During late glacial and early post-glacial times, the Blindman River drainage basin was developed on the general slope to the Red Deer river. Two streams, one draining into the glacial Red Deer River and one into glacial Gull Lake,

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were probably present during glacial time. Modification of the drainage occurred in early post-glacial time, leading to the development of the present drainage pattern.

Two types of aquifers occur in the Blindman River valley: permeable sandstone lenses in the Tertiary Paskapoo Formation, and sands and gravels in surficial deposits. The former are more extensively developed and are economically more important. About thirty per cent of stream discharge during baseflow recession is calculated to be of groundwater origin.

Groundwater from wells in recharge areas is much harder than from wells in discharge areas, because in travelling through the bedrock to discharge areas, it is softened by ion-exchange in bentonitic materials. Water high in sulfates is also high in total solids. Groundwater from the Paskapoo Formation is chemically satisfactory and sufficiently abundant for municipal and industrial use.

The proposed scheme to employ groundwater for raising the level of Gull Lake would probably be unsuccessful, because of the great quantities required. An alternate method, reduction of evaporation, is suggested.

The interrelated phases of the hydrologic cycle are probably better studied on the basis of drainage basins rather than map quadrangles.

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