This data represents LiDAR-derived breaklines for the Milwaukee Metropolitan Sewerage District (MMSD) in 2021. It was derived from the original point cloud (LAS) collected in 2020. Hydro breaklines maintain the definition of water-related features in an elevation model. They are used to capture linear discontinuities in the surface, lake shorelines, single-line drains for small rivers, and double-line drains for large rivers.