I would say that the language of paragraph 3(3)(d) ensures that the strategy must include whatever measures are identified in paragraphs 3(3)(a), 3(3)(b) and 3(3)(c).
As noted at various points, responsibility for flood and drought forecasting is shared with provinces and territories and lies principally with provinces and territories. Based on the fact that the government has two years to develop the strategy, I think that using the language of “may” is appropriate, given that it's unclear what the strategy will uncover as it's being developed.