this is a standard training pond I have built before. I also add a small island in the SE quadrant. if there are no cattle in the area, no sand is needed. a clay hard bottom will not ne too muddy. But sand added to the NW and SE banks will allow you full use year round taking into account thr prevailing winds (NW for fronts and SE for Summer)I added cattails after the 1st year. that was a mistake as they got out of hand very quickly. Due the drought in this area they died witch was a blessing. (the distance from the NW bank diagonally SE the SE bank is 101 yards) I almost always worked most of the year from the NW end. This has been a pretty easy to pond to build and maintain! please contact if you have any questions. JB