Analysis of Canal Pumping Test Adjacent to Everglades National Park Using a One-Dimensional Flow Model Considering Storage and Skin Effect in a Finite-Width Sink

A solution in which drawdowns are calculated in a one-dimensional leaky aquifer subject to a specified discharge pumped from a canal was used to determine properties for the Biscayne Aquifer adjacent to the Everglades National Park in southeastern Florida, U.S.A. This solution, in which a Laplace-space solution for drawdowns is inverted numerically to the time domain, considers the effects of the discharge being partly derived from storage in a finite-width canal and the additional resistance due to canal sediments expressed as a skin effect. In this application, the discharge from a length of the L-31N canal was maintained at a nearly constant rate during a canal pumping test, and groundwater levels were measured in monitoring wells adjacent to L-31N. A match-point procedure was used to calculate values for aquifer and canal parameters using drawdown data from the monitoring wells. At well MW-2, which is located 640.1 m west of L-31N, values for transmissivity and storativity were determined to be T = 2.31 x 10⁵ m²d^–1 and S = 0.20. During the test, the Biscayne Aquifer in the vicinity of L31-N and well MW-2 was unconfined, and there was no vertical leakage from overlying ponded areas into the aquifer. Thus, leakance K'/b' = 0. The coefficient for skin friction, which is the ratio of the hydraulic conductivity of the Biscayne Aquifer in the vicinity of L-31N divided by the leakage coefficient for sediment deposits in L-31N, was S_k = 156.8 m. For this analysis at well MW-2, the effects that pumping from storage in the canal and the skin effect due to canal sediments had on aquifer drawdowns were small, but significant. For wells closer to L-31N, the effects of pumping from storage in the finite-width canal and the skin effect were greater.