 One stipulation the USACE placed on the permit , however , was that no work in the Arkansas riverbed could take place after May 1 if it would interfere with the interior least tern nesting period , which was possible if the birds selected nesting sites around the bridge site . As a result , OTA worked to complete the bridge as quickly as possible to avoid the possibility of having to suspend the construction . By April 1991 , work in the riverbed was mostly complete , with the remaining work on the bridge posing no threat to the terns . 
