From water chemistry and oxygen and hydrogen stable isotopes, origin of spring water within the Kushiro Moor was estimated. Water chemistries of the spring water within the Kushiro Moor are different from those of river water within the Kushiro Moor. Stable isotopes in the spring water are relatively lower than those of the surrounding river water and are in agreement with those in the upper stream of the river at the north of Kushiro Moor. Therefore, the recharge area of spring water within the Kushiro Moor is thought to be at the north of the Kushiro Moor.
