Estimation of Aquifer Transmissivity From Analysis of Long-Term Monitoring With the Thiem Solution.

The application of the Thiem equation to support the interpretation of comprehensive long-term monitoring datasets, made possible through modern datalogging technology, is presented as an alternative to constant-rate aquifer testing to obtain representative transmissivity estimates in settings where controlled hydraulic testing may be impractical. Water levels logged at regular intervals can be readily converted to average water levels over time periods corresponding to periods of known pumping rates. By regressing average water levels during multiple time periods of known but variable withdrawal rates, steady-state conditions can be approximated and Thiem's solution applied to estimate transmissivity, without performance of a constant-rate aquifer test.

Rapid Cleanup of a Perchlorate Plume from Fireworks.

Perchlorate was detected in a municipal wellfield in Evart, Michigan in April 2015. Perchlorate concentrations were detected initially in six of the City's wells at concentrations ranging up to 20 μg/L. An investigation to identify the source determined that the perchlorate was from fireworks launched during the annual 4th of July show held at the fairgrounds located upgradient from the wellfield.