Karst Aquifer evolution in fractured, porous rocks

Kaufmann, George; Braun, Jean

doi:10.1029/1999wr900356

Cited by 125 publications

(69 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The method is inspired by speleogenetic process based models (Dreybrodt et al, 2005;Kaufmann and Braun, 2000). In order to accelerate the simulation, we use a proxy allowing to mimic the final result (mature system) without modeling the physical and chemical processes.…”

Section: Karst Conduit Simulationmentioning

confidence: 99%

See 1 more Smart Citation

A pseudo-genetic stochastic model to generate karstic networks

Borghi

Renard

Jenni

2012

Journal of Hydrology

View full text Add to dashboard Cite

s u m m a r yIn this paper, we present a methodology for the stochastic simulation of 3D karstic conduits accounting for conceptual knowledge about the speleogenesis processes and accounting for a wide variety of field measurements.The methodology consists of four main steps. First, a 3D geological model of the region is built. The second step consists in the stochastic modeling of the internal heterogeneity of the karst formations (e.g. initial fracturation, bedding planes, inception horizons, etc.). Then a study of the regional hydrology/ hydrogeology is conducted to identify the potential inlets and outlets of the system, the base levels and the possibility of having different phases of karstification. The last step consists in generating the conduits in an iterative manner using a fast marching algorithm. In most of these steps, a probabilistic model can be used to represent the degree of knowledge available and the remaining uncertainty depending on the data at hand.The conduits are assumed to follow minimum effort paths in a heterogeneous medium from sinkholes or dolines toward springs. The search of the shortest path is performed using a fast marching algorithm. This process can be iterative, allowing to account for the presence of already simulated conduits and to produce a hierarchical network.The final result is a stochastic ensemble of 3D karst reservoir models that are all constrained by the regional geology , the local heterogeneities and the regional flow conditions. These networks can then be used to simulate flow and transport. Several levels of uncertainty can be considered (large scale geological structures, local heterogeneity, position of possible inlets and outlets, phases of karstification).Compared to other techniques, this method is fast, to account for the main factors controlling the 3D geometry of the network, and to allow conditioning from available field observations.

show abstract

Section: Karst Conduit Simulationmentioning

confidence: 99%

“…The most advanced ones are based on modeling the physics and chemistry of the speleogenesis processes (Dreybrodt et al, 2005;Kaufmann and Braun, 2000). This approach allows understanding the kinetics of karst evolution, and give precious information about the speleogenesis processes.…”

Section: Introductionmentioning

confidence: 99%

A pseudo-genetic stochastic model to generate karstic networks

Borghi

Renard

Jenni

2012

Journal of Hydrology

View full text Add to dashboard Cite

show abstract

“…Several sensitivity studies have evaluated the parameters in karst aquifers. Kaufmann and Braun (2000) reported that boundary conditions and sink recharges are important to the preferential flow path in a karst aquifer. Scanlon et al (2003) also confirmed that recharge is important to karst spring discharge.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling and sensitivity analysis of seawater intrusion in a dual-permeability coastal karst aquifer with conduit networks

2018

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. Long-distance seawater intrusion has been widely observed through the subsurface conduit system in coastal karst aquifers as a source of groundwater contaminant. In this study, seawater intrusion in a dual-permeability karst aquifer with conduit networks is studied by the two-dimensional density-dependent flow and transport SEAWAT model. Local and global sensitivity analyses are used to evaluate the impacts of boundary conditions and hydrological characteristics on modeling seawater intrusion in a karst aquifer, including hydraulic conductivity, effective porosity, specific storage, and dispersivity of the conduit network and of the porous medium. The local sensitivity analysis evaluates the parameters' sensitivities for modeling seawater intrusion, specifically in the Woodville Karst Plain (WKP). A more comprehensive interpretation of parameter sensitivities, including the nonlinear relationship between simulations and parameters, and/or parameter interactions, is addressed in the global sensitivity analysis. The conduit parameters and boundary conditions are important to the simulations in the porous medium because of the dynamical exchanges between the two systems. The sensitivity study indicates that salinity and head simulations in the karst features, such as the conduit system and submarine springs, are critical for understanding seawater intrusion in a coastal karst aquifer. The evaluation of hydraulic conductivity sensitivity in the continuum SEA-WAT model may be biased since the conduit flow velocity is not accurately calculated by Darcy's equation as a function of head difference and hydraulic conductivity. In addition, dispersivity is no longer an important parameter in an advectiondominated karst aquifer with a conduit system, compared to the sensitivity results in a porous medium aquifer. In the end, the extents of seawater intrusion are quantitatively evaluated and measured under different scenarios with the variabilities of important parameters identified from sensitivity results, including salinity at the submarine spring with rainfall recharge, sea level rise, and a longer simulation time under an extended low rainfall period.

show abstract

“…Individual fractures have been assembled into fracture networks in order to model patterns of evolving conduit systems (Lauritzen et al, 1992;Groves and Howard, 1994;Siemers and Dreybrodt, 1998;Kaufmann and Braun, 2000;Liedl et al, 2003). A typical benchmark setting emerged out of the Ewers's hardware models.…”

Section: Evolution Of a Discrete Network Under Pressurized Flow Condimentioning

confidence: 99%

Evolution of karst conduit networks in transition from pressurized flow to free-surface flow

Perne

Covington

Gabrovšek

2014

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. Most of the existing models of speleogenesis are limited to situations where flow in all conduits is pressurized. The feedback between the distribution of hydraulic head and growth of new solution conduits determines the geometry of the resulting conduit network. We present a novel modeling approach that allows a transition from pressurized (pipe) flow to a free-surface (open-channel) flow in evolving discrete conduit networks. It calculates flow, solute transport and dissolution enlargement within each time step and steps through time until a stable flow pattern is established. The flow in each time step is calculated by calling the US Environmental Protection Agency Storm Water Management Model (US Environmental Protection Agency, 2014), which efficiently solves the 1-D Saint-Venant equations in a network of conduits. Two basic scenarios are modeled, a low-dip scenario and a high-dip scenario. In the low-dip scenario a slightly inclined plane is populated with a rectangular grid of solution conduits. The recharge is distributed to randomly selected junctions. The results for the pressurized flow regime resemble those of the existing models. When the network becomes vadose, a stable flow pathway develops along a system of conduits that occupy the lowest positions at their inlet junctions. This depends on the initial diameter and inlet position of a conduit, its total incision in a pressurized regime and its alignment relative to the dip of the plane, which plays important role during the vadose entrenchment. In the high-dip scenario a sub-vertical network with recharge on the top and outflow on the side is modeled. It is used to demonstrate the vertical development of karst due to drawdown of the water table, development of invasion vadose caves during vadose flow diversion and to demonstrate the potential importance of deeply penetrating conductive structures.

show abstract

Karst Aquifer evolution in fractured, porous rocks

Cited by 125 publications

References 23 publications

A pseudo-genetic stochastic model to generate karstic networks

A pseudo-genetic stochastic model to generate karstic networks

Numerical modeling and sensitivity analysis of seawater intrusion in a dual-permeability coastal karst aquifer with conduit networks

Evolution of karst conduit networks in transition from pressurized flow to free-surface flow

Contact Info

Product

Resources

About