Many pages of the Codex Leicester are devoted to the quest for efficient solutions to prevent rivers from damaging embankments and bridge foundations and endangering the stability of weirs. Leonardo recommends that one should not contrast the flow of the current by violent means, but rather tame it by gradually altering its direction. He compiles a detailed list of the various types of erosion. He studies the accumulation of river-borne sediments that cause the emergence of temporary islands. Lastly, he analyzes the erosion generated by the confluence of two or more rivers with different discharges and flow rates.
A river which has to be diverted from one place to another should be coaxed and not coerced with violence.
Codex Leicester, f. 13r