Drainage plan for a beach community

A Property Owners Association in Florida on the East coast of the US has major drainage issues. There are over 1200 units located directly on/near the beach. They have a golf course with five ponds. Many areas flood often with only a few înches of rain. They need to address this in stages and are looking for approaches or samples of RFPs to request proposals to develop and implement in stages a drainage plan.  One of the many questions is whether there is an open access map data available that would show elevation. Feedback much appreciated as to the best process to create a biddable document that focusses on primary issues and includes what data the community needs to provide in order to get good bids.  Your feedback much appreciated