By definition, a lake really is just another component of Earth's surface water. A lake is where surface-water runoff (and maybe some ground-water seepage) have accumulated in a low spot, relative to the surrounding countryside. It's not that the water that forms lakes get trapped, but that the water entering a lake comes in faster than it can escape, either via outflow in a river, seepage into the ground, or by evaporation.
The Earth has a tremendous variety of freshwater lakes, from fishing ponds to Lake Superior (the world's largest), to many reservoirs. Most lakes contain fresh water, but some, especially those where water cannot escape via a river, can be salty. In fact, some lakes, such as the Great Salt Lake, are saltier than the oceans. Most lakes support a lot of aquatic life, but the Dead Sea isn't called "Dead" for nothing -- it is too salty for aquatic life! Lakes formed by the erosive force of ancient glaciers, such as the Great Lakes, can be thousands of feet deep. Some very large lakes may be only a few dozen feet deep -- Lake Pontchartrain in Louisiana has a maximum depth of only about 15 feet.
In one of the towns in Malaysia, the man-made lake had provided beautiful sights and people have been using the lakes as a recreational area and getting fresh air. Photographs below try to explain why it is so.Lake Garden AA