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ABSTRACT: Samples from 107 piñon pines (Pinns edulis) at four sites were used to develop a proxy record of annual (June to June) precipitation spanning the 1226 to 2001 AD interval for the Uinta Basin Watershed of northeastern Utah. The reconstruction reveals significant precipitation variability at interannual to decadal scales. Single-year dry events before the instrumental period tended to be more severe than those after 1900. In general, decadal scale dry events were longer and more severe prior to 1900. In particular, dry events in the late 13th, 16th, and 18th Centuries surpass the magnitude and duration of droughts seen in the Uinta Basin after 1900. The last four decades of the 20th Century also represent...
Categories: Publication;
Types: Citation;
Tags: Tree r,
drought,
paleohydrology,
time-series analysis
Availability of long-term information on the variability of water resources in a given area is particularly important for sustainable resource management. Developing watershed simulation models that can be run using annually-resolved proxy climate data provides a way to improve reconstructions of hydrological parameters over multi-century time scales. Through the addition of a snowmelt modeling component, we enhanced a simple water-balance model to simulate streamflow at seasonal resolution. The model was calibrated to the upper Meadow Valley Wash, Nevada, USA, using USGS gage number 09417500 streamflow records. PRISM data at 2.5 arc-min resolution were used to reconstruct streamflow at the seasonal timescale (October...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado River basin,
Dendrohydrology,
Journal of Hydrology,
Nevada,
Paleohydrology,
Samples from 107 piñon pines (Pinns edulis) at four sites were used to develop a proxy record of annual (June to June) precipitation spanning the 1226 to 2001 AD interval for the Uinta Basin Watershed of northeastern Utah. The reconstruction reveals significant precipitation variability at interannual to decadal scales. Single-year dry events before the instrumental period tended to be more severe than those after 1900. In general, decadal scale dry events were longer and more severe prior to 1900. In particular, dry events in the late 13th, 16th, and 18th Centuries surpass the magnitude and duration of droughts seen in the Uinta Basin after 1900. The last four decades of the 20th Century also represent one of the...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal of the American Water Resources Association,
Uinta Basin Watershed,
Utah,
drought,
paleohydrology,
A regional synthesis of paleoflood chronologies on rivers in Arizona and southern Utah reveals that the largest floods over the last 5000 years cluster into distinct time periods that are related to regional and global climatic fluctuations. The flood chronologies were constructed using fine-grained slackwater deposits that accumulate in protected areas along the margins of bedrock canyons and selectively preserve evidence of the largest events. High-magnitude floods were frequent on rivers throughout the region from 5000 to 360014C yrs BP (dendrocalibrated age = 3800-2200 BC) and increased again after 2200 BP (400 BC), with particularly prominent peaks in magnitude and frequency around 1100-900 BP (AD 900?1100)...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Arizona,
Geomorphology,
Holocene climate,
Utah,
fluvial geomorphology,
Although our current (1990) knowledge of hydrologic and hydraulic processes is based on many years of study, there are river environments where these processes are complex and poorly understood. One of these environments is in mountainous areas, which cover about 25 percent of the United States. Use of conventional hydrologic and hydraulic techniques in mountain-river environments may produce erroneous results and interpretations in a wide spectrum of water-resources investigations. An ongoing U.S. Geological Survey research project is being conducted to improve the understanding of hydrologic and hydraulic processes of mountainous areas and to improve the results of subsequent hydrologic investigations. Future...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Journal of the American Water Resources Association,
flood-frequency analysis,
floods,
hydraulics,
hydrology,
The expected moments algorithm (EMA) [Cohn et al., 1997] and the Bulletin 17B [Interagency Committee on Water Data, 1982] historical weighting procedure (B17H) for the log Pearson type III distribution are compared by Monte Carlo computer simulation for cases in which historical and/or paleoflood data are available. The relative performance of the estimators was explored for three cases: fixed-threshold exceedances, a fixed number of large floods, and floods generated from a different parent distribution. EMA can effectively incorporate four types of historical and paleoflood data: floods where the discharge is explicitly known, unknown discharges below a single threshold, floods with unknown discharge that exceed...
Categories: Publication;
Types: Citation;
Tags: Floods,
frequency analysis,
historical floods,
paleohydrology
Mississippian paleokarst served as a dust trap for the oldest known Paleozoic loessite in North America. The early Pennsylvanian Molas Formation consists of loessite facies (sorted, angular, coarse-grained quartz siltstone), infiltration facies (loess redeposited as cave sediments within paleokarst features of the underlying Mississippian Leadville Limestone), colluvium facies (loess infiltrated into colluvium surrounding paleokarst towers) and fluvial facies (siltstone-rich, fluvial channel and floodplain deposits with paleosols). The depositional system evolved from an initial phase of infiltration and colluvium facies that were spatially and temporally related to the paleokarst surface, to loessite facies that...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Loessite,
Paleoclimatology,
Paleohydrology,
Paleokarst,
Sedimentary Geology,
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