Frank Mann Preserve, formerly known as GS-10 is partially open to the public from the Joel Blvd. entrance. Current allowed activities include kayaking & canoeing, fishing, bird watching, and walking in limited open areas. Please park your vehicle at designated parking spots and do not venture into hazardous closed off areas. LA-MSID is using equipment in closed areas to begin construction on a regional hydrological restoration and water quality improvement project. Frank Mann Preserve was used for mining activities in east Lee County.

Frank Mann Preserve is a partnership project co-managed by Lee County Parks & Recreation and Lehigh Acres Municipal Services Improvement District (LA-MSID). A conceptual project for Frank Mann Preserve (GS-10) proposes to reconfigure an existing mine lake into a filter marsh for stormwater treatment and a storage reservoir for flood control. Stored water may be diverted into the Greenbriar Swamp for extending wetland hydro-periods. This conceptual project controls flow in a six square-mile area with weirs to control discharges and utilizes the mine lake as a stormwater detention basin.