Filling in a sloped portion of backyard

Back in the day when I was a draftsman for a civil engineering firm, one of my goals was to balance the cut/fill amounts. But, I could only do that after getting a contour map from the surveyors. If you have any construction surveying friends, now would be a good time to bribe them with significant amounts of beer. Especially if the slope is not uniform.

You can try to do it by eye, and if you do, plan on making the area to be level significantly larger than what you actually need for the pool.