81.  Since surface water is so scarce, many people want to pump more water from underground aquifers.

82.  Surface aerators have vanes or propellers that draw up the surface water and allow it to fall back.

83.  Tetra Tech, a small, fast-growing company, specializes in the analysis of complex ground and surface water contamination problems.

84.  That creates an instability in which surface water begins to sink, displacing the deeper water that is heavily charged with carbon dioxide.

85.  That makes it safer to spread on fields as fertilizer, and should reduce the contamination of surface water and underground springs caused by hog operations.

86.  Surface waters in the eastern Atlantic are still relatively cool in early July, an unfavorable environment for tropical storms.

87.  That is because the chilled surface waters of the southern ocean sink to great depths, where they can remain for centuries.

88.  The accident, however, certainly illustrates how unforgiving a surface water can be.

89.  That way the lawn gets a good soaking, but when the sun rises it quickly burns off the excess surface water.

90.  The complaint also charges that the company failed to properly contain wastewater run-off and violated state surface water quality standards.