trof...18 inch=1.5ft, 1.5/7=0.214285714 or 21% av wae from bottom tu water level
delta-wide=6 ft....0.21485714*6ft=1.2857142857 ft
so, water surfus wide=6+1.28571428 ft=7.2857142857 ft
area=10ft*7.2857142857
=72.857142857 sq ft
dekta volume=10 ft^3/minut
delta rise=10/72.857142857=0.1372549 ft/minut or 1.6470588 inch/minut
or 98.8235 inch/our