Soil drainage is a relatively simple classification of the soil profile that describes the likelihood of seasonal wetness (Webb & Lilburne 2011). It is based on the occurrence within specific depths of redox segregation and low chroma colours indicative of waterlogging and reduction (Milne et al. 1995). This layer is a "dissolved" representation of the soil drainage attribute for S-map soils, where neighbouring S-map polygons have been combined if they have the same value of the attribute. Please refer to document Smap Data Dictionary Dissolved Layers.pdf at https://lris.scinfo.org.nz/document/22129-smap-data-dictionary-dissolved-layers/