Sampling site As already ...

Sampling site

As already mentioned by previous contributors, the selection of sampling sites is directly dependent upon your monitoring objectives. If your objective is to assess general water quality or to track water quality trends, it could be argued that one station could be used to represent any lake. In most cases, a site over the lake's the deepest area best represents "average" conditions in the lake. Lake Malawi is a long lake, additional sites can be located in transect (line) along its midsection. In many cases, water quality differences will be noticeable between the transect sites. Avoid sampling near shore, near inflows, or in downwind areas (unless specifically targeting these areas to document worst case conditions.

Conversely, to characterize an entire lake, a large lake with a number of shallow bays, inflowing streams, or other distinguishing characteristics, you may need more than one station to provide an adequate characterization. 

To learn how the lake functions, stations in physically diverse locations and at different depths should be selected.

I refer you to the document attached.