List of Roman canals
Germania
Table:
Construction date

Connection

Canal type

Comment

Refs.

12 BC

Rhine–Yssel (Fossa Drusiana)

Inland to coast

For quick deployment of troops to the Frisian coast, avoiding the dangerous passage on the North Sea off the mouth of the Rhine; 14 km long

[8][9][10]

c. 9 BC

Rhine dyke

Inland

Built by Drusus the Elder to retain sufficient water to navigate his Fossa Drusiana; demolished by revolting Civilis in 70 AD

[8]

47 AD

Rhine–Meuse (Fossa Corbulonis)

Inland

Allowed to navigate both rivers without sailing into North Sea; c. 35 km long

[8][10]

Per the details in the tabular data covering 'List of Roman canals' in the 'Germania' section, compose one sentence describing only the highlighted cells and format it within the following JSON object {"answer": "YOUR ANSWER"}.