What specific Medieval Rus waterway engineering examples are there?

I’ve been investigating a statement (cited below) made in Nicolle’s ‘Lake Peipus 1242’ which describes waterway engineering by Medieval Russian princes but doesn’t bring any specific examples. Which specific examples are there of waterway engineering (canals, removing large rocks, and paved portages) in Medieval Russia?

In fact communications were easier in winter than summer, for when the rivers froze, they formed highways for sledges. In summer the rivers still formed the main arteries of communication, though rapids and cataracts made frequent portages necessary. Russian princes did what they could to improve things by building wooden bridges (though these were easily damaged by floating ice during the spring thaw) and by paving portages with timber. Rulers also offered military protection for the most important portages. In the north there were even efforts to improve rivers by digging canals and removing large rocks.

In the north seems to refer to Novgorod; but I don’t know of any specific canals or portage constructions there. Wikipedia doesn’t mention any in the article on Novgorod.

Wikipedia’s List of canals in Russia has a list, but most of these are post-18th century. The two exceptions are the Don–Volga portage and the Vyshny Volochyok Waterway, but despite these pages mentioning that the routes were in use in Medieval times, there is no specific note of what was done to make these better/more easily usable.

The Volga trade route article is interesting, but also says that the route lost importance by the 11th century. No specific mention is made of portage improvements, but using portages is described in the briefest detail. The Dniepr trade route article also mentions portages, but no specific upgrades (and really can’t be described as matching Nicolle’s description of "in the north").

I found this article, ‘The Impact of the Water Routes of Novgorod…’, which looks like it would be useful, but I don’t have access.