Ecological Engineering Design: Conversations About Water

New Conversations About Water Resource Demands

Kids Talk Radio science students are reading the book “Ecological Engineering Design,” by Marty Matlock and Robert Morgan.  We are in agreement that water is the first need for human survival. An estimated 30 percent of people currently live in areas of chronic water stress (Vorosmarty et al. 2000, Millennium Ecosystem Assessment, 2005).  Water resource demands have two major facets: water quality and water quantity.  Our study group is talking about water quality issues and how they are predominantly pathogens and mineral (salt) content.  The disease burden from water, sanitation, and hygiene issues is estimated at to be 4 percent of all deaths and 5.7 percent of the total disease burden in disability-adjusted life years (DALY’s) occurring wolrdwide.

The rate at which water is cycled across the landscape affects the concentration of pollutants.  As water resources become increasingly scarce, a given volume of water is cycled more frequently as it moves through hydrologic cycle.  Salinity of may water resources in arid systems is rising due to diversion of flows for irrigation and other uses (Reynolds et al., 2007).  The irrigated water collects salts as it flows across tilled soils, evaporating (leaving more salts behind) and infiltrating into groundwater (Williams, 1999).

Water resource allocation will be an increasingly contentious issue in the twenty-first century.  More than 70 percent of fresh water globally in appropriated for irrigation for agricultural production.  In less developed countries, as much as 90 percent of freshwater resources are used for agriculture.  Freshwater consumption worldwide has more that doubled since World War II and it is expected to rise another 25 to 40 percent by 2030 (Foley et al., 2005) .  Hoekstra and Chapagain (2008) suggest the minimum water rights should be elevated to a human right to potable water before any other allocation is made.  More that 2.5 billion people live in arid and semi-arid areas (mean annual rainfall between 25 and 500mm); these regions will become increasingly stressed as populations increase and pressures on finite water resources continue to grow.

What does this all mean for the Cabo Verde Tenth Island Project?  How will our group manage water?

Meeting the water demands for 9.25 billion people will require allocations of fresh water for basic human consumption, agricultural production, biofuels production, municipal sanitation, industrial use, and other applications.  There is a growing concern that humanity has passed peak water, or the point of maximum production/utilization of water resources (Gleick, 2009)  Humanity uses 26 percent of evapotranspiration and 56 percent of accessible terrestrial runoff (Postel et al., 1996) Globally, 20 percent of freshwater fish are in danger of extinction or are already extinct, and -47 percent of all listed endangered species in the U.S. are freshwater species (Jackson et al., 2001), increasingly water consumption will decrease biodiversity.  There will be global demand for ecological engineering design solutions to water scarcity.

1.   How will we deal with the water scarcity on the island of Santa Luzia, Cape Verde?

2.   New methods are available to turn salt water into fresh water?

3.   What will be the best plan to use water for agricultural purposes?

4.   What will be the best plan for using water for sanitation?

5.   What will we do with the waste on Santa Luzia Island?

6.   If we turn salt water into fresh water, what will we do with the salt?

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