CONTINUED SLUMPING ALONG I-94 ADJACENT TO ST. JOHN'S ABBEY LANDS, STEARNS COUNTY, MINNESOTA

Slumping continues to occur on the north-facing, 16° slope of the I-94 right-of-way adjacent to the lands of the St. John's Abbey in Stearns County, central Minnesota. The crest of the slope, immediately above the slump, is tree-covered (poplars & pines), but the right-of-way slope, where the slumping continues to occur, is grass covered (reed canary & sweet clover). The slump occurs in Late Wisconsinan supraglacial till deposited by the Superior lobe during the final retreat from the St. Croix moraine. The till is composed chiefly of clays and sandy loam with unsorted pebbles, cobbles, and boulders. Rain water remains for a significant period in the arcuate scars and depressions of the slump. This section of the interstate was completed in 1977, and the first slump occurred in 1991. The Minnesota Department of Transportation (MnDoT) used a backhoe to return the slope to its original form. Following a heavy snow pack in1997, another large slump occurred at the same location and an earthflow at the base of the slump remained as a slightly active process until spring, 2000. During this period, annual precipitation was lower than normal and the local water table had dropped significantly. In the late spring, 2000, MnDoT bulldozed the site and returned it to the pre-1997 slope, however the slippage surface was not modified. The resulting scar quickly disappeared as vegetation "reclaimed" the slope. During the 2000/01 winter, the region received 1.43 meters of snow. Record low temperatures meant that ground remained frozen throughout the winter and most of the snow remained until rapid melting occurred during the last week of March and first week of April. During the third week of April slumping occurred in the same location as previous mass wasting, but has cut back higher on the slope into the first line of trees. MnDoT is presently undecided as to how to what course of action to take regarding this slope.