This report specifies different two-dimensional benchmark environments for estimating active sonar performance in Swedish shallow waters, where active sonars are often limited by reverberation. The purpose of these environments is to be able to consistently evaluate and compare the performance of different active sonars. Four generic shallow water areas and one reference blue water area are specified as follows: One area corresponding to the Stockholm archipelago, with a range dependent seabed. Two areas corresponding to the Baltic Sea, one with a flat, soft seabed, one with a range dependent seabed. One area corresponding to the Swedish west coast, with a flat, soft seabed and high salinity. One blue water area corresponding to a deep ocean with a high salinity. Every generic area is accompanied by two sound speed profiles, one summer profile and one winter profile. Finally, one to three sonar depths are included for each typical area, evaluated for both sound speed profiles, resulting in a total of 24 cases. This report gives an overview of the benchmark environments, but avoids long tables of parameters that vary with depth and range. Instead, the data is attached to the report in digital format as .csv files. The environments are not given in enough detail to be suitable for use with low frequency passive sonar (below around 1 kHz), where shear waves and multiple sediment layers in the seabed have a significant impact on the sound propagation. To give an idea of how these benchmark environments can influence the performance of active sonars, an appendix is included. There the transmission loss and reverberation are illustrated for one lower frequency (2 kHz) and one higher frequency sonar (25 kHz).