CONNECTFLOW is the suite of Serco Assurance's groundwater modelling software that includes the NAMMU continuum porous medium (CPM) module and the NAPSAC discrete fracture network (DFN) module. CONNECTFLOW is also the name given to the concept of nesting NAMMU and NAPSAC sub-models into a combined CPM/DFN model. CONNECTFLOW is very flexible tool for modelling groundwater flow and transport in both fractured and porous media on a variety of scales.

CONNECTFLOW has been developed by Serco Assurance (formally AEA Technology) over the last 10 years. It is developed under a rigorous quality system that conforms to the international standards ISO 9001 and TickIT. CONNECTFLOW can be used to model the following physics and geometries:

• 3D models;
• single or multiple DFN sub-regions nested within CPM regions;
• single CPM sub-regions nested within DFN region;
• stratigraphic layers with DFN representation can be interfaced to layers with a CPM representation;
• models are built up of grids with different patches being assigned to either a CPM or DFN subdomain;
• nesting of detailed DFN models within nested CPM models using embedded ('constraint') grids to represent site-scale and region-scales;
• stochastic DFN and CPM models;
• steady-state and transient constant-density groundwater flow;
• advective transport through a combined DFN/CPM based on a particle tracking approach.

CONNECTFLOW can be used to model the following features:

• local DFN models to represent the detailed flow in fractures around tunnels, shafts, canisters or boreholes nested within a CPM model that extends the model to appropriate boundaries;
• detailed CPM models of tunnels, shafts and canisters within a DFN model to represent the interaction between flow in a fractured media and backfilled tunnels;
• continuous representation of deterministic faults/fracture zones through the DFN and CPM sub-models using consistent data formats and a combination of explicit fracture planes in DFN regions and an implicit fracture zone (IFZ) method in the CPM region.
• quantifying conceptual uncertainties between DFN and CPM models.

Using the CONNECTFLOW suite of programs allows the development of integrated groundwater flow and transport models using the combined concepts of discrete fracture networks and continuum modelling without the need to export boundary conditions from one model to another.