National River Flow Archive
The UK National River Flow Archive serves daily streamflow data, spatial rainfall averages and information regarding elevation, geology, land cover and FEH related catchment descriptors.
There are currently data APIs under development that provide access to the following services:
metadata catalogue (JSON),
catalogue filters based on a geographical bounding-box,
catalogue filters based on metadata entries,
gauged daily data and catchment mean rainfall for about 400 stations (WaterML, the OGC standard used to describe hydrological time series).