Anaqsim
/ˈæn-ək-sɪm/
(AN-uhk-sim)
Hard to pronounce. Easy to use.
Designed by engineers for engineers and geoscientists, Anaqsim offers unmatched flexibility and ease of use when modifying your models. This enables you to quickly set up, test, and refine your ideas in a virtual design lab—where it’s cost-effective to push your designs to their limits and easy to discover what works best.
What makes this possible? The Analytic Element (AE) method.
The AE method was pioneered by visionary professor Otto Strack in the late 1970s— back when the digital computer was in its infancy and required a PhD to operate. Strack began developing this innovative method while forecasting groundwater impacts for the U.S. Army Corps of Engineers. His goal? To develop an efficient solution that could tackle complex groundwater problems while overcoming the computational limits of the time.
As computing power advanced over the following decades, so too did the AE method. In the 2000s, Charlie Fitts (PhD under Strack) introduced a breakthrough: ‘spatially variable area sinks’ (SVAS) that simulate both vertical leakage between layers and transient flow in and out of storage. At the same time, Charlie introduced sub domains that divided groundwater models into smaller regions, each with its own unique and possibly anisotropic properties. This innovation made it possible to build fully 3-dimensional models with heterogeneity, anisotropy, multiple layers, and transient simulations — all while maintaining the speed and flexibility of the AE method.
In 2011, Fitts combined his advancements with the AE method to create Anaqsim – short for Analytical Aquifer Simulator, bringing together a vision decades in the making.
The rest, as they say, is history…
How does Anaqsim work?
Anaqsim blends the strengths of both analytical and numerical modeling. It’s designed to help you efficiently solve groundwater flow problems without the need for grids or meshes, offering a faster and more flexible approach compared to traditional methods like finite element or finite difference models.
Get to know the key concepts behind Anaqsim’s approach:
Superposition of Element Functions:
Anaqsim simulates hydrogeologic features, such as wells, rivers, or zones of different conductivity, using “element” functions. These elements are both modular in structure and additive in their effects allowing you to quickly adjust and rerun your model in real time during analysis and design.
Exact Solutions
Anaqsim uses “analytic” calculations for each element that ensure mathematically accurate groundwater flow calculations. The only mathematical approximations occur when meeting boundary conditions, where Anaqsim calculates unknown coefficients numerically. These exact solutions free you from the headaches of computation inaccuracies encountered with the approximation methods used in finite element and finite difference methods.
No Grids, Just Boundaries:
Unlike grid-based methods, Anaqsim only focuses on system boundaries (internal and external). This means there’s no need to divide the entire domain into a mesh, making the model grid-independent, which eliminates tedious mesh/grid building and offers you the ultimate flexibility in adding, removing and adjusting your model details.
Scalability:
Anaqsim’s models are not constrained by spatial size. Instead, they scale with the complexity of the system being modeled, which enables you to create or add detailed representations anywhere in your model at any time!
Anaqsim allows you to simulate complex groundwater systems—whether 3D, multi-layered, or heterogeneous—with the computational accuracy of analytical methods and the conceptual complexity of numerical methods.
AnAqSim allows the modeler to easily define complex boundary conditions, which is a significant advantage over grid-based methods.
Get Charlie Fitts’ textbook
From the physics of groundwater flow, to modelling systems and of course the AE method and Anaqsim
The instructional text book used by:
Our Commitment to You
At Anaqsim, we believe in the importance of thoughtful design and rigorous problem-solving. Our values are rooted in helping you strike the right balance between theoretical precision and practical, real-world applications. We’re passionate about water – especially groundwater – and dedicated to equipping you with the tools and knowledge needed to manage this vital resource responsibly.
We go beyond software by offering regular video-group sessions on both the theoretical aspects of mathematical modeling and the practical side of engineering, including experiential design and writing proposals. Additionally, our library of pre-built, customizable models is designed to help you jump-start your projects efficiently. Together, we aim to foster engineering excellence while supporting your efforts to deliver effective and sustainable solutions.
Free 14-day trial
No credit-card required
References
Omar, P. J., Pandey, V. P., Suthar, S., & Kumar, R. (2019). Groundwater Modelling Using an Analytic Element Method and Finite Difference Method: A Comparative Study. Journal of Water Resource and Protection, 11, 1019-1037. https://doi.org/10.4236/jwarp.2019.118060
Le Moine, N. (2022). On the Computation of the Basal Envelope Surface of Talwegs using the Analytic Element Method. Comptes Rendus Geoscience, 355(S1), A9.
https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.164/