Hydrology J. Sahlberg and Earth System Sciences, 7(3), 268–282 (2003) © EGU Physical modelling of the Akkajaure reservoir

• Main Author: J. Sahlberg
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: temperature profile; reservoir; 1-D lake model; stratification. Sweden; Luleälven; Northern Sweden
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.371.8636; http://hal.archives-ouvertes.fr/docs/00/30/47/78/PDF/hess-7-268-2003.pdf

This paper describes the seasonal temperature development in the Akkajaure reservoir, one of the largest Swedish reservoirs. It lies in the headwaters of the river Luleälven in northern Sweden; it is 60 km long and 5 km wide with a maximum depth of 92 m. The maximum allowed variation in surface water level is 30 m. The temperature field in the reservoir is important for many biochemical processes. A one-dimensional lake model of the Akkajaure reservoir is developed from a lake model by Sahlberg (1983 and 1988). The dynamic eddy viscosity is calculated by a two equation turbulence model, a k–ε model and the hypolimnic eddy diffusivity formulation which is a function of the stability frequency (Hondzo et al., 1993). A comparison between calculated and measured temperature profiles showed a maximum discrepancy of 0.5–1.0 o C over the period 1999-2002. Except for a few days in summer, the water temperature is vertically homogeneous. Over that period of years, a weak stratification of temperature occurred on only one to two weeks a year on different dates in July and August. This will have biological consequences.