We were treated to a completely unexpected view at one of our on-going excavations when a small hole appeared in the bottom of one of our trenches. We were hoping to find the bore-hole for a domestic water pump which we knew was nearby but instead found a large circular rainwater cistern, measuring about 10ft in diameter and 8ft deep!
This photo shows the aperture after enlargement - the pump's down pipe (around 2" in diameter) can just be seen standing almost upright in the darkness below.
In the interest of safety for ourselves and others, we had the onerous task of filling in most of the tank but at least we know where it is if future investigation is required!
Before making it safe, we gingerly lowered a camera into the cistern and were greeted with some fantastic images. This one shows that the reservoir consists of courses of brickwork laid on top of a hollowed out sandstone base. The photo at the top of this article shows one of the massive sandstone slabs which cover the top of the cistern, sitting on the bricks.