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Ryan D. Stewart Aditi S. Bhaskar Anthony J. Parolari Dustin L. Herrmann Jinshi Jian Laura A. Schifman William D. Shuster 《水文研究》2019,33(26):3349-3363
Uncontrolled overland flow drives flooding, erosion, and contaminant transport, with the severity of these outcomes often amplified in urban areas. In pervious media such as urban soils, overland flow is initiated via either infiltration‐excess (where precipitation rate exceeds infiltration capacity) or saturation‐excess (when precipitation volume exceeds soil profile storage) mechanisms. These processes call for different management strategies, making it important for municipalities to discern between them. In this study, we derived a generalized one‐dimensional model that distinguishes between infiltration‐excess overland flow (IEOF) and saturation‐excess overland flow (SEOF) using Green–Ampt infiltration concepts. Next, we applied this model to estimate overland flow generation from pervious areas in 11 U.S. cities. We used rainfall forcing that represented low‐ and high‐intensity events and compared responses among measured urban versus predevelopment reference soil hydraulic properties. The derivation showed that the propensity for IEOF versus SEOF is related to the equivalence between two nondimensional ratios: (a) precipitation rate to depth‐weighted hydraulic conductivity and (b) depth of soil profile restrictive layer to soil capillary potential. Across all cities, reference soil profiles were associated with greater IEOF for the high‐intensity set of storms, and urbanized soil profiles tended towards production of SEOF during the lower intensity set of storms. Urban soils produced more cumulative overland flow as a fraction of cumulative precipitation than did reference soils, particularly under conditions associated with SEOF. These results will assist cities in identifying the type and extent of interventions needed to manage storm water produced from pervious areas. 相似文献
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Wania Greiffo Klaus Herrmann Georg Müller Karl W. Strauss 《Contributions to Mineralogy and Petrology》1984,87(4):418-419
A sulfate-bearing Sr-Ba phosphate (Sr-gorceixite) formed by supergene alteration in rich iron ores from Minas Gerais, Brazil, has been studied by means of microprobe techniques. Analytical data and the structural formula are presented. 相似文献
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Recent trends in vegetation dynamics in the African Sahel and their relationship to climate 总被引:26,自引:1,他引:26
Stefanie M. Herrmann Assaf Anyamba Compton J. Tucker 《Global Environmental Change》2005,15(4):394-404
Contrary to assertions of widespread irreversible desertification in the African Sahel, a recent increase in seasonal greenness over large areas of the Sahel has been observed, which has been interpreted as a recovery from the great Sahelian droughts. This research investigates temporal and spatial patterns of vegetation greenness and rainfall variability in the African Sahel and their interrelationships based on analyses of Normalized Difference Vegetation Index (NDVI) time series for the period 1982–2003 and gridded satellite rainfall estimates. While rainfall emerges as the dominant causative factor for the increase in vegetation greenness, there is evidence of another causative factor, hypothetically a human-induced change superimposed on the climate trend. 相似文献
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Piotr Maloszewski Werner Rauert Peter Trimborn Andreas Herrmann Rolf Rau 《Journal of Hydrology》1992,140(1-4):343-360
Measurements of tritium and 18O concentrations in precipitation and runoff were used to provide further insight into the groundwater storage properties of the Wimbachtal Valley, a catchment area of 33.4 km2, extending between 636 and 2713 m a.s.l. in the Berchtesgaden Alps. The catchment includes three aquifer types: a dominant porous aquifer; a fractured dolomite; a karstic limestone aquifer. Employing a simple hydrological model, information about mean transit times of environmental tracers is derived for the groundwater runoff component and several karst springs from the application of the exponential and dispersion flow models to the isotopic input and output data. The mean transit times calculated from a dispersion model with transit times of 4.1 years for 18O and 4.2 years for tritium, which agree well, allow calculation of total (mobile + stagnant) groundwater storage volume, which is equivalent to 6.6 m of water depth. Direct runoff appears negligible as in many other cases. 相似文献
17.
