Rivers and Lakes + Otters

It would be amazing if lakes, streams, rivers etc. Would generate more realistically, with flows down the mountains, little ponds here and there, mountail lakes, big rivers and more. In addition, Otters that build dams and such could spawn and create better seperations between water-height-levels. We could maybe even have stackable wooden branches in these dams or make it so the otter collects random items and we could find them.