HomeMy WebLinkAboutGEC_potential_allotment_trespassGUSTAVUS ELECTRIC COMPANY
P.O. Box 102 Gustavus, Alaska 99826
(907) 607-2299 Fax (907) 697-2355
October 23, 2007
To: Ernest Jack
Hoonah Indian Association
254 Roosevelt Street
PO Box 602
Hoonah, AK 99829
Subject: Probable Trespass
Dear Ernest,
Richard Levitt, project manager
for the Falls Creek Hydroelectric
Project, asked me to provide an
impartial assessment of the po-
tential for a construction-related
trespass onto U.S.S #944 (hereinaf-
ter referred to as “the allotment”),
including options for minimizing
and mitigating damages. This report
will also be forwarded to Tom Mills
Sr. (Caretaker of the allotment) and
Charles F. Bunch of the Bureau of
Indian Affairs (BIA).
Background
The majority of excavation work
for the Falls Creek Hydroelectric
powerhouse site was completed in
March of 2007. At that time there
was a near vertical 50 foot face
comprised of 30-40 feet of bedrock
overlain by 10-20 feet of clay till.
The top of this cut approached the
allotment boundary to within ~ 20
feet at its closest point.
In May of 2007 Gustavus Electric
Company (GEC) contracted Geo-
technical services from R & M
Consultants to consider options
for stabilizing the cut-slope above
the powerhouse site. A report was
Above: the condition of the cut-slope in May of 2007.
Below: the condition of the cut-slope in October of 2007.
provided to GEC soon after. This report can be found at www.gustavuselectric.com.
R & M suggested that stabilizing this slope would require some form of retaining structure. From page 6 of the
geotechnical report:
“One solution and probably the most practical would be soil nailing, which consists of driving or drilling steel dowels into
the face of the soil slope. The slope is then covered with a wire mesh which is also attached to the nails. The mesh is then
covered with shotcrete. The spacing and length of the nails would need to be analyzed and designed, and is beyond the
scope of this report.”
After recieving the geotechnical report from R & M GEC decided to monitor the stability of the slope prior to
deciding how to best proceed. After a couple of months it became apparent that some of the water contribut-
ing to erosion of the slope is coming through the interface between the clay-till and the bedrock. This flow is
(practically speaking) impossible to control. It is likely that erosion from behind a shotcrete wall would reduce
the probability of long-term success in avoiding a trespass so GEC chose not to pursue this solution.
On June 4th 2007 an inspection of the Falls Creek Hydroelectric powerhouse site was conducted by the Hoo-
nah Indian Association, Bureau of Indian Affairs and Mr. Tom Mills Sr. It was agreed at that time that all parties
present would be notified immediately if a trespass occurred and GEC would continue to explore options for
minimizing the chances of a trespass.
Current Status
Erosion of the cut-slope, especially of the clay dominated areas, has progressed more rapidly than expected. As
of October 19th 2007 the top of the cut-slope is now within a few feet of the allotment boundary and it is clear
that a trespass is imminent in the near future.
At this point there are 3 general construction options that could be explored for preventing/minimizing this
trespass:
Bench the clay-till by building a road along the allotment boundary from the uphill side.1.
Build a rock wall and bench from below.2.
Build a sheet pile retention wall.3.
The first option would necessitate a trespass for the bench to be constructed. There is probably not enough
lead time left to completely avoid a trespass with any of these construction options.
Each of the above construction options may only yield partial long-term successes. In lieu of the construction
options mentioned above Mr. Levitt has told me that he would consider paying for a loss of property value or
purchasing the portion of the allotment that is likely to be impacted by the trespass.
GEC is eager to collaborate with HIA, BIA and the allotment ownership on a solution to this situation as soon as
possible. Please contact Me or Richard Levitt of GEC at your earliest convenience to discuss options.
Sincerely,
Bob Christensen
Environmental Compliance Monitor for the Falls Creek Hydroelectric Project