SPATIAL AND TEMPORAL CHANGES IN HYDRAULIC CONDUCTIVITY IN CAVE SEDIMENTS FROM BEROME MOORE, PERRY COUNTY, MISSOURI

Hydraulic conductivity (K) from four hydraulically distinct locations within Berome Moore Cave (Missouri) were measured using the falling head method and calculated from grain size data using the empirical formula derived by Campbell (1985). These four locations are the edge of a perennial waterfall plunge pool, a clay and gravel point bar along the main cave stream, a stagnant conduit except when the main stream overflows, and a clay bank in a conduit that has evidence of “pipe-full” flow. Data were collected in February to October of 2006. Falling head K values for each area over the sampling period ranged from 3.04x10^-7 to 3.28x10^-7 m/s (standard deviation (σ) of 1.01x10^-8 m/s), 2.01x10^-7 to 2.17x10^-7 m/s (σ of 5.49x10^-9 m/s), 2.31x10^-7 to 2.45x10^-7 m/s (σ of 5.27x10-9 m/s), and 3.03x10-7 to 3.16x10-7 m/s (σ of 5.33x10^-9 m/s) respectively. The Campbell derived K values ranged from 2.07x10^-7 to 2.15x10^-7 m/s (σ of 5.90x10^-9 m/s), 1.44x10^-7 to 1.54x10^-7 m/s (σ of 3.99x10^-9 m/s), 1.26x10^-7 to 2.11x10^-7 m/s (σ of 3.26x10^-8 m/s), and 1.91x10^-7 to 2.38x10^-7 m/s (σ of 1.67x10^-8 m/s). The K values, both spatially and temporally, are with in one order of magnitude, suggesting that they are actually the same K. Statistical testing of these values suggests that they are significantly different, both in time and space. However, the small sample size of three points for each space and time, the large heterogeneity observed in the sediment piles, and the observation that the sediment piles were completely immobile over the course of the study makes this hard to confirm. The K values of 10^-7 m/s are in agreement with pervious studies on the hydraulic conductivity of cave sediments, which suggest that cave sediments can be modeled as part of the cave matrix which has hydraulic conductivity range of 1x10^-9 to 6x10^-6 m/s.