Teddington is situated on the north bank of the River Thames, and its large lock (1912) marks both the North Sea tidal limit on the Thames and the upstream limit of the jurisdiction of the Port of London Authority.
It is enough that the upstream limit of the solution is available.
In the Douro estuary, freshwater inflow is regulated by an electric power dam that represents its upstream limit.
Near the charge edge, the sonic locus is always tangential to the upstream limiting characteristic of the rarefaction fan.
Yangtze River effects are attenuated in the Lake with distance from the River, but nonetheless propagate some 100 km to the Lake's upstream limit.
Netham Lock in east Bristol is the upstream limit of the harbour.
It is the first lock east of Netham, the upstream limit of the Floating Harbour, beyond the suburbs of the city of Bristol.
Transverse DBs are distributed across the entire ash body but dominate at the upstream limit.
Lunate DBs occur in the middle and lower part of the ash body but are absent near the upstream limit.
A clear evolution of the DB type is visible: At the upstream limit (SW), only large transverse DBs outcrop, organized in train with the sharp onset of the ash body (the only transverse DBs observed in train).
The system can measure the shockwave from an accident, for example, and automatically reduce upstream speed limits to prevent an accordion effect of stop-and-go traffic.
