We had been thinking that there were no interesting underground locations in Great Novgorod. Once we had visited the basement of monument of a Man on a Horse, we new about some shelters under the main railway station and plants. But once Mutabor had found out a location subscribed as "Former river Gzen" at the Wikimapia, and then had found an evidence that this river had been put into a 2-meter wide and high sewer. So evetually we took a chance and tried to find and explore this river.
We had made a first attempt in winter. Rambling in show fields and bushes, we were lucky and finally came to the outlet. But because of the frost the river in the sewer was covered by ice, which made obstacles to us. In addition, under the ice and water there was a layer of the marshy silt. So we were able to advance only for some tens meters and got tired (pic 1–13).
We had made another attempt to conquer Gzen in summer, in parallel with visiting the Novgorod civil airport. We already new where we should find the outlet. But there was no it there! The answer was simple: the water level of Volkhov (and hence of Gzen, which is its inflow) was so high, that the outlet was completely covered by water! So the underground river had turned into the underwater one! (pic 14–16)
In autumn the level of Volkhov went down, and we tried to pass through the Gzen sewer again. We had started from the leftmost pipe, where the flow was stronger and less silt was accumulated. But after about a hundred meters there were nevertheless so much silt, that one couldn't go ahead... (pic 17–20)
Once Lanivs was lucky and had found out another way to get into the sewer through a manhole. He didn't have water mocassines, so he could only made some pictures in the chamber (pic 21–23).
Finally Mutabor and Lanivs had managed to explore the Gzen sewer a little bit more. From the chamber with the manhole they got into the next one downstream, where the rectanglar sewer turned into the three already known pipes, each more than half filled with silt. In the upstream direction led the double square sewer, each line was about 2 meter wide and high. But the silt layer at the bottom had about a meter thickness, so one could only crawl on all four there. This was the reason why we didn't reach the next chamber upstream (pic 24–29).