To begin to address pollution prevention or remediation, we must understandhow surface water and groundwater interrelate. Groundwater and surface waterare interconnected and can be fully understood and intelligently managed onlywhen that fact is acknowledged. If there is a water supply well near a source ofcontamination, that well runs the risk of becoming contaminated Figure 2.For example, both water and certain contaminants flow in the direction of thetopography from recharge areas to discharge areas. Soils that are porous and permeable tend to transmit water and certain types of contaminants with relative ease to an aquifer below. Just as groundwater generally moves slowly, so do con- taminants in groundwater. Because of this slow movement, contaminants tend to remain concentrated in the form of a plume Figure 3 that flows along the samepath as the groundwater. The size and speed of the plume depend on the amount and type of contaminant, its solubility and density and the velocity of the surrounding groundwater.