Hydrogeology Today™

Hazlett-Kincaid, Inc.
Specialized Geological Modeling Services

In this issue:

NAPLVOL™ - Read all about HKI's new LNAPL volume estimation process

Hydrogeology Consortium - Karst Modeling Conference

An internet-based electronic publication of Hazlett-Kincaid. Copyright 2001. Hazlett-Kincaid, Inc. All rights reserved. 
Volume 2, Number 4
(December 2001)

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Akron, PA 17501

ph: 717.859.1413
FAX: 801.912.4751
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Comments or Questions?

e-mail:
Timothy J. Hazlett, Ph.D.
Todd R. Kincaid, Ph.D.

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LNAPL Volume Estimation

We have developed at Hazlett-Kincaid a new, high-resolution approach to LNAPL volume estimation. When we develop new services, they are always based on cutting-edge computational and numerical resources as well as sound science. This new service is no exception. Both LINUX and Windows NT parallel supercomputing clusters provide our workhorse computational power, while we create our world class visualizations on our SGI 540 Visual Workstation.

The visualization shown here (html version only) is from an actual LNAPL plume volume estimate. The 3-D plume thickness is shown (orange pancake shape) along with a 3-D spatial parameterization of saturated hydraulic conductivity (browns and yellows, where Kbrown<<Kyellow). In a physical sense, the visualization reveals that the LNAPL is trapped beneath a relatively impermeable layer. Our LNAPL volume estimation process capitalizes on our dual-modeling approach, where sophisticated site conceptual, geologic, and parameter modeling is coupled to predictive and process models in order to gain both a holistic and quantitative grasp on any problem.

The code that forms the backbone of our quantitative estimation is called NAPLVOL™, which was developed by HKI's in-house capabilities. NAPLVOL capitalizes on the fine, site-scale resolution provided by HKI's parameter models to provide the client with a high-precision estimate of LNAPL volume that is many times more precise than prior approaches. We have accomplished this by modifying the Van Genuchten soil parameter approach. NAPLVOL uses three-phase constitutive relations (oil-water-air) to obtain the vertical distribution of fluid saturation and to compute the free product volume in the soil as well as the residual oil volume in the unsaturated and saturated zones. Lastly, our process allows further refinement of the actual volume of LNAPL present in the system by integrating in time, which accommodates fluctuations in the water table and smearing of the LNAPL zone.

LNAPL volume estimation is crucial not only from a site characterization standpoint, but also as a tool for remediation. Having the best possible estimate of the volume and 3-D distribution of LNAPL allows more precise and confident design of remedial systems and overall shorter time to cleanup. We are confident that this approach is the best available and one that should be applied at any site where LNAPL is present and needs to be remediated or mitigated.(back to top)

Karst Modeling Conference

In cooperation with The Hazardous Waste Regulation Section of the FL. DEP, FSU's Geophysical Fluid Dynamics Institute, and Hazlett-Kincaid, Inc., the Annual Workshop of the Hydrogeology Consortium was held November 8th and 9th in Orlando, FL. The conference was deemed a great success by all in attendance.

Four topics, all related to flow modeling in karst environments, were introduced by the following experts:
 

The four topics were then discussed in "breakout" sessions, led by the expert panels. Finally, each of the panels reported back to the entire attendance regarding the findings and conclusions developed in their respective sessions.

Some of the main findings of fact coming from the discussions included:

1. continuum models, such as MODFLOW, are generally applicable in Florida karst only at the scale of counties, or bigger. Below that scale, karst features likely become significant enough that they should be explicitly included in the modeling approach, especially when it comes to fate and transport.
2. In karst settings, K's scale dependence requires that one collect data at different scales of resolution. This led to the idea that new field techniques for data collection in karst settings need to be developed.
3. Surface water and groundwater systems in Florida exchange so rapidly that they should be considered all part of the same system. Furthermore, surface water and groundwater models need to interface directly.

The proceedings of the conference are currently being organized for publication and should be available in Spring 2002, through the Hydrogeology Consortium (http://hydrogeologyconsortium.org) (back to top)