Variability in rainfall at monitoring stations and derivation of a long-term rainfall intensity record in the Grand Canyon Region, Arizona, USA

Scientific Investigations Report 2016-5012
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Abstract

In this study, we examine rainfall datasets of varying temporal length, resolution, and spatial distribution to characterize rainfall depth, intensity, and seasonality for monitoring stations along the Colorado River within Marble and Grand Canyons. We identify maximum separation distances between stations at which rainfall measurements might be most useful for inferring rainfall characteristics at other locations. We demonstrate a method for applying relations between daily rainfall depth and intensity, from short-term high-resolution data to lower-resolution longer-term data, to synthesize a long-term record of daily rainfall intensity from 1950–2012. We consider the implications of our spatio-temporal characterization of rainfall for understanding local landscape change in sedimentary deposits and archaeological sites, and for better characterizing past and present rainfall and its potential role in overland flow erosion within the canyons. We find that rainfall measured at stations within the river corridor is spatially correlated at separation distances of tens of kilometers, and is not correlated at the large elevation differences that separate stations along the Colorado River from stations above the canyon rim. These results provide guidance for reasonable separation distances at which rainfall measurements at stations within the Grand Canyon region might be used to infer rainfall at other nearby locations along the river. Like other rugged landscapes, spatial variability between rainfall measured at monitoring stations appears to be influenced by canyon and rim physiography and elevation, with preliminary results suggesting the highest elevation landform in the region, the Kaibab Plateau, may function as an important orographic influence. Stations at specific locations within the canyons and along the river, such as in southern (lower) Marble Canyon and eastern (upper) Grand Canyon, appear to have strong potential to receive high-intensity rainfall that can generate runoff which may erode alluvium. The characterization of past and present rainfall variability in this study will be useful for future studies that evaluate more spatially continuous datasets in order to better understand the rainfall dynamics within this, and potentially other, deep canyons.

Suggested Citation

Caster, Joshua, and Sankey, J.B., 2016, Variability in rainfall at monitoring stations and derivation of a long-term rainfall intensity record in the Grand Canyon region, Arizona, USA: U.S. Geological Survey Scientific Investigations Report 2016-5012, 38 p., http://dx.doi.org/10.3133/sir20165012.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Materials and Methods
  • Short-Term Spatial Rainfall Variability
  • Long-Term Rainfall Depth Variability
  • Long-Term Rainfall Intensity Variability
  • Results
  • Validation of Seasonal Depth-Intensity Models
  • Estimation of Rainfall Intensity at NOAA COOP Stations
  • Discussion
  • Conclusions
  • References Cited

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Variability in rainfall at monitoring stations and derivation of a long-term rainfall intensity record in the Grand Canyon Region, Arizona, USA
Series title Scientific Investigations Report
Series number 2016-5012
DOI 10.3133/sir20165012
Year Published 2016
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Southwest Biological Science Center
Description iv, 38 p.
Country United States
State Arizona
Other Geospatial Grand Canyon
Online Only (Y/N) Y
Additional Online Files (Y/N) Y
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