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Main channel below dam, showing that they are actual shale  shelfs, instead of small sand riffles about 2 feet tall
"Pretty awesome images Rollie. I cant completely decipher them - but the detail here is amazing." --Ryan, 03/03/08
"Ryan, when you are running down the main channel, and your graph shows you the bottom fluctuating up and down, it is these shale ledges that you see in this picture." --Rollie, 03/03/08
"Ok - how is the bottom of the reservoir/lake oriented within these various images? Is the reservoir bottom displayed vertically?" --Ryan, 03/04/08
"Ryan, This particular shot, is approx a mile downstream from the dam, on the left side of the island, if your are headed to the dam, which I was. So, the direction of travel, is parallel to the river, going upstream, so to say. When I turned the boat perpendicular to the river, then several of the ledges showed up on each side, because I was now shooting perpendicular to the direction of the ledges also. The blue boatlike figure at the center of the picture, is the location of the boat. The distance I was shooting left and right, was 69 feet, and is adjustable from zero to 360 ft left and right. There is a "dead zone" in the water column below, that the side imaging doesnt read (6 degree cone angle), but the depth finder covers this area for you. As you can see, where the dark line of the "dead zone" widens out, that reveals a drop in the bottom, as proven by the viewing of the shale ledge where the side imaging does show the bottom." --Rollie, 03/04/08
""Is the reservoir bottom displayed vertically?" No, you are looking down at it, from this view. If you look at the difference between the ledges on the left and right, you will see that the left ledge doesnt cast an shadow, as the beam is shooting into it, while the right ledge, cast a shadow on part of it, where the beam cannot see, so it shows a shadow. While both ledges represent a rise in the bottom, because of the direction they are laying, one casts the shadow, and the other dont." --Rollie, 03/04/08
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