Modelling of dissolved oil product migration in groundwater at the former

ABSTRACT: To estimate the risk caused by migration of dissolved in groundwater jet fuel products to the Daugava river, the 3D-hydrogeological model (HM) has been created for the former Rumbula airbase. The nearby Getlini waste disposal site is also included. Due to a bioremediation, only a small part of fuel reaches Daugava. Contaminants coming from Getlini are mostly caught by two ditches falling into this river. 1 CASE HISTORY The former Rumbula airbase was selected as the pilot site for the project Cooperation between Latvia and Denmark on transfer and know-how concerning investigation and remedy of oil pollution in groundwater. The airbase is located not far from the centre of Riga. The sandy aquifer of the site is contaminated with im-miscible and dissolved jet fuel products (subsequently referred to as oil). The airbase was operational over a 25-year period and was shut down in 1978. The project commenced in 1996 and was performed by the Hedeselskabet from Denmark, the VentEko Ltd., and the Environment Modelling Centre (EMC) of the Riga Technical University from Latvia. Presently, only investigations regarding the immiscible oil products are completed and recovery of free oil is on-going. The following research studies have been performed (Report 1996, Report 1998, Report 2000): • six oil plumes (b6, b9, b12, b15, b23, b34) were identified (Fig. 1) and volumes of the contaminate