Diemel basin

The Diemel () is a river in Hesse and North Rhine-Westphalia, Germany. It is a western and orographically left tributary of the Weser. It is the first, and therefore southernmost, of the larger Weser tributaries after its formation at the confluence of the Fulda and Werra rivers.

thumb|Dam and power station from the north

thumb|290px|Twistesee panorama The Twistesee is a reservoir on the Twiste in the county of Waldeck-Frankenberg in North Hesse, Germany.