You can measure various geometrical things about lakes:
- area of water surface
- water volume
- maximum depth
- shoreline length
- lake length: this is equal to shortest distance through the water surface between the most distant points along the shore (Figure 5-2). This gets tricky when lakes have complicated surface geometry.
- lake breadth: this is equal to the length of a line perpendicular to the length defined above, at any point; the mean breath is equal to the area divided by the length (Figure 4-2).
In plan view, lakes range from equidimensional or irregular to very elongated. In certain special situations lakes are approximately circular—for example, kettle lakes (see Chapter 5).
In cross section, lakes are usually much wider than they are deep, especially large lakes. Small lakes are often deeper relative to their width than large lakes.
Figure 4-2. Length and breadth of a lake.
Table 4-1 gives some data about several well-known large lakes around the world.
Table 4-1. Data on large lakes of the world.