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Application of stable isotopes in the study of lake and reservoir leakage
M.J. Wu, Y.J. Lin, T.P. Lu & J. Niu
Key Laboratory of Plateau Lake Ecology and Global Change, Yunnan Normal University, Yunnan, China
W.X. Zhang
Key Laboratory of Plateau Surface Process and Environmental Change, Yunnan Province, China
ABSTRACT: Leakage of lakes and reservoirs is a common geological problem, especially in karst areas, which directly affects the security of regional water. On the basis of the systematic summary of research on water seepage models, the advantages of various models and their applicable conditions are analyzed and compared. The results indicate that the calculation of the leakage amount of lakes and reservoirs, by the stable isotope mass balance and water balance model, is more accurate, and there is a wide scope of application. This study will provide a scientific basis for the quantitative and accurate calculation of the leakage of lakes and reservoirs, the evaluation of water seepage prevention measures and effects, and the rational allocation of regional water resources and deal with global change.
1 INTRODUCTION
The water cycle is linked with core and bond for various spheres of terrestrial surface. Isotope as the main component of natural water bodies is very sensitive to environmental changes, and can record the information of the water cycle. Hydrogen and oxygen stable isotopes are often used as the tracer in the study of water cycle, and it allows us to further understand the geochemical process (Craig H, 1961; Friedman I, 1953; Kohn M J., 2005). By the comprehensive analysis of the temporal and spatial variation of precipitation and reservoir water stable isotopes, the amount of reservoir leakage can be evaluated, and the effects of regional water cycle on ecosystems are quantitatively estimated by water stable isotopes. It also can provide a scientific basis for reasonable allocation of water resources and environmental change.
On the basis of the linear Darcy law, Guangxi mining areas of karst water system were simulated by using a triple-ring medium model (Cheng, 1998). The water balance of the river basin was calculated by the WetSpass model, which evaluated the amount of the utilizable water resources in the northern Ethiopia Geba Basin (Tesfamichael G., 2013). Pang (2005) studied the atmospheric precipitation with stable isotopes. Zhang et al. simulated the stable isotope fractionation of evaporation water (Zhang, 2003) and analyzed the difference between the characteristic of stable isotopes and the remaining water under the balanced mode and the dynamic model. Although the current research on the use of stable isotopes to explore the leakage of water is large, especially in the karst area, there is little research on the safety of the lives of the people of Yunnan in terms of the reservoir water seepage. Therefore, how to make use of hydrogen and oxygen stable isotopes to study the leakage of reservoir has an important theoretical and practical significance.
On the basis of the study of the relevant water leakage model, comparison of the water leakage models and the applicable conditions of the models have been discussed. Furthermore, the research will provide a scientific basis for the quantitative and accurate calculation of the leakage of lakes and reservoirs, the evaluation of water seepage prevention measures and effects, and the rational allocation of regional water resources, and deal with global change.
2 DEVELOPMENT OF LAKE AND RESERVOIR SEEPAGE MODEL
2.1 Darcy’s law
In the 1850s, Henry Philibert Gaspard Darcy obtained reflect water seepage law in rock pores by a large number of scientific experiments, that is, Darcy’s law. This law is widely applied in the research of sandy soil and finely fissured rock. A large number of experimental results show that the penetration is proportional to the first power of friction head loss during the small seepage velocity. Its expression is:
| (1) |
where Q: permeate flow; ω: cross section of water; L: penetrating path; V: seepage velocity; K: permeability coefficient; I: hydraulic gradient; H1 and H2: upstream and downstream cross section.
2.2 Water balance
Water balance is the area or water of any choice in any period of time; the difference between the amount of water income and the amount of water consumption will be equal to the amount of change impoundment period in the area or in the water (Zhang, 2014). Since the 1960s, because of the development of the need of water resources, many scholars have gradually sh...
