bluuebunny/crossref_metadata_2025_split huggingface dataset:
Overland flow generation and continuity on stone‐covered soil surfaces
Authors: Lavee H. , Poesen J. W. A. 
Published: February 2007

AbstractThe influence of stone cover on the generation and continuity of overland flow is a function of several variables, primarily stone size, distance (spacing) between stones, and stone position (on top of the soil surface or partially embedded). The initial hypothesis of the present study were that stone size affects overland flow generation by inducing ‘concentration overland flow’ and that the distance between stones affects overland flow continuity.With respect to stone size and distance between stones, opposing results have been found in the literature. Accordingly, the present paper reports on laboratory experiments which were conducted to investigate, systematically, the effect on overland flow of stone size, distance between stones, and stone position.The main conclusions were:

Stone cover tended to induce overland flow, relative to bare soil. Small stones, however, especially in a low‐cover percentage setting, and when resting on top of the soil surface, produced less overland flow than bare soil.
Overland flow was positively related to stone size, but inversely related to distance between stones.
Overland flow yield was always greater when stones were embedded than when on top of the soil surface.
The effect of stone size on increasing the degree of overland flow was of greater significance than the effect of the distance between stones on reducing overland flow.
Sediment and nutrient transport dynamics in two tributaries of Lake Erie: A numerical model
Authors: Stone M. , English M. C. , Mulamoottil G. 
Published: February 2007

AbstractThe objective of this research is to investigate spatial and temporal variation in the transport of phosphate by grain size fractions of suspended sediment in two Lake Erie tributaries. A sediment‐phosphate transport model is proposed to evaluate and quantify the kinetic control of dissolved phosphate by fluvial sediment. A first‐order assessment of the sediment‐phosphate export from Big Otter Creek and Big Creek to Lake Erie is presented. Output from this model was calculated using historical discharge and sediment data collected by Environment Canada in combination with adsorption coefficients derived from laboratory experiments for a range of sediment grain size fractions. Results of these calculations provide a quantitative interpretation of the influence of suspended sediment on phosphate dynamics in tributaries and the potential impact on water quality of receiving waters.
Tritium in ground water of the georgia piedmont: Implications for recharge and flow paths
Authors: Rose Seth 
Published: February 2007

AbstractEnvironmental tritium was measured in 33 natural water samples representative of precipitation, stream runoff, and groundwater (derived principally from production wells) within the Georgia Piedmont Province. Major ion analyses were used to assist in the interpretation of the tritium results. Tritium concentrations were significantly greater within shallow groundwater derived from the regolith (28–34 TU) and stream runoff (25–30 TU) than within recent rainfall (4–17 TU). Based upon the decay‐corrected tritium input function, this probably indicates that at least some of the shallow water is stored within the regolith for a period of approximately 25 years.A ‘post‐bomb’ component of recharge was present in all groundwater derived from production wells in the study area. Groundwater sampled from the bedrock aquifers was commonly less tritiated than either stream runoff or shallow water stored in the regolith. the lower tritium concentrations May, have resulted from the mixing of ‘pre‐bomb’ water stored within the fractures or the transitional zone directly above the bedrock and modern water stored in the shallow regolith. the preponderance of modern water provides evidence that groundwater flow paths are areally restricted within this setting, probably confined to local surface water drainage basins. the residence time of groundwater in the Piedmont is limited by the lack of deep, gravity‐driven regional flow and the localized vertical flow induced by pumping. the results of this study indicate that relatively small tritium concentration variations (10‐20 TU) May, have regional hydrological significance in the southeastern Piedmont Province and similar settings.
Towards identifying sources of subsurface flow: A comparison of components identified by a physically based runoff model and those determined by chemical mixing techniques
Authors: Robson Alice , Beven Keith , Neal Colin 
Published: February 2007

AbstractA physically‐based semidistributed model, TOPMODEL, is applied to a 340 hectare spruce forested catchment in mid‐Wales. the model is calibrated to runoff and the subsurface flow is divided into components of flow identified by depth of origin. in addition, chemical mixing techniques are used to provide a hydrograph separation between acidic soil waters and well buffered deep waters. the short‐term variations in the components of flow identified by these two approaches compare well.
The hydrological influence of black locust plantations in the loess area of northwest China
Authors: Yanhui Wang 
Published: February 2007

AbstractBlack locust (Robina pseudoacacia) has become one of the most important shelter species in the loess area of northwest China. This paper summarizes recent research concerning its hydrological influence, including canopy interception, litter absorption capacity, its effect on rainfall kinetic energy, infiltration rates, surface runoff, soil moisture, and evapotranspiration, and its role in soil conservation. Several predictive models are listed. on the basis of existing results, optimum characteristics for an effective plantation are defined, and problems requiring further research are identified.
Low path dimensionality and hydrological modelling
Authors: Chappell Nick , Ternan Les 
Published: February 2007

