When it's in, the Middle Bosque makes for a great playboating run. Both
Texas Whitewater and local paddlers suggest 3.8' as the minimum runnable level (below that, you may be scraping bottom and/or walking.) Beta from paddlers suggests that the river generates a lot of play features below 5'. At higher levels, some of those features wash out, but the ones that are left become more optimal. Beta suggests that, above 9', river-wide waves form that are big enough for 3-4 boaters to surf simultaneously. The river is known to have been run-- and still playable-- as high as 13-14'.
Distance and gradient measured using GIS tools in 2015.