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With increasing concerns about the impact of warming temperatures on water resources, more attention is being paid the relationship between runoff and precipitation, or runoff efficiency. Temperature is a key influence on Colorado River runoff efficiency, and warming temperatures are projected to reduce runoff efficiency. Here, we investigate the nature of runoff efficiency in the upper Colorado River (UCRB) basin over the past 400 years, with a specific focus on major droughts and pluvials, and to contextualize the instrumental period. We first verify the feasibility of reconstructing runoff efficiency from tree-ring data. The reconstruction is then used to evaluate variability in runoff efficiency over periods...
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The goal of this project was to inform implementation of the Greater Yellowstone Coordinating Committee (GYCC) Whitebark Pine (WBP) subcommittee’s “WBP Strategy” based on climate science and ecological forecasting. Project objectives were to: 1. Forecast ecosystem processes and WBP habitat suitability across the Greater Yellowstone Area (GYA) under alternative IPCC future scenarios; 2. Improve understanding of possible response to future climate by analyzing WBP/climate relationships in past millennia; 3. Develop WBP management alternatives; 4. Evaluate the alternatives under IPCC future scenarios in terms of WBP goals, ecosystem services, and costs of implementation; and 5. Draw recommendations for implementation...
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Paleohydrologic records provide a valuable perspective on the variability of streamflow and hydroclimate that is critical for water resource planning and placing present day and future conditions into a long-term context. Until now, key insights gained from streamflow reconstructions in the other river basins across the Western U.S. have been lacking in the Milk and St. Mary River Basin. Here we utilize a new database of naturalized streamflow records for the Milk and St. Mary Rivers and an expanded network of tree-ring records from the region to reconstruct streamflow at eight gaging locations located in the mountains, foothills, and plains reaches of the basins. The network of streamflow reconstructions presented...
To characterize eruption activity of the iconic Old Faithful Geyser in Yellowstone National Park over past centuries, we obtained 41 new radiocarbon dates of mineralized wood preserved in the mound of silica that precipitated from erupted waters. Trees do not grow on active geyser mounds, implying that trees grew on the Old Faithful Geyser mound during a protracted period of eruption quiescence. Rooted stumps and root crowns located on higher parts of the mound are evidence that at the time of tree growth, the geyser mound closely resembled its current appearance. The range of calibrated radiocarbon dates (1233–1362 CE) is coincident with a series of severe multidecadal regional droughts toward the end of the Medieval...
Categories: Publication; Types: Citation
Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/2015GL067613/full): This empirical study examines the influence of precipitation, temperature, and antecedent soil moisture on upper Colorado River basin (UCRB) water year streamflow over the past century. While cool season precipitation explains most of the variability in annual flows, temperature appears to be highly influential under certain conditions, with the role of antecedent fall soil moisture less clear. In both wet and dry years, when flow is substantially different than expected given precipitation, these factors can modulate the dominant precipitation influence on streamflow. Different combinations of temperature, precipitation, and soil moisture...
With increasing concerns about the impact of warming temperatures on water resources, more attention is being paid the relationship between runoff and precipitation, or runoff efficiency. Temperature is a key influence on Colorado River runoff efficiency, and warming temperatures are projected to reduce runoff efficiency. Here, we investigate the nature of runoff efficiency in the upper Colorado River (UCRB) basin over the past 400 years, with a specific focus on major droughts and pluvials, and to contextualize the instrumental period. We first verify the feasibility of reconstructing runoff efficiency from tree-ring data. The reconstruction is then used to evaluate variability in runoff efficiency over periods...
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Samples of silicified wood remnants from 8 trees were collected under research permit YELL-SCI-8030 on June 17, 2023, and on September 19, 2023 adjacent to Artemisia Geyser in the Upper Geyser Basin of Yellowstone National Park. Samples were collected for radiocarbon (14C) dating of the wood to determine when the trees grew. Trees do not grow on active geyser mounds (Hurwitz and others, 2020, 2024) and therefore, trees grew around Artemisia Geyser during a protracted period of eruption quiescence. The study of silicified trees at Artemisia Geyser follows similar studies at Old Faithful Geyser in the Upper Geyser Basin (Hurwitz and others, 2020) and at Steamboat Geyser in Norris Geyser Basin (Hurwitz and others,...
Under climate change, ecosystems are experiencing novel drought regimes, often in combination with stressors that reduce resilience and amplify drought’s impacts. Consequently, drought appears increasingly likely to push systems beyond important physiological and ecological thresholds, resulting in substantial changes in ecosystem characteristics persisting long after drought ends (i.e., ecological transformation). In the present article, we clarify how drought can lead to transformation across a wide variety of ecosystems including forests, woodlands, and grasslands. Specifically, we describe how climate change alters drought regimes and how this translates to impacts on plant population growth, either directly...
Categories: Publication; Types: Citation
This study builds on a collaboration with a water resource management community of practice in the Upper Colorado River Basin to develop scenarios of future drought and assess impacts on water supply reliability. Water managers are concerned with the impacts of warming on water year streamflow, but uncertainties in projections of climate make the application of these projections to planning a challenge. Instead, water managers considered a plausible scenario for future drought to be historical droughts to which warming is added. We used a simple statistical model of water year streamflow with temperatures increased by 1 °C to 4 °C, and then examined reductions in flow and runoff efficiency (RE) with each degree...
Categories: Publication; Types: Citation
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Tree-ring reconstructions of water-year (Oct 1 through Sep 30th) flow for 31 gaging sites in Missouri River basin, with complete data for 1685 through 1977 (n = 293 water years). The complete 105 tree-ring reconstructions of streamflow used in the Nature Scientific Reports paper were obtained from various sources; 74 flow reconstructions were obtained from the web resource, TreeFlow (http://www.treeflow.info/), and an additional 31 flow reconstructions (provided here) for the Missouri River basin were obtained from the U.S. Geological Survey in Bozeman, Montana.
