Urban water resource management has been an important issue of concern for municipalities in water scarce regions. It is now become even more important with the increasing number of cities and the growing contribution of cities in water related issues in the light of the estimated water shortage in the next century. To avoid the worst scenario, it is of critical importance for municipalities to figure out a long-term vision of the role of cities in the nation's economy, economic structure and population size from the view point of water resource management.

Though many cities are currently facing water resource problems, they are usually recognized as local issues because of the diversity of both phenomena and measures taken. However, these local cases are representing common aspects of the issue, such as the unbalance between resource capacity and economic growth of cities, inter-regional allocation and inter-sector allocation of resources, and resource quantity versus quality.

This paper aims to present the common challenges facing urban water resource management. Through field survey and analyzing existing materials, the local lessons of Tianjin City, China, which is facing typical water resource problems, are drawn after a step-wise analysis of water flow in cities. Through the case study, it has been found that with the economic growth and urbanization process, the contribution of cities in water resource problems is increasing. These problems can not be solved independently, but rather need a systematic approach including natural ecosystem and socio-economic system in a wider region. Based on the lessons from case study, challenges facing urban water resource management and possible strategies are presented.

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 裸地の浸食量と植栽の効果，森林の効用を含めた水文モデル作成．名大でGEWEX/GAMEのシベリアを担当し，永久凍土帯での観測やレナ川流出過程のモデル化．「地球研」では乾燥地河川・黄河を対象．結果は「黄河断流」出版．

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中国の黄河流域において，大西ら（2006）の推計した水資源需給構造と，Ichinose et al.（2009）の推計した地下水利用構造とを地域別に直接比較することにより，データが存在せず実態把握の困難であった当該流域における地表水の利用構造を描き出すことを試みた。黄河流域に大部分が含まれる35 の地級行政単位を抽出し，立地の近接性と水資源需給構造の形態的類似性（共通する特徴）に着目してそれらを12 の小流域に分類した。一般に上流域では地表水に依存し，農業での利用割合が低いため，地下水利用の季節変動性は小さい。一方，中流域から下流域では地下水への依存の度合いが高くなり，農業での利用割合が高くなるため，地下水利用の季節変動性は大きくなる。とりわけ，その傾向は黄土高原において顕著である。また，最下流域では再び地表水に依存している。さらに地下水利用構造の類似性にもかかわらず，小流域の中でも地表水を含めた水資源の需給構造に多様性が見られる地域がある。とりわけ中流域では，大河川へのアクセスの状況に応じて多様性が顕著である。

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  Water resources at Dalad, Inner Mongolia had been investigated by groundwater sampling and metering during 2002-2006. Since Dalad is located in the middle reach area of the Yellow River basin and classified as arid or semi-arid area with less than 360mm precipitation and more than 2,200mm potential evaporation, the river water is not sufficiently supplied to the area and therefore, farming inevitably depends on mainly groundwater resources. During the investigation period, three procedures ; 1) 18 sampling tube wells were installed or prepared in the southern part of the study area to find the fluctuation of the groundwater level and water qualities such as pH and EC, 2) location, approximate withdrawals and water qualities at almost all the existing wells in the southern part of the study area were identified and measured simultaneously, and 3) 14 sampling tube wells were used to find the water levels and water qualities, were carried out. The obtained data show that the groundwater resource of the study area is recharged by mainly the groundwater flow from the Desert Kubuchi and partly by the seepage water from the Yellow River. The amount of the groundwater tended to decrease slightly in the study period, but it might be due to the condition of the precipitation and might not connect to depletion. Some ionic matters indicated by EC seems to be conveyed by the flow directing to the North in the southern part of the study area and then EC at some wells showed relatively high values as more than 3.00mS/cm. Only, EC and pH did not show significant defect and degradation as a whole study area. As a result the followings are indicated. Inadequate groundwater withdrawal might induce more serious draught of the Yellow River and also inadequate fertilizer application might worsen the groundwater quality especially in the middle part of the study area. Therefore, continuing observation is essential to maintain the water resources at Dalad.

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  Groundwater resources at Dalad, Inner Mongolia were investigated by groundwater metering in 2013 as supplementary investigation during 2002-2006. Since Dalad is located in the middle reach area of the Yellow River basin and classified as arid or semi-arid area with less than 360mm precipitation and more than 2,200mm potential evaporation, the river water is not sufficiently supplied to the area and therefore, irrigation and industrial waters inevitably depend on groundwater resources. As a result of the investigation, groundwater levels at almost of all the observation wells have descended remarkably since 2005 and especially the decreases in the southern part of the objective area are severe by a range of 0.8-5.4m. The groundwater amount in the southern part in 2013 is roughly estimated to be 2.91×10⁷m³, which proves a distinct downward trend. According to the autoregressive-like forecasts, including the Holt-Winters method, the unconfined groundwater in the southern part would be unavailable in the middle of 2030’s. The groundwater amount of the objective area is also decreasing severely and the increase in irrigation and industrial waters must be its potential reasons, except the decrease in the precipitation during 2005-2013. The change of the groundwater usage and flows might decrease the discharge of the Yellow River through the groundwater seepage and it is not only a water resources problem in this area, but also in the basin scale. Therefore, the groundwater management in this area is a pressing issue and should be done by local government or some water-utilization association against both irrigation water and industry water users. The water resources are inherently including uncertainty, so continuing observation is essential to maintain the water resources at Dalad.

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The confrontation between China and India concerning water resources in the Brahmaputra River (known as “Yarlung Zangbo” in Chinese), which flows through both countries, has been deepening in recent years. There have also been diplomatic negotiations between the two countries. This study aims to analyze the conflict and cooperation over the Brahmaputra’s waters.
First, the study describes the South–North Water Transfer Project, a multi-decade Chinese infrastructure mega-project that aims to channel the abundance of fresh water from southern China to the more arid north through canal systems. One development included in a western route of this project involves expanding the Brahmaputra. Ten dams have already been completed on this river, and China plans to build the world’s largest dam, even larger than the Three Gorges Dam, on the Brahmaputra. India fears that the project will have a significant impact on the lower river region.
Second, the study considers both India’s protest as a lower riparian country and China’s reaction as an upper riparian country. Even though India’s fisheries industry and ecological system are affected by Chinese development on the river, China did not publicly acknowledge its development activities until 2010. Instead it pursued what could be called a silent strategy. Since admitting the project’s existence, China has sought to minimize the impact on downstream countries. However, the initial silent strategy has clearly amplified distrust on the Indian side.
Third, the study considers steps toward a cooperative relationship between the two countries. Although there is no binding legal agreement, China and India have established an expert-level committee and provided hydrological information to each other. They have also signed a memorandum of understanding that will guide expansion of their cooperative relationship.
As a guide to future work, the study indicates the immaturity of international standards and law to settle a conflict concerning an international river. In this respect, it is important to analyze the applicability of “the Convention on the Law of the Non-Navigational Uses of International Watercourses,” which entered into force in August 2014. Furthermore, the study indicates that there is a third country, Bangladesh, with concerns regarding the Brahmaputra’s resources. A water allocation agreement has been signed between India and Bangladesh.
When we emphasize only the aspects of conflict taking place regarding this international river, it appears that two large Asian countries are heading toward a collision. However, as shown in this study, China and India are trying to build a cooperative relationship. This situation can be perceived as a case study in international trust-building.

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