Date of this Version
The municipal wellfield for Lincoln, Nebraska, consists of 44 wells located adjacent to the Platte River near Ashland, Nebraska. The herbicide atrazine was monitored in the river and two transects of monitoring wells. The amount of atrazine transported down the Platte River in 1989, 1990, and 1991 was shown to increase each year. Induced recharge from the Platte River results in movement of atrazine from the river into the aquifer. A 21-day lag time was determined for the movement of atrazine from the river to a transect of monitoring wells 10 feet west of the bank. The role that colloids play on the transport of atrazine was determined to be insignificant. A small percentage of atrazine found in the river was determined to come from rain water. The infiltration of agrichemical-contaminated river water was shown to significantly reduce the quality of raw water and finished water being produced by the adjacent aquifer.