About the research
The Iowa Department of Transportation (DOT) maintains a railroad underpass on Iowa 63 (E. Mullen Ave) in Waterloo between Dane and Newell Streets. This underpass is depressed below the natural ground surface, and below the existing groundwater table, which results in the potential for seepage from the groundwater into the underpass. To control this seepage the Iowa DOT installed and maintains a groundwater dewatering system that depresses the groundwater table at the underpass to below the underpass elevation. In the future, the Iowa DOT plans to replace the railroad underpass with an overpass, and fill in the existing underpass. It is unknown at present what impact this will have on the groundwater table at and in the vicinity of the existing underpass. The objective of this study is to provide technical assistance to the Iowa DOT Office of Location and Environment with regard to evaluating the possible impacts on the groundwater system in the vicinity due to the removal of the existing railroad underpass.
Phase I has been completed and the results indicated that the current field data is not sufficient to adequately define the zone of influence of the current dewatering system. Additional field data collection and modeling is needed to adequately define the impact of the current dewatering system on the groundwater table in the vicinity of the underpass. This information is critical to determining what, if any, dewatering system will needed, and to document any changes in the groundwater zone of influence with the change from an underpass to an overpass at US 63. The objective of Phase II is to collect the field data necessary to adequately define the zone of influence of the current dewatering system at the US 63 underpass.
Phase II will focus on the collection and modeling of field data to adequately define the groundwater surface in the vicinity of the site. In particular this will include: New groundwater monitoring wells: Additional groundwater monitoring wells are needed to better define the zone of influence of the dewatering system. The principal investigator (P l) will provide suggested locations for the new wells. The Iowa DOT will make the final selection and have the wells installed.