When you reach GZ and climb high, you will find information signs.
•A = How many billion liters of water are treated each year?
•B = How many thousand tonnes of biosolids are processed each year?
•XXX = A - 305
•YY = B + 785
The cache is located at N49 10.XXX, W122 56.YYY
It is a nice walk up to the viewing stand. Enjoy!