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Title: Vegetation Assessment at Project 57 for 2019

Abstract

During the late 1950s, the Atomic Energy Commission (AEC), now the U.S. Department of Energy (DOE), conducted a series of experiments in Emigrant Valley to determine if a nuclear device subjected to a large conventional explosives detonation would result in a nuclear yield. One of these tests, Project 57, disseminated plutonium across the ground surface. Plutonium isotopes dispersed across the land surface can adhere to soil particles, particularly fine soil materials. Plutonium can be redistributed beyond the Contamination Area (CA) boundary by both wind and water. A vegetation survey was initiated in 2016 to assess the vegetation cover of the Project 57 CA and was repeated in 2018 and 2019. The purpose of the survey was to inform managers and provide data about the site’s vegetation with a perspective toward aeolian (wind) transport of soil particles. Results from the 2019 survey are reported here, with comparison to previous surveys. Perennial cover has remained stable (16 percent) during the survey time period, from 2016 to 2019. Shrub cover measured for the 2019 survey was calculated at 14 percent, which is slightly less than reported in earlier surveys but still typical for Great Basin valley shrublands. Annual plant cover was dramatically highermore » in 2019 at 33 percent, comprised primarily of forbs. This is because of the even distribution of precipitation events from the prior winter compared with previous years. Annual plant cover was 17 percent in 2016 and less than 2 percent in 2018. The spike in annual production following a wet winter demonstrates the variability and resiliency of the desert shrubland environment, which can be difficult to predict over long time periods. Consequently, the percent of bare soil was considerably less than seen in prior years, down from 60 percent to 47 percent, primarily because of the high percentage of annuals. The burned area of the CA remained dominated by native annual plants. The entirety of the plant cover within the burned area as surveyed was comprised of annuals (44 percent), primarily bristly fiddleneck (Amsinckia tessellata), leaving 56 percent of the burned area as bare ground. No bromus tectorum (cheatgrass) was recorded in the 2019 survey in the burned area, but it was observed throughout the area in general. Lacking perennial shrub cover and despite the dramatic increase in annual cover in 2019, the burned area remains a potential and geographically large source for sediment transport. Therefore, the variability of annual plant cover and the potential for changes in the perennial plant cover because of fire or drought mortality continues to suggest sediment transport from the Project 57 study site could vary dramatically over time.« less

Authors:
 [1]
  1. Desert Research Inst. (DRI), Reno, NV (United States)
Publication Date:
Research Org.:
Desert Research Institute, Nevada University, Reno, NV (United States)
Sponsoring Org.:
USDOE Office of Environmental Management (EM)
OSTI Identifier:
1566841
Report Number(s):
DOE/NV/0003590-38
DOE Contract Number:  
DE-NA0003590
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; P57, Emigrant Valley, plutonium isotopes, ground surface, nuclear devise, vegetation survey, aeolian transport

Citation Formats

Cablk, Mary E. Vegetation Assessment at Project 57 for 2019. United States: N. p., 2019. Web. doi:10.2172/1566841.
Cablk, Mary E. Vegetation Assessment at Project 57 for 2019. United States. doi:10.2172/1566841.
Cablk, Mary E. Mon . "Vegetation Assessment at Project 57 for 2019". United States. doi:10.2172/1566841. https://www.osti.gov/servlets/purl/1566841.
@article{osti_1566841,
title = {Vegetation Assessment at Project 57 for 2019},
author = {Cablk, Mary E.},
abstractNote = {During the late 1950s, the Atomic Energy Commission (AEC), now the U.S. Department of Energy (DOE), conducted a series of experiments in Emigrant Valley to determine if a nuclear device subjected to a large conventional explosives detonation would result in a nuclear yield. One of these tests, Project 57, disseminated plutonium across the ground surface. Plutonium isotopes dispersed across the land surface can adhere to soil particles, particularly fine soil materials. Plutonium can be redistributed beyond the Contamination Area (CA) boundary by both wind and water. A vegetation survey was initiated in 2016 to assess the vegetation cover of the Project 57 CA and was repeated in 2018 and 2019. The purpose of the survey was to inform managers and provide data about the site’s vegetation with a perspective toward aeolian (wind) transport of soil particles. Results from the 2019 survey are reported here, with comparison to previous surveys. Perennial cover has remained stable (16 percent) during the survey time period, from 2016 to 2019. Shrub cover measured for the 2019 survey was calculated at 14 percent, which is slightly less than reported in earlier surveys but still typical for Great Basin valley shrublands. Annual plant cover was dramatically higher in 2019 at 33 percent, comprised primarily of forbs. This is because of the even distribution of precipitation events from the prior winter compared with previous years. Annual plant cover was 17 percent in 2016 and less than 2 percent in 2018. The spike in annual production following a wet winter demonstrates the variability and resiliency of the desert shrubland environment, which can be difficult to predict over long time periods. Consequently, the percent of bare soil was considerably less than seen in prior years, down from 60 percent to 47 percent, primarily because of the high percentage of annuals. The burned area of the CA remained dominated by native annual plants. The entirety of the plant cover within the burned area as surveyed was comprised of annuals (44 percent), primarily bristly fiddleneck (Amsinckia tessellata), leaving 56 percent of the burned area as bare ground. No bromus tectorum (cheatgrass) was recorded in the 2019 survey in the burned area, but it was observed throughout the area in general. Lacking perennial shrub cover and despite the dramatic increase in annual cover in 2019, the burned area remains a potential and geographically large source for sediment transport. Therefore, the variability of annual plant cover and the potential for changes in the perennial plant cover because of fire or drought mortality continues to suggest sediment transport from the Project 57 study site could vary dramatically over time.},
doi = {10.2172/1566841},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {9}
}