English: Kostivere karstfield in Northern Estonia. Large part of estonian bedrocki is composed of ordovician and silurinan limestone that is prone to karstification where carbonate limestone is exposed to leeching and dissolution by atmospheric water. kostivere karstfield is actually developed in a river valley. During the flood seasons kostivere river flows in its bed but during the summer the river dries out and river only flows in underground cave systems....