Ward and I recently went to Brighton Dam. The main purpose of the outing was to enjoy the pleasant fall weather and to explore a new place that we had heard about but hadn't seen. While the trip lived up to all of its expectations and we had a lovely time, something more important came from it. We had a very real reminder that when you make assumptions, many times you can be wrong.
We assumed that there should be no problem with water supply around the dam with 7 billion gallons of water available.
However, we were wrong. The reality (and irony) was that water supply is limited around the dam because it comes from a well, not from the reservoir.
"Water, water everywhere, but not a drop to drink."
"Don't count your chickens until they've hatched."
"You can't judge a book by its cover," or "You can't judge a park's water supply by its reservoir."
When you make assumptions, you may, "Jump the gun."
The park's water was "Sold down the river."
Okay, I'll stop now. You're welcome.