Detection and Implications of Hydraulic Relationships between Fractured-Rock and Deposit Aquifers

裂隙岩与沉积含水层之间水力关系的检测及其意义

• 批准号: RGPIN-2014-05353
• 负责人: Chesnaux, Romain
• 金额: $ 1.6万
• 依托单位: Université du Québec à Chicoutimi
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=636203
• 关键词: Detection; Implications; Hydraulic; Relationships; between

Pumping wells are usually installed in a well-identified aquifer, either granular (composed of sand and gravel) or fractured rock. It is assumed that the groundwater extracted from the well comes from the aquifer in which the well is installed. However, there is a particular case which has not yet been well documented in the literature, nor thoroughly investigated so far: that of pumping wells which are installed either in deposit or in fractured rock, but in both instances, close to the interface between these two types of aquifers. Within a regional geological framework where granular layers usually overlay the fractured bedrock, pumping wells may happen to be installed either in the lower part of the deposit just above the bedrock, or in the upper part of the bedrock, just below the deposit. In both of these configurations, one may suspect that the water produced by the pumping well could be composed of a mix of two different groundwaters: one coming from the deposit and the other coming from the bedrock. This situation would arise if hydraulic connections exist between the two types of aquifers. Such connections may be naturally preexisting, where discontinuities of the fractured rock would naturally intersect with the deposit. Or they may be artificially induced, in the case where drilling operations through the rock have created a hydraulic connection between the aquifers (preferential pathways along the bottom part of the casing, penetrating the upper part of the fractured rock). In both configurations, the pumping wells could be qualified as “mixt wells” because they collect waters originating from both the granular aquifer and the fractured rock aquifer. The aim of this proposed research is to set up a methodology allowing on the one hand to detect mixt wells, and on the other hand to characterize the hydraulic connections and preferential flow rates of the two types of aquifers. This detection and characterization would allow us to assess the consequences of mixt wells, to quantify the groundwater exchanges between the two types of aquifers close to the wells and at local and regional scales, and to help to understand the origin of groundwater supplied by wells. These aspects are of crucial importance when appropriately managing groundwater resources and being able to better quantify the quantity of groundwater flowing not only within an aquifer but also between different aquifers. Furthermore, a better knowledge of the origin of groundwater will allow to better understand the chemical composition of groundwater and its possible contamination when pumped by a mixt well (cross-contamination between aquifers), depending on its flow paths through different aquifers. More knowledge will be gained about origins of possible contaminations. This proposed research will also lead to the establishment of new tools for assessing the vulnerability of aquifers and ensuring a better protection of the resource. The proposed approach to perform this research is holistic in nature and combines the following: establishing the theoretical bases of the investigated issue, performing in situ field tests, laboratory tests, modeling and numerical tests. Two aspects of the research will be developed more specifically in order to address methodology issues. Firstly, the strictly physical consequences (hydraulics) of the connections between fractured rock and granular aquifers on the hydraulic tests performed in mixt wells should allow us to detect these connections. Secondly, we will study the chemical signature of the water sources, establishing that groundwater supplied by mixt wells is composed of a combination of two different chemical signatures, one from a fractured rock aquifer and the other from a deposit aquifer.

泵送的含量安装在颗粒状的含水层（由沙子和砾石组成）或从井中提取的地下水中的颗粒层安装。到目前为止，还没有进行彻底的调查：在沉积物或破裂的岩石中都属于重质含水框架中这些类型的含水剂之间的接口，而骨折的床架则靠近这些类型的含水液，而骨折的床架则可能会安装在他的下部。仅在矿床下方的基岩上的基岩或基岩的上部，这两个配置都可以怀疑泵送的水可以从矿床和床上的开口如果存在两种类型的含水层之间的水合物可能是自然存在的，那么在这种情况下，破裂的岩石的不连续性会自然地与沉积物相交。含水层之间的液压连接（沿着骨折岩石底部的底部的优先途径）在两种配置中）都被称为“混合井”，因为它们收集了源自颗粒含水层和裂缝的岩石的水域。拟议的研究的目的是建立一种方法，允许手头检测混合井连接和两种含水层的优先流速。 EXCHANGES BETWEEN THE TYPES OF AQUIFERS CLOSE THE WELLS AND AND AND AND AND AND AND AND AND AND AND AND AND AND AND EGIONAL SCALES, And TO HELP TO UNDERSTAND THE ORIGIN OF GROUNDWATER SUPPLIED BY WELLS. These aspects is of crucial Importance When AppRopriaTely Managing Resources并更好地量化不同的含水层的量，还可以在不同的含水层之间进行污染。可能的污染。这项拟议的研究会导致建立新工具，以弥补对资源的苦难的脆弱性。现场测试通过开发的两个方面进行了研究，以解决在Mixt Wellow Ustect中执行的水真菌测试中断裂的岩石和粒状含水层之间的连接。水源的签名，建立了Mixt Wells提供的地下水的剧院，由ACO A组成，由两个不同的化学签名组成，一个来自碎石含水层的岩石含水层和其他其他其他其他其他含水层。