Article 12
Notification concerning planned measures with
possible adverse effects
Before a watercourse State implements or permits the implementation of planned measures which
may have a significant adverse effect upon other watercourse States, it shall provide those States with
timely notification thereof. Such notification shall be accompanied by available technical data and
information, including the results of any environmental impact assessment, in order to enable the
notified States to evaluate the possible effects of the planned measures.
Article 13
Period for reply to notification
Unless otherwise agreed:
(a) A watercourse State providing a notification under article 12 shall allow the notified States a
period of six months within which to study and evaluate the possible effects of the planned measures and
to communicate the findings to it;
(b) This period shall, at the request of a notified State for which the evaluation of the planned
measures poses special difficulty, be extended for a period of six months.