Verification of and Expansion Upon the Use of Cave Scallops in Recreating Hydrogeologic Conditions in Karst Aquifers

Hall, Andrew; Springer, Gregory S.

doi:10.1130/abs/2018am-323139

Cited by 1 publication

(3 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Monte Carlo simulations were run in R using for statements and the built-in sample() function. The R scripts can be obtained from the corresponding author and the data are available as a supplemental table in the appendices of Hall (2019).…”

Section: The Equation For An Elliptical Cross Section Ismentioning

confidence: 99%

“…We also measured 60 samples of scallops in active stream passages of three nearby caves. Sample sizes were from 30 to 40 scallops and 57 of the 60 sets are log-normal (p > 0.05) (Hall, 2019). But given the wide range in scallop lengths commonly observed in field data a large sample size is recommended to adequately test for log-normality because the Wilks-Shapiro test is sensitive to the tails of a distribution.…”

Section: The Equation For An Elliptical Cross Section Ismentioning

confidence: 99%

“…We explore the effect of sample size using Monte Carlo simulations to sub-sample 100 scallop measurements with n ranging from 10 to 30. An upper limit of 30 measurements was chosen because such samples are generally log-normal and, therefore, presumably reflective of the population they were drawn from (discussed below) (Hall, 2019). And, from a practical standpoint, 30 measurements are believed to balance time, discomfort of some cave environments, and other practical considerations.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Uncertainties associated with the use of erosional cave scallop lengths to calculate stream discharges

Springer¹,

Hall²

2020

IJS

Self Cite

View full text Add to dashboard Cite

Scallops are extremely valuable indicators of past water flows in caves because they often record events that cannot be safely witnessed nor measured. Qualitatively, the inverse relationship between their lengths and formative water velocities is useful for determining how flow changes along a cave passage, but they are most valuable because they can be used to directly estimate actual water velocities and discharges. We explore the effects of sample size, measurement choices, and other methods commonly applied to the use of cave scallops in estimating cave stream velocities and discharges. We measured 100 scallops on a cave wall and find them to be log-normally distributed. We used Monte Carlo simulations to sub-sample the 100 scallops for sample sizes of 10 to 30. As expected, smaller sample sizes yield widely varying means with precision increasing slowly with sample size. A sample size of 30 results in greater than 50% of simulated means falling within one standard deviation of the mean for all 100 scallops. This is also true of sample sizes as small as 20, so we recommend a minimum of 20 to 30 scallop measurements in the field. The formulas we use to estimate water velocities and discharges explicitly use the Sauter mean of scallop lengths, but some authors use the arithmetic mean. We simulated the use of both the Sauter and arithmetic means and find that the latter yields substantially larger velocities and discharges. We recommend use of the Sauter mean because that is consistent with the original formulations and the arithmetic mean may cause significant overestimation of velocity and discharge. cave, scallops, karst hydrology, stream, water

show abstract

Section: The Equation For An Elliptical Cross Section Ismentioning

confidence: 99%

Section: The Equation For An Elliptical Cross Section Ismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation