bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of basin lag time in rainfall‐runoff investigations
Authors: Jin Chang‐Xing 
Published: February 2007

AbstractBasin lag time varies not only between basins but also within a basin. To explain this variation, the basin lag time was hypothesized as a function of the ratio of the channel length from the centroid to the outlet of the basin, divided by the velocity of flow at the gauging site at the time of passage of peak discharge. The records of six basins were used to test this hypothesis. The results are not incompatible with this hypothesis.
Sampling strategy to describe the temporal hydrochemical characteristics of an alpine proglacial stream
Authors: Gurnell A. M. , Brown G. H. , Tranter M. 
Published: February 2007

AbstractA hierarchical sampling programme (including continuous monitoring, twice‐daily sampling and sampling at hourly intervals over selected 24 hour periods) was devised to support hydrochemical and hydrological research programmes on an alpine proglacial stream. The rationale for the research and for the sampling programme are explained and the hydrochemical time series generated over an ablation season are analysed to assess the degree to which they support the study aims. It appears that there is no satisfactory substitute for the chemical analysis of at least two water samples taken at approximately maximum and minimum discharge every day, if seasonal variations in meltwater chemistry are to be effectively characterized. Such time series data can be used to estimate Box‐Jenkins transfer function‐noise models between particular solutes (SO2−4, Ca2+, Mg2+, Na+ and possibly K+) and either discharge or electrical conductivity, which can then be used to fill any short gaps in the data. This approach is not satisfactory even for filling short gaps in the twice‐daily determinations of pH, HCO−3 and NO−3. At the diurnal time‐scale (based on hourly determinations over 24 hour periods) electrical conductivity seems to provide a good surrogate for most of the solutes studied. HCO−3, SO2−4, Ca2+ and Mg2+ were found to be particularly strongly related to electrical conductivity and there was little if any significant serial autocorrelation in the residuals from all of the simple linear regression relationships that were estimated between individual species and conductivity. It is concluded that the hierarchical sampling design was suitable for the purposes of the study, and that the continuous monitoring of electrical conductivity provides excellent supporting information to the chemical analysis of water samples if it is used carefully as a means of short term calibration and interpolation of the solute record.
In‐channel surficial fine‐grained sediment laminae. Part II: Chemical characteristics and implications for contaminant transport in fluvial systems
Authors: Stone M. , Droppo I. G. 
Published: February 2007

AbstractSamples of surficial fine‐grained laminae (SFGL) were collected in three south‐western Ontario rivers. Each sediment sample was subjected to a sequential extraction procedure designed to partition particulate metals (Cd, Pb, Cu, Zn) into five operationally defined fractions: (1) exchangeable; (2) bound to carbonates; (3) bound to Fe‐Mn oxides; (4) bound to organic matter; and (5) residual. Particulate phosphus was sequentially extracted from the sediment samples into three fractions: (1) non‐apatite inorganic P; (2) apatite P; and (3) organic P.The major accumulate phases of trace metals in SFGL are carbonates, Fe‐Mn oxides and organic matter. The content of NAIP in SFGL ranged from 17 to 38% of total particulate P. Compared with suspended and bed sediments, levels of P and trace metals in SFGL were lower at the study sites. A conceptual overview of physical, chemical and biological processes influencing formation of SFGL and the potential role of this fine‐grained sediment for contaminant transport in fluvial systems is presented.
Invariance and scaling properties in the distributions of contributing area and energy in drainage basins
Authors: La Barbera P. , Roth G. 
Published: February 2007

AbstractThe cumulative probability distributions for stream order, stream length, contributing area, and energy dissipation per unit length of channel are derived, for an ordered drainage system, from Horton's laws of network composition. It is shown how these distributions can be related to the fractal nature of single rivers and river networks. Finally, it is shown that the structure proposed here for these probability distributions is able to fit the observed frequency distributions, and their deviations from straight lines in a log‐log plot.
Flow transmission along an arid zone anastomosing river, cooper creek, australia
Authors: Knighton A. David , Nanson Gerald C. 
Published: February 2007

