当两座水库中有一座来水为枯水，另一座来水不为枯水时，流域河道外需水较常

When there is a runoff in two reservoirs to dry, and the other is not low water runoff outside the river basin water demand will increase more than normal. To ensure the Songhua River in Harbin section of shipping traffic over the river, the difficulty will be greater. Especially when low water reservoir occurs continuously conduct reservoirs joint operation would be necessary. Since the two reservoirs are regulating reservoir, water regulation capability, both have joint use conditions. Case for joint use of the reservoir and can play better benefits for: wet and dry, dry Feng, flat dry, dry flat, these types of statistics occurrence frequency of 43.16%.

When one of the two reservoirs has dry water and the other is not dry, the water demand outside the river basin will increase year-round. It will be more difficult to ensure the shipping flow of the section above the Harbin section of the Main Stream of songhua River. Especially when the reservoir has continuous dry water, it is necessary to carry out the joint application of the two reservoirs. As both reservoirs are regulated for many years, the water volume regulation ability is strong, and both have the conditions for joint application. Suitable for the joint use of reservoirs and can play a better role in the situation is: rich, dry, flat, dry, these cases of statistical frequency of 43.16%.

When one of the two reservoirs is low water and the other is not, the water demand outside the river channel of the basin will increase. It is difficult to ensure the navigation flow of the main stream of Songhua River above Harbin section. Especially in the case of continuous low flow, it is necessary to carry out the joint operation of the two reservoirs. Since both reservoirs are multi-year regulating reservoirs with strong water regulation capacity, they are all qualified for joint operation. The conditions that are suitable for the combined use of the reservoir and can give full play to its benefits are: high and low water, low and high water, low and low water, and the statistical frequency of these situations is 43.16%.<br>