A convective flow is generated in the sidearm of a lake due to surface cooling. In this paper, steady, incompressible, and 2D Row in a horizontal sidearm having constant width is analyzed. The vertical acceleration terms and the variation of the temperature function along the sidearm (which were neglected in the previous studies) are considered. The equations governing the distributions of velocity and temperature were developed, then solved numerically by using a "shooting technique" and Runge-Kutta method. The numerical results were compared with the available field data for validation.