Grid of streamflow variability index for Ohio

A generalized streamflow-variability index coverage was created by interpolating
a grid (with 6,066-ft^2 cells) from at-site values of the streamflow-variability
index computed for 133 rural, unregulated streamflow-gaging stations in Ohio and
nearby areas of adjacent states. Grid interpolation was done by means of the
interpolate surface routine contained in the Spatial Analyst extension of ArcView.
The inverse distance weighting (IDW) algorithm was used based on the 12 nearest
neighbors.

The streamflow-variability index at a streamflow-gaging station is defined as the
standard deviation of the logarithms of the 19 streamflow values at 5-percent
class intervals from 5 to 95 percent on the flow-duration curve (Searcy, 1959) of
daily mean streamflow for the analysis period.

Searcy, J.K., 1959, Flow-duration curves, manual of hydrology-part 2, low-flow
techniques: U.S. Geological Survey Water-Supply Paper 1542-A, 33 p.