Project Description
ISWS has been working on a water resource project with the Illinois Department of Transportation (IDOT) in the East St. Louis, IL area since the 1980s. Historically, this project has been predominantly focused on the regional groundwater, as rising groundwater levels (rebounding from diminished industrial withdrawals) threaten to inundate major interstate thoroughfares through East St. Louis, IL. As such, a dewatering system, comprised of more than 40 wells spread along roadsides in the municipality, removes an average of more than 10 million gallons of groundwater and stormwater daily. Even with the substantial dewatering system, roadways in East St. Louis, IL often flood during major precipitation events, halting traffic and the associated interstate commerce.
For this project, our research team often provides consulting services for maintaining the efficiency and productivity of the wells. However, our team was recently asked, “Hypothetically, what would happen if the dewatering system were to lose power? And, what if that happened while it was raining?”
This immediately piqued our interest. Any models constructed to analyze this question would require accounting for numerous hydrologic factors, including groundwater recovery, precipitation infiltration, precipitation recharge to the aquifer, overland runoff, shallow groundwater return flows, antecedent groundwater and soil conditions, and anthropogenic hydrologic factors (e.g., canals and culverts to divert floodwaters).
We are currently building a model to account for all these hydrologic processes to provide managerial solutions for preparing for and handling these complicated hydrologic situations. Eventually, with a fleshed-out model of the surface water–groundwater interactions along these roadway corridors, we hope to provide a tool to optimize the efficiency of the dewatering system and minimize any unnecessary impacts to the surrounding water resources. The work by ISWS scientists not only preserves infrastructure and commerce; understanding the integrated hydrological processes and resulting risks has the potential to save lives.
For one location, model results are presented below. In the presented results, all wells were pumping at 600 gpm, before being shutoff to monitoring the groundwater table rise. The pumping wells are turned off at time 00:00 in the gifs below. The roadway begins to flood from groundwater seepage as early as 15 hours after the wells are shutdown. However, significant flooding does not occur until closer to 20 hours after flooding. The colorbar for flooding in the gifs below begins at a quarter-inch of water depth above land surface up to one foot of flooded water above land surface. However, the maximum surface water depth observed in this simulation was 4.06 inches.
