The Hydrologist, the Detective, and the Shaman. Harding Lake Fluctuations: Past, Present, and Future

John Fox
Department of Forest Sciences, University of Alaska, Fairbanks

This presentation will focus on the past, present, and future lake level fluctuations in Harding Lake and my attempts to understand how that lake operates. Part of my message will be the need for site-specific data, and part will be what I have done in lieu of such data. My interest began in 1974 and over the years I have reviewed scientific studies, looked for old maps, aerial photos, and historic ground photos, retraced old survey notes and markers, tromped around in the woods, looked at tree ring cores, talked to property owners, and evoked the voodoo of modeling. Over the years I have transformed the original model of Kane et. al. (1979) to be used as a teaching tool. I recently simulated an historical time series of Harding lake under various assumptions about surface and subsurface inflow and outflow. All of this may fit into the category of “Useless Mathematics” but with some caution, might render insight into how the lake operates. The major frustration has been the lack of systematic measurements of the water balance components, particularly an objective measure of lake levels. As many of you know, funding recently became available to plan, design and implement a structure to re-channel part of Rogge Creek flow into Harding Lake. Unfortunately, none of that funding was allocated to further “scientific studies” or data gathering, per se. The operational perspective was clear: re-divert the stream and the lake level will rise! And I have no quarrel with that point of view. However, being an academic and somewhat sentimental nerd, I still wondered fundamentally how Harding Lake worked. When I heard of the renewed activity at Harding Lake I harkened back to 1974 when the late Professor Jacqueline LaPerriere first mention the problem to me. My curiosity got the best of me I decided to bootleg a little unfunded project of my own. In 2004 I installed a water-level recorder on Harding Lake in hopes of documenting the pre- and post- diversion lake levels. This past summer marks the first season of post-diversion record. I also installed an evaporation pan and hope to tease out how much water loss from the lake is due to evaporation and how much might be due to net groundwater seepage. I also have had 3 undergraduate students in Natural Resources Management use the Harding Lake situation to develop senior thesis projects. One student looked at the ice-shove ridges along the north shore, another looked at historic trends in simulated lake levels, and a third is currently investigating changes in lake level during winter. I hope to use these data to better understand the hydrology of Harding Lake and help managers estimate how the lake will respond to the renewed contributions of Rogge Creek.

For more information contact: Jeff Derry (907) 322- 3026