Other+Habitats


 * Glaciers and Glacial Silt**

UAS students collected water samples throughout the summer of 2002 and measured the amount of glacier silt in Mendenhall Lake and at the outlet at the beginning of the Mendenhall River near the US Forest Service Campground.At the Lake outlet the average silt concentration was 0.19 milligrams per liter while the average concentration of sediment at the lake surface was 72 milligrams per liter.

A sediment sampler we had on the bottom near the glacier measured roughly 0.5 gm per cm^2 per hour was settling onto the lake bottom. In 2006-2007 Juneau-Douglas HS freshman Pauline Zheng measured silt in the Mendenhall River every day throughout the winter under back Loop Bridge for her Science Fair Project and found winter silt concentrations ~.006 mg/l.

In the summer the silt concentration rises with increased flow from glacier melt and rainfall. In the winter during low flow, the silt values seem to be disconnected from river flow, especially when it gets below freezing. Somehow the sockeye salmon make it all the way up into Steep Creek near the Glacier Visitor Center by swimming from Gastineau Channel near the airport wetlands up the Mendenhall River and across Mendenhall Lake. How they can cope with all of that glacier silt is a mystery to a geologist!

Dr. Cathy Connor University of Alaska Southeast Here is poster we presented at a science conference about Mendenhall suspended sediment in the river.