Collaborative Research: Hydrogeochemical Investigation of Seasonal Transition and Land Use Change Effects on Tropical Hydrology

在过去六年中，巴拿马季节性热带地区的水文和地球化学研究揭示了温带气候中看不到的径流行为。 这个综合性的国际研究计划结合了季节性热带地区的水文，地球化学和地球物理测量，包括原位数据收集和分析，并通过使用天然和引入的示踪剂和建模来增强。 这项合作研究计划的总体目标是了解重要的径流产生过程中的季节性热带地区和径流机制阈值的季节转换和土地利用变化的作用。 在一系列尺度上收集的水文、地球化学和同位素数据将比较几乎原始的414平方公里古老的上里约查格雷斯和邻近的330平方公里大部分被砍伐的里约帕科拉流域，以研究土地使用变化的影响。 不同的基岩类型覆盖这些盆地，因此地球化学和同位素将用于帮助确定流动路径和停留时间以及模型和假设检验。 潮湿的热带地区覆盖了地球陆地表面的22%，居住着36%的人类。选定的研究地区是潮湿的热带地区的代表，促进转让所获得的知识，以地理上的大区域。有三个非常重要的问题，这项研究将有助于回答。 砍伐森林或重新造林对季节性热带地区集水区的产水量有何影响？ 为什么雨季初期的径流产生与一年中的其他时间不同？ 我们如何通过改进的水文模型更好地预测这些影响？ 巴拿马运河流域对世界贸易极为重要，因为流域的径流推动了对美国至关重要的巴拿马运河。 这些研究成果将传达给巴拿马运河管理局、巴拿马大学，并通过同行评审文章广泛传播。 该项目每年将举办一次热带水文学国际实地课程，并向合格的美国和巴拿马研究生和本科生开放。 该项目是对史密森热带研究所巴拿马运河流域实验的补充，史密森热带研究所是合作者，巴拿马运河管理局和巴拿马科技大学也是合作者。

Hydrological and geochemical studies in the seasonal tropics of Panama over the past six years have revealed runoff behaviors not seen in temperate climates. This integrated international research program combines hydrological, geochemical, and geophysical measurements in the seasonal tropics including in situ data collection and analysis, enhanced by the use of natural and introduced tracers and modeling. The overall objective of this collaborative research program is to understand important runoff generating processes in the seasonal tropics and the roles of seasonal transitions and land-use changes on runoff mechanism thresholds. Hydrologic, geochemical and isotopic data collected over a range of scales will compare the virtually pristine 414 km2 old-growth Upper Rio Chagres and adjacent 330 km2 largely deforested Rio Pacora watersheds to examine land-use change effects. Different bedrock types underlay these basins, so geochemistry and isotopes will be used to assist in identifying flow paths and residence times and in model and hypothesis testing. The humid tropics cover 22% of the Earth's land surface and are home to 36% of humanity. The selected study area is representative of the humid tropics promoting transferability of the knowledge gained to a geographically large region. There are three very important questions that this research will help answer. What is the effect of deforestation or reforestation on the water yields from watersheds in the seasonal tropics? Why does runoff generation behave differently early in the rainy season than at other times of the year? How can we better predict these effects by improved hydrologic models? The Panama Canal watershed is extremely important for world commerce because the runoff from the watershed drives the Panama Canal, which is vitally important to the United States. These research results will be communicated to the Panama Canal Authority, Panamanian Universities, and broadly disseminated through peer-review articles. An international field course on tropical hydrology will be held each year of the project and will be open to qualified U.S. and Panamanian graduate and undergraduate students. The project compliments the Smithsonian Tropical Research Institute (STRI) Panama Canal Watershed Experiment, and STRI is a collaborator, as are the Panama Canal Authority and the Technological University of Panama.