AbstractIncreasingly, research is indicating that subsurface flow paths govern ion transport within river catchments. Distributed prediction of these solute flow paths in typically heterogeneous catchments must inevitably be highly uncertain without some identification of a spatial structure relating small‐scale measurements of soil properties to flow predictions distributed over large catchments. To date, the evidence for profile and catenal structure within soil hydrological properties and resultant solute flow paths is not fully embraced by the hydrological community. as a consequence soil parameters are often poorly distributed within catchment‐scale distributed models. This paper seeks, first, to generalize the disparate sources of evidence of parameter and flow path structure within the profile‐ward and catena‐ward dimensions. Second, to outline how much of this structure has been incorporated into previous hydrological simulations using distributed models, and third, to examine the physical basis of attempts to simplify parameter and flow path dimensions using pedological classifications. the available evidence suggests that a considerable number of world soils show profile‐ward structure within their hydrological properties and resultant flow paths. Changes in profile‐ward patterns along catenal sequences remain uncertain. the Plynlimon region of mid‐Wales has been the focus for many detailed studies of solute flow paths, catchment‐scale model simulations, soil property characterizations and soil classification. Comparison of these studies suggests that most model simulations and hydromorphic classifications of soil taxa fail to distinguish adequately between soil horizons and soil types with markedly different property distributions. Preliminary analysis, however, suggests that by using a catena based criterion to classify the hydromorphic characteristics of soils, soil elements with distinct patterns of properties and flow paths can be identified. This might suggest that the accuracy of distributed predictions of ion movements within river catchments could be greatly improved by the derivation of profile‐specific patterns in soil properties. These profile‐specific effective parameters need to be derived from measurements over a range of scales, including individual layers, profiles and complete catenas.
Simulation of summer storms of differing recurrence intervals in a semiarid environment using a kinematic routing scheme
Authors: Faulkner Hazel 
Published: February 2007

AbstractA kinematic flood routing procedure has been devised for a small dendritic headwater gully network on the Western slope of Colorado. the program is spatially‐distributed, incorporating lateral inflows from 103 field sites on the network for which channel geometry variables are known. This model, in which a lateral inflow algorithm for the sideslopes between each channel site is convoluted into a Freeze‐type (1978) numerical scheme, is fully developed in this paper.Although the field basis of the lateral inflow algorithm has been tested elsewhere (Faulkner, 1990), sensitivity tests were needed for the roughness and hillslope velocity estimates used in the routing procedure. After these successful tests, a suitably precalibrated run of the model was compared with a field‐monitored runoff event on the watershed, and results again were encouraging. However, peak attentuation downstream was more pronounced in reality than on the simulation, so the model was also modified by inclusion of allowances for transmission loss. the tendency that the model had displayed for peak size attenuation downstream was considerably enhanced.Using the model, the geomorphic role of the flashfloods which affect the watershed in the summer months is briefly considered by applying the model to existing records of local summer storm rainfall events as a basis for event simulation. These simulations show that downstream attenuation of the flood wave on concave networks in steep semiarid terrain was likely to be a common occurrence, possibly resulting in down‐net deposition and differences in geomorphic behaviour between upstream and downstream sites. the discussion is finally broadened to consider the relative importance of ‘common’ as compared to ‘freak’ watershed events in maintaining these differences.
Channel geometry, bed material, and inferred flow conditions in ephemeral stream systems, barrier range, western N.S.W. Australia
Authors: Dunkerley D. L. 
Published: February 2007

AbstractStreams draining the Barrier Range uplands in arid western N.S.W. are ephemeral and undergo rapid channel contraction away from the uplands as a consequence of transmission loss. These processes are documented on the basis of surveys of channel form and bed material at sequential sites located along the contracting lowland reaches of two representative streams.Channel width and depth display considerable fluctuation downstream, but cross‐sectional area and maximum bed surface grain size decline in a very regular manner. Flood discharge, estimated from the channel capacity and predicted critical and mean flow velocities, also declines regularly. the trends are well fitted by log‐linear models, and are reported in terms of a half‐distance, the channel length in km over which the value of a morphometric parameter declines by 50 per cent. Rates of channel contraction and transmission loss are inferred to be inversely proportional to the volume of flow delivered from the upland section of the drainage basin.Unusual channel characteristics, including extensive tree growth in the bed, make application of ordinary flow equations difficult, because friction factors cannot be estimated with confidence. Systematic changes in the nature of the bed surface in contracting streams such as those studied here also have implications for the application of critical velocity equations, and highlight a need for further study of desert channels.
Measurement of near surface soil water content using a capacitance probe
Authors: Robinson M. , Dean T. J. 
Published: February 2007

