High tunnel Rainwater catchment swimming pond

Check out my cement pond video. I built in 2012. Its 32 ft wide 52 ft long stair stepped to  11ft deep 2 inches of cement covered chain link and chicken wire. It is for swimming fishing and irrigation. Its on the very highest part of my property and have no problem filling in the rainy season with the run off of my high tunnel.I dug a ditch and lined it with plastic and filled with gravel which leads to a 4 inch pipe and then into the pond. Crystal clear water, in my video you can see the bottom at 11 ft. I plan on building a lower pond, probably not concreted to use to circulate and keep the upper (cement pond) at a constant level and the overflo would also act as a skimmer to keep floaty junk out.
Check it out on youtube
  if this link does not work my channel is william e   the video is called  My cement pond