Discovery Bay, CA, 94505

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Subject: Public Comment – 2-Gates Fish Protection Demonstration Project

Given that the project intends to produce changes in both the water flow and quality within the project boundaries, (and though not addressed, will most surely do so at an increased level within the Town of Discovery Bay):

We find no references in the report as to the effect that reduced flows and the resulting changes in turbidity and changes to water chemistry will have on the algae bloom problem in the southern and western delta and, more importantly, in the Town of Discovery Bay.

  • Blue-green algae (cyanobacteria) are any of a number of species of microscopic bacteria that are photosynthetic. They may exist as single cells or groups of cells. They occur naturally in surface waters.
  • When conditions are optimal, including light and temperature, levels of nutrients (i.e., phosphorous and nitrogen, and the ratio of the two), and lack of water turbulence, blue-green algae can quickly multiply into a bloom.
  • When blooms occur, exposure to the blue-green algae and their toxins can pose risks to humans, pets, livestock and wildlife. Exposure may occur by ingestion, dermal contact, and aspiration or inhalation.
  • Exposure to blue-green algae can cause rashes, skin and eye irritation, allergic reactions, gastrointestinal upset, and other effects. At high levels, exposure can result in serious illness or death.
  • Depending on the particular cyanobacterium, and the amount to which one is exposed, blue-green algae have the potential to cause a variety of adverse health effects, including liver toxicity (e.g., Microcystis aeruginosa) and neurotoxicity (e.g., Anabaena circinalis). Microcystin toxins may also promote tumor growth.
  • Destruction of cyanobacteria cells may release the toxins into surrounding waters, so care must be taken in dealing with blue-green algae blooms.
  1. The CA State Dept of Health recommends avoiding body contact with blue-green algal blooms. This includes swimming, wading, water-skiing. How much of an increase of these algae will be present in the local surface water, especially in Discovery Bay, given the reduction of water levels and flow that result from this project, on a seasonal basis? Will these increased levels lead to situations where currently safe levels will become unsafe?
  2. The CA State Dept of Health also recommends that children should especially avoid contact. Their small body weight means their exposures to blue green algae will be higher than adults, given the same volume of water exposure/intake. How will the changes to water quality and algae levels due to the project effect children? How does the project intend to monitor the water, inform the public and mitigate the problem when it occurs?
  3. There have been some reports of blue-green algae toxin in fish tissues. What effect will increased levels of algae produced as a byproduct of the project have on this situation? Will fish populations be affected? Will the fish continue to be safe to eat?

Until this is answered in full, we MUST OPPOSE the project.


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