I hope the experts involved with plans for a park-like naturalizing of portions of Arroyo Seco aren't too optimistic and have read their history. What if another "100-year" flood such as that in 1938 comes along?
As a Los Angeles Times reporter in 1938, I saw the power of the scoffed-at Los Angeles River, which tossed boxcars to spots 60 to 90 feet above their tracks in the usually dry riverbed--especially in the area where the Arroyo Seco (hardly seco then) added its force near Elysian Park and the battered Broadway bridge.
Still later, after flood control channels had been constructed, as a reporter I've accompanied many politicians along the riverbed as they got free publicity by explaining their latest schemes for utilizing the channel for new rail or freeway routes.
Not too curiously, the U.S. Corps of Engineers and others aware of the sensitivity of the hydraulics involved always seemed to lag behind, less than enthusiastic and never approving the latest plan.