Urban Drainage Mapping
Urban drainage consists of drains, ditches, culverts, tunnels, and other features that move water across the landscape. Mapping these features in sufficient detail to be useful for hydrological modelling is a new challenge for OSM.
A data model for drains can be seen at Dar es Salaam/Ramani Huria
A drainage mapping team needs measurement tools specifically for the dimensions of drains, as well as a method of recording the results. Ramani Huria has been using OpenDataKit (ODK) with the GeoTrace feature to record drain polylines, and has developed a set of physical tools for drain measurement.