Harding Lake Levels

What's happening to the water level of Harding Lake, near Fairbanks?

The current low water level of Harding Lake appears to be part of a natural cycle of rising and falling which is tied to climatic cycles and is seen in many lakes around the world. The changes are especially dramatic at Harding Lake because it has a very small contributory watershed; much of its water is provided by seepage. The lake has no visible outlet. While Harding is the deepest unglaciated lake in interior Alaska, it also has extensive shallows which cause the shoreline near some homes to move out dramatically with only a small drop in actual water level.

The University's Institute of Water Resources at Fairbanks has received many reports that the lake was much lower during the 1930s than it is now and the current low began to occur in the early 1970s. Therefore, the cycle may be as long as forty years between natural lows and natural highs. The lake was first settled in the 1920s so it is impossible for us to gauge the exact length of the cycle from residents' reports.

However, hydrologists from the Institute of Water Resources have been studying the phenomenon, and further work on the hydrology of this lake is being conducted this summer during preliminary studies before extraction of a core of sediments. This core will be extracted by a team of Japanese and Alaskan scientists who will attempt to use the material in the core to determine the past cycles of the climate back through geologic time.

Schemes for diverting additional water into the lake have been proposed and include cutting a trench from the Salcha River to Harding Lake. This scheme would be costly and would add water of much different quality than that Harding lake normally receives. Investigations would first have to be conducted to determine the effects river water would have on fish and other life in the lake.

Further study is also needed to determine the hydrologic results of any proposed action. The increased lake level that would occur during spring runoffs and the varying summer rains needs to be predicted. Some important social questions are: Who will determine the optimum lake level? Who will control and maintain the diversion device? And, who will be responsible for property damage due to flooding? Such flooding could occur if optimum lake level was attained early in the summer with the aid of a diversion device and such diversion was then followed by a heavy rainfall.

Jacqueline D. LaPerriere works at the Institute of Water Resources, University of Alaska Fairbanks.