In the 1800s the river was dammed to give at least 3.05m of water to Stourport* by a series of weirs. Going downstream these are: Lincomb (2.44m of water over lock cill, 7m lock chamber depth, built 1844*); Holt (2.44m, 7m, 1844*); Bevere (2.44m, ?, 1844* or 1846*); Diglis (?, ?, 1844*); Upper Lode/Tewkesbury (2.74m, ?, 1844* or 1858*) (note, this is sometimes confused as Lower Lode); and Gloucester (?, 7.5m, 1812 and then 1827*) (by comparision, the more coastal *Sharpness Lock, which doesn't take the river navigation, has a cill depth of 6.71m*). You can read about the background to this on Chris Witt's site.
Above Stourport there are now rapids, first appearing as you move upstream at Eymore and Highley*. These are likely to be natural, though note that water is extracted from the system above them today* and the river flow is strongly controlled by the Clywedog dam*. Above this navigability is limited for larger boats, though there are weirs, for example, at Shrewsbury.