Blue Spring of Covanera Nature · Tubilla del Agua, Páramos, Burgos A karst spring of blue water with a mouth seven metres across and ten metres deep, discharging an average of a thousand litres a second, with peaks of 4,710 in high water and lows of 34 at the driest time of year. Photo: Dhoca73 (Public domain) What to see and do in Tubilla del Agua