The Fractal Lentic-Lotic Basin Complex as a Conceptual Basis for Future Urban Water Systems

Tambo Norihito, Masahisa Nakamura, Xiaochang C. Wang



The explosive population growth and the rapid urbanization and industrialization in the 20th Century have led to serious water shortage and environmental deterioration in many parts of the world. The modern water and wastewa­ter technologies evolved over the past century have successfully addressed many such problems, but overall, the era of modern water and wastewater systems is rapidly approaching its terminus, with the diminishing water and energy resources and the rising cost of bulk transport and treatment technologies clearly emerging as serious constraints.  What then would emerge as the post-modern socio-technological prospects? This article proposes that meeting such challenges calls for a concept of water metabolism focusing on regional and natural hydrological cycle, characterized by the fractal (self-similar and nesting form in overlapping scales) nature of river-lake systems ubiquitously found in most river basins that serve as sources of water supply and as receptor of wastewaters. The fractal river-lake basin systems, more appropriately definable as lotic-lentic water systems, actually represent also the way the humans have interacted with nature in different scales of water governance. Typically, the unit of water governance may range from households all the way to major continental transboundary water systems.  This article make specific reference to a scale of urban water and sewage systems organized in what may be regarded as units of water districts, or interdependent water metabolic systems using clean water only for potable purposes and harvesting non-potable water from various local water resources such as rainwater and reclaimed used water in a city area. The used water in such systems is reclaimed and supplied for various non-potable uses via various supply measures. The concept of environmental lakes as the key lentic part of the aquatic system is proposed to serve as quality and quantity buffering systems. The impact of water use in one water district on the downstream basins can thus be minimized by integrated river basin management, and the conservation of environmental resources would be realizable both domestically and internationally.


Keywords: Water district; Water metabolism; River basin; Fractal nature; Lentic and lotic water systems; Post-modern era