SGER: Sampling and Isotopic Analysis of Yucatan Groundwater: Impact of Hurricane Isadore

[03:13847]本提案旨在评估热带风暴降水，特别是飓风降水作为地下水运动的天然示踪剂的作用。众所周知，热带风暴降水具有特殊的氧和氘同位素组成，使其与正常降水区别开来。由于热带风暴产生的雨量是普通风暴的许多倍，因此它们能够在一次事件中向含水层增加大量的水。本研究的目的是确定同位素标记水的段塞在穿越含水层时是否可以通过稳定同位素测量来追踪。这项研究可以建立一种强大的新技术来研究飓风频繁发生的热带地区的地下水。计划和建立一个适合于监测飓风的实验是很困难的，而建立一个庞大的监测站网络，仅仅因为热带风暴可能在该网络的某个地方发生，这将是昂贵的。这就是使这一建议增加紧迫性的原因。飓风伊萨多最近经过尤卡坦半岛北部，在那里，PI之前已经获得了当地地下水同位素组成的背景数据。尤卡坦半岛北部特别适合进行这种监测技术的试验：它的喀斯特含水层极具渗透性，确保了地下水的快速流动；它几乎没有可能阻碍飓风降水快速进入含水层的土壤；含水层相对来说并不复杂。因此，当飓风降水经过时，监测含水层中水成分的变化就相对容易了。地下水样本将在一年内分三次采集。这些数据将从市政井、覆盖的岩溶天坑和气压计（如有）中获得。学生将参与收集样本和分析数据。同位素分析将在墨西哥国立自治大学的稳定同位素实验室进行。这个项目的智力价值将是更好地理解地下水这种宝贵资源的行为，并开发一种新的无污染技术来绘制其运动轨迹。这项活动的广泛影响将包括：1)开发有关地下水运动的信息，从而更好地管理和保护尤卡坦含水层中非常敏感的地下水（对人类健康、农业生产力、工业发展和旅游业至关重要）；2)在墨西哥科学家和美国科学家之间建立更密切的合作，通过在这项研究中的密切合作来完成；3)对学生进行有关收集有意义的地下水样本和评估本研究分析结果的程序的教育。

0313847PerryThis proposal is to evaluate the use of tropical storm precipitation,especially that from hurricanes, as a natural tracer of groundwatermovement. Precipitation from tropical storms is known to have a specialoxygen and deuterium isotope composition that distinguishes it fromnormal precipitation. Because tropical storms also produce many times asmuch rain as normal storms, they are capable of adding a large batch orslug of water to an aquifer during a single event. The objective of thisstudy is to determine whether that slug of isotopically labeled watercan be traced by stable isotope measurements as it moves through anaquifer. This research could establish a powerful new technique to studygroundwater in tropical areas where hurricanes are frequent. It is difficult to plan and set up an experiment suitable formonitoring a hurricane, and it would be expensive to establish a largenetwork of monitoring stations purely on the chance that a tropicalstorm might occur somewhere within that network. That is what adds anelement of urgency to this proposal. Hurricane Isadore recently passedover the northern Yucatan Peninsula, an area where the PI has previouslyobtained background data on the isotopic composition of the localgroundwater. Northern Yucatan is especially well suited for a trial ofthis monitoring technique: its karst aquifer is extremely permeable,insuring rapid groundwater movement; it has almost no soil that mightimpede rapid movement of the hurricane precipitation into the aquifer;and the aquifer is relatively uncomplicated. Thus, it will be relativelyeasy to monitor changes in the composition of water in this aquifer asthe hurricane precipitation moves through. Samples of groundwater will be collected in three sampling tripsover a period of one year. These will be obtained from municipal wells,covered karst sinkholes, and piezometers (where available). Studentswill be involved in collecting the samples and analyzing the data.Isotopic analyses will be performed in the stable isotope laboratory ofthe Universidad Nacional Autonoma de Mexico. Intellectual merit of this project will be a betterunderstanding of the behavior of groundwater, a precious resource, andthe development of a new, non-polluting technique for charting itsmovement. The broader impacts of this activity will include: 1)development of information on groundwater movement that can lead tobetter management and protection of groundwater in the very sensitiveYucatan aquifer (essential for human health, agricultural productivity,industrial development, and tourism), 2) establishment of closercollaboration between Mexican scientists and scientists in the UnitedStates, accomplished by close collaboration in this research, and 3)education of students in the procedures used to collect meaningfulsamples of groundwater and to evaluate the analytical results of thisstudy.