As my readers know, I participated in the dig at Tel-Gezer in 2009 and again this summer. Both times I took a group of students who came to experience archaeology and the land of the Bible.
One of the spin off projects from the dig has been the efforts by Dan Warner and his team to clear out and study the water system. The entrance to the water tunnel is located inside the original Canaanite city and exits someplace outside the side of the Tel. A good portion of that tunnel has been filled in over time by debris that must be removed to study it.
The project is a challenge for at least two reasons.
First, there is 100's if not 1000's of years of pigeon and bat dung in the cave. It certainly does not make for a pleasant breathing environment.
Second, not all of the debris in the tunnel ended up there via "natural erosion." A significant amount of dirt and large boulders were placed there by previous excavators. It must have seemed a convenient place to get rid of the dirt from excavations in other parts of the Tel. Of course, no one is "confessing" who put the materials there, although the Dever excavations in the 1960's and 70's seem to be the best suspect. But my understanding is that when the question was asked at recent party at the Albright, no one was "confessing" but there was plenty of finger pointing in other directions.
But the good news is that Warner and his team from New Orleans Baptist Seminary have made tremendous headway over the last few seasons and are getting very close to the source of the ancient spring. I understand that they hit mud this summer, which might suggest they will find the spring next season.
There is a nice writeup about the project in Baptist Press. I also managed to find a youtube clip in which Dan Warner describes the project and shows some of the challenges related to this type of archaeology. If you think all archaeologists use paintbrushes and dental tools you need to see the way these folks are using a crane. I wish we had used that thing on other parts of the Tel.