Some knowledgeable help would see the job done OK. Water needs to be drained off slowly with any ocherous discharge captured in ponds downstream where it could dry out and then be removed.
I am sure that someone will be more than willing to help and advise.
Of course the water may not be ocherous, but one still has to be careful of any sudden mass release which could cause damage downstream. Peoples gardens, roads or whatever.
There can be a loose - loose situation whereby if an adit becomes blocked water can build up especially after heavy rain and then a sudden blowout can happen all on its own.
So ensuring continuity of drainage can be a good idea anyway.
I think you have come to the right shop for help.
My avatar is a poor likeness.