operation and data management of the water-authority with a specific focus on the ability to provide a sustainable water supply for the next century in the Caribbean. This literature review will examine previous studies (both qualitative and quantitative) of water sustainability and specific problems related to water quality, such as the build-up of nitrogen in the water supply. It will also review ways to assess water quality through the use of geographic information system (GIS) and remote sensing (RS) as a feasible tool of water management. The review will conclude with different philosophies of water delivery in the developing world, specifically the use of Integrated Water Resources Management (IWRM) and the philosophy's pros and cons.
According to Gleick (1998), the impending water crisis is one which will have seismic political and environmental consequences, if not addressed soon: "as human populations continue to grow, these problems are likely to become more frequent and serious. New approaches to long-term water planning and management that incorporate principles of sustainability and equity are required and are now being explored by national and international water experts and organization" (Gleick 1998: 571). Throughout much of the 20th century, the focus was on increasing water access, with little concern for the environment. Gleick proposes a technique of 'backcasting' rather than 'forecasting' given that building new water delivery systems is likely to be very challenging in the future. Criteria include basic human water requirements; basic environmental requirements; water quality standards (reflecting that different uses may require different levels of quality); renewability of water resources; data collection and availability; and institutions, management, and conflict resolution (Gleick 1998: 577).
Gleick argues that a multitude of considerations should be taken into account when setting water policy, including issues of social justice as well as physical needs and environmental needs. Opportunity costs are inevitable but when trade-offs are made they should be done in the most equitable fashion possible. "Perhaps the greatest flaw with many water institutions is their failure to adequately address issues of equity. Equity is a measure of the fairness of both the distribution of positive and negative outcomes as well as the process used to arrive at particular social decisions" (Gleick 1998: 577). Gleick acknowledges that human needs, then environmental needs must come first but argues we cannot ignore the discrepancies of social justice in water provision across the world. "The first two criteria require that we identify and meet basic allocations for humans and ecosystems, which are to be satisfied before other demands" but social value judgments as well as concerns about renewability should still be addressed (Gleick 1998: 578).
According to Basnyat (2000), another imperative to make better use of available water supplies is through pollution reduction. "Basin characteristics such as land use/land cover, slope, and soil attributes affect water quality by regulating sediment and chemical concentration" (Basnayat 200: 65). Manipulation of land use and land cover cane use used to improve water quality, specifically in reducing different types of pollutants that can leech into drinking water such as nitrates. By using geographic information system (GIS) and remote sensing (RS) analysis tools, forces contributing to nitrate pollution can be identified and classified. In the study conducted for the article, "a 'land use/land cover-nutrient-linkage-model' was developed which suggests that forests act as a sink, and as the proportion of forest inside a contributing zone increases (or agricultural land decreases), nitrate levels downstream will decrease. In the model, the residential/urban/built-up areas have been identified as strong contributors of nitrate. Other contributors were orchards; and row crops and other agricultural activities" (Basnayat 200: 65).
By taking such factors into consideration it is hoped that future contamination can be reduced. However, the pattern identified in the article indicated the extent to which highly concentrated areas of people are specifically linked to high nitrogen build-up, and avoiding these types of building patterns, while desirable, may be challenging in the future. Nitrogen is a particularly problematic nutrient because as well as being added as a pollutant, it can also be in high concentrations because of 'naturally' reoccurring factors. "Nitrogen concentration downstream is a function of multiple controlling factors, and different streams have different responses to the set of controlling factors. One of the important factors is vegetation, which at times can be manipulated to maintain or improve water quality" (Basnayat 200: 65-66). Rainfall intensity, basin delineation, and land use all play a complex role in water quality but predicting how they interact can be an inexact science even with the use of GIS and RS. Sui (1998) likewise concluded in his review of the technology that "current stand-alone and various loose/tight coupling approaches for GIS-based urban modelling are essentially technology-driven without adequate justification and verification for the urban models being implemented" (Sui 1997: 8).
The use of GIS and RS has proven to be somewhat controversial, in terms of evaluating its efficacy. As noted by Buogo & Chevalier, relying upon GIS in all contexts is not always ideal given the fact that the tool is not always able to show multiple representations of reality, as is necessary for a full portrait of the complexities of a water delivery system. "GIS, as a computer tool, are still limited for the integration of multiple representations of the same concept…conceptual level modeling in GIS does not yet fully make use of the informational richness found in reality for integration within a GIS" (Buogo & Chevalier 1995: 161). But Aspinall & Pearson (2000) have contended that GIS can be quite beneficial when "models implemented in GIS allow indicators to be combined within water catchments by setting them within a specific geographic context and integrating the descriptions of environmental variability across the geographic area. This spatial integration is necessary to place individual, site-specific indicators within a broader geographic context; the models allow this context to reflect the ecological and hydrological functioning of the water catchment. Scale and other geographic effects associated with integration are managed using an approach that partitions the landscape into a hierarchical series of nested functional units" that can assess the region's overall likelihood of providing sustainable water (Aspinall & Pearson 2000: 299).
Regardless of the capabilities of the tools used, one increasingly popular philosophy to improve water delivery internationally is that of Integrated Water Resources Management (IWRM), particularly in South Africa. As noted by Rahaman & Varis (2005) in their summary of the history of IWRM, its proponents defend IWRM as a philosophy with a long-standing existence and supported by decades of established research. It is defined "as a process, which promotes the coordinated development and management of water, land and related resources in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems" (Rahaman & Varis 2005: 15). A series of international World Water conferences have supported IWRM and clarified it over the years, including the Dublin Conference whose principles included recognizing "fresh water as a finite, vulnerable, and essential resource, and suggested that water should be managed in an integrated manner; using "a participatory approach, involving users, planners, and policymakers, at all levels of water development and management; acknowledging "women's central role in the provision, management, and safeguarding of water; and viewing water "as an economic good" rather than merely a physical product of the environment (Rahaman & Varis 2005: 16).
However, even between the advocates of IWRM there have been controversies. At the second World Water Conference at the Hague, in the Netherlands, there was a debate over the extent to which water privatization could enhance quality. "Making Water Everybody's Business" was its theme. "Water privatization and public-private partnerships were widely promulgated as means to achieve the vision objectives" although many opposed privatization, "arguing that the water sector is interrelated to many functions that demand government presence, i.e. flood control, drought alleviation, water supply, and ecosystem conservation" (Rahaman & Varis 2005: 18). The tension between the need for privatization and government support has marked many debates regarding issues in the developing world, and water use is no exception.
Not all conferences have proven to be so divisive. The Bonn IWRM conference action addressed issues "such as poverty, gender equity, corruption mitigation, and water management" as key components of ensuring governments were more responsive to water use (Rahaman & Varis 2005: 18). However, the most critical landmark was perhaps the World Summit on Sustainable Development (WSSD), held in Johannesburg, South Africa because it was the first to set specific, measurable, and quantifiable "targets and guidelines for implementing IWRM worldwide, including developing an IWRM and water efficiency plan by 2005 for all major river basins of the world; developing and implementing national/regional strategies, plans," along with setting broader goals about "improving water-use efficiency; facilitating public-private partnerships; developing gender-sensitive policies and programs" as well as improving management, education, and eliminating corruption (Rahaman & Varis 2005: 18-19). A later conference in Kyoto likewise affirmed these ideas solidified at the South African conference.