(1)六73.4-0.1=73.2,五73.2-0.49=72.71,四72.72+0.13=72.85,三72.85-0.06=72.79,二72.79+0.18=72.97,一72.97-0.52=72.45上周末72.45-0.25=72.2,答:那么本周一水位是72.45米,上周末的水位是72.2米;(2)73.4>73.2>72.85>72.97>72.79>72.71>72.45,答:本周周末河流水位最高是73.4米,与警戒水位平,周一水位最低是72.45米,低于警戒水位;(3)73.4-72.2=1.2(米)答:与上周相比,本周末河流水位是上升了1.2米.