PROBLEM E: Are we heading towards a thirsty planet?

Will the world run out of clean water? According to the United Nations, 1.6 billion people (one quarter of the world's population) experience water scarcity. Water use has been growing at twice the rate of population over the last century. Humans require water resources for industrial, agricultural, and residential purposes. There are two primary causes for water scarcity: physical scarcity and economic scarcity. Physical scarcity is where there is inadequate water in a region to meet demand. Economic scarcity is where water exists but poor management and lack of infrastructure limits the availability of clean water. Many scientists see this water scarcity problem becoming exacerbated with climate change and population increase. The fact that water use is increasing at twice the rate of population suggests that there is another cause of scarcity – is it increasing rates of personal consumption, or increasing rates of industrial consumption, or increasing pollution which depletes the supply of fresh water, or what? **

Is it possible to provide clean fresh water to all? The supply of water must take into account the physical availability of water (e.g., natural water source, technological advances such as desalination plants or rainwater harvesting techniques). Understanding water availability is an inherently interdisciplinary problem. One must not only understand the environmental constraints on water supply, but also how social factors influence availability and distribution of clean water. For example, lack of adequate sanitation can cause a decrease in water quality. Human population increase also places increased burden on the water supply within a region. When analyzing issues of water scarcity, the following types of questions must be considered. How have humans historically exacerbated or alleviated water scarcity? What are the geological, topographical, and ecological reasons for water scarcity, and how can we accurately predict future water availability? What is the potential for new or alternate sources of water (for example, desalinization plants, water harvesting techniques or undiscovered aquifers)? What are the demographic and health related problems tied to water scarcity?

Problem Statement

The International Clean water Movement (ICM) wants your team to help them solve the world’s water problems. Can you help improve access to clean, fresh water?

Task 1: Develop a model that provides a measure of the ability of a region to provide clean water to meet the needs of its population. You may need to consider the dynamic nature of the factors that affect both supply and demand in your modeling process.

Task 2: Using the UN water scarcity map (http://www.unep.org/dewa/vitalwater/jpg/0222-waterstress-overuse-EN.jpg) pick one country or region where water is either heavily or moderately overloaded. Explain why and how water is scarce in that region. Make sure to explain both the social and environmental drivers by addressing physical and/or economic scarcity.

Task 3: In your chosen region from Task 2, use your model from Task 1 to show what the water situation will be in 15 years. How does this situation impact the lives of citizens of this region? Be sure to incorporate the environmental drivers’ effects on the model components.

Task 4: For your chosen region, design an intervention plan taking all the drivers of water scarcity into account. Any intervention plan will inevitably impact the surrounding areas, as well

as the entire water ecosystem. Discuss this impact and the overall strengths and weaknesses of the plan in this larger context. How does your plan mitigate water scarcity?

Task 5: Use the intervention you designed in Task 4 and your model to project water availability into the future. Can your chosen region become less susceptible to water scarcity? Will water become a critical issue in the future? If so, when will this scarcity occur?

Task 6: Write a 20-page report (the one-page summary sheet does not count in the 20 pages) that explains your model, water scarcity in your region with no intervention, your intervention, and the effect of your intervention on your region’s and the surrounding area’s water availability. Be sure to detail the strengths and weaknesses of your model. The ICM will use your report to help with its mission to produce plans to provide access to clean water for all citizens of the world. Good luck in your modeling work!

Possible Resources

An Overview of the State of the World’s Fresh and Marine Waters. 2nd Edition, 2008. (http://www.unep.org/dewa/vitalwater/index.html).

The World’s Water: Information on the World’s Freshwater Resources. (http://worldwater.org).

AQUASTAT. Food and Agriculture Organization of the United Nations. FAO Water Resources. (http://www.fao.org/nr/water/aquastat/water_res/index.stm).

The State of the World's Land and Water Resources for food and agriculture. 2011. (http://www.fao.org/docrep/017/i1688e/i1688e00.htm).

