Dammed Ditch

It's our visitors' last full day today so we decided to take a walk from home and look at some of the local beavers' creations. 
This dam is built across what is essentially a drainage ditch between two fields. The ditch is about 2 metres deep and carries a small stream. This dam is about 1,5 metres high and the ditch has now become a small lake, rather narrow but stretching back 50 or so metres. I'm a bit puzzled about where the beavers actually live as there is no lodge along the whole stream, though there are 4 or 5 dams/pools. More exploration is obviously required.