Complex sentence: By the first edition OS map the river had reached its current position, however it is apparent that some rivulets and inlets have been lost since, however, some have been identified in archaeological work on the site of the former House of Industry and gasworks.
Split into simpler sentences: By the first edition OS map the river had reached its current position. However, it is apparent that some rivulets and inlets have been lost since, although some have been identified in archaeological work on the site of the former House of Industry and Gasworks.