Tapei and San Jose, CA have done similar river-widening projects, without the island. Both have parks along a river flood plain, parks that are intended to be flooded during unusually wet periods. Taiwan's riverside park [1] is on both sides of the main channel of the Tamsui River. The edges of the park have high walls to protect the city. Guadalupe Park and Gardens in downtown San Jose[2] is a smaller example of the same concept. In both cases, the parks will take damage when flooded, so they only contain things that can handle flooding or easily replaced.<p>[1] <a href="https://www.google.com/maps/place/Taipei,+Taiwan/@25.030306,121.457588,3a,75y,297.12h,86.69t/data=!3m5!1e1!3m3!1sVIlj4GTR58deSaBJENnGCg!2e0!3e5!4m2!3m1!1s0x3442ac72bce20a99:0x3f6a35cedd0ac2e0!6m1!1e1" rel="nofollow">https://www.google.com/maps/place/Taipei,+Taiwan/@25.030306,...</a>
[2] <a href="http://www.grpg.org/river-park-gardens" rel="nofollow">http://www.grpg.org/river-park-gardens</a>