If you want to be successful as a trader you have to identify the characteristics that make certain markets different from others and trade strategies that are suitable. Yes, you can use Donchian channels on intraday/swing trading timeframes - but not on markets that are strongly mean reverting as was previously mentioned. If you really are limiting yourself to indices, you should just forget about Donchian channels intraday - not doable.
Or perhaps, the Turtles were just lucky: http://www.automated-trading-system.com/turtles-just-lucky/ If it won't work with a stock that is "mean reverting" (such as the indexes apparently?), why not just fade it, then. Intraday.