1DTempPro V2: New Features for Inferring Groundwater/Surface‐Water Exchange          下载免费PDF全文

Franklin W. Koch  Emily B. Voytek  Frederick D. Day‐Lewis  Richard Healy  Martin A. Briggs  John W. Lane Jr.  Dale Werkema 《Ground water》2016,54(3):434-439

A new version of the computer program 1DTempPro extends the original code to include new capabilities for (1) automated parameter estimation, (2) layer heterogeneity, and (3) time‐varying specific discharge. The code serves as an interface to the U.S. Geological Survey model VS2DH and supports analysis of vertical one‐dimensional temperature profiles under saturated flow conditions to assess groundwater/surface‐water exchange and estimate hydraulic conductivity for cases where hydraulic head is known.  相似文献   

Downstream trends in sediment size and composition of channel-bed, bar, and bank deposits related to hydrologic and lithologic controls in the Llano River watershed, central Texas, USA     

Franklin T. Heitmuller  Paul F. Hudson   《Geomorphology》2009,112(3-4):246-260

The downstream fining of fluvial sediments is a fundamental tenet of drainage systems and, for decades, has been the subject of considerable research. Most of this research has focused on variability in channel-bed material. Other sedimentological components such as channel bars and banks, however, represent distinctively different processes occurring at various flow magnitudes and durations and thus provide an opportunity to examine a more comprehensive set of controls on the larger fluvial system. This study analyses downstream patterns of sediment size and composition for channel-bed material, bars, and banks in the Llano River watershed (11,568 km²) in central Texas, USA.Fluvial deposits in the study area were characterized through field, laboratory, and statistical analyses and standard sedimentary indices (d₁₆, d₅₀, d₈₄, sorting) were computed. Two hundred thirty-eight sediment samples were collected at 15 sites along the main-stem channel with sampling occurring at the low-flow channel (thalweg), lateral bars, banks, and overbank locations. Channel-bar deposits are characterized by a downstream reduction in particle size, but low-flow-channel deposits have a substantially weaker trend, a discrepancy possibly attributed to uniformity and continuity of hydraulic sorting mechanisms during moderate and high flows. Channel-bar deposits reveal an abrupt downstream reduction in gravel size in the upper watershed, which is attributed to an increase in drainage area. Further, an abrupt gravel-to-sand transition occurs immediately downstream of a distinct lithologic change from mostly carbonate rocks to igneous and metamorphic rocks. The downstream decrease in channel-bar particle size occurs despite an increasingly constricted alluvial valley, commonly associated with greater unit stream power and relatively coarse sediment. Contrasting with channel-bed material, particle size of channel banks increases downstream, which is attributed to the addition of sand-sized sediment from igneous and metamorphic rocks. The consideration of distinctive sedimentological components of a dynamic fluvial system represents a more comprehensive and nuanced study of the topic of downstream sediment trends than prior studies, which is important to a range of engineering, biological, and planning issues at the watershed scale.  相似文献   

Three Spaces of Spatial Cognition     

Barbara Tversky  Julie Bauer Morrison  Nancy Franklin  David J. Bryant 《The Professional geographer》1999,51(4):516-524

As we move about and interact in the world, we keep track of different spaces, among them the space of navigation, the space immediately around the body, and the space of the body. We review research showing that these spaces are conceptualized differently. Knowledge of the space of navigation is systematically distorted. For example, people mentally rotate roads and land masses to greater correspondence with global reference frames, they mentally align roads and land masses, they overestimate distances near the viewpoint relative to those far from it. These and other distortions indicate that the space of navigation is schematized to elements and spatial relations relative to reference frames and perspective. The space around the body is organized into a mental framework consisting of extensions of the major axes of the body. Times to report objects around the body suggest that the relative accessibility of the axes depends on their perceptual and functional properties and the relation of the body to the world. Finally, times to verify named or depicted body parts indicate that body schemas depend on perceptual and functional significance. Thus, these spaces (and they are not the only ones important to human interaction) differ from one another and are not conceptualized as Euclidean. Rather they are schematized into elements and spatial relations that reflect perceptual and conceptual significance.  相似文献   

An approach to the use of packaged statistical programs for cluster,classification, and discriminant analysis of trace element data     

Vanda Vitali  Ursula M. Franklin 《Geoarchaeology》1986,1(2):195-201

The purpose of this paper is to present an approach to be taken when using packaged statistical programs for the evaluation of multivariate data, in particular those programs designed for clustering, classification, and discrimination purposes. A systematic step-by-step approach is outlined starting with those steps which should be conducted in order to assure that the assumptions underlying the statistical analyses are satisfied. The use of various methods and computational options in cluster, classification, and discriminant analysis is then discussed. Finally the need for an assessment of the results in view of the overall knowledge of the problem is pointed out.  相似文献   

What's Next Now That the Boom in Contaminant Hydrogeology Has Busted?     

