Stream-groundwater exchange is described at the watershed/basin (50 to 500 km2), valley segment (100 to10,000 m2), reach (10 to 100 m2) and channel/habitat-unit (1 to10 m2) scales in this section as delineated in Figure 15 (Bisson et al., 2006).
Figure 15 – Stream-groundwater exchange at multiple scales. a) At the watershed/landscape scale, shallow local and intermediate groundwater discharges to, or is recharged by, tributaries and the main channel. Basin scale groundwater flow discharges to the main channel (large dashed arrows). b) Smaller stream valleys and floodplains induce groundwater exchange. c) Channel-scale exchange includes surface water circulating within the beds and banks as well as local, intermediate and/or regional groundwater exchange (black arrows) (modified from Healy et al., 2007).