AbstractCooper Creek is characterized by an exceptionally wide floodplain and a complex system of anastomosing channels which together can accommodate a large range of highly variable flows. In consequence flood frequency curves are unusually steep. With minimal tributary contribution over the two study lengths — Currareva‐Nappa Merrie (> 400 km) and Nappa Merrie‐Innamincka (32 km) — downstream output is largely controlled by upstream input, so that similar flow regimes and hydrograph forms can be maintained despite transmission losses and the variable activation of channels.Input‐output relationships defined in terms of total flow volume and peak discharge suggest that, above a threshold flow of about 25% duration, transmission losses exceed 75% on average over the Currareva‐Nappa Merrie length. The large difference in absorption between primary channels on the one hand and subsidiary channels and the floodplain surface on the other means that transmission losses vary non‐linearly with stage. They are relatively low when flow is confined to the primary channels, but increase at higher stages as lesser channels and the floodplain are activated. Early levels do not recur until flows of < 0.5% duration are attained when output/input ratios increase rapidly with discharge. The influences of seasonality and background flow on output discharge are small relative to that of input discharge.Despite the long river distance, peak flows at Currareva and Nappa Merrie are well correlated. However, over the shorter Nappa Merrie‐Innamincka length with its more confined system of channels, correlations are better and transmission losses less. They vary from 60% just above the threshold discharge to <10% at flows below 20% duration. Over this length outflow hydrographs can be effectively estimated by the three parameter Muskingum procedure, at least on an event by event basis, but further application must await additional records to understand fully how the parameters vary in an environment where streamflow is transmitted through a highly variable system of channels.
Testing and comparison of four ionic tracers to measure stream flow loss by multiple tracer injection
Authors: Zellweger Gary W. 
Published: February 2007

AbstractThe ionic tracers lithium, sodium, chloride and bromide were used to measure flow loss in a small stream (≈︁ 10 ls−1). An injectate containing all four tracers was added continuously at five sites along a 507 m study reach of St Kevin Gulch, Lake County, Colorado to determine which sections of the stream were losing water to the stream bed and to ascertain how well the four tracers performed. The acidity of the stream (pH 3.6) made it possible for lithium and sodium, which are normally adsorbed by ion exchange with stream bed sediment, to be used as conservative tracers. Net flow losses as low as 0.8 ls−1, or 8% of flow, were calculated between measuring sites. By comparing the results of simultaneous injection it was determined whether subsections of the study reach were influent or effluent. Evaluation of tracer concentrations along 116 m of stream indicated that all four tracers behaved conservatively. Discharges measured by Parshall flumes were 4–18% greater than discharges measured by tracer dilution.
Sources and sinks of sea salt in a newfoundland blanket bog
Authors: Price Jonathan S. 
Published: February 2007

AbstractOver an oceanic peatland, the concentration of Na in fog averaged 38.1 mgl−1 compared with 1.8 mgl−1 in rain, resulting in a significant flux of mineral elements to the surface. Between 16 May and 20 June 1990 the average mass flux of Na to the bog surface by fog, rain, and dry deposition was 21.9, 10.4 and 7.0 mg m−2 d−1. There was little long‐term storage of Na within the peatland system, where Na losses measured in stream runoff averaged 34.8 mg m2 d−1, and deep groundwater losses 4 mg m−2 d−1. Calcium and Mg were preferentially retained in the organic soil, whereas K was relatively mobile. Potassium tended to become concentrated in the unsaturated zone. Stream runoff had a consistently higher pH than groundwater, corresponding to higher Ca and Mg concentrations, which may have been from mineral sources in the headwater ponds. Otherwise, the stream water chemistry was closely related to groundwater in the upper layers of the peat deposit.
Converting tropical rain forest to forest plantation in sabah, malaysia. Part I. Dynamics and net losses of nutrients in control catchment streams
Authors: Grip H. , Malmer A. , Wong F. K. 
Published: February 2007

