The water level of Lake Endla has lowered several times, as a result of which most of its former aquatorium and islands have become land areas.
Neist tuntumad on Sinijärv ja Männikjärv. Endla järve veetaset on mitmel korral alandatud, mille tulemusena on suurem osa selle endisest akvatooriumist ja saared maismaastunud.