StreamStats for Kentucky was developed in cooperation with the Kentucky Energy and Environment Cabinet, Department of Environmental Protection, Division of Water.
Kentucky StreamStats incorporates regression equations for estimating instantaneous peak flows with annual exceedance probabilities of 50, 20, 10, 4, 2, 1, 0.5, and 0.2 percent. These peak flows have recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively. Equations for estimating mean annual flows, harmonic mean flows, and the 7-day 2-, 10-, and 20-year and 30-day 2- and 5-year low flows also are included. In addition, Kentucky StreamStats include equations for estimating bankfull flow, area, width, and depth. The reports below document the regression equations available in StreamStats for Kentucky, the methods used to develop the equations and to measure the basin characteristics used in the equations, and the errors associated with the estimates obtained from the equations. Users should familiarize themselves with these reports before using StreamStats to obtain estimates of streamflow statistics for ungaged sites.
- Brockman, R. A., Agouridis, C. T., Workman, S. R., Ormsbee, L. E., Fogle, A. W., 2012, Bankfull regional curves for the Inner and Outer Bluegrass Regions of Kentucky, Journal of the American Water Resources Association, v. 48, no. 2, p. 391-406.
- Hodgkins, G.A. and Martin, G,R., 2003, Estimating the Magnitude of Peak Flows for Streams in Kentucky for Selected Recurrence Intervals, U.S. Geological Survey Water-Resources Investigations Report 03-4180, 68 p., 1 plate.
- Martin, G.R., 2002, Estimating Mean Annual Streamflow of Rural Streams in Kentucky: U.S. Geological Survey Water-Resources Investigations Report 02-4206, 35 p.
- Martin, G.R., and Arihood, L.D., 2010, Methods for estimating selected low-flow frequency statistics for unregulated streams in Kentucky: U.S. Geological Survey Scientific Investigations Report 2010-5217, 83 p.
- Martin, G. R. and Ruhl, K. J., 1993, Regionalization of harmonic-mean streamflows in Kentucky: U.S. Geological Survey Water-Resources Investigations Report 92-4173, 47 p., 1 pl.
Click on this link to obtain general information on the Kentucky application, as well as specific sources and computation methods for basin characteristics.
Availability of peak-flow estimates
The peak-flow regression equations are implemented only for hydrologic regions 2, 3, 5, 6, and 7 in Kentucky. Drainage area is the only explanatory variable in these equations. Equations for hydrologic regions 1 and 4 are not implemented at this time because an additional explanatory variable, stream slope, is needed to solve the equations. The capability for StreamStats to compute stream slope in a manner that duplicates the method used in the report by Hodgkins and Martin (2003) has not yet been devised.
Probability of zero-flow estimates
The equations in Kentucky StreamStats for estimating the 7-day 2-, 10-, and 20-year and 30-day 2- and 5-year low flows (Martin and Arihood, 2010) were developed using logarithmic transformations of the variables, and thus they are unable to estimate zero flow. Consequently, the authors also developed equations for estimating the probabilities of zero flow occurring at the times of the 7-day 2-, 10-, and 20-year and 30-day 2- and 5-year low flows. These two sets of equations should be used in tandem. If the probability of zero flow is larger than the inverse of the return period, then the statistic is estimated to be zero. Alternatively, if the probability of zero flow is equal to or less than the inverse of the return period, then the estimated value of the low-flow statistic should be used. For example, if the PROBZ7Q20 statistic is larger than the inverse of the return period (1/20 or 0.05), then the value of M7D20 is estimated to be zero. If the PROBZ7Q20 statistic is less than or equal to 0.05, then the regression equation should be used to determine the value of M7D20.
Related Content
Methods for estimating selected low-flow frequency statistics for unregulated streams in Kentucky
Estimating the magnitude of peak flows for streams in Kentucky for selected recurrence intervals
Estimating mean annual streamflow of rural streams in Kentucky
Regionalization of harmonic-mean streamflows in Kentucky
Related Content
- Publications
Methods for estimating selected low-flow frequency statistics for unregulated streams in Kentucky
This report provides estimates of, and presents methods for estimating, selected low-flow frequency statistics for unregulated streams in Kentucky including the 30-day mean low flows for recurrence intervals of 2 and 5 years (30Q2 and 30Q5) and the 7-day mean low flows for recurrence intervals of 5, 10, and 20 years (7Q2, 7Q10, and 7Q20). Estimates of these statistics are provided for 121 U.S. GeoAuthorsGary R. Martin, Leslie D. ArihoodEstimating the magnitude of peak flows for streams in Kentucky for selected recurrence intervals
This report gives estimates of, and presents techniques for estimating, the magnitude of peak flows for streams in Kentucky for recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years. A flowchart in this report guides the user to the appropriate estimates and (or) estimating techniques for a site on a specific stream. Estimates of peak flows are given for 222 U.S. Geological Survey sAuthorsGlenn A. Hodgkins, Gary R. MartinEstimating mean annual streamflow of rural streams in Kentucky
Mean annual streamflow ( Q a ), defined as the mean of the series of annual mean streamflow values, was determined for selected rural stream sites in Kentucky. Streamflow data for the available period of record through the 1999 water year (October 1, 1998-September 30, 1999) at 235 continuous-record streamflow-gaging stations with at least 5 years of record located in and adjacent to Kentucky wereAuthorsG. R. MartinRegionalization of harmonic-mean streamflows in Kentucky
Harmonic-mean streamflow (Qh), defined as the reciprocal of the arithmetic mean of the reciprocal daily streamflow values, was determined for selected stream sites in Kentucky. Daily mean discharges for the available period of record through the 1989 water year at 230 continuous record streamflow-gaging stations located in and adjacent to Kentucky were used in the analysis. Periods of record affecAuthorsGary R. Martin, Kevin J. Ruhl