Lake abundance, potential water storage, and habitat distribution in the Mackenzie River Delta, western Canadian Arctic

The complete landscape surface of the active Mackenzie River Delta ( 13,135 km(2)) was manually partitioned into discrete lakes ( 3331 km(2)), channels ( 1744 km(2)), wetlands ( 1614 km(2)), and dry floodplain area ( 6446 km(2)) via GIS analysis of digital topographic maps recently available for the system. The census total of lakes ( 49,046) is almost twice as large as prior estimates. Using this new information, total lake volume in the delta during the post river flooding period is estimated as 5.4 km(3). Total floodwater storage in the delta lakes and floodplain at peak water levels is estimated at 25.8 km(3) and thus is equivalent to about 47% of Mackenzie River flow ( 55.4 km(3) yr(-1)) during the high-discharge period of delta breakup. During this period the stored river water can be envisioned in the form of a thin layer of water ( 2.3 m thick on average) spread out over 11,200 km(2) of lakes and flooded vegetation and exposed to 24 h d(-1) solar irradiance. Consequently, this temporarily stored water has significant potential to affect the composition of river water flowing to the Beaufort Shelf as it recedes to the river channels after the flood peak.