Riparian:
: relating to or living or located on the bank of a natural watercourse (such as a river) or sometimes of a lake or a tidewater
riparian trees [Merriam-Webster]
Noted in “Egypt will ‘uphold and protect its inherent right to life,’ FM Shoukry tells UNSC,” Dina Ezzat, ahramonline:
“This is a situation that Egypt cannot, and will not, tolerate,” [Egyptian Foreign Minister] Shourky said [to the UN Security Council]. He added, “Otherwise, if its riparian rights are jeopardized or if its survival is imperiled, Egypt will be left with no alternative but to uphold and protect its inherent right to life that is guaranteed by the laws and customs of nations and the imperatives of nature”.
The top Egyptian diplomat commended the statement that the European Union issued Thursday to express worry over Ethiopia’s execution of the second filling of the reservoir of the GERD in the absence of an agreement among the three concerned riparian countries. He called on the members of the UN Security Council to issue a similar statement and to adopt a draft resolution that Tunis had tabled to call on the three countries to resume negotiations under the AU umbrella in good faith and with a plan to reach an agreement in a reasonable timeframe.
The waterway in question is the Nile River. More here.