Isotopes for Improving Hydrologic Modeling and Simulation of Watershed Processes

Abstract

Lake water quality management is an important component of watershed protection and restoration. Hydraulic residence time (HRT) is a guiding parameter for quantifying the extent of exposure of lake ecosystem to chemicals. The impact on the δD and δ18O-year amplitude depends on the lake shape, basin size, connectivity, geology and climate characteristics, perineal fluctuations in lake water mass balance, and hydraulic residence time. HRT in the lake can be dynamic. Usually, HRT is calculated based on the balance between lake’s volume and its input and output parameters, but there is a relatively simple and approximate method that uses stable water isotopes to assess the direction and possible speed of runoff in a lake. This study establishes the importance of stable isotopes in hydrologic modeling.