Downspout drainage with nowhere to go

Where or how can I drain this downspount? I have a downspout that on 3 sides has a hard barrier and the 4th is the stairs to the sidewalk. Everything is very flat. The only idea I've had is to run a 2 inch pipe to the bottom of the stairs but I don't want it to wash out the retaining wall or drain onto the sidewalk, which is against city code.

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