The Shoreline Development Factor (SDF) compares the shorelength of a lake to the circumference of a circle with the same area as the lake.


shoreline development factor =

= (length of the shoreline around the lake in miles) / (circumference of a circle in miles with the same area as the lake)


area of circle in square miles =

= PI() * ((radius of circle in miles)^2)


circumference of circle in miles =

= PI() * 2 * (radius) = 2 * SQRT(PI() * (area of lake in square miles))



• 640 acres equals 1 square mile.



• A lake that is a perfect circle will have an SDF of 1.

• The higher the SDF the more irregular the shoreline. An irregular shoreline may pose greater safety risks and limit the use of certain watercraft.


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