There's actually two dams with the towers, Howden and Derwent, the picture above was the top one, Howden - there's also a third lower one, Lady Bower - with no towers, but a giant 'plug hole' in the middle, my dad actually worked on it's construction .
Picture below of the Derwent - bit more water in this one:
And here's the elevation plot of my walk:
Incidentally, the elevation track and pictures are from my Garmin GPSMAP 62sc, so the pictures are all geo-tagged. Notice feet and miles, none of this EU metric crap!.
I struggled with the uphill part, and was really tired by the end of the walk - my feet were killing me
Although looking at the plot I see I climbed about 900 feet.
The downhill part of that graph is where the Softrak in the picture went down
I first saw it in the distance at about the highest point, but only caught it up at the bottom (where it had stopped). It's like a little pickup truck, and they had picked up a big metal box, covered in camouflage netting (presumably some sort of hide?) - I helped them slide it on to a trailer for taking away. Interestingly the team doing this (and who lifted in on the Softrak in the first place), were one man and three women