Integrated Modeling

Integrated Groundwater Surface Water Modeling

When do I need an integrated model?

An integrated model is required whenever a) there is a need to solve a water resources problem involving groundwater / surface water interactions; and b) a deterministic (predictive) tool is needed to find answers to the questions that will ultimately lead to a viable solution to the problem.

What are the components of an integrated model?

Integrated models (as with all physically-based hydrologic and hydraulic models) can be classified as either lumped-parameter or spatially distributed. Lumped-parameter models are discretized along user-defined basin/subbasin boundaries, often with simplified storage terms to represent subsurface layers and surface water bodies. In the spatially distributed case, the model domain is subdivided via a horizontal grid or mesh, with multiple vertical layers to represent land surface and the various subsurface layers of interest. A full discussion of all integrated modeling components is well beyond the scope of this page, but in short, integrated models of both types (lumped and distributed) typically include some representation of the following processes:

  • Rainfall
  • Interception
  • Evapotranspiration
  • Infiltration
  • Runoff (overland flow)
  • Flow through the unsaturated subsurface zone
  • Horizontal and/or vertical flow through the saturated zone

Other potential components include irrigation, groundwater withdrawals, point sources, sediment transport, and water quality processes. Integrated models use various coupling algorithms for transferring fluxes and heads between the model sub-domains (surface water, unsaturated zone, saturated zone). These techniques range from loose “linkages” to implicit coupling mechanisms.

How do I choose a modeling tool?

In many cases, public domain software tools are the best option due to their wide usage, transparency and acceptance by public agencies. The modeling experts at Interflow have extensive training and experience in applying a variety of public domain software capable of simulating groundwater / surface water interactions. These options include (among others) EPA SWMM (with the groundwater routines enabled), HSPF with various options for coupling surface water levels with confined and unconfined aquifer heads, and MODFLOW with the various surface water (Lake, Reservoir, River, and Stream) packages.

interflowmodelingmapIn other instances, a proprietary modeling tool may provide an advantage by virtue of its capabilities for processing model input and output data, or it may contain a required set of hydrologic or hydraulic process representations that cannot be found in “off-the-shelf” public domain tools. An example of a proprietary integrated modeling tool commonly used in Florida is the MIKE SHE / MIKE 11 suite, which provides a number of advanced options for physically based, fully distributed integrated modeling. Currently, Interflow has two full licenses for MIKE SHE / MIKE 11. Whatever the modeling project, the experts at Interflow can help identify the available options, characterize their strengths and weaknesses, and choose the right tool for the job.

Why Choose Interflow?

myakaarivermodelingInterflow’s hydrologists all have advanced university degrees in water resources. At the outset of any modeling project, we invest the time and effort to fully understand the problem at hand, to define the modeling objectives, and to characterize the important processes that must be represented accurately in the model. We have the training and experience to setup and calibrate models efficiently and to do so within our client’s scheduling and budgeting constraints. As we combine our understanding of hydrology, hydraulics, and numerical modeling with the use of advanced GIS techniques, innovative post-processing algorithms and quality control procedures, we routinely provide defensible, high value services in return for our Client’s investments.