Fish passage structures that simulate natural stream characteristics, or nature-like fishways, have begun to be recognized as economically and ecologically viable alternatives to traditional technical fish ladders on lakes and rivers with barriers to anadromous fish migration. However, little research has been done on the specific hydraulics and passability of these unique structures. The design approach is still in its infancy, and has not been readily accepted as a proven fish passage approach in the United States. This project is an effort to fill in some of the gaps in hydrologic research on nature-like fishways. Detailed field measurements were taken at two recently constructed nature-like fishways on Guilford Lakes, in Guilford, Connecticut, and on the Sennebec River, in Union, Maine. The project produced maps of the diverse velocity cross-sections of these two fishways. These results were then compared with the acceptable velocity ranges of a variety of riverine resident and migratory fish species, in an attempt to demonstrate the versatility of these fishways as compared with traditional fish ladders.