RESEARCH OF SCALE-DEPENDENT DISPERSION THROUGH CONVERGENT FLOW TRACER TESTS AT THE TTAAN ISLE, GIMHAE CITY, KOREA

Convergent flow tracer tests for 2 m (IW-1 well) and 5 m (IW-2 well) of test scale were conducted at the alluvial aquifer with high permeability and very much storativity. Pumping rate for convergent flow tracer tests were 2,500 m3/day, and chloride (5 kg) were instantaneous injection in IW-1 and IW-2 wells. Using concentration breakthrough curves for chloride, differences of first arrival time and peak concentration were analyzed. Recovered ratios of chloride mass were analyzed by recovered cumulative mass curves. And, Increment and decrement for chloride concentration were analyzed through chloride concentration versus recovered cumulative mass ratio graphs. Also, increment and decrement ratios of chloride concentration were estimated through linear regression analyses for increment and decrement intervals of chloride concentration. Longitudinal dispersivities were estimated by "Converging Radial Flow with Instantaneous Injection" method using CATTI code. Longitudinal dispersivities estimated by CATTI code were 0.4152 m between pumping well and IW-1 well, and 3.2665 m between pumping well and IW-2 well. Longitudinal dispersivity with distance from pumping well was more highly, and ratios of distance and longitudinal dispersivity were estimated 0.21 between pumping well and IW-1 well, and 0.65 between pumping well and IW-2 well.