Franklin W. Schwartz  Yiding Zhang  Motomu Ibaraki 《Ground water》2019,57(2):205-215

This paper shows how important the historical contaminant boom, 1975 to 2005, has been to hydrogeology. Its role in this respect has never been well documented or appreciated. We use text mining and machine learning to extract information describing research trends in subsurface hydrology (SH), groundwater plus the vadose zone. The analysis, using articles from Water Resources Research (WRR) and Environmental Science and Technology, shows how SH grew from a small niche area within broader hydrologic sciences in the 1960s to become the dominant area of research by 1995. Subsequently, the performance of SH has declined, as other areas of hydrologic sciences have emerged. These patterns reflect the growth and decline of research related to contaminant topics in SH. Thus, the decline is economic—less money leads to less research. The boom in contaminant hydrogeology was effectively a 1000-year flood of money for SH. It let us outcompete the non-SH areas for a while. From 1991 to 2000, SH research in WRR was dominated by papers on contaminant-related themes. More recently, these themes and all other areas of SH except one have declined significantly in WRR. All major topics related to non-SH areas are growing except one. This evidence points to a continuing decline in competitiveness of basic research in SH. The fact that critical problems or social needs for research still exist has not changed this basic trend. The focus of research has clearly shifted away from SH to areas of hydrology associated with climate change, water cycle modeling and similar themes.  相似文献   

Gas flux and carbonate occurrence at a shallow seep of thermogenic natural gas   总被引：1，自引：1，他引：0  

Franklin S. Kinnaman  Justine B. Kimball  Luis Busso  Daniel Birgel  Haibing Ding  Kai-Uwe Hinrichs  David L. Valentine 《Geo-Marine Letters》2010,30(3-4):355-365

The Coal Oil Point seep field located offshore Santa Barbara, CA, consists of dozens of named seeps, including a peripheral ～200 m² area known as Brian Seep, located in 10 m water depth. A single comprehensive survey of gas flux at Brian Seep yielded a methane release rate of ～450 moles of CH₄ per day, originating from 68 persistent gas vents and 23 intermittent vents, with gas flux among persistent vents displaying a log normal frequency distribution. A subsequent series of 33 repeat surveys conducted over a period of 6 months tracked eight persistent vents, and revealed substantial temporal variability in gas venting, with flux from each individual vent varying by more than a factor of 4. During wintertime surveys sediment was largely absent from the site, and carbonate concretions were exposed at the seafloor. The presence of the carbonates was unexpected, as the thermogenic seep gas contains 6.7% CO₂, which should act to dissolve carbonates. The average δ¹³C of the carbonates was ?29.2?±?2.8‰ VPDB, compared to a range of ?1.0 to +7.8‰ for CO₂ in the seep gas, indicating that CO₂ from the seep gas is quantitatively not as important as ¹³C-depleted bicarbonate derived from methane oxidation. Methane, with a δ¹³C of approximately ?43‰, is oxidized and the resulting inorganic carbon precipitates as high-magnesium calcite and other carbonate minerals. This finding is supported by ¹³C-depleted biomarkers typically associated with anaerobic methanotrophic archaea and their bacterial syntrophic partners in the carbonates (lipid biomarker δ¹³C ranged from ?84 to ?25‰). The inconsistency in δ¹³C between the carbonates and the seeping CO₂ was resolved by discovering pockets of gas trapped near the base of the sediment column with δ¹³C-CO₂ values ranging from ?26.9 to ?11.6‰. A mechanism of carbonate formation is proposed in which carbonates form near the sediment–bedrock interface during times of sufficient sediment coverage, in which anaerobic oxidation of methane is favored. Precipitation occurs at a sufficient distance from active venting for the molecular and isotopic composition of seep gas to be masked by the generation of carbonate alkalinity from anaerobic methane oxidation.