By Scott T. Prinos

CORRELATION ANALYSIS OF A GROUND-WATER LEVEL MONITORING NETWORK

Analytical Considerations

Seasonal Water-Level Variation

The seasonal pattern of rainfall, combined with the way in which the hydrologic system is managed in southern Florida, creates distinct differences in the water levels at monitoring wells in the wet and dry seasons. The seasonal variation in aquifer water levels depends on the hydrology and management of the area. The monthly variation in mean water levels and the variation in monthly standard deviation of water levels for wells G-620, G-864, G-1183, and S-18 are shown in figure 4. Some differences in water levels that occur seasonally at these wells include the: (1) timing of the transition from lowest to highest water level, with the lowest water levels typically occurring in May at well G-620 and in April at wells G-1183 and G-864; (2) extent of variation in mean monthly water levels, with mean monthly water levels and their standard deviation displaying less seasonal variation at well S-18 than at wells G-620, G-864, and G-1183; and (3) timing and extent of monthly standard deviation of water levels, with the monthly standard deviation of water levels being greater at well G-864 than at well G-620 from May to October, but the reverse being true from November to April. These seasonal differences in water levels, whether responding primarily to natural or anthropogenic effects, in turn, can affect the extent of correlation of the water-level data being compared.

Figure 4. Graphs showing seasonal variation in mean water levels and variation in monthly standard deviation of mean water levels for wells G-620, G-864, G-1183, and S-18. Link to larger version

The widely varying amounts of rainfall at differing locations that occur in southern Florida particularly during the wet season (fig. 3A and 3B) can have a direct effect on how well the water-level data from different monitoring wells correlate. Conversely, during the dry season, the allocation of water through the system of canals, control structures, and well fields can become an overriding factor in determining whether water levels at two different wells will correlate. Therefore, an important consideration is whether water levels at wells in the ground-water monitoring network correlate from season to season.

Next: Temporal Changes in Correlation Between Monitoring Wells