The aim of this thesis is to understand the morphologic changes to a set of historically braided rivers that have been narrowed. Braided rivers from the agriculturally developed Canterbury Plains, New Zealand, were studied from a period prior to much development (mid-1900s) to the present. Narrowing of channels, decreased braiding intensity, and loss of braided planforms were determined based on aerial imagery, changing the geography of braiding along all rivers. Channel width and count were statistically correlated and show the predictability of braiding change based on narrowing. Reaches with initially wide channels require more narrowing to induce a simplification of braiding, while narrower reaches may be closer to a threshold of change and require less narrowing to transition. The implications of the results can be used in river management to create wide enough river corridors that allow the rivers to maintain their naturally braided planforms while mitigating flood risk.