Enhanced dispersion in groundwater caused by temporal changes in recharge rate and lake levels

✍ Scribed by Kangjoo Kim; Mary P. Anderson; Carl J. Bowser

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 611 KB
• Volume: 23
• Category: Article
• ISSN: 0309-1708
• DOI: 10.1016/s0309-1708(99)00050-0

✦ Synopsis

Dispersion of solutes in groundwater is caused mainly by spatial variation in aquifer properties (i.e., heterogeneity) but additional dispersion can be induced by temporal ¯uctuations in the ¯ow ®eld. We studied dispersion of an oxygen isotope plume in an aquifer in northern Wisconsin, where signi®cant ¯uctuations in the velocity ®eld are caused by temporal changes in recharge rate and lake levels. The enhanced vertical spreading caused by these transient eects was quanti®ed by tracking pathlines for approximately 32 years of simulated time in a transient cross-sectional model of the groundwater ¯ow system. In this system heterogeneity, ¯uctuations in recharge rate, and distance from the transient boundary stresses have a signi®cant in¯uence on the vertical transverse dispersion of the plume, while dispersion caused by ¯uctuations in lake levels alone have a relatively small eect.