A preliminary investigation of the geology of the ridge north-
west of the lower end of Eklutna Lake was made in the period
June 11-18, 1947, by the writer, assisted by L. A. Hale. The
purpose of this study was to obtain geological information bearing
on the feasibility of constructing a tunnel through this ridge as
part of a hydroelectric power development under consideration by
the city of Anchorage.
Several traverses were made up each side of the ridge in a
belt judged to include the most logical routes for the proposed
tunnel. For the purpose of localizing the study two tentative
routes were selected, of which one would require the shortest possible
length of tunnel, and tho other would be somewhat longer but would
place the lower portal of the tunnel at a location considered to
be the most favorable for the construction of the penstock and
power plant. The first route extends northwestward from tho most
westerly embayment on the north shore of the lake to the canyon
about half a wile east of Pioneer Creek (see map) . The second
route extends from tho same point in the lake to the nearest
point on the steep slope southwest of the mouth of Goat Creek.
The distance along the first route from the lake shore (elevation
862 feet) to the 800-foot contour on the north side of the ridge is 4.3 miles. The distance between corresponding points along the
second route is 4.5 miles. The length of the tunnel would exceed
these distances by amounts depending on the elevation and grade at
which the tunnel is constructed.
