Ashburton River
... that the two branches of New Zealand's Ashburton River flow in parallel less than 3 kilometres (1.9 mi) apart for 20 kilometres (12 mi) before they join?
... that the two branches of New Zealand's <b id="mwDls"><a class="mw-redirect" href="./Ashburton_River_(New_Zealand)" id="mwDlw" rel="mw:WikiLink" title="Ashburton River (New Zealand)">Ashburton River</a></b> flow in parallel less than <span about="#mwt76" data-mw='{"parts":[{"template":{"target":{"wt":"convert","href":"./Template:Convert"},"params":{"1":{"wt":"3"},"2":{"wt":"km"},"3":{"wt":"mi"}},"i":0}}]}' id="mwDl0" typeof="mw:Transclusion">3 kilometres (1.9</span><span about="#mwt76" typeof="mw:Entity"> </span><span about="#mwt76">mi)</span> apart for <span about="#mwt77" data-mw='{"parts":[{"template":{"target":{"wt":"convert","href":"./Template:Convert"},"params":{"1":{"wt":"20"},"2":{"wt":"km"},"3":{"wt":"mi"}},"i":0}}]}' id="mwDl4" typeof="mw:Transclusion">20 kilometres (12</span><span about="#mwt77" typeof="mw:Entity"> </span><span about="#mwt77">mi)</span> before they join?