The City of Chesapeake has over 300 stormwater ponds, some of which have fish living in them. Occasionally, environmental conditions change significantly enough to kill at least some of the fish in a pond. The 3 most common causes of fish kills are:
- Higher than normal tides raise water levels in ditches high enough to allow fish to swim upstream from creeks and rivers into the ponds and become trapped when the tides return to normal.
- Extended periods of high heat combined with high growth rates for algae cause a depletion of oxygen in a pond. Algae blooms are most often triggered by elevated levels of phosphorous and/or nitrogen from lawn fertilizers and animal wastes.
- Contamination of pond water caused by the dumping of household chemicals or other toxic materials into storm drains that discharge into the pond.