Compass RiverSolver LogoThe Compass RiverSolver provides distance and proximity information along complex river networks. RiverSolver is a special application of our more general Network Solver tool. For organisations such as the Environmental Protection Agency (EPA), RiverSolver helps answer important monitoring, risk assessment and licencing questions, such as:

  • Which individual segments lie between two points on a river network?
  • What is the distance between any two points on such a network?

How Does It Work?

RiverSolver finds points on a river network that lieRiverSolve screenshot upstream and downstream from a location indicated by the user, and calculates the distances between pairs of points. It returns lists of river segment codes between two locations on the river network, along with the lengths of the segments.

To use, simply ‘click’ near a river on the map displayed in the Compass web map viewer (MapView), and the upstream and downstream points light up. Then ‘hover’ over these points with the mouse for more details, including their distance from the start point. Additional information can be provided, depending upon the specific applications.

Typical RiverSolver Applications

To assess applications for restricted discharges, the EPA Assimilative Capacity Tool screenshotdetermines the capacity of a river to receive the discharge and the potential environmental impact, using the Assimilative Capacity Tool (ACT). This web-based tool allows the user to carry out the assimilative capacity calculations in three simple steps, using data from across the organisation, enabling informed decisions on proposed discharges. The system helps improve the EPA’s ability to meet one of the ‘2020 Vision’ targets – “Control discharges to waters by those we licence, to ensure that there is no detrimental impact on receiving waters.”


Eel Management System dashboardRiverSolver was used by the Irish Central Fisheries Board to assess breeding grounds for eels in Irish rivers. Barriers were defined on the river network representing known places where eels could not migrate upstream. Then RiverSolver was used to find which lakes were accessible to eels for breeding, and what engineering projects could be undertaken to open up the maximum numbers of lakes to encourage eel production in Ireland.

Download the Compass RiverSolver Fact Sheet.