Arnold has very specific and stringent regulations for all construction in the Meramec and Mississippi River floodplains below 420 feet above sea level which range from permit requirements to enforcement provisions. In addition, the lowest floor of all floodplain construction must be elevated to at least three feet above the base flood elevation and in the floodways encroachments shall not result in any increase in flood levels during occurrence of the base flood discharge. Although not part of the ordinances, Arnold has a very aggressive buyout program for floodplain dwellers.