Note: Recommended sites are marked with a star (*).
Location: 1.5 miles past the end of Thane Road.
Site data: The Dupont site may require a 1.5-mile extension of Thane Road. A rough estimate places the cost of a good quality gravel road at $1.3 million to $1.8 million per mile, plus 40 percent administrative overhead, according to a city study. Transporting passengers by boat is another possibility.
Noise: No homes fall under proposed Dupont flight routes. The noise would be audible at seven cabins at Lucky Me and two at Marmion, across the channel on Douglas Island.
Landholder: The One Nine Company, a group of 10 Juneau residents who have owned about 100 acres at Dupont since 1965, according to part-owner Bill Schmitz.
Infrastructure: The site has electricity. Water and sewer would be needed.
Other: Dupont also could be used as a floatplane base.
Location: Past the end of Montana Creek Road.
Site data: The Montana Creek drainage includes a number of muskeg wetlands, but a heliport could be built to minimize or avoid them, according to the study. The footbridge at the end of the road would need to be replaced to accommodate vehicle traffic.
Noise: None of four helicopter routes from a Montana Creek heliport to the glacier would fly over homes. The route that follows the contour of Mount McGinnis to the glacier is the only one that will be audible in residential areas and likely will be the most heavily used of the four.
Flights would be audible at three homes on Montana Creek Road and for some of the homes in subdivisions near the Mendenhall Campground. The frequency of flights would increase, but the loudness of aircraft noise would decrease for those residents, according to the study.
Landholder: State of Alaska.
Infrastructure: Electricity would need to be extended from the rifle range along Montana Creek Road to the site. Water and sewer also would be needed.
Location: 3.2 mile Thane Road.
Site data: Sheep Creek would be a combination of two sites, one at the Alaska-Juneau mine portal and the other at the old Thane townsite on the Sheep Creek delta.
The upper site would reduce noise, but could be used only on days when the cloud ceiling is above 3,000 feet. Airport weather records show the ceiling has been above 3,000 feet during the summer three-quarters of the time during the past two years. Ceiling conditions along ridges are often lower, which could make the upper site usable roughly 50 percent of the time.
Noise: The lower Sheep Creek site would bring increased noise for some residents who live nearby. The noise footprint at Sheep Creek would cover 85 homes, mostly on days with low cloud ceilings.
Landholder: AJT Mining Properties, owned by Alaska Energy and Resources Co. AERC also owns Alaska Electric Light and Power.
Infrastructure: Electricity is available at both sites. Both the upper and lower sites have existing wells and septic systems that probably will need to be upgraded. Mine buildings at the upper site could be adapted for heliport use, according to the study.
Location: Off Glacier Spur Road, about one-half mile from the Mendenhall Glacier Visitor Center.
Site data: Era Helicopters operated a base at the Mendenhall Glacier in the late 1960s.
Noise: While a Mendenhall Glacier heliport would reduce the number of homes under helicopter flight paths overall, it would shift the impact to a new group of homes. Noise levels would be higher at homes in two Brigadoon subdivisions and near the Skaters Cabin campground. Noise also would increase at the Mendenhall Glacier Visitor Center.
Landholder: The U.S. Forest Service. The agency has expressed reservations about a heliport at the glacier, according to the study. Juneau District Ranger Pete Griffin said the Forest Service wants to make sure all sites are properly studied before they are rejected.
Infrastructure: Electricity, water and sewer are available at the site.
Other: Noise on the West Glacier trail would be about the same with this heliport, but noise on the East Glacier trail would increase.