the "trouble on the river" the lochage was referring to

When Severian is brought to meet the lochage, he mentions that there had been trouble at the river. Could this be a reference to the later astral trip that Silk/Horn took to Nessus in Short Sun?

No. Different seasons. It was early spring when Sev left the tower. (Soon after he left, Talos was whacking the heads off wildflowers in the field near the city gate.) When Sev found Triskele, it was bitterly cold. (Sev was outside the tower trying to unclog a frozen drain pipe at the time.) Sev had the dog for only about a week. He showed the dog to Silkhorn. Jahlee was running around naked when the party from Blue came to Nessus, not a cold-weather thing to do. <g> -Roy