AbstractThe portable surface capacitance insertion probe was used to measure the in situ water content of near surface soil layers. The probe readings were calibrated against gravimetric samples collected over a wide range of water contents, and were found to be very closely correlated. The capacitance probe was used repeatedly in time and space at a field site where ridges and furrows ensured a regular pattern of soil water variations. The observed spatial variations of the water content were related to topography and land mangement. The degree of variability was dependent on the average water content.
Infiltration characteristics of a complex lateritic soil profile
Authors: Ruprecht J. K. , Schofield N. J. 
Published: February 2007

AbstractLarge infiltration ponds (10–15 m2) were used, in conjunction with a ring infiltrometer and a well permeameter, to determine the infiltration characteristics of a complex lateritic soil profile in the jarrah (Eucalyptus marginata) forest of Western Australia. Simultaneous measurements of soil water content and soil water potential allowed a description of the infiltration and redistribution in the soil profile. The infiltration ponds effectively measured the conductivity of a subsurface lateritic duricrust which was found to have a relatively high saturated hydraulic conductivity (Ks) of 2.7 m d−1, despite its apparently massive and extensive nature. Removal of the topsoil identified large (≈1 m2) infilled holes penetrating the duricrust over about 6% by area. Measurements indicated that these large ‘holes’ had a high Ks value (≈ 10 m d−1), whereas the remaining duricrust had a lower Ks value (≈ 2m d−1). These results have implications for probable maximum flood design calculations and assessing the hydrological impact of extensive open‐cut bauxite mining.
Device for finely resolved sampling of littoral lake regions: Design and operation
Authors: Gubala Chad P. , Driscoll Charles T. , Newton Robert M. , Schofield Carl 
Published: February 2007

AbstractAlthough littoral regions in northern lakes may sustain fish spawning grounds, little is known of the temporal or spatial aspects of their thermal and chemical regimes. This shortcoming is due in part to the difficulty in properly sampling these regions throughout the year with adequate spatial resolution. This problem is especially critical in lakes affected by episodic acidification during the spring snowmelt, a period of substantial importance to fisheries recruitment. A device was constructed to alleviate the problems associated with conventional water quality sampling of littoral regions. Constructed of thick walled polyvinyl chloride and permanently installed in the nearshore regions of an Adirondack lake, the episodic event sampler (EES) provided finely resolved (0.25 m) temperature and water chemistry data during the spring snowmelt period (February to May) of 1989. Although the construction and installation of the sampler represented a significant investment in labour and materials, this was offset by the high quality of the data collected. As the samplers were relatively undamaged by freeze‐thaw activity, it is expected that they will continue to provide excellent information for several years.
Characterization of colloidal and particulate matter transported by the magela creek system, Northern Australia
Authors: Hart Barry T. , Douglas Grant B. , Beckett Ronald , Van Put Annick , Van Grieken Rene E. 
Published: February 2007

AbstractThe composition and amount of colloidal and suspended participate matter transported during a small flood event in Magela Creek in tropical northern Australia was investigated. The flood studied constituted approximately 3 % of the total annual flow, most (90%) of which occurred between mid‐January and mid‐February of the study year. Three fractions were separated from water samples using a sequential method involving a continuous flow centrifuge to separate suspended particulate matter (SPM; nominally > 1 μm) followed by hollow fibre filtration, first using a 0.1 μm filter to separate course colloidal matter (CCM; nominal size 1–0.1 μm) and then a 0–015 μm filter to separate fine colloidal matter (FCM; nominal size 0.1–0.015 μm). The SPM was predominantly inorganic (organic matter 21 %), whereas the colloidal fractions were dominantly organic matter (CCM 60%; FCM 83%). Analysis of individual particles using electron microprobe and automated image analysis indicated that the mineral fractions in both the SPM and CCM were dominated by iron‐enriched aluminosilicates (including kaolinite) (72–82%) and quartz (9–10%), indicative of a highly weathered and extensively laterized catchment. Surprisingly there was very little difference in the composition of the SPM or CCM fractions during the flood event studied, which may indicate either that sediment availability was restricted following the major run‐off events in January and February, or that all the sediment sources within the catchment are geochemically similar.Approximately the same amounts of particulate (20 tonne), colloidal (21 tonne) and dissolved material (17 tonne) were transported during the 25 hour period of the main flood peak; over 90% of the colloidal matter was 0.1–1.0 μm in size. These data suggest that previous estimates of the amounts of particulate (and colloidal) matter transported by Magela Creek, which were based on suspended solids measurements, may have underestimated the particulate matter load by as much as 50%. It is possible that the relatively high proportion of colloidal matter is unique to Magela Creek because coagulation and aggregation of colloidal matter to particulate matter is slow due to the very low concentations of calcium and magnesium in these waters. However, if the result is more widespread, there are important implications for the global estimates of fluvially transported particulate and dissolved materials as many of the previous studies may have underestimated the particulate load and overestimated the dissolved load.
III. Measuring surface soil moisture using passive microwave remote sensing
Authors: Jackson Thomas J. 
Published: February 2007

