Horizontal hydraulic conductivity (K_h) of the Surficial aquifer at the different sites was estimated by three methods: calculations based on sieve analysis results of unconsolidated samples, steady-state air permeability tests on limestone cores, and slug tests. The permeability tests also directly estimated vertical hydraulic conductivity (K_v). K_v also was mathematically inferred from sieve and slug test results (Walton, 1987). Hydraulic conductivity (K) of the peat was determined using bail tests from drive points, seepage meter data, and head data from drive points and surface water (Harvey and others, 2000).

Hydraulic conductivity was calculated for the unconsolidated samples obtained from six boreholes, using a software program by Vukovic and Soro (1992). This approach determines K_h by averaging the results of 10 different calculations of conductivity. Resulting K_h estimates for unconsolidated samples ranged from 5.9 to 510 ft/d. Detailed results for each borehole are listed in Harvey and others (2000, p. 132-145).

Permeability tests were conducted on 16 core samples from the ENR and 11 samples from WCA-2A (Core Laboratories, Inc., 1999). Porosity and vertical and horizontal hydraulic conductivity were determined. The minimum, maximum, and average horizontal hydraulic conductivity values for all sites ranged from 0.02 to 510 ft/d. Detailed results from ENR core samples are provided in Harvey and others (2000) while data from all WCA-2A sites are presented in table 6.

Core samples from the ENR boreholes generally were limestone with varying amounts of sand. One sample at MOP1 was cemented limy sand. The majority of samples were moldic, had pinpoint porosity, and contained a variety of fossils. The total porosity of these ENR samples ranged from a low of 9.4 percent in a shallow layer at MP3 to a high of 32 percent in a deep layer in the same borehole. The geometric mean of all porosities in the ENR samples was 17 percent.

The K_h of the core samples from ENR ranged from less than 0.02 ft/d to about 510 ft/d, with a geometric mean of 31 ft/d. This mean value is much higher than the average reported K_h of limestone of 5.9 ft/d (Kasenow, 1994). The K_v of the sediments ranged from 0.002 to 3400 ft/d with a geometric mean of 7.5 ft/d. This value is slightly higher than the reported average K_v of 3.1 ft/d (Kasenow, 1994). The ratios of vertical to horizontal hydraulic conductivity (K_v/K_h) ranged from a minimum of 0.002 to a maximum of 8, with a geometric mean of 0.2. The mean ratio of 0.2 is slightly lower than the average value reported for limestone (0.5) by Kasenow (1994). Because of this lower K_v/K_h ratio, the preferential flow is more likely to be horizontal where the consolidated material is present.

Cores from WCA-2A primarily were limestone with varying amounts of sand. One sample at U1GW3 contained very fine limy sand. Limonite, formed by oxidation of iron-bearing minerals or by precipitation in bogs, was seen in shallow samples at E4GW3 and F4GW3. Fossils were found in most samples and pinpoint porosity was seen at sites F4GW3 and S10C. About half the samples were moldic or showed rootlets. The porosity of WCA-2A samples ranged from 10.9 percent between -3 to -8 ft NGVD (E4GW3) to 31.3 percent at -20 to -25 ft NGVD (U3GW3). The geometric mean of all porosities in the WCA-2A core samples was 19.6 percent.

The K_h of the cores ranged from 4.1 ft/d to nearly 502 ft/d, with a geometric mean of 63 ft/d. This geometric mean is an order of magnitude larger than the mean published value of 5.9 ft/d (Kasenow, 1994). Likewise, K_v of the cores ranged from 6.1 to 430 ft/d with a geometric mean of 26.4 ft/d, an order of magnitude larger than published averaged values. The ratios of vertical to horizontal hydraulic conductivity (K_v/K_h) ranged from 0.04 to 3.5 with a geometric mean of 0.4. The mean ratio of 0.4 is similar to the mean values calculated for limestone (0.52) using data from Kasenow (1994).