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Contributions to the hydrology of the United States, 1919
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Contributions to the hydrology of the United States, 1921
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Variation in annual run-off in the Rocky Mountain region: Chapter A in Contributions to the hydrology of the United States, 1923-1924
Records of run-off in the Rocky Mountain States since the nineties and for a few stations since the eighties afford a means of studying the variation in the annual run-off in this region. The data presented in this report show that the variation in annual run-off differs in different areas in the Rocky Mountain region, owing to the differences in the sources of the precipitation in these areas. Except in the drainage basins of streams in northern Montana the year of lowest run-off shown by the records was 1902, when the run-ff at one station was only 36 per cent of the mean run-ff for the periods covered by the several records available. The percentage variation of run-ff for streams in different parts of Colorado is less for any one year than that for streams in the mountain region as a whole, and for streams in the same major drainage basin the annual variation is markedly similar. The influence of topography upon variation in annual run-ff for streams in Colorado is marked, the streams that rise in the central mountain region having a smaller range in variation than the streams that rise on the eastern or western edges of the central mountain mass. The streams that rise on the plains just east of the mountains have a greater variation than those of any of the mountain groups. The ratio of any 10-year mean to the mean for the entire period covered by the records ranges from 72 to 133 per cent. For the South Platte, Arkansas, and Rio Grande the run-off during the nineties was below the normal, but since about 1903 it has been above normal. For the Cache la Poudre low-water periods occurred during the eighties and from 1905 to 1922, but during the nineties the run-off was above the normal.
Power resources of Snake River between Huntington, Oregon and Lewiston, Idaho: Chapter C in Contributions to the hydrology of the United States, 1923-1924
Thousands of people are familiar with that part of Snake River where it flows for more than 300 miles in a general westward course across the plains of southern Idaho, but few have traversed the river where it flows northward and for 200 miles forms the boundary between Idaho and Oregon and for 30 miles the boundary between Idaho and Washington. Below the mining town of Homestead, Oreg., which is the end of a branch line of the Oregon Short Line Railroad, Snake River finds its way through the mountain ranges that seem to block its way to Columbia River in a canyon which, though not so well known, so majestic, nor so kaleidoscopic in color, is in some respects worthy of comparison with the Grand Canyon of the Colorado, for at some places it is deeper and narrower than the Grand Canyon at El Tovar. The Snake, unlike the Colorado, can be reached at many points through the valleys of tributary streams, and the early prospectors no doubt thoroughly explored all parts of the canyon. To traverse the river between Homestead, Oreg., and Lewiston, Idaho, is, however, a difficult undertaking and there are only a few records of boat journeys through the entire stretch. It has long been known that this portion of Snake River contains large potential water powers, but until recently no detailed surveys or examinations covering the entire stretch of the river had been made to determine their location or extent. A railroad has been proposed between Homestead and Lewiston which would provide a direct connection between the railroad systems of northern and southern Idaho. One function of the Geological Survey is to determine the possible interface between transportation routes on land and potential water-power development, and the information set forth in this paper has a bearing on that problem.
Some floods in the Rocky Mountain region: Chapter G in Contributions to the hydrology of the United States, 1923-1924
In 1923 severe floods occurred on the larger streams in Wyoming and a number of cloudburst floods on small streams in Wyoming and especially in Colorado. An investigation of the principal floods in each State was made, and the results are given in this paper, together with descriptions of two Colorado floods of 1922. In addition a study was made of all cloudburst floods to determine the areas chiefly subject to them.
