutrient-rich soil into nearby lakes. The Moses Lake Watershed Council believes that participation by EVERYONE will help with the long-term solution of cleaning up the lake. To receive notifications about public meetings, email ronnie-sawyer@columbiabasincd.org or call the Columbia Basin Conservation District office at (509) 765-9618.
  • How do I learn about current advisories?
    For current advisories and blue-green algae monitoring information visit the Grant County Health District.
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