Sometimes there’s just too much rain. We were building a new runway, had several hundred acres of open ground, when the big rains came. We were using the stormwater ponds to collect all of the water for a 10 year 24 hour storm event, or 3 inches of rain. All of the water in the ponds was being treated with chitosan-enhanced sand filtration systems before discharge.
The storm of November 6, 2006 was something over the 50 year 24 hour event and something under the 100 year 24 hour event. With the rainfall and the pond over topping, water was discovered draining from the base of the pond. Rock and ecoblocks were placed as an emergency fix to keep the pond from a catastrophic failure. All of the dirty water drained to a creek, but, nothing we could do.