Contributions to the hydrology of the United States, 1926
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Contributions to the hydrology of the United States, 1929
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Contributions to the hydrology of the United States, 1930
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Contributions to the hydrology of the United States, 1932
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Using mercury stable isotope fractionation to identify the contribution of historical mercury mining sources present in downstream water, sediment and fish
Ecosystems downstream of mercury (Hg) contaminated sites can be impacted by both localized releases as well as Hg deposited to the watershed from atmospheric transport. Identifying the source of Hg in water, sediment, and fish downstream of contaminated sites is important for determining the effectiveness of source-control remediation actions. This study uses measurements of Hg stable isotopes in soil, sediment, water, and fish to differentiate between Hg from an abandoned Hg mine from non-mine-related sources. The study site is located within the Willamette River watershed (Oregon, United States), which includes free-flowing river segments and a reservoir downstream of the mine. The concentrations of total-Hg (THg) in the reservoir fish were 4-fold higher than those further downstream (>90 km) from the mine site in free-flowing sections of the river. Mercury stable isotope fractionation analysis showed that the mine tailings (δ 202 Hg: −0.36‰ ± 0.03‰) had a distinctive isotopic composition compared to background soils (δ 202 Hg: −2.30‰ ± 0.25‰). Similar differences in isotopic composition were observed between stream water that flowed through the tailings (particulate bound δ 202 Hg: −0.58‰; dissolved: −0.91‰) versus a background stream (particle-bound δ 202 Hg: −2.36‰; dissolved: −2.09‰). Within the reservoir sediment, the Hg isotopic composition indicated that the proportion of the Hg related to mine-release increased with THg concentrations. However, in the fish samples the opposite trend was observed—the degree of mine-related Hg was lower in fish with the higher THg concentrations. While sediment concentrations clearly show the influence of the mine, the relationship in fish is more complicated due to differences in methylmercury (MeHg) formation and the foraging behavior of different fish species. The fish tissue δ 13 C and Δ 199 Hg values indicate that there is a higher influence of mine-sourced Hg in fish feeding in a more sediment-based food web and less so in planktonic and littoral-based food webs. Identifying the relative proportion of Hg from local contaminated site can help inform remediation decisions, especially when the relationship between total Hg concentrations and sources do not show similar covariation between abiotic and biotic media.
Mapping wetland burned area from Sentinel-2 across the southeastern United States and its contributions relative to Landsat 8 (2016-2019)
Prescribed fires and wildfires are common in wetland ecosystems across the Southeastern United States. However, the wetland burned area has been chronically underestimated across the region due to (1) spectral confusion between open water and burned area, (2) rapid post-fire vegetation regrowth, and (3) high annual precipitation limiting clear-sky satellite observations. We developed a machine learning algorithm specifically for burned area in wetlands, and applied the algorithm to the Sentinel-2 archive (2016–2019) across the Southeastern US (>290,000 km 2 ). Combining Landsat-8 imagery with Sentinel-2 increased the annual clear-sky observation count from 17 to 46 in 2016 and from 16 to 78 in 2019. When validated with WorldView imagery, the Sentinel-2 burned area had a 29% and 30% omission and commission rates of error for burned area, respectively, compared to the US Geological Survey Landsat-8 Burned Area Product (L8 BA), which had a 47% and 8% omission and commission rate of error, respectively. The Sentinel-2 algorithm and the L8 BA mapped burned area within 78% and 60% of wetland fire perimeters ( n = 555) compiled from state and federal agencies, respectively. This analysis demonstrated the potential of Sentinel-2 to support efforts to track the burned area, especially across challenging ecosystem types, such as wetlands.
