Stream-Channel and Watershed Delineations and Basin-Characteristic Measurements using Lidar Elevation Data for Small Drainage Basins within the Des Moines Lobe Landform Region in Iowa

Basin-characteristic measurements related to stream length, stream slope, stream density, and stream order have been identified as significant variables for estimation of flood, flow-duration, and low-flow discharges in Iowa. The placement of channel initiation points, however, has always been a matter of individual interpretation, leading to differences in stream definitions between analysts. This study investigated five different methods to define stream initiation using 3-meter light detection and ranging (lidar) digital elevation models (DEMs) data for 17 streamgages with drainage areas less than 50 square miles within the Des Moines Lobe landform region in north-central Iowa. Each DEM was hydrologically enforced and the five stream initiation methods were used to define channel initiation points and the downstream flow paths. The five different methods to define stream initiation were tested side-by-side for three watershed delineations: (1) the total drainage-area delineation, (2) an effective drainage-area delineation of basins based on a 2-percent annual exceedance probability (AEP) 12-hour rainfall, and (3) an effective drainage-area delineation based on a 20-percent AEP 12-hour rainfall. Generalized least squares regression analysis was used to develop a set of equations for sites in the Des Moines Lobe landform region for estimating discharges for ungaged stream sites with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent AEPs. A total of 17 streamgages were included in the development of the regression equations. In addition, geographic information system software was used to measure 58 selected basin-characteristics for each streamgage.

• Record URL:
  • https://pubs.usgs.gov/sir/2017/5108/sir20175108.pdf
• Corporate Authors:

  U.S. Geological Survey

  Reston, VA  United States 

  Department of the Interior

  Washington, DC  United States 

  Iowa Department of Transportation

  Ames, IA  United States  50010

  Iowa Highway Research Board

  800 Lincoln Way
  Ames, IA  United States  50010
• Authors:
  • Eash, David A
  • Barnes, Kimberlee K
  • O'Shea, Padraic S
  • Gelder, Brian K
• Publication Date: 2017

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; Maps; References; Tables;
• Pagination: 34p

Subject/Index Terms

• TRT Terms: Drainage basins; Floods; Laser radar; Methodology; Regression analysis; Stream gages; Streams; Watersheds
• Geographic Terms: Des Moines (Iowa)
• Subject Areas: Hydraulics and Hydrology; Transportation (General);

Filing Info

• Accession Number: 01665923
• Record Type: Publication
• Report/Paper Numbers: Scientific Investigations Report 2017–5108
• Contract Numbers: Project TR–692
• Files: TRIS, ATRI, STATEDOT
• Created Date: Apr 11 2018 5:21PM