In order to study transferring water problems during ice period for the main channels of Middle Line scheme of Diversion Project from South to North,through analysis of ice conditions from field data of the Daqinghe River,verification calculations for water stages and water temperatures,calculations and analyses of effect of ice conditions were performed .

The main channel with long route, large discharge, number of dividing and control gates is also a great transportation system with wide areas for water supply, numerous crossing construction and complicated running control.

By research on the freezing expansion proof of the concrete lining in the main canal (Hebei section) of the South-to-North Water Diversion Project, some regulations governing the freezing expansion ratio for the soil in the seasonal freezing areas have been found.

To optimize water head allocation of main canal is important for saving investment and reasonably designing Structures.

,the heightening of Danjiangkou dam, the extension works of Taocha Sluice,the Zhanghe Aqueduct on the main canal, etc.

In this paper the geology problems of the total channel,e.

Measures for seepage prevention for middle and down reach in Duolang main canal;