1.   The oars had churned up the mud, clouding the water.

2.   Erosion, another byproduct of development, sends soil runoff into the lake, nourishing algae that further cloud the water.

3.   Other murk-producing particles that cloud waters include disintegrated material and bottom sand stirred up by turbulence, says Madin.

4.   Phosphorus, found in manure and fertilizer, feeds algae that cloud the water, blocking sunlight for fish-nurturing bottom plants.

5.   These can alter the balance of the water garden and cloud the water.

6.   They also eat up aquatic plants and cloud water.

7.   This method can block microscopic protozoa and viruses and remove particles that cloud water.

8.   While they live, these organisms can cloud the water, shutting off the supply of sunlight to larger aquatic plants.

9.   When trees are cut near streams, runoff can cloud the water and the lack of shade makes the streams too warm for salmon.