Under construction.

Polish map does not show any referance to any BYUA canal near the tripoint.   (Geoportal.gov.pl, 2010).

Another, but older Polish map.  The BYPL boundary seems never to flow together with the Canal Moscickogo (Polish name), but seems to follow just south of the canal. (General Staff map, sheet M-34-024-A "Wlodawa", 1987.)

Byelorussian map. The BYUA boundary seems not to flow together with the canal.

Ukrainian map. Here the BYUA is clearly south of the canal.  (Volins'ka oblast 1:200.000, VKF TS ZS, 2007.)

Soviet map, showing the position of bordermarker 1123 next to the tripoint. PLUA numbers seems to follow an other system as the PLSU (Polish - Soviet Union). The BYUA is south of the canal.