By Scott T. Prinos

CORRELATION ANALYSIS OF A GROUND-WATER LEVEL MONITORING NETWORK

Analysis Results

Results of a water-level correlation analysis can be used to aid in the evaluation of well redundancy. Table 3 lists each network well and the number of other network wells with data correlated at coefficient values that are 0.99, 0.95, and 0.90 or greater, on average, for the wet and dry seasons.

When arranged geographically (north-south and west-east), the correlation matrices (app. I and II) indicate several geographic areas where water-level data in many wells correlate to a high degree. The degree of correlation in the water-level data of network wells was almost always in excellent agreement with the spatial distribution of the wells. Wells that had highly correlated water-level data usually were near each other and/or influenced by the same hydrologic controls such as municipal well fields, canals, or drainage basins.

Examination of the GIS coverages of wet- and dry-season correlation revealed areas where wells could be spatially separated into groups for which the water levels from each well were correlated to those of one or more additional wells within the same group with an average coefficient of 0.95 or greater. For the wet and dry seasons, these groupings are depicted in figures 7 and 8, respectively. Differences between the wet- and dry-season spatial grouping are most likely indicative of seasonal differences in the hydrologic system.

Figure 7. Map showing grouping of wells based on average correlation of water-level data during the wet season. Link to larger version

Figure 8. Map showing grouping of wells based on average correlation of water-level data during the dry season. Link to larger version

To aid in the assessment of redundancy, it was necessary to identify wells that would be highly correlated to other wells during both the wet and dry seasons. Examination of the GIS coverages of correlation revealed five well groups where the water levels from each well were correlated to those of one or more additional wells within the same group with an average coefficient of 0.95 or greater during both seasons (fig. 9). Three of the five groups are located near the Hialeah-Miami Springs, Florida Keys Aqueduct Authority, and West Well Fields (fig. 9). The remaining two groups are located in or near the C-1 and C-102 basins and the C-6 and C-7 basins, respectively. The information for these well groupings is summarized in table 4.

Figure 9. Map showing grouping of wells based on average correlation of water-level data during both the wet and dry seasons. Link to larger version

Next: West Well Field