According to the Environment Agency, the overall volume of rainfall in the regions of the UK is expected in the course of an "average" year to remain similar to historic levels. However, the pattern of the rainfall is expected to change, with more falling in the winter months, and less in the summer. The intensity of rainfall is also predicted to become more tropical in nature, arriving in short heavy downpours, rather than prolonged steady "drizzles". The predicted impact of this predicted changing pattern of rainfall on winter and summer river levels is shown below, with the winter increase in river levels raising the probability in flooding:
The predicted heavier rainfall in the winter months will increase the risk of flooding, a risk that will be exacerbated by the development of homes and workplaces to accommodate predicted population growth. The flood-protection measures currently being taken to manage these increased risks of flooding, will often be aimed at controlling the surface-water levels by increasing the effectiveness of waterways in carrying the rain out to sea as expeditiously as possible, rather than aiming to store it for later re-use. This, along with the increasing demand for water of a growing population, will exacerbate pressures on water supplies during the drier summer months. The predicted effect of this on the agricultural industry, for example, is shown below: