Shallowing a concrete pool

We have an old concrete pool 25x40'. Shallow end is 4' deep end is 8' with a slope in the middle. We're in the process of repairing cracks in the bottom caused by an earthquake in the late 1970'. The pool has not settled, and the water level shows less than 1/4" difference across all walls and corners..

While in the process we need to decease the deep end to 5' for water conservation measures. We're looking for additional input on bonding the new floor to the walls.

The presend design calls for road rock to shallow the depth, #3 rebar epoxyed 12" oc into the walls and a 2" high by 1" construction groove around the entire intersection.
The new floor will be 6" thick with a #3 rebar mat 12"x12".

Any input would be helpful.

Got to say, this one stumped me!

Where did you get the idea that making the deep end more shallow would reduce water use? Except for initial filling, I can't think of any way that it would do so.