The ridges are divided by the rivers Elbe, Mumlava, Bílé Labe, Velka Úpa, Malá Úpa and Jizera, which originates in the Jizera mountains. The rivers on the Czech side often fall over steep edges into valleys formed by ice-age glaciers. The largest waterfalls on the southern side of the mountains are the Labský vodopád with a height of , Pančavský waterfall (, the highest waterfall in the Czech Republic), Horní Úpský waterfall, Dolní Úpský waterfall and Mumlavský waterfall (). The most important rivers on the Polish side are Kamienna, Łomnica and Bóbr (Bober). They also form impressive waterfalls, such as Wodospad Kamieńczyka (), Wodospad Szklarki ( Wodospad na Łomnicy () or Wodospad Podgórnej ().