Cool mod! And I know you have put a lot of effort into the new draining mechanic which is awesome btw but I think could still be improved slightly. Would it be possible to drain the tiles in different steps for deep/shallow water? That is to say, after a certain threshold, maybe 50%, begin the conversion of shallow water to dry, and deep water to shallow, then at the current point drain the new shallow water as well?
It would also be cool if you had a setting to require you to move your pump when the tile below it is converted to land.

I've got the CanalBuilder mod which lets players and biters walk across shallow water which would be an interesting combination with this draining mechanic, I think.

Keep up the great work!

better idea. 80% the shallow gets cliff borders around the lake. 50% the deep end gains another ring of cliff and deep becomes shallow till it empties.

now missing Rain MOD that it fills closed cliffs to shallow and rain event occurs it charts if there another and fills that to shallow and increase the previous to DEEP. got to balance coverage area and total Rain that would be generated. to be distributed to the tiles being filled. mark threshold before it fills the next level.

I like the sounds of this idea as well!

i guess the total tile coverage of the boarder of the pool. add all of them together (Each tile =? amount of water) then shallow water expands the size of the pool.

another would be a scenario after you drain the lake you can deepcore mine the area or a hidden underground caves. with loot?