The DREAM model, originally developed as a biology-based exposure and effect assessment model for fish and zooplankton, can be applied to calculate the potential risk on the sediment in addition to potential risk in the water column from discharges from production and drilling activities. It includes calculation procedures for both the EIFPW and the EIFDD, which are based on scientifically sound and internationally agreed principles for hazard and risk assessment. Both EIFs are developed along the same lines, defining water volumes and sediment areas with risk > 5%.

DREAM calculates the physical-chemical fates of the various compounds in the discharges in three spatial dimensions and time. The model includes processes like near-field mixing, dilution in the sea due to currents and turbulence, and biodegradation of organic compounds in the discharge. The model can include hundred compounds simultaneously in the discharge and multiple release locations.

The model also computes deposition of particulate matter on the sea floor, including chemicals that are attached or adsorbed to particulates. In the sediment, the deposited matter is subject to bioturbation and biodegradation.