This cache is a bonus for having completed the Adventure Lab- Watershed Park. To get the coordinates you must visit each location in the Adventure Lab to get a piece of the coordinates which will be displayed in the Journal Entry after successfully completing each stop.Once you gather the information it can be inserted into the following formula:
N47 AB.CDE W122 FG.HIJ
There is an additional hint in one of the Journal Entries
Have a wonderful Adventure as you walk the trails of majestic Watershed Park and discover it's history and natural beauty.