Restoring an old/dried groundwater pond

HI folks, first post!

So Im restoring an old pond site that 150 yrs ago had loads of water. The old shape is roughly 50 by 30 meter and on the lowest point im handdigging a new pond (+-30-35m2) to the groundwater level (2 meters lower). Roughly calculated that its around at least 100m3 with 2 people and a homemade tractor for transport. The soil is used on other sites and the sand will become partly concrete, beach and floor cover in a stable.

On the back of the picture you can see the uphill slopes of the old pond, the ground is topsoil combined with loam. Planning to reuse the loam, guide some water from roofs to the pond.'How much problems am i gonna get with changing waterlevels/rain?  

I remember 2 yrs ago that i only had to dig 50cm for water now its 2 meters any effects for ducks/geese? Im not planning for fish, or maybe tiny fish.