August 19, 1981
TO: Bobby Laseter, Division Director, Field Services
FROMi William D.. Courser, Chief, Environmental Section/
SUBJECT: Harney Flats/Tampa Bypass Canal
With reference to Hillsborough County's concern (letter of 27 July 1981) over
the levels of the Tampa Bypass Canal, the following should be of value in
addressing their concern.
1. Based on the U. S. Geological Survey "quad" maps and other reports, the
Harney Flats area is a natural wetland area. According to various sources,
six-mile creek was an attempt to drain the area beginning in the 1920's. The
attempt was not completely successful because the area is fed by springs and
seeps from the aquifer. Indeed, the county park facility was named Eureka
Springs Park and developed around the wet nature of the area.
2. The Tampa Bypass Canal was designed to prevent overdrainage of the area.
Buffalo Avenue Structure, S-162, was added because the project, as originally
designed, would overdrain and lower aquifer levels to the detriment of the
water resources of the area. Even with S-162 in place and the canal maintained
at 14-15 feet m.s.l., the potentiometric surface has been lowered by the project.
Spring flow has lessened and this even caused the county to complain about the
canal overdraining the area, especially at the county park.
3. Lowering water levels further in Harney Flats by lowering Tampa Bypass Canal
levels would cause significant environmental impacts on the wetlands of the area.
Lowering the canal would also increase discharge of the aquifer, lowering poten-
tiometric levels, which would increase well complaints, but, more importantly,
have a negative effect on the potential of the canal as a water supply.
4. Finally, lowering water levels would require state and federal approvals.
Much concern was expressed by the District and state and federal agencies over
the hydrological and biological impacts of the Tampa Bypass Canal. The reviews
of the District's Environmental Statement and the Corps EIS reflected this concern.
Such a change would probably require filing an addendum to the federal EIS and
soliciting state and federal comments.
I concure with Mr. C. H. Miller's evaluation (4 August 1981) that the present
water levels in Tampa Bypass Canal are not abnormal nor unreasonable from a
good water management standpoint. From a historical standpoint, the canal has
probably facilitated development in the area by somewhat lowering water levels.
August 19, 1981
Page 2 fS
My recommendation would be the same as C. H. Miller's.
cc: W.C. Tatum