Geologic framework, anthropogenic impacts, and hydrodynamics contribute to variable sediment availability and shoreface morphology at the Rockaway Peninsula, NY
Recent field and modeling studies have shown that barrier island resiliency is sensitive to sediment fluxes from the shoreface, making it important to evaluate how shoreface sediment availability varies in coastal systems. To do this, we assessed shoreface geology and morphology along the Rockaway Peninsula, NY, USA. We find that spatial variability in shoreface volume is influenced by sediment accommodation above the Holocene-Pleistocene (H-P) contact, historical barrier island evolution, and natural and engineered morphologic features, suggesting that simply identifying the H-P boundary may not be adequate for defining the shoreface reservoir. Further, sediment flux from the lower shoreface to the beach may be reduced by geologically limited cross-shore sediment distribution and shoreface steepening mediated by human modifications to the shoreline. Finally, the geologic limit of the shoreface is often shallower than a wave-based estimate of shoreface extent, implying that the geologic shoreface extent at our study site can be mobilized over short time scales (years-decades) and that the wave-based shoreface extent may be inaccurate when estimating shoreline response to sea-level rise. Our results demonstrate that the combination of hydrodynamics, humans, and geology on shoreface sediment fluxes impact how barrier islands respond to future changes in sediment supply and climate.
Extreme precipitation and flooding contribute to sudden vegetation dieback in a coastal salt marsh
Climate extremes are becoming more frequent with global climate change and have the potential to cause major ecological regime shifts. Along the northern Gulf of Mexico, a coastal wetland in Texas suffered sudden vegetation dieback following an extreme precipitation and flooding event associated with Hurricane Harvey in 2017. Historical salt marsh dieback events have been linked to climate extremes, such as extreme drought. However, to our knowledge, this is the first example of extreme precipitation and flooding leading to mass mortality of the salt marsh foundation species, Spartina alterniflora . Here, we investigated the relationships between baseline climate conditions, extreme climate conditions, and large-scale plant mortality to provide an indicator of ecosystem vulnerability to extreme precipitation events. We identified plant zonal boundaries along an elevation gradient with plant species tolerant of hypersaline conditions, including succulents and graminoids, at higher elevations, and flood-tolerant species, including S. alterniflora , at lower elevations. We quantified a flooding threshold for wetland collapse under baseline conditions characterized by incremental increases in flooding (i.e., sea level rise). We proposed that the sudden widespread dieback of S. alterniflora following Hurricane Harvey was the result of extreme precipitation and flooding that exceeded this threshold for S. alterniflora survival. Indeed, S. alterniflora dieback occurred at elevations above the wetland collapse threshold, illustrating a heightened vulnerability to flooding that could not be predicted from baseline climate conditions. Moreover, the spatial pattern of vegetation dieback indicated that underlying stressors may have also increased susceptibility to dieback in some S. alterniflora marshes.Collectively, our results highlight a new mechanism of sudden vegetation dieback in S. alterniflora marshes that is triggered by extreme precipitation and flooding. Furthermore, this work emphasizes the importance of considering interactions between multiple abiotic and biotic stressors that can lead to shifts in tolerance thresholds and incorporating climate extremes into climate vulnerability assessments to accurately characterize future climate threats.
Reversal of forest soil acidification in the northeastern United States and eastern Canada: Site and soil factors contributing to recovery
As acidic deposition has decreased across Eastern North America, forest soils at some sites are beginning to show reversal of soil acidification. However, the degree of recovery appears to vary and is not fully explained by deposition declines alone. To assess if other site and soil factors can help to explain degree of recovery from acid deposition, soil resampling chemistry data (8- to 24-year time interval) from 23 sites in the United States and Canada, located across 25° longitude from Eastern Maine to Western Ontario, were explored. Site and soil factors included recovery years, sulfate (SO 4 2− ) deposition history, SO 4 2− reduction rate, C horizon pH and exchangeable calcium (Ca), O and B horizon pH, base saturation, and exchangeable Ca and aluminum (Al) at the time of the initial sampling. We found that O and B horizons that were initially acidified to a greater degree showed greater recovery and B horizon recovery was further associated with an increase in recovery years and lower initial SO 4 2− deposition. Forest soils that seemingly have low buffering capacity and a reduced potential for recovery have the resilience to recover from the effects of previous high levels of acidic deposition. This suggests, that predictions of where forest soils acidification reversal will occur across the landscape should be refined to acknowledge the importance of upper soil profile horizon chemistry rather than the more traditional approach using only parent material characteristics.