**5. Conclusion**

IPCC Report 4 [5] has clearly emphasised on the linkage of atmospheric warming to the large-scale changes in the hydrological cycle, increase in the water vapour content, changing in the patterns of precipitation, increased frequency and intensity of precipitation, reaching extremes of dry season and flooding, reduced snow cover, enhanced melting of ice and reduced permafrost, changes in soil moisture content and increased runoff. A remarkable spatial and inter-decadal variability in the precipitation has been observed. The events of intensive precipitation have increased worldwide on one hand, and area classified as very dry land has increased to double on the other hand. The snow cover and water stored in glaciers have decreased considerably. This ice melting related phenomenon with snow-fed rivers, run-off in glaciers and increased number of glacier lakes have been observed in last few decades. Such changes have also been associated with disastrous flash floods, landslides, riverine floods and heavy mud flow. Sustainability of the surface water due to delicate hydrological cycle seem to be disrupted beyond cure.

Climate change models are predicting increased precipitation in higher latitudes and decreased precipitation in subtropical and lower mid-latitude regions, increasing disparity and creating extreme conditions in different parts of the world. As a result, increase in average river water availability and run off is predicted in the higher latitudes and a decreasing trend towards dry tropics. Reduction in the water supplies in glaciers causes reduced water availability in rivers, hence creating water stress conditions.

Freshwater resources are also influenced by many non-climatic drivers such as changes in the patterns of population, food consumption and production of food and other products. The economics of water pricing, technology and societal views towards value of freshwater ecosystems also plays a role [2]. Thus, climate change is one of the many factors causing future water stresses, effecting sustainable water flows. The socioeconomic and technological changes along with demographic changes can prove to be more effective towards water management in most regions of the world and on most time scales. Talking about the effect of extreme events, the impacts more often depend upon the socioeconomic vulnerability. The development pattern, wealth distribution, demographics and environmental conditions determine the severity of such disasters like extreme weather events and migration of disease vectors.

The water management practices presently in action are not enough to cope with the impacts of climate change and may not be able to assess and manage risks such as devastating floods, human health, food insecurity, damaged ecosystems and inadequate power supplies. The current variability in climate is impossible to predict completely and plan for long term adaptation strategies. The effect of climate change stress in tropical and sub-tropical regions is more pronounced and a threat to sustainable surface water flow. The indirect stressors such as population growth, urbanization etc., will aggravate the conditions. The challenges posed by changing climate in the past can be a good guidance for planning for the future. The management practices based on projected hydrological changes may help to avoid disastrous events and bring situation under control. The adaptation strategies for maintaining sustainable flow of surface water require integrated strategies for both

*Sustainable Water Flows in Era of Climate Change DOI: http://dx.doi.org/10.5772/intechopen.101064*

demand and supply sides. Improving water-use efficiency, recycling of water, water harvesting, water conservation, water metering and water markets may be valuable efforts in this regard. Integrated water resource management, expanded use of economic incentives and providing framework adaptation strategies in administrative systems, across socio-economic barriers are the key factors. Integrated approaches must be at appropriate scales to be effective in practice and to provide total environmental solution. Such mitigation methods will not only reduce the impact of global warming but will also reduce the stress of adaptation to changing climate.
