1 The thyroidal basis of the research methods about EWR directs the reasonable ascertainments of the time scale, space scale and protected projects in research.

2 Water shortages in arid areas in our country and socioeconomic use of water often squeezing ecological water requirement (EWR) lead to vegetation degradation.

3 The paper proposed a research method considering EWR of the river corridor as EWR of the natural oasis and thus developed an EWR model for arid areas.

4 The proportion of actual EWR of the Haihe River during 1999-2002 revealed that the EWU has not been satisfied.

5 To the question, based on a careful review of the existent researches, a concept system of EWR and advices on its use were put forward in this article.

6 Based on the introduction of the concept and meaning of ecological water requirement(EWR) for reservoirs, the blind number theory was applied to calculate the EWR for the Shuangxi Reservoir.