MOLE DRAINAGE.

A mole drainage system has proved very effective in reclaiming many acres of low-lying, poorly drained agricultural lands and should prove a valuable tool in the construction of airfields under similar conditions. It is believed that even in soils containing some sand or silt, the mole drains would greatly increase drainage for short periods of time with resultant construction benefits. It was recognized that the mole drains usefulness was severely limited unless some simple but effective method of making the drain a relatively stable structure in a wide variety of soil conditions could be achieved. It was to study this problem that a series of laboratory investigations and model tests were initiated in the Soils Laboratory of the New England Division, Corps of Engineers, in Boston in 1946. The investigations to date have followed two general paths of study First, to attempt to strengthen the existing soil walls of the mole drain by a coating or liner cast in place during the passage of the mole plow and, second, to insert a suitable prefabricated liner into the mode drain behind the plow.