A 70 m long beach is located in the Uboka cove on the western cost of the Rijeka bay. From 2 January to 12 April 2012, 11 measurements of the beach topography were performed by applying the-from-Motion (SfM) photogrammetry which generated 3-D point clouds of high precision and resolution. The applied methodology facilitated an inexpensive and fast survey of geomorphological changes. Significant changes in the beach body were recorded, caused by the interaction of wave action and surface water and groundwater discharges and leading to the beach erosion through a formation of channels within its body. After water discharges the beach quickly recovered and resumed its original form through the wind wave action. The cahnnel position was quickly replaced by the beach berm, followed by a stable, high berm. In the case of channelled torrential watercourses on the beach, a significant increase in the velocities occurs in comparison to the natural runoff, as described in this paper, and leading up to potential permanent beach erosion.