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Channel conveyance, channel size and water levels in the Athabasca River Delta were investigated in detail during three summer seasons. The Athabasca Delta is between 58°N and 59°N, in Alberta, Canada, and is formed immediately upstream of where the river enters Lake Athabasca. Ice-free flow rates in the river and in the various distributary channels were measured by acoustic Doppler profiler, and water surface elevations by differential GPS and pressure transducer recorders. Approximate values were measured for river bank heights, and a profile of elevation for the river bank for a distance of 80 km upstream of the lake was established. Computed bankfull flows for cross-sections starting at the delta apex were found to reduce significantly in the downstream direction. High values for bankfull conveyance at the head of the delta, equivalent to 50-year return period flood flows, were noted. For medium Athabasca River flows (about 800-1100 m3/s), a comparison was made of water surface elevations at the delta apex during the survey, and data from 1971. A significant increase of water surface height for the same flow rate, by as much as 0.8 m, is apparent, indicating rapid channel aggradation. [ABSTRACT FROM AUTHOR]