Lake Macalania is one of the two areas that make up Macalania with the second of those areas being Macalania Woods. You will need to pass through this area on your way to Macalania Temple.
For first time players it can be difficult to distinguish between the various areas of Macalania, but Lake Macalania is easily recognizable as any of the areas with snow or near the frozen pools of water. You will first reach Lake Macalania when you reach Rin’s Travel Agency (shown in the screenshot above).
Refer to the walkthrough and strategy guide section for more information passing through this area and defeating the Crawler enemy that the Al Bhed throw your direction: