In the town Valmiera of Latvia, the abandoned former black fuel storage area was not inspected before on the area contamination and its effect on the quality of groundwater at the storage environs. In 2016-2017, the storage area was investigated. In 2017, the quality of groundwater in the area environs was estimated and the oil contamination migration was explored by means of numerical modelling. The local hydrogeological model (HM) was developed jointly by specialists of the Latvian Environment, Geology and Meteorology Centre and Riga Technical University. The model was created by extracting information from the HM of Latvia LAMO4 and by supplying and reshaping its regional data by detailed information on the model area. The results of modelling ensure that in the closest storage area environs the groundwater quality has been only slightly worsened and no pollution of the nearby river should happen. Methods of developing and using the local hydrogeological and contaminant migration models may be useful for specialists dealing with groundwater contamination problems.