The Iowa Water Science Center recently investigated and updated several grids to improve the basin characteristic computations in StreamStats. The updated grids result in more consistency between StreamStats computed basin characteristics and basin characteristics used to derive regression equations to estimate flow statistics in Iowa. This results in StreamStats estimates more closely matching published estimates in previous reports using the following basin characteristics:  

STREAM_VARG: Streamflow variability index as defined in WRIR 02-4068, computed from regional grid

TAU_ANN_G: Average annual base-flow recession constant as defined in SIR 2008-5065

SSURGOKSAT: Saturated hydraulic conductivity in micrometers per second from NRCS SSURGO database