In Maryland, we had Baby Jessica parties after she was found. The incident also resulted in intensified inspections of all wells, septic systems, and dry wells across the State, looking for open pits.

As you have said it is down hill of the house, I have doubts that it is a cistern. It looks an awful lot like the dry wells we had. We'd sometimes have two or three on the property to collect the ground water that would super saturate the ground after big snows followed by spring thaws and rains. The intent was to help keep the houses from sliding down the hills. They were dug very deep and would release water into the ground as it dried out enough to accept it. Sometimes, plumbing from an over flow on the septic tank would also be run into them because it could take weeks before the fields could handle it.

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The only reason some people get lost in thought is because it's unfamiliar territory.
- Paul Fix