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Table of Contents
Foreword
Preface
Glossary

Chapter 3: Geologic Structure and Landforms

3.15: Incised Meanders and Slumping: Souris River at Wawanesa

Downstream from figure 3.13 the Souris River valley exhibits classic incised meanders. Here the river channel is over 100 feet (30.5 m) below the flat surrounding countryside that has been cleared for agriculture (1 and 2). As incision took place the river continued to erode laterally, leaving behind scars (3 and 4) on the insides of bends and steep cliffs 5, 6 and 7 on the outsides. The river is incised into glaciolacustrine deposits overlying till which in turn overlies the Cretaceous shales that in the field can be seen at the bases of the river cliffs. Erosion has resulted in a large slumped mass 8 that deflects the river course. Slumping continues particularly where a monument to the explorer/cartographer Thompson is now located well down the valley side several metres below the point at which it was erected 9. This 1945 photograph shows a road at the top of the cliff (between 10 and 11); now much of it has disappeared over the cliff top. Talus of fallen material causes a minor deflection in the river’s course 12. A small south bank tributary has produced a gully 13, and nearby clearing for agriculture has resulted in rain splash erosion of the gully side producing white patches 14.

Figure 3.15: Incised Meanders and Slumping: Souris River at Wawanesa

Figure 3.15: Incised Meanders and Slumping: Souris River at Wawanesa

Figure 3.15

Vertical air photograph: A11123-310

Flight height: 17,300 feet a.s.l.; lens focal length: 6 inches

Date: September 25, 1947

Scale: 1:35,000 (approx.)

Location: Township 7, Range 17 WI

Map sheets: 1:250,000 62G Brandon

1:50,000 62G/12 Wawanesa