ISSUE 13: Do emergency spillways in lagoon embankments encourage illegal discharges ?
RESPONSE: That is NOT a design intent. Proper engineering design standards and specifications include an emergency spillway in the aboveground embankment, dam or dike of any impoundment, freshwater or otherwise. The spillway is part of the emergency action plan to protect the embankment in case of unusual weather-related events such as thunderstorms of unusual magnitude or hurricanes. It is to allow the excess diluted liquid from rainfall events greater than the legal containment requirement of a 25-year, 24-hour storm to be released from the surface of the impoundment through a designed channel at controlled rates, to prevent loss of the entire dam. It is legal to release any surface liquid greater than the 25-year, 24-hour storm. It is illegal to release any contents of the impoundment prior to the storm or any rainfall less than this storm event, regardless of whether this discharge is through a pipe, over the top of the dam, or through a designed emergency spillway.
