GROUNDWATER RESIDENCE TIMES IN UNCONFINED CARBONATE AQUIFERS
GROUNDWATER RESIDENCE TIMES IN UNCONFINED CARBONATE AQUIFERS
复制标题
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
S. Worthington;W. Groundwater
中科院分区：
文献类型：
--
作者：
S. Worthington;W. Groundwater
示踪剂已广泛用于无承压碳酸盐含水层，以测量地下水流速和传播时间。注入示踪剂主要用于测量从下沉的溪流到泉水的行程时间。环境示踪剂主要用于估计含水层中的总停留时间，给出的时间通常比注入示踪剂估计的时间长一百倍。使用环境示踪剂和注入示踪剂可以计算许多含水层中扩散和管道成分的停留时间和存储体积。通过添加渗透率数据，可以计算基质、裂缝和河道成分的存储和流动成分。结果表明，岩石基质提供了几乎所有的储存，但停留时间很长，特别是在较老的碳酸盐岩中。渠道提供的存储量很少，占据了大部分流量，并且停留时间很短。裂缝在基质和通道之间起中间作用，并且具有较低的存储和适中的停留时间。这些相同的对比在许多不同的含水层中都存在，并且很可能在所有非承压碳酸盐含水层中都存在。因此，这些含水层的特点并不是从管道流到扩散流类型，而是具有三重孔隙度，并在基质、裂缝和通道中形成对比的流动和储存特性。环境和注射示踪剂的结合为阐明这些对比特性提供了强大的工具。
Tracers have been widely used in unconfined carbonate aquifers to measure groundwater velocities and travel times. Injected tracers have largely been used to measure travel times from sinking streams to springs. Environmental tracers have largely been used to estimate overall residence times in an aquifer, and give times that are typically one hundred times longer than estimates from injected tracers. Use of both environmental and injected tracers has enabled residence times and storage volumes to be calculated for both diffuse and conduit components in a number of aquifers. With the addition of permeability data it is possible to calculate storage and flow components for the matrix, fracture and channel components. Results show that the matrix of the rock provides almost all storage, but has very long residence times, especially in older carbonates. Channels provide little storage, account for most of the flow, and have very short residence times. Fractures play an intermediate role between the matrix and channels and have low storage and moderate residence times. These same contrasts are found in many different aquifers and are likely to be found in all unconfined carbonate aquifers. Thus these aquifers are marked not so much by ranging from conduit flow to diffuse flow types, but rather in having triple porosity with contrasting flow and storage properties in the matrix, fractures and channels. The combination of environmental and injected tracers provides a powerful tool for elucidating these contrasting properties.