H

highways agency
The government agency responsible for strategic highways, ie motorways and trunk roads

highway authority
A local authority with responsibility for the maintenance and drainage of highways maintainable at public expense.

highway drain
A conduit draining the highway. On a highways maintainable at the public expense it is vested in the highway authority.

hydrograph
A graph illustrating changes in the rate of flow from a catchment with time

HOST (Hydrology of Soil Types)
A classification used to indicate the permeability of the soil and the percentage runoff from a particular area