This attribute identifies areas where valley floors and their floodplains expand and contract. Where sigificant narrowing occurs, hyporheic flow upwelling can occur, which can lead to cooler waters merging into the stream flow (See Figure). Conversley, where floodplains abruptly expand, downwelling can occur. Positive values represent provisional upwelling or potential cool water refugia. If these attributes are not available for your own watershed, please contact us.   See more.