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Satellite Imagery of Manitoba's Great Lakes - 2009




September 20    

The north basin bloom is less evident today, perhaps dispersed or sunk in the last few days. The plumes of high DOC water that have been largely confined to the east shore river outflows appear to be mixing further offshore. Considerable erosion is occurring on the north shore and influencing the clarity of the water in that area as well as the west side of Playgreen Lake. Similarly, high turbidity continues to predominate south of Berens Island.


September 14

September 13

September 9

The north basin algal bloom persists largely in the northeast quadrant with a thin extension down the centre of the basin toward Reindeer Island and a less dense extension to near Berens Island. Both images show how remarkably heterogeneous this lake can be. September 9th includes Lake of the Woods in the bottom right corner of the image - note the large algal bloom covering much of the east basin.

September 6 September 2

August 31

Finally some unobscured images of Lake Winnipeg reveal interesting changes occurring in the north basin over the last few days. A notable algal bloom has formed in the northeast quadrant of the north basin, curling around Long Point and reaching the east shore, extending south to near Berens River. The high turbidity in the south basin and narrows is likely preventing any large-scale bloom formation in those areas - so far at least. The Winnipeg River plume extends well into the south basin and north along the east shore.


August 13 August 12 August 6
August 4 August 1

Algal cells - north basin bloom

Until early August, it had been fairly uneventful in terms of visible cyanobacterial blooms. By the second week of August, however, surface blooms were becoming more visible in the north basin - at the tip of Long Point and north of Grand Rapids (August 6th), and offshore of Poplar River and north toward Warren's Landing (by August 13th). Results by Hedy Kling indicate that this bloom consisted of a mix of Anabaena flos aquae, A. mendotae, some A. lemmermannii and low numbers of single filaments of Aphanizomenon species (see photomicrograph above). Preliminary results from the summer research cruise (ended late July) indicate that the algal community is considerably different this year than in past years with a predominance of diatoms and cryptophytes, instead of primarily cyanbacteria with some diatoms. In addition, the biomass of algae is lower so far this year than in previous years. The summer thus far has been quite wet, cool and windy - with a change in weather to calm and warm, the characteristic cyanobacterial blooms may still form this year, especially given that there is plenty of phosphorus in the lake to fuel their growth.

July 25 July 18(1) July 18(2)

Three relatively unobscured images recorded in the third week of July reveal a highly turbid lake for the most part. No substantial algal blooms have developed yet, although the small wisp of bright green in the far north of the July 25th image indicates a small surface bloom.

July 12(1) July 12(2)  

These two images were taken on the same day. Again, highly turbid water dominates much of the lake with the exception of the area near the mouth of the Saskatchewan River, which remains clear. Interestingly, this dark, clear water is making its way around the tip of Long Point. July 12(2) includes the mouth of the Nelson River at Hudson Bay - note the influence it has on the receiving waters. Quite remarkable!

July 9 July 5  

With the exception of the area north of Long Point, near Grand Rapids, the lake appeared increasingly turbid during the first week of July.

June 30 June 25 June 14

Just three images for June. The Red River continued to influence the southern half of the south basin, and the Winnipeg River, with its high dissolved organic carbon (DOC), dominated the north half of the south basin. The east shore rivers, with their high DOC concentrations, were still visibly influencing the lake as well. However, by the last week of June, this distinction was less apparent as the lake mixed and appeared more turbid overall - note the interesting flow pattern just north of Moose Island in Fisher Bay in the June 30th image (you will need to zoom in). The distinctive dark, clear water in the north basin near the Saskatchewan River outflow, north of Long Point, contrasts greatly with the bright, highly turbid, clay-rich water along the far north shore and flowing into Playgreen Lake via Two-Mile Channel.

May 31 May 29  

By the end of May, the entire lake was ice free. This is a little late compared to recent years. The influence of the inflowing rivers on the lake is well illustrated in the May 29th image. For example, the effect of the high sediment load of the Red River on south basin turbidity was evident. Also, the dark brown along much of the east shore was due to the inflowing rivers that contain high concentrations of dissolved organic carbon (DOC), originating from wetlands in the Precambrian Shield. The influence of the lake on the outflow and downstream environment is also illustrated here (and in many of the subsequent images - see July 12 for Hudson Bay) by the light-coloured area along the north shore, near the outflow (Two-Mile Channel) into Playgreen Lake. This is due to erosion of clay- and silt-rich materials form the north shore.

May 24 May 22 May 18

By mid- to late-May, the south basin, narrows and outflow were ice-free.There was some open water in the north basin - and the ice remaining is visibly deteriorating. By and large, however, the ice still dominates the north basin.

May 11 May 4 (north basin) May 4 (south basin, narrows)

Spring break-up is well underway in the south basin and narrows. By May 4th, the mouth of the Red River and Winnipeg River are open - the influence of those rivers on lake clarity is apparent. The ice near Black Island is gone and Playgreen Lake is largely open as well.

April 9    

Red & Assiniboine river valley. The whole image stretches from Lake Diefenbaker on the Saskatchewan River, in the west, to east of Lake of the Woods, and from the Lake Winnipeg and the Duck Mountains in the north to the Missouri River in the southwest.

The whole of the Red River valley is clear of clouds; if you look closely, you can see the Devil’s Lake and the Sheyenne River, all of the Red, and the Qu’Appelle and Assiniboine at least as far as Lake of the Prairies. The white in the lower left quarter (southwest of the Missouri River) is mostly cloud; however, the whitish tones in the rest of the image are mostly snow on the ground. To the southwest of Winnipeg, the river valley running diagonally through an amorphous white area in the upper left quadrant is the Pembina; there is still lots of snow not yet melted in its watershed - but much of the Assiniboine and Qu’Appelle valleys to the north and west are nearly snow-free.

You can clearly see the extent of flooding along the mainstem of the Red River river – very dark brown, muddy water.  The most widespread flooding is still south of the U.S. border (on a parallel with the southern basin of Lake of the Woods, at the right of the image) but there is now also a large brown lake stretching from Emerson to Morris. Lots more in the image if you look for it, but I’ll leave that to you. (GM)