| Bassett Creek is Minneapolis' best known subterranean stream. Until 1991, the term "Bassett Creek Tunnel" meant only one thing: the old, limestone rubble masonry tunnel, dating back to 1913, that ran just below street level for a distance of 1 1/2 miles to the Mississippi River. For more background information see the Bassett Creek Watershed District website. The following photos are arranged in a downstream sequence. |
 |
 |
 |
| VIRTUAL TOUR OF THE BASSETT CREEK TUNNEL: THE 1993 SURVEY |
 |
 |
| The object in the center is a "teakettle," a manhole projecting up into the stream, in which you can hear "boiling," which is actually the sound of sanitary sewage rushing through a tunnel at a lower level. There are six of these teakettles in the DuPont Avenue segment of the tunnel. Up until Bassett Creek was rerouted into the deep tunnel, enormous "beaver dams" of driftwood would build up behind the teakettles, ponding back stagnant water, and incommoding would-be explorers. |
 |
| At right is the Bassett Creek medusa, the largest formation in the tunnel, deposited from groundwater infiltration. Located downstream from the great Lyndale sandbar, it was destroyed in the late nineties when this part of the tunnel was relined. |
| Bassett Creek passes under Bryant Avenue at this point. The trend of the tunnel is diagonal to the street pattern in this segment, as may be seen from the orientation of the squinch arches in this photo. |
| As you proceed downstream, the size of the tunnel increases. This segment, constructed of Kasota Stone, appears to have originally been a bridge that was incorporated into the tunnel. A concrete box section is seen beyond. |
| Light at the end of the tunnel. The deepest water is encountered at the exit. This photo, taken just downstream from the Egyptian Gallery, is the part that you used to be able to look down into from Rudolph's Ribs, in the 1980s, when the viewing port in the floor was there. This segment of the tunnel also has bats. |
 |
| The Ship's Prow, a double box-section of the tunnel with reinforcing divider. Note the cast-iron water main passing overhead. There is a repetitive, zoned distribution of sediments in the Bassett Creek Tunnel. Where side-branches discharge water into the tunnel, I found gravel bars, then sand bars, and finally silt, when walking in a downstream direction--the heavier particles settling out first. I also saw many shopping carts, looking like ribcages sticking from the sandbars. In 1993, I mapped the location of the sandbar "islands" as part of an effort to monitor the downstream migration of large objects in the tunnel. I noticed that in double box-sections, dry sand banks usually filled one side or the other, leaving the base-flow stream to occupy the opposite side. Another characteristic of the sand deposits was the presence of megaripples, produced during high-flow conditions. |