Immokalee Road to Camp Blanding

Sent September 9, 2011

I have now completed walking Alligator Creek from Immokalee Road to the Camp Blanding property line.  The primary purpose was to look for sinkholes.  I saw nothing that would lead me to believe there is a sinkhole in this part of the creek.  However due to the width (as much as 200 feet in places), the dense growth (3 ½ foot maidencane grass and 10 foot dog fennels) and the thick matting of maidencane thatch over most of the creek bottom it is impossible to say absolutely. 

See attached annotated air photo for a visual of the following:

There are four fences across the creek.  The two southerly ones are field wire and recently constructed.  They fence in a residential back yard.  The two northerly ones appear to be barbed wire but the growth adjacent to them is so thick I could not be sure.  The part I crossed (crawled under) south of the fence intersection is definitely barbed wire.

The southerly bridge is recent construction and pedestrian only.  There is 4-5 feet of clearance beneath this bridge.  The northerly bridge is older construction (30 years?), 60-70 feet long and wide enough for an automobile.   There is 3-4 feet of clearance beneath this bridge.

I noted two depressions in the creek bed south of the southerly bridge.  These depressions are 2-3 feet deep, the width of the creek bed (10 feet) and about 30 feet long.  These may have been excavated but not recently.

There is a large depression (labeled pond on the air photo) between the northerly most fence and the northerly bridge.  This depression is 4-6 feet deep, 50 feet wide and 200 feet long.  This was probably excavated.  The current owner says this depression was there when he purchased the property in 1980. 

There is NO water anywhere in this part of Alligator Creek.

Attached also are two photos.  One is of the maidencane grass that covers 75% of the creek bed.  The other is the maidencane thatch that covers most of the creek bed including where the grass and the dog fennels are growing.

Frank Host

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Thank you for your effort Frank;

As a surface water conveyance system this overgrown channel system does not look very promising.  Unless we can clean the system and keep it clean, we can expect significant surface water conveyance losses.  As a rough estimate, I believe that one acre of vegetation may transpire approximately 40 to 42 inches per year.  Wet sand might loose possibly 30 inches per year to evapotranspiration losses. Thus the estimated water loss  from a surface water channel which is covered with overgrown vegetation may be as high as one acre-feet per year or nearly 900 gallons per day per acre of overgrown channel bottom.

Unless the surface water channels from Blue Pond to Lake Brooklyn can be kept “clean” permanently, we might have to consider other conveyance options.

Peter Schreuder

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Peter,

Both the maidencane and the dog fennel will die back in the winter and a controlled burn would clean the channel.  I wonder if 10 mgd (15.5 cfs) is enough to mainten a cleaning flow in a channel this large.

The channels between Magnolia, Lowry and Blue Pond are reasonably clean (for a creek in the woods) because they have constant flow.

Frank