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This dataset includes processed tree ring data from avalanche paths in Glacier National Park and the Flathead National Forest in northwest Montana. The data were processed in three distinct phases that resulted in this dataset: collection, processing, and avalanche signal analysis. This dataset consists of samples from 647 trees with 2304 growth disturbances identified from 12 avalanche paths.
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In the past century, eruptions of Steamboat Geyser in Yellowstone’s Norris Geyser Basin were mainly clustered in three episodes: between 1961 and 1969, between 1982 and 1984, and in a sequence of eruptions that began in 2018 (Reed et al., 2021) and resulted in extensive damage to, and mortality of the surrounding trees. To characterize tree response to geyser activity over time, and the response of geyser activity to climate variability, aerial and ground imagery were analyzed to document changes in tree coverage around the geyser since 1954. Twenty samples of silicified tree remnants were collected from near the geyser vent for radiocarbon (14C) dating to determine if trees grew during periods when the geyser was...
Abstract (from Wiley): With increasing concerns about the impact of warming temperatures on water resources, more attention is being paid to the relationship between runoff and precipitation, or runoff efficiency. Temperature is a key influence on Colorado River runoff efficiency, and warming temperatures are projected to reduce runoff efficiency. Here, we investigate the nature of runoff efficiency in the upper Colorado River (UCRB) basin over the past 400 years, with a specific focus on major droughts and pluvials, and to contextualize the instrumental period. We first verify the feasibility of reconstructing runoff efficiency from tree‐ring data. The reconstruction is then used to evaluate variability in runoff...
The Milk and St. Mary Rivers are international waterways straddling the United States and Canada and traversing four Tribal Nations before draining into the Missouri and South Saskatchewan Rivers respectively. Management of water resources in the region is challenged by the complexity of stakeholder interests, the limitations of existing management infrastructure, and by a limited characterization of the long-term streamflow and hydroclimatic variability across the area. We used existing records of natural streamflow to investigate the relationships between seasonal climate variability and differences in the timing and volume of flow from the headwaters to the prairie tributaries. Then, using a network of tree-ring...
Categories: Publication; Types: Citation
Abstract (from https://www.sciencedirect.com/science/article/pii/S2405880717300924): Water managers are increasingly interested in better understanding and planning for projected resource impacts from climate change. In this management-guided study, we use a very large suite of synthetic climate scenarios in a statistical modeling framework to simultaneously evaluate how (1) average temperature and precipitation changes, (2) initial basin conditions, and (3) temporal characteristics of the input climate data influence water-year flow in the Upper Colorado River. The results here suggest that existing studies may underestimate the degree of uncertainty in future streamflow, particularly under moderate temperature...
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A tree-ring based cool season (September-June) total precipitation reconstruction for Deschutes County, Oregon, spanning years 1000-1991 CE
In recent decades, Rocky Mountain accumulated snowpack levels have experienced rapid declines, yet long-term records of snowpack prior to the installation of snowpack observation stations in the early and mid 20th century are limited. To date, a small number of tree-ring based reconstructions of April 1 Snow Water Equivalent (SWE) in the northern Rocky Mountains have extended modern records of snowpack variability to ∼1200 C.E. Carbonate isotope lake sediment records, provide an opportunity to further extend tree-ring based reconstructions through the Holocene, providing a millennial-scale temporal record that allows for an evaluation of multi-scale drivers of snowpack variability, from internal climate dynamics...
Categories: Publication; Types: Citation


map background search result map search result map Science and Forecasting to Inform Implementation of the Greater Yellowstone Coordinating Committee’s Whitebark Pine Management Strategy Multi-century reconstructions of temperature, precipitation, and runoff efficiency for the Upper Colorado River Basin Paleohydrologic reconstructions of water-year streamflow for 31 stream gaging sites in the Missouri River Basin with complete data for 1685 through 1977 Tree ring dataset for a regional avalanche chronology in northwest Montana, 1636-2017 Multi-century reconstructions of temperature, precipitation, and runoff efficiency for the Upper Colorado River Basin A network of eight naturalized streamflow reconstructions for the Milk and St Mary Rivers spanning years 1017 – 1998 CE Cool Season (September-June) Total Precipitation Reconstruction for Deschutes County, Oregon, 1000-1991 CE Radiocarbon dating of silicified wood from around Steamboat Geyser in Norris Geyser Basin, Yellowstone National Park, 2021-2022 Radiocarbon dating of silicified wood from around Artemisia Geyser in the Upper Geyser Basin, Yellowstone National Park Radiocarbon dating of silicified wood from around Artemisia Geyser in the Upper Geyser Basin, Yellowstone National Park Tree ring dataset for a regional avalanche chronology in northwest Montana, 1636-2017 Cool Season (September-June) Total Precipitation Reconstruction for Deschutes County, Oregon, 1000-1991 CE A network of eight naturalized streamflow reconstructions for the Milk and St Mary Rivers spanning years 1017 – 1998 CE Multi-century reconstructions of temperature, precipitation, and runoff efficiency for the Upper Colorado River Basin Multi-century reconstructions of temperature, precipitation, and runoff efficiency for the Upper Colorado River Basin Paleohydrologic reconstructions of water-year streamflow for 31 stream gaging sites in the Missouri River Basin with complete data for 1685 through 1977 Science and Forecasting to Inform Implementation of the Greater Yellowstone Coordinating Committee’s Whitebark Pine Management Strategy