Runoff/infiltration links carry runoff and infiltration from catchments to rivers, reservoirs, and groundwater nodes. Catchment runoff and infiltration is water from precipitation, snow and ice melt, irrigation and soil moisture storage that is not consumed by evapotranspiration or losses to increased soil moisture. Catchment Runoff can also be designated as the headflow to a river. To do this, move the catchment inflow node to the top of the river. Runoff/infiltration links can also link one groundwater node to another, in order to model subsurface flow from one to the other.