In 2012, the Swedish fortification agency started an environmental program for their real estate in northern Sweden. For the Boden garrison this meant an evaluation was needed for their storm water handling. The evaluation fell upon Grontmij AB in Boden. This thesis concerns the pollution from the storm water pipes into its recipient Lule River. Its aim was also to evaluate the areas for the event of a bigger oil spill, since there are many mechanical garages within the garrison. The pollution concerning oil was evaluated by calculating the flow in each outlet into the river, with different rain intensities. For other pollutants, the volumes of storm water each year, for every outlet were calculated. With concern for the snow melting process, it was also calculated for which period of the year would be interesting to keep an extra watch for pollutant concentrations and maximum flows. Results showed that for a 50-year period, none of the years would have had their peak flow because of the snow melt. The results for evaluation of an oil spill showed that none of the outlets were equipped for an accident of such sort, should it coincide with a rainfall of a high intensity. The results also showed that one of the outlets had an oil trap only dimensioned for rainfall of the lowest intensity. The calculating of pollutant volumes raises the concern for reliable data, but measures have already been taken to meet this concern.