Droughts and Floods. (1) The Parties undertake to co-ordinate their actions within six months to one year and to develop measures to mitigate the effects of droughts and floods.
(2) The flow regimes of the Incomati and Maputo watercourses during flood and drought periods shall be adjusted in accordance with the measures referred to in subArticle (1).
(3) The Parties shall notify each other without delay and by the most expeditious means of any flood danger.
(4) During flood alarm situations, the affected Party may require the other Parties to adopt the measures referred to in subArticle (1) and any other urgent measures agreed upon, which may be deemed necessary.
(5) During a drought period, the Parties shall be obliged to manage, in a co-ordinated manner, water storage infrastructure in accordance with the measures referred to in Sub-Articles (1) and (2).
Droughts and Floods. The Parties undertake to co-ordinate their actions within six months to one year and to develop measures to mitigate the effects of droughts and floods. The flow regimes of the Incomati and Maputo watercourses during flood and drought periods shall be adjusted in accordance with the measures referred to in subArticle (1). The Parties shall notify each other without delay and by the most expeditious means of any flood danger. During flood alarm situations, the affected Party may require the other Parties to adopt the measures referred to in subArticle (1) and any other urgent measures agreed upon, which may be deemed necessary. During a drought period, the Parties shall be obliged to manage, in a co-ordinated manner, water storage infrastructure in accordance with the measures referred to in Sub-Articles (1) and (2).
Droughts and Floods. Droughts have been defined as those years when the net inflow into Okanagan Lake is less than the water requirements along the mainstem system namely 244,000 acre-feet. A drought year does not necessarily mean a shortage of water providing there is sufficient to carry over storage in Okanagan Lake to make up the deficit or failing this Okanagan Lake is drawn down below its normal low water elevation. However, it is estimated that a re- occurrence of the 1929 to 1932 drought would result in Okanagan Lake being drawn down some 3.2 feet below its normal low water elevation assuming all water requirements are met at all times. Under these conditions, the lake would drop below its normal low water elevation in the middle of the second year of the drought and not refill to a level of 3 feet about normal low water until 3 years later. Such a prolonged drought has only occurred once in this century and was prevalent over much of North America. At the other end of the spectrum are those years in which excessive inflows or flood occur. In general, a forecast seasonal inflow greater than 550,000 acre-feet is considered to indicate a potential flood and Okanagan Lake would have to be drawn down to its normal low water elevation or even lower prior to the freshet. In the flood of 1972, Okanagan Lake exceeded its normal high water elevation by 0.9 feet in controlling the maximum April to July inflow to occur in this century. The estimate flood damage around Okanagan Lake amounted to $56,500, exclusive of flood damage at the mouths of Mission, Kelowna and Trout Creeks and other tributaries. During this period Osoyoos Lake which has about 7% of the area of Okanagan Lake and whole outflow was severely restricted by flood flows in the Similkameen, rose almost 5 feet to reach a maximum elevation of 917.1 GSC. It is estimated that some $212,000 worth of damage occurred within the Canadian portion of Osoyoos Lake through property damage or lost revenue to the tourist industry.
