Philippines Groundwater Outlook (PhiGO)

世界上人口超过10万的城市中，有一半位于流域内，其中一半以上的可用水供应在一年中的部分时间内耗尽。这些缺水的城市发现，要获得支持其增长所需的额外供水极其困难和昂贵。水安全对菲律宾城市尤其令人担忧，这些城市被指定为亚洲城市水安全最差的城市之一。气候变化和城市人口密度的增加将给他们的水资源带来更大的压力。目前对到2050年的气候预测表明，菲律宾将变暖，旱季气温上升，降雨量减少，雨季极端降雨事件增多。这无疑将加剧干旱期间的水供应和暴雨期间的洪灾事件。这种敏感性导致菲律宾在气候变化风险最大的国家中一直名列前茅。除了气候变化带来的水资源压力外，到2050年，人口预计将增加约50%，同期城市人口将翻一番。这将进一步加剧未来水资源的压力。气候和人口变化的影响将对地下水产生严重影响，目前菲律宾50%以上的饮用水供应和85%的自来水供应来自地下水。地下水对当前和未来的水供应具有重要的战略和经济意义，是旱季河流流量的主要来源，而旱季河水又常常用于饮用水供应。尽管高度依赖地下水资源、合理覆盖地下水数据集和若干区域一级的地下水管理计划，但几乎没有对气候和人口压力来源进行实时监测、例行每月预报或影响评估。通过数据收集、知识交流、实地工作、数值模拟和利益攸关方参与的方案，菲律宾地下水展望项目力求对人口和气候变化对区域地下水资源的影响进行评估，并将这些评估转化为可用的洪旱风险预测。有两个截然不同的时间框架，项目的吸收和潜在利益将在这两个时间框架内实现。短期的季节性预报将有助于应急准备，而长期的十年尺度预报可用于采取主动步骤，以减少极端水文气象事件未来的物质和经济影响。为了更好地了解地下水水位极端情况的潜在社会经济影响和潜在的水资源管理战略，菲律宾政府还侧重于通过关键基础设施量化洪水和干旱的级联影响，并分析不同的水资源管理和城市规划方案的成本效益。

Half of the world's cities with populations above 100,000 are located within water basins where over half of the available water supply is depleted for part of the year. These water-stressed cities are finding it extremely difficult and expensive to secure the additional water supplies needed to support their growth. Water security is of particular concern for Filipino cities, which have been designated amongst the worst in Asia for urban water security. Changing climate and increasing urban population density will put more stress on their water resources. Current projections of climate up to 2050 suggest the Philippines will become warmer, with increasing temperature and decreasing rainfall during the dry season and more extreme rainfall events during the wet season. This will undoubtedly exacerbate both water availability during periods of drought and the magnitude of flood events during periods of heavy rainfall. This susceptibility has led to the Philippines being consistently ranked near the top of countries most at risk to climate change. In addition to water stresses from a changing climate, population is expected to increase by ~50% up to 2050, with urban population set to double over the same period. This will further exacerbate pressures on future water resources.The influence of climate and population change will have an acute impact on groundwater, which currently supplies more than 50% of the potable water supply and 85% of the piped water supply in the Philippines. Groundwater is strategically and economically important to current and future water supply and is the principle source of dry season river flows, which in turn are often used for potable supply. Despite the high reliance on groundwater resources, reasonable coverage of groundwater datasets and several regional-level groundwater management plans, there has been little in the way of real-time monitoring, routine monthly forecasting or impact assessment of climate and population stressors. Through a programme of data gathering, knowledge exchange, fieldwork, numerical modelling and stakeholder engagement the Philippines Groundwater Outlook (PhiGO) project seeks to undertake assessments of population and climate change impacts on regional groundwater resources and translate these into usable forecasts of flood and drought risk. There are two distinct timeframes at which uptake and potential benefits of the project will be realised. Short term, seasonal-scale forecasts will aid in reactive preparedness, whilst long term, decadal-scale forecasts can be used to take proactive steps towards reducing the future physical and economic impacts of extreme hydrometeorological events. To better understand the potential socio-economic impacts of groundwater level extremes and potential water management strategies, PhiGO is also focussed on quantifying the cascading impacts of flood and drought through key infrastructure and analysing the cost-benefit of differing water management and urban planning scenarios.