Pool 25: Land Ownership Requirements in Moving the Control Point to the Dam
Dates
Publication Date
1997-03
Summary
We estimated the amount of land that would have to be acquired if an alternative water-level management plan was used for Pool 25 on the Upper Mississippi River. The work was performed as part of a study to evaluate water regulation alternatives that could minimize negative impacts and increase ecological benefits of dam operation. We used a one-dimensional model (HEC-2) to estimate the ordinary high-water profile and water surfaces at various discharges and management options, by river mile. Maps of these data were then created with a geographic information system, along with maps of land elevations, both above and below the surface of the river, lands controlled by the managing agency, and levees. The ownership and easement, ordinary [...]
Summary
We estimated the amount of land that would have to be acquired if an alternative water-level management plan
was used for Pool 25 on the Upper Mississippi River. The work was performed as part of a study to evaluate
water regulation alternatives that could minimize negative impacts and increase ecological benefits of dam
operation. We used a one-dimensional model (HEC-2) to estimate the ordinary high-water profile and water
surfaces at various discharges and management options, by river mile. Maps of these data were then created
with a geographic information system, along with maps of land elevations, both above and below the surface
of the river, lands controlled by the managing agency, and levees. The ownership and easement, ordinary high
water, and levee coverages were combined to represent areas that would not have to come under Government
control at a discharge that creates the ordinary high-water profile. As a validation exercise, we estimated the
amount of lands that would have to come under Government control if the dam were to be constructed now and
no lands were under Government control. The estimated area was 11,276 acres, which can be compared with
11,039 acres owned or controlled by the Government with fee title and flowage easement lands. The difference,
237 acres or 2.1%, is considered to be satisfactory, given the lack of resolution of our elevation coverage,
possible sedimentation of backwater areas since the dam was built, and possible differences in the high-water
line between the present prediction and the ordinary high-water line estimated before the dam was constructed.
The model predicted that no lands would need to be purchased under any scenario for the first 13 miles upriver
of the dam. The maximum amount of land needed upriver of this point would be 738 acres. This acreage
estimate would be higher if the managing agency elects to purchase or obtain easements on entire parcels of
land rather than just the lands the model predicts may be covered by water. The acreage estimate may be lower
if some affected lands were already under the control of another Government agency.