AbstractSoil moisture is one of the few directly observable hydrological variables that has an important role in water and energy budgets necessary for climate studies. At the present time there is no practical approach to measuring and monitoring soil moisture at the frequency and scale necessary for these large scale analyses. Current and developing satellite systems have not addressed this important question. A solution utilizing passive microwave remote sensing is presented here and an optimum system, soil moisture estimation algorithms and a microwave simulation model are described.
IV. Water resource modelling using remote sensing and object‐oriented simulation
Authors: McKim Harlan L. , Cassell E. Alan , Lapotin Perry J. 
Published: February 2007

AbstractRemote sensing technology has matured significantly over the past decade. Operational satellites provide reliable, periodic coverage for all areas of the Earth. Data from these satellites are in a digital format that provides enhanced flexibility in hydrological modelling. Considerable advances in acquiring hydrological data from airborne and in situ sensors have also been achieved. Additionally, data from non‐traditional remote sources such as weather radar from which spatial and temporal rainfall rates may be estimated are widely available. These new data acquisition capabilities have been paralleled by equal advancements in digital array processing and geographic information systems, which allow the effective extraction of both temporal and spatial information. This paper examines the use of object‐oriented programming techniques to create dynamic hydrological models, and explores their potential to receive real and near real‐time data from remote sensors as input to improve hydrological forecasting. In particular, the COE SSARR model is used to illustrate how an established hydrological model may be adapted to create a dynamic object model.
Fractionation and concentration of suspended particulate matter in natural waters
Authors: Douglas G. B. , Beckett R. , Hart B. T. 
Published: February 2007

AbstractA scheme for the fractionation and concentration of suspended particulate matter (SPM) from natural waters has been tested. This scheme involves the sequential use of three fractionation techniques—sieving, continuous flow centrifugation and tangential flow filtration to collect gram amounts of SPM over the entire particulate and colloidal size range. The separation scheme is able to process large samples (ca. 1001), within reasonable times (ca. 1 day) and the apparatus is portable. Reproducibility and potential artifacts introducing during the fractionation and concentration of SPM, particularly when tangential flow filtration is used, are discussed. It has been shown that there is a systematic increase in the content of organic carbon, Mg, Ca, Na, K, Cu and Zn with decreasing particle size, highlighting the importance of the colloidal ( < 1 μm) fraction.
Computerized streamflow measurement using slug injection
Authors: Kite Geoff 
Published: February 2007

AbstractUsing current meters to estimate flows in fast mountain streams is difficult and inaccurate. The salt dilution method offers an easier and more accurate alternative. The method has been used for many years but is time consuming and messy because of the need to mix chemical solutions and measure chemical concentrations in the field. A computer program has been developed which uses a laptop computer to calculate the mixing length and the mass of salt needed. The program controls the conductivity measurements and calculates the streamflow directly in the field. The development of this program is described and examples are presented of the application of the method in the Rocky Mountains of Alberta and British Columbia.
Vulnerability of three spatially variable soil groups for solute leaching
Authors: Wösten J. H. M. , Van Der Zee S. E. A. T. M. 
Published: February 2007

AbstractSolute leaching in unsaturated soil is influenced by the variability in hydraulic functions (water retention and conductivity) that govern the flow process. Variability in measured soil hydraulic functions of a coarse‐, medium‐ and fine‐textured soil group was quantified with the scaling theory of similar media. Solute leaching in these soils was calculated with Monte Carlo simulation assuming, successively, hydraulic conductivity, K, volumetric water content, 0, and pressure head, h, to be constant. In addition to variability in hydraulic functions, variability in the solute retardation factor was also taken into account. To examine this effect five solutes were considered: a conservative solute (chloride), a non‐retarded solute subject to decay (nitrate), a retarded solute that does not decay (cadmium) and two organic solutes which are retarded but have different sorption and decay parameters (the pesticide atrazine and a chlorinated hydrocarbon). The numerical results obtained with Monte Carlo simulation were in a number of instances verified with analytical solutions. The three soil groups distinguished showed considerable differences in vulnerability for leaching of the five solutes, emphasizing the importance of the effect of variability in soil hydraulic functions when studying solute leaching. Numerical and analytical results showed good agreement. Therefore, in relatively simple situations analytical solutions are attractive. However, in complicated situations, analytical solutions are cumbersome and numerical solutions are the only realistic alternative.