AbstractStreamwatcr chemistry was monitored for five years in six streams in a paired catchment experiment in Mendolong, Sabah, Malaysia, including controls in rain forest and secondary vegetation after the [Borneo fire] of 1982–3 and comparing the effects of different ways of establishing forest plantations with Acacia mangium. Three catchments were covered with selectively logged lowland hill dipterocarp forest (W4‐W6) and three (W1‐W3) with secondary vegetation after forest fires. The control catchments, W3 and W6 reported in this paper, had no treatments applied. Reference monitoring at all streams was for 25 months and the total period of study reported here is 64 months. The soils in the catchments were mainly Orthic Acrisol in W3 and Gleyic Podsol in W6 and a mix of both soil types in the other catchments.Element baseflow concentrations were generally low and not significantly different from stormflow concentrations for all streams during the reference period. Concentrations were also generally consistently low for the two control streams during the whole period of measurement. Chemical inputs as wet deposition were low as a result of a high input from local convection.The rain forest on the Podsol had a tight nutrient circulation indicated by small net losses of macronutrients. The Podsol was found to have poorer conditions for soil mineralization and more surficial runoff, resulting in higher loads of S, C and N in the organic phases, with higher organic C/N ratio, in the discharge. Nitrogen was found to accumulate in both catchments. An almost double accumulation of N in W3 was attributed to a larger biomass accumulation continuing after the forest fire 3–8 years earlier. On the other hand, the Acrisol in W3 had much larger net losses of S, Si, K, Ca, Mg and Na. Most of differences could be attributed to differences in weathering between the soils and local mineralogical differences.
Hydrological management of a cutover peatland
Authors: Heathwaite A. L. 
Published: February 2007

AbstractMechanisms for preserving the hydrological balance of Thorne Moors National Nature Reserve (NNR) while allowing peat extraction to continue in the surrounding peatland are examined. Three strategies exist for modifying seepage losses from the NNR: (I) re‐direction of pump drainage waters from the peat extraction areas; (II) provision of a hydrological buffer zone around the NNR; and (III) mechanical compaction of the boundaries of the buffer zone. Strategy II (increased width of the buffer zone) should be used together with strategy III (compaction) for the maximum reduction of seepage losses from the NNR. If strategy I (water level manipulation) is also adopted, it may be possible to reduce the width of the hydrological buffer zone around the NNR.
Hydrology and related changes after harvesting native forest catchments and establishing pinus radiata plantations. Part 2. The native forest water balance and changes in streamflow after harvesting
Authors: Rowe L. K. , Pearce A. J. 
Published: February 2007

AbstractSix small, steep, south‐west facing catchments (1.63–4.62 ha) have been monitored in Westland, New Zealand since 1974. Two catchments were retained in native mixed evergreen forest and the rest were subjected to various harvesting and land preparation techniques before being planted with Pinus radiata between 1977 and 1980.The 11‐year water balance for the native forest catchments was: rain = streamflow + interception loss + transpiration + seepage (2370mm = 1290mm + 620mm + 360mm + 100mm). In the year after treatment streamflow generally increased by 200–250 mm, except for one treatment (clearfelling, herbicide application, no riparian reserve) where the increase was 550 mm. The catchments were planted with Pinus radiata, but rapid colonization by bracken (Pteridium esculentum) and Himalayan honeysuckle (Leycesteria formosa) led to a rapid decline in streamflow, which returned to pre‐treatment levels after an average of about five years. Streamflow yields then continued to decline for another two to three years before stabilizing at a level about 250mm yr−1 lower than pre‐treatment levels. At this time the catchments had a dense bracken/honeysuckle understorey beneath 5 m tall pine trees.
Hydrology and related changes after harvesting native forest catchments and establishing pinus radiata plantations. Part 3. Stream temperatures
Authors: Rowe L. K. , Taylor C. H. 
Published: February 2007

AbstractEight small steep south‐west facing catchments (1‐63‐8‐26 ha) have been monitored in Westland, New Zealand since 1974. Two catchments were retained in native mixed evergreen forest and the rest were subjected to various harvesting and land preparation techniques before being planted with Pinus radiata between 1977 and 1980. Stream temperatures were measured in all catchments for 11 years, including up to four years before harvesting.The streamwater temperature regime under the native forest cover has a seasonal cycle, with an annual mean of about 9°C and mean daily temperatures ranging between a winