Integrated Water Management – Southern California Perspective

中国环境学会  2011年 06月21日

  Jason J. Wen, Ph.D., P.E.  Utilities Superintendent, City of Downey, California, USA; 562-448-8946

  California is often recognized as a land of extremes and variability including its water resources.  Precipitation, which is the root of California water supplies, varies greatly from place to place, season to season, and year to year.   Most of the state’s snow and rain fall in the mountains in the north and eastern parts of California; most water used in the valleys and west coastal plains.
  With its semi desert climate, the Los Angeles region and much of Southern California consistently face serious water supply threats from numerous factors, including increasing population, reliance on imported water, overuse of groundwater, and consequences of climate change. For more than 100 years, to meet increasing water demand, people has been focusing on finding and developing new water supplies.  These include building aqueducts to convey the water from a few hundred miles away to the region, and building dams and reservoirs to facilitate the water storage.  In recent years, people found out that large water resource projects created many long-term environmental and ecological problems, and importing water to meet the local demand is not a sustainable solution.  To restore a health of ecosystem and environment, federal and state and local governments have promulgated many regulations on wastewater and storm water management, and environmental protection.  The regulations have been posting a huge additional challenge for the traditional way of water resource development and management.
  Integrated water management is the paradigm for the 21st century. Integrated water management plans should drive water resources decision-making processes and serve as the basis for developing regulatory programs. The true spatial, environmental and institutional, dimensions of problems must be recognized, and they must be dealt with accordingly. The water resource development and management now must use an integrated system approach to face the new multi-dimension challenges.  Technology along may not provide the solution for the problems. Integrated water management means putting all of the pieces together. Social, environmental and technical aspects must be considered. Issues of concern include: providing the forums; reshaping planning processes; coordinating land and water resources management; recognizing water source and water quality linkages; addressing institutional challenges; protecting and restoring natural systems; reformulating existing projects;  articulating risk; educating and communicating; uniting technology and public policy; forming partnerships; and emphasizing preventive measures, etc.
  This paper will share the perspectives and experiences from the Southern California cities in dealing with the following issues related to urban water management:
  Water resource.  How does a city work with developer to allocate new water resource and build new water infrastructure for the services.
  Storm water management.  To comply with storm water regulation, the city has requested the developer to invest local storm-water facility to prevent storm water pollution and enhance groundwater recharge.
  Recycled water use.  The City has encouraged and sometime requested new and remodeling construction sites to use recycled water when it is readily available to reduce the potable water demand.
  Local regulation. The city has been utilizing ordinance to enforce some water conservation requirement and also worked together with developer to build a more water sustainable project.
  Conservation.  Conservation has been redefined not only a sustainable life style but also as a water resource.  Actually, it is a rather green resource.  The city working with federal and state and other local governments has provided financial incentives to enhance the conservation activities, including public event, school education program, and distribution of free water and energy efficient appliances.
  New tools of reducing water demand may include conservation, urban and agriculture use efficiency, new technology, incentive, and pricing.  Water supply could be increased by conjunctive management and groundwater storage, precipitation enhancement, desalination, recycled water.
  Water quality plays a critical role to determine if the supply can be utilized for potable application. New way of improving water quality may include groundwater aquifer treatment, watershed protection, salt management, urban run-off management, treatment.
  Some lesions learned include
  Managing for sustainability relies on the full consideration of social, economic, and environmental values in policy and decision making.
  Water conservation, recycling, and greater system efficiency should be a fundamental strategy.  The cumulative effect has an enormous impact on future water supplies and water quality.
  We can better prepare for future droughts and climate change, and improve water supply reliability and water quality by taking advantage of long-term storage capacity of groundwater basins when managed in closer coordination with surface water resources.
  The challenge is to guide water management decision-making into flexible, holistic, and environmentally sound directions.
  Preventive, rather than remedial actions should be emphasized.
  Experience of water resource management in the US in recent years might be ‘seen’ in China today or in a near future.  The lessons learn to manage a sustainable development will be informative to assist Chinese local government and society to face these new challenges.  Integrated water management will flourish a more balanced and sustainable water supply for the future.

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