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Homer Spit Road and Harbor Construction

The Homer Spit forms a distinguishing natural feature in Kachemak Bay. The Spit itself is the second longest landform of its type in the world, extending four and one-half miles into the Bay. Composed of unconsolidated sands and gravels, the geologic origin of the Spit is believed to be both glacial and littoral. The Spit was created approximately 14,000 to 15,000 years ago as the submarine end moraine of a glacier that filled the Bay during the Naptowne glaciation (Reger and Pinney 1997). The process of erosion and the movement of longshore currents then worked together to deposit sand and gravel from the adjacent bluffs, building the Spit up over time. Though erosional and depositional processes continue to shape the Spit, more dramatic changes are brought about by the actions of humans.

Anthropogenic effects have transformed the Spit from a natural feature of the Bay, into a bustling commercial, industrial, and tourist center. These effects have ranged from road construction and erosion control, to major excavation projects associated with the building of various small boat harbors. The following text and images are designed to show some of the various anthropogenic developments that have occurred on the Spit over time. Although the 50 year time period covered does not reflect the entire history of human use on the Spit, this temporal scale is appropriate for showing the majority of long-term anthropogenic effects that have occurred on the Spit.

The first permanent structure built on Homer Spit was the Spit Road. In 1927, a gravel road was built, extending from the town of Homer proper to the end of the Spit (U.S. Corps of Engineers 1961). This route followed an abandoned railroad bed that ran along a berm on the seaward side of the Spit. In 1945, the berm, upon which this road rested, was breached near the base of the Spit (Soberg 1991). This was a fairly common occurrence during high tides and effectively cut off access to the Spit. Though the normal practice was to fill the gap with more sand and gravel and rebuild the road surface, the state of Alaska decided to construct a more permanent solution.

The Evolution of the Spit Road(s)

cribbingEarly in 1945, Hawley Sterling of the Alaska Road Commission, designed a road that would bisect Mud Bay at the base of the Spit and attach to the existing roadbed further down the Spit. This would move the area of the roadbed most prone to breaching away from the intense wave action and storm surge common in its previous position. Ralph Soberg, who had constructed bridges all across Alaska, was brought in to lay the road across the soft sediments of Mud Bay (Soberg 1991). To span the silt and mud, the road crew had to lay almost 1,000 feet of wood cribbing. The logs for the cribbing were felled and brought over from an area near Halibut Cove, on the southern side of the Bay.
large dikes

  The cribbing was built in large, log cabin-like sections. During construction the cribbing was filled with mud in an effort to keep it from floating away during high tides. This failed repeatedly, and eventually bulldozers were used to build up large dikes alongside the cribbing to keep the tides away from the roadbed. The dikes often failed to keep high tides from carrying the cribbing away. Eventually however, all of the cribbing was in place and connected. The tides came in and removed the mud from within the cribbing, but the framework held firm (Soberg 1991). In order to complete the road, Soberg and his crew had to find gravel, which was in short supply in Mud Bay. Gravel was "stolen" from the Spit itself (Soberg 1991), mostly from the western side at the base of the Spit, just north and west of current day Mariner Park (Klein, pers. comm.). Gravel was also found in a couple of locations near the airport. The road was finished in late September of 1945, was first paved in 1962, and is still in use today. Spit Road survived approximately 20 years without incident, but that changed in 1964.

grader

On March 27, 1964, south central Alaska was rocked by a 9.2 magnitude earthquake. The quake caused differential compaction of the unconsolidated materials of the Spit, as well as tectonic subsidence, resulting in an elevational drop on the Spit ranging from two to six feet (Waller and Stanley 1966). Although high tides immediately after the quake caused salt water damage to some of the buildings, the real effects of this subsidence were not realized until the following autumnal high tides, when almost 70 percent of the Spit was inundated.

dump truck

The massive flooding events from this high tide completely covered the road in several areas (although the Mud Bay section held strong). The following year, the State of Alaska brought in bulldozers and graders, adding more sand and gravel materials to the Spit . Many areas of subsidence were filled and graded during this time, raising the Spit to its current elevation (Waller and Stanley 1966).

Homer Spit Road

Since 1964, Spit Road has suffered relatively little damage. Occasional winter storms have overtopped the seaside berm and flooded the road, but these events have been relatively minor (U.S. Corps of Engineers 1989). The addition of revetments and seawalls, structures that either jut out into the ocean or run along the shore and provide for the protection of the shoreline and road, are discussed in the "Erosion Control" section. The major change in roads on the Spit in the past 35 years has been the addition of new roads. As illustrated in the following series of photos, the number of roads has dramatically increased in recent times. With the addition and expansion of harbors, the increase in commercial and sport fisheries, and the overall growth of the tourist industry, roads have been added in a number of different areas to deal with the increased use of the Spit by motorists. There are now many more miles of road than the original four and one-half from the base of the Spit to its tip.

Continue to Next Section: Development of the Small Boat Harbor

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Author

Ben Bloodworth, Alaska Department of Fish and Game


References