GrowingBlue: Water. Economics. Life. (http://growingblue.com).

World Resources Institute. www.wri.org.

**Note that the 2013 Mathematical Competition in Modeling (Problem B) and the 2009 High School Modeling Competition in Modeling (Problem A) were related to modeling different aspects of water scarcity.

Your ICM submission should consist of a 1 page Summary Sheet and your solution cannot exceed 20 pages for a maximum of 21 pages. Note: The appendix and references do not count toward the 20 page limit.

E: 將世界上跑出乾淨的水？根據聯合國，1.6十億人（四分之一世界人口的）經驗的水資源短缺。用水一直在增長，在人口上個世紀增長率的兩倍。人類需要水的資源用於工業，農業和住宅用途。有兩個主要的原因水資源短缺：物理稀缺性和經濟匱乏。物理稀缺性是有水的地方不足的區域，以滿足需求。經濟稀缺性就是存在水，但管理不善和缺乏基礎設施限制了清潔水的供應。許多科學家看到這樣的水資源短缺問題變得更加惡化與氣候變化和人口增長。水的使用越來越多，在人口增長率的兩倍，這一事實表明，有稀缺性的另一個原因 - 它是增加個人消費率，或增加工業消費率，或增加汙染，消耗新鮮水，或者是供應？ **

是否可以提供清潔的食水就完了嗎？供水必須考慮水的物理可用性（例如，天然水源，技術進步，如海水淡化廠或雨水收集技術）。瞭解水的供應是一種固有的跨學科的問題。其中不僅要了解供水環境的制約，又受社會因素如何影響可用性和乾淨的水分佈。例如，缺乏足夠的衛生設施會導致水質下降。人類人口的增加也對地方的供水區域內負擔增加。在分析水資源短缺的問題，問題如下型別必須加以考慮。如何有人類歷史上加劇或緩解水資源短缺？什麼是地質，地形和生態原因，水資源短缺，如何才能準確地預測未來水的供應？什麼是新的或備用水源（例如，海水淡化工廠，集水技術或未被發現的含水層）的潛力？什麼是綁在水資源短缺的人口與健康有關的問題？

問題陳述

國際清潔水運動（ICM）希望你的團隊，幫助他們解決全球水問題。你能幫助改善獲得清潔，新鮮的水？

任務1：建立一個模型，它提供了一個地區提供清潔的水，以滿足人民的需要的能力的度量。您可能需要考慮的影響在建模過程中供需兩方面的因素的動態性。

任務2：使用聯合國水資源短缺的地圖（http://www.unep.org/dewa/vitalwater/jpg/0222- waterstress-過度-EN.jpg）選擇一個國家或地區的水要麼是嚴重或中度超載。解釋為何以及如何缺水在該地區。確保通過解決物理和/或經濟稀缺性來解釋的社會和環境的驅動程式。

任務3：從任務2您所選擇的地區，使用任務1中的模型表明缺水狀況將在15年內是什麼。請問這個情況影響該地區人民的生活水平？一定要結合對模型元件的環境司機的影響。

任務4：對於您所選擇的地區，設計以水資源短缺的所有驅動程式在內的干預計劃。任何干預計劃將不可避免地影響到周邊地區，以及

作為整個水生生態系統。討論此影響，並在此大背景中計劃的整體優勢和劣勢。請問你的計劃，緩解水資源短缺？

任務5：使用在任務4設計的干預和你的模型來預測水供應到未來。你所選擇的區域可以變得不那麼容易缺水？將水成為未來的關鍵問題？如果是的話，什麼時候才能稀缺性發生的呢？

任務6：寫一個20頁的報告（單頁的彙總表並沒有在20頁計算），說明你的模型，缺水的地區，沒有干預，您的干預，和你的干預對您所在地區的影響及周邊地區的水供應。一定要詳細模型的長處和短處。該ICM將使用您的報告，以幫助其使命，生產計劃，提供清潔的水世界的所有公民。好運氣在你的建模工作！

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