If you installed a large monk through a beaver's dam, wouldn't the beavers build and maintain your dam for you? Then you can control the water level as needed and the spring floods wouldn't break the dam so maybe it could just be built bigger each year? What do you think?
Beavers to me are like the arch villains that inspire my greatest admiration. be careful that encouraging them doesn't destroy all the tree and shrub plants nearby that you also might cherish
beavers live to impound water and coppice trees, and as such they could be an easy part of a permaculture system, they'll even strip the bark from many of the trees leaving rocket fuel behind them (although you might have to steal it from their dam), and i've heard that they have a problem associating the water leaking through a pipe placed in back of their dam at a distance with the actual pipe, although i wouldn't count on that. friends had beavers move into a pond and they repeatedly clogged the overflow pipe, so if your monk was well above water level except when in use during the day(beavers are nocturnal) you'd probably be ok,, but if you left it submerged overnight you might have some unclogging to do in the morning