Continuity Equation of Water Body Stable Isotopes in Finite Length River Reach

Based on the principle of water balance and stable isotope mass conservation principle,taking a finite length river reach for an example,continuity equation of hydrogen and oxygen stable isotopes is derived by considering evaporation,precipitation and interaction of river water and groundwater.And it gives the specific application of hydrogen and oxygen stable isotope composition differential equation model of river water.The results show that the method decreases the difficulty of applying the model so that the model can be generalized more easily.