| Groundwater circulation wells (GCW) create three-dimensional circulation patterns within aquifers by drawing water into the bottom of the wells, pumping the water through the wells, and reintroducing the water into the aquifer at a different level. A "permeable reactive barrier" (PRB) for preventing migration of a contaminant plume can be designed by installing an array of GCWs packed with reactive media. The required well spacing depends on the hydraulic capture zone for each well, which will be related to the circulation pumping rate and the aquifer hydraulic conductivity. In this study, a combination of groundwater flow and particle tracking modeling (using the MODFLOW and MODPATH software packages) was used to illustrate the effect of hydraulic conductivity, well spacing, and pumping rate on hydraulic capture efficiency. Model simulations were performed for rows of 1 to 10 GCWs in aquifers with hydraulic conductivities representative of sand and gravel, fine sand, and silt. |