William?W.?Kirby-SmithEmail author Martin?E.?Lebo Robert?B.?Herrmann 《Estuaries and Coasts》2003,26(6):1480-1485
Nekton abundance and water quality were examined over 8 yr (1986–1993) in Isaac Creek, a small (2.5 km long), shallow (1–2 m), estuarine creek draining to Adams Creek (Neuse River system), North Carolina, United States. Water quality and nekton were sampled at 8 to 12 stations at 2–3 wk intervals from April to October (76 dates). The nekton assemblage, sampled by trawl, included 42 taxa but was dominated by 11 species (7 fish and 4 decapod crustaceans). Nekton and water quality (temperature, salinity, dissolved oxygen [DO], salinity gradient) data were grouped and analyzed by three (upper, middle, and lower) creek zones to determine if estimated abundance was correlated with water quality. Potentially stressful water quality conditions for salinity (<5 ppt), temperature (>30°C in morning), and DO (<2 mg 1−1) mainly occurred in the upper and middle zones. The most frequent occurrence of potentially stressful conditions for salinity was in the spring and for dissolved oxygen and temperature in middle to late summer. The frequency of potentially stressful conditions increased during a 3-yr period following timber harvest of a large portion of the watershed. Canonical correspondence analysis (CCA) suggested little correlation between the top 11 species and water quality and indicated an assemblage with regular seasonal changes. Comparison of nekton use of the middle and upper zones of the creek for 3-yr pre- and post-harvest periods showed an increase in proportion of nekton caught in those zones, despite the higher frequency of potentially stressful water quality conditions. This observation suggests that a complex set of factors, including water quality, influence the pattern of nekton use in Isaac Creek. 相似文献
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Susanne P. Schwenzer Siegfried Herrmann Ratan K. Mohapatra Ulrich Ott 《Meteoritics & planetary science》2007,42(3):387-412
Abstract— This study provides a complete data set of all five noble gases for bulk samples and mineral separates from three Martian shergottites: Shergotty (bulk, pyroxene, maskelynite), Zagami (bulk, pyroxene, maskelynite), and Elephant Moraine (EET) A79001, lithology A (bulk, pyroxene). We also give a compilation of all noble gas and nitrogen studies performed on these meteorites. Our mean values for cosmic‐ray exposure ages from 3He, 21Ne, and 38Ar are 2.48 Myr for Shergotty, 2.73 Myr for Zagami, and 0.65 Myr for EETA79001 lith. A. Serious loss of radiogenic 4He due to shock is observed. Cosmogenic neon results for bulk samples from 13 Martian meteorites (new data and literature data) are used in addition to the mineral separates of this study in a new approach to explore evidence of solar cosmic‐ray effects. While a contribution of this low‐energy irradiation is strongly indicated for all of the shergottites, spallation Ne in Chassigny, Allan Hills (ALH) 84001, and the nakhlites is fully explained by galactic cosmic‐ray spallation. Implanted Martian atmospheric gases are present in all mineral separates and the thermal release indicates a near‐surface siting. We derive an estimate for the 40Ar/36Ar ratio of the Martian interior component by subtracting from measured Ar in the (K‐poor) pyroxenes the (small) radiogenic component as well as the implanted atmospheric component as indicated from 129Xe, * excesses. Unless compromised by the presence of additional components, a high ratio of ~2000 is indicated for Martian interior argon, similar to that in the Martian atmosphere. Since much lower ratios have been inferred for Chassigny and ALH 84001, the result may indicate spatial and/or temporal variations of 40Ar/36Ar in the Martian mantle. 相似文献
20.
Edward W. Herrmann 《Geoarchaeology》2016,31(1):58-74
Although Paleoindian sites in Indiana, USA, are commonly located on late Wisconsin (Last Glacial Maximum) outwash terraces, drainage basin development since deglaciation often obscures the visibility of such sites on flood plains by either burying them under alluvium or destroying them through erosion. Significant clusters of Paleoindian and Early Archaic sites, however, have been identified proximal to the modern White River channel in central Indiana on what is mapped as “floodplain.” These site cluster locations are patterned. They typically occur within bedrock‐controlled river reaches but are rare along unconfined meandering reaches. Subsurface reconnaissance and chronology indicate that despite the fact that they often flood, portions of the so‐called flood plains within bedrock‐confined reaches are actually terraces constructed of late Wisconsin outwash with minimal overbank sedimentation. Terrace preservation in these settings is a result of bedrock structure that protects older sediments from lateral erosion and differentially preserves archaeological sites near the modern channel in bedrock‐controlled reaches. Comparisons of archaeological sites within bedrock‐controlled segments of the White River to those in unconfined meandering segments suggests that significant numbers of Paleoindian and Early Archaic sites may be missing from river settings across the midcontinent. These findings demonstrate that bedrock channel controls are important to recognize when assessing prehistoric settlement distributions. 相似文献