Review of Laboratory Scale Models of Karst Aquifers: Approaches, Similitude, and Requirements

This review focuses on the simulation of groundwater flow and solute transport through karst/fractured rock aquifers through the use of laboratory scale models. It consists of a collection of different size and types of laboratory scale models. The previously developed laboratory scale models are categorized into four groups including sand box, rock block, pipe/fracture network, and pipe-matrix coupling, based on the concept of groundwater flow through single continuum or coupled discrete-continuum media. The groups of laboratory scale models are compared and their advantages and disadvantages highlighted. The authors conclude that new developments in experimental methods and measurement devices in laboratory scale models may play an important role in simulating groundwater flow and solute transport in heterogeneous karst/fractured-rock aquifers and the testing of new approaches for the characterization and modeling of groundwater flow and solute transport. Newer technologies such as 3D printing, CT scan, X-ray and the potential advantages of nano-materials allow for greater flexibilities of laboratory scale models for understanding the effects of different natural and anthropogenic stresses. A few requirement are introduced for validating laboratory scale model for karst/fractured-rock aquifers: (1) the ability to establish non-Darcian flow regime and exchange flow between matrix and conduits/fractures, (2) adequate sampling points and intervals, and (3) achieving some degree of geometric, kinematic and dynamic similitude.

Impact/Purpose

Development of new methods to characterize karst/fractured-rock aquifers is necessary because of the difficulties in predicting groundwater flow and contaminant transport. Moreover, development and validation of modeling methods are also important. Both of these could be tested under controlled conditions. One way to do this is with laboratory scale synthetic aquifers which is what we are reviewing here. Laboratory scale models can be used to simulate in a forward sense flow and transport. It can be very useful for testing of these new modeling approaches and new characterization approaches under a controlled setting. This review is a first attempt to highlight the improvements in laboratory scale modeling of karst/fractured rock aquifers and to categorize the various approaches. The objectives of this paper are: (1) to present an overview of the implemented laboratory scale models and approaches with a main focus placed on karst groundwater modeling, and (2) to introduce some guidelines for laboratory scale modeling of karst/fractured rock aquifers.

Citation

Mohammadi, Z., W. Illman, AND M. Field. Review of Laboratory Scale Models of Karst Aquifers: Approaches, Similitude, and Requirements. Wiley-Blackwell, Hoboken, NJ1-12, (2020).

• https://ngwa.onlinelibrary.wiley.com/doi/10.1111/gwat.13052