Sustainable Water Resource Development

Water is an essential resource for all life on the planet. Of the water resources on Earth, only 2.5 percent of it is fresh. Two-thirds of the freshwater is locked up in ice caps and glaciers. Of the remaining one-third, a fifth is in remote, inaccessible areas and much seasonal rainfall in monsoonal deluges and floods cannot easily be used. As time advances, water is becoming scarcer; having access to clean, safe, drinking water is limited among countries. At present, only about 0.08 percent of all the world’s fresh water is exploited by mankind in ever increasing demand for sanitation, drinking, manufacturing, leisure and agriculture. Due to the small percentage of water remaining, optimizing the fresh water we have left from natural resources has been a continuous difficulty in many places of the world. 

 For meeting the increasing demand for water supply, especially in the urbanized and industrialized regions, water resource development is always the basic measure. However, over exploitation of the limited available natural water resources have been proven unsustainable. Based on the concept of Water Sustainability, we have to put the topic of sustainable water resource development onto top priority.

Conventional Water Resources

Conventional water resources usually mean all the fresh water resources available for exploitation and utilization. These are fresh waters from natural sources, including Surface Waters such as rivers and lakes, and Groundwater stored in underground aquifers. We say they are Conventional because human beings have known them well and understood how to utilize them from the beginning of civilization. However, within the scope of water sustainability, we have to stress that the natural water resources do not mean the total volume of water in each of the water bodies but their Renewable amount within a given period of time (such as per annual). Surface water and/or groundwater development can be Sustainableonly when the exploited water amount is always within the renewable limit. Otherwise, the manner of water resources development becomes Unsustainable. 

Unconventional Water Resources

Contrast to conventional water resources, Unconventional water resources mean the waters that are not fresh in nature but can be converted to the quality meeting the requirement for certain purposes of water utilization. They mainly include waters from the following sources:

Reclaimed Water

Reclaimed Water is the water reclaimed from used water which may be domestic sewage or industrial wastewater. Usually, domestic sewage and industrial wastewater have to be treated before being discharged to the environment. However, if such kind of waste flows can be further treated to the quality meeting the requirement for non-potable utilizations (such as gardening, toilet flushing, and other environmental purposes in the case of domestic water use, and cooling and process water in the case of industrial water use), they can become usable water resources. Potable utilization of reclaimed water can also be made possible by using advanced water treatment processes.

Harvested Rainwater

Harvested Rainwater is the water directly collected from natural rainfall or during its runoff process. As rainwater is not seriously polluted under normal conditions, it may not need very sophisticated treatment processes for converting the harvested rainwater to the quality for meeting various water use purposes. In fact, natural water bodies are frequently replenished by receiving rainwater. For on-purpose rainwater use, the provision of sufficient storage is usually more important than water treatment.

Water Desalination

Water Desalination is also an alternative measure for water supply in regions where seawater or brackish water is available. In this case, salt removal from the saline water is the main task.

The development of these unconventional water resources is thought to be Sustainable because they almost have no limitations of source provision. For reclaimed water, because a city or an industry discharges almost constant waste flows, as long as technically and economically feasible, a constant amount of water can always be reclaimed to meet the needs of alternative water supply. Although rainwater is not a stable water source, its total quantity is predictable and by rational utilization of natural and artificial storage conditions it can be turned as a utilizable source. Regarding saline waters, especially the seawater, its enormous volume can provide a stable water source.

Sustainable Water Resource Conservation

Sustainable water resource development should be based on careful conservation of all available water resources. The main tasks include the followings: 

Water Resources System Planning it to plan and/or design a whole system made from connected hydrologic, infrastructure, ecologic, and human processes that involve waters in a region, a watershed, or all water elements closely related to a city where centralized water supply is required to meet the needs of various purposes of water use. For such a water resource system, no matter large to small, related plans need to be periodically updated and adapt to new information, new objectives, and updated forecasts of future demands, costs, and benefits. Current decisions should not preclude future generations from options they may want to consider, but otherwise current decisions should be responsive to current needs and opportunities, and have the ability to be adaptable in the future to possible changes in those needs and opportunities.

Water Resource Evaluation/Assessment is the process of measuring, collecting and analyzing relevant parameters on the quantity and quality of water resources for the purposes of a better development and management of water resources. It is a tool to evaluate water resources in relation to a reference frame, or evaluate the dynamics of the water resource in relation to human impacts or demand. The evaluation and/or assessment usually link social and economic factors to the sustainability of water resources and associated ecosystems. It is a systematic study of the status of water services and resources, and of trends in accessibility and demand within a specific domain of interest.

Water Resources Protection involves the protection of surface water sources and groundwater sources to avoid water pollution. In the past, the need for water resources protection has often been neglected. As a consequence, many water sources, especially the sources of drinking water supply have become contaminated making sophisticated water purification measures indispensable. Implementing water resources protection may not only require technological measures, but more importantly a legal framework. This usually involves a protection plan, which formulates responsibilities, specific protection measures and basic rules that apply to all community members and water source users. Generally, three basic strategies exist for protection, namely Prevention of the discharge of waste, pollutants or untreated water from entering aquatic systems, Treatment of polluted water prior to discharge into water bodies, and Restoration of Ecosystems so as to enable or support natural rehabilitation processes.