U.S. Department of the InteriorU.S. Geological Survey

Implementation of the U.S. Geological Survey’s StreamStats Program in Kansas— A Web Application for Streamflow Statistics and Basin Characteristics Kansas Water Science Center

Jenny Lanning-Rush, Geographer

Flood Frequency Analysis USGS routinely publishes reports that provide predictor

equations that correlate discharge to other independent geomorphologic and climatic basin parameters for much of the United States.

The multivariable linear regression equations for estimating the magnitude and frequency of peak discharges in rural ungaged streams are periodically updated to account for additional years of record

These regional flood-frequency regression equations are used by engineers, ecologists, public works directors, and many others in their day-to-day work

Regional Regression Analysis Input Variables require extensive time and computational resources to computeEquation for estimating the 100-year peak flow (the peak flow that has a 1 percent probability of being exceeded in any given year) from Rasmussen and Perry takes the form:

Q100 = 0.810(CDA)0.532(P)2.070(S)-0.309(Sl)0.272

 

where:

CDA is the contributing drainage area for the site, in square miles

P is the average annual precipitation for the entire drainage area, in inches

S is the average soil permeability for the entire basin, in inches per hour

Sl is the slope of the main channel, in feet per mile, as measured by dividing the difference in elevation at points in the channel at 10 and 85 percent of the main channel length by the intervening main channel length.

USGS StreamStats is a Map-based Web Application StreamStats uses geographic information system (GIS)

software and programming techniques to extract watershed parameters with minimal time and resources.

Extracted watershed characteristics (area, CN, …) are “Sent” to NFF and results are “Published” to the web browser

Arc Hydro tools implement specialized data structures and tools Use Arc Hydro tools for terrain

preprocessing. They build an interconnected set of spatial data that facilitate quick execution for analytical tools, a “analytical data cache” Raster data:

DEM, flow direction, flow accumulation, drainage lines, sinks, …

Vector data: Drainage lines, catchments, adjoint catchments, sinks,

lakes, …

Watershed Delineation from a Point

SS website uses Arc Hydro tools for watershed delineation, characterization, and analysis that leverage the preprocessed data structures.

Sample from Basin Characteristics Report

Parameter Value

Contributing drainage area, in square miles 51.18

Contributing drainage area minus the area upstream of NRCS floodwater-retarding structures, in square miles

51.18

Percent of contributing drainage area regulated by NRCS floodwater-retarding structures

0.0

Mean basin elevation, in feet 1250

Elevation at outlet in feet 1070

Mean basin slope in percent, computed from 10-meter DEM

4.50

Longest-flow-path 10-85 slope in feet per mile 11.5

Soil permeability from STATSGO, in inches per hour

0.420

These attributes are also stored in shapefile of the delineation & can be downloaded

1) Select area

2) Delineate watershed

3) Get results

Development for new skin (SSv4) targeted for FY16