DOI: 10.25921/8b56-he94
title: NOAA/WDS Paleoclimatology - Graumlich et al. 2003 Upper Yellowstone River Flow Reconstruction

description: Climate variability, coupled with increasing demand is raising concerns about the sustainability of water resources in the western United States. Tree-ring reconstructions of stream flow that extend the observational record by several centuries provide critical information on the short-term variability and multi-decadal trends in water resources. In this study, precipitation sensitive Douglas-fir (Pseudotsuga menzeisii) tree ring records are used to reconstruct annual flow of the Yellowstone River back to A.D. 1706. Linkages between precipitation in the Greater Yellowstone Region and climate variability in the Pacific basin were incorporated into our model by including indices Pacific Ocean interannual and decadal-scale climatic variability, namely the Pacific Decadal Oscillation and the Southern Oscillation. The reconstruction indicates that 20th century streamflow is not representative of flow during the previous two centuries. With the exception of the 1930s, streamflow during the 20th century exceeded average flows during the previous 200 years. The drought of the 1930s resulted in the lowest flows during the last three centuries, however, this probably does not represent a worst-case scenario for the Yellowstone as other climate reconstructions indicate more extreme droughts prior to the 18th century.
description: Tree ring reconstruction of annual flow on the upper Yellowstone River at Corwin Springs, Montana. Tree-ring series were developed from Douglas-fir (Pseudotsuga menziesii) tree cores collected on three ridges in southwestern Montana. At each site we sampled trees growing in open stands on steep, rocky slopes. The Yellow Mountain Ridge (YMR) and North Fork Ridge (NFR) sites (45o17'N, 111o21'W; 2440 m a.s.l) are both located on south-facing slopes, 35 kilometers northwest of Yellowstone National Park. The Mount Everts site (MEV) is also south facing and is located at the northern boundary of YNP near Gardiner, MT (44o59'N,110o40'W; 2560 m a.s.l). At each site, living Douglas-fir trees were cored. Cross-sections were also obtained from remnant wood, which was abundant at each site. At NFR, YMR and MEV, 35 trees (36 radii),31 trees (46 radii) and 48 trees (69 radii), respectively, were sampled. The MEV chronology is a combination of cores and disks obtained during the summers of 1999-2001 and a previously constructed chronology obtained from the International Tree Ring Databank (Gardiner, MT submitted by C. W. Ferguson). These data have also been contributed to the International Tree Ring Databank. The streamflow series extending back to 1911 consists of annual (water year) volume of flow (m3/year) for the Upper Yellowstone River measured at Corwin Springs, Montana (CSflow). The watershed above Corwin Springs encompasses 6800 km2 of mountainous terrain within the boundary of YNP and is unregulated for water diversion in its upper stretches above the gage at Corwin Springs. Reconstruction used ITRDB data sets mt110 (https://www.ncdc.noaa.gov/paleo/study/3716), mt114 (https://www.ncdc.noaa.gov/paleo/study/3740), and wy027 (https://www.ncdc.noaa.gov/paleo/study/3321)