4 Modeling Surface Runoff , Groundwater Flow and their Interaction with PCSWMM and MODFLOW - for the City of Rostov the Great , Russia

The City ofRostov the Great (Rostov) is one of the oldest cities in the Russian Federation. Many buildings need to be restored due to advanced degradation of the wooden and stone foundations. This degradation and other environmental problems are in large part caused by high groundwater levels, which are in turn directly associated with human activity over the years. Technical analyses were completed for surface runoff and groundwater flow in order to define potential interventions to lower the groundwater levels. Surface runoff for the old part was modeled with PCSWMM, while the groundwater was analyzed with MODFLOW. The chapter describes the complex conditions that were analyzed, and different approaches to use the results from the surface runoff model as input to the groundwater model. The PCSWMMmodel was developed using the availableinfonnation on the drainage system and limited data for calibration gathered during one spring and one summer. For MODFLOW, the model was based on historical data on groundwater regime at different wells installed since 1977 as well as other wells put in place specifically for the project in 2000 and 2002. Different approaches to integration of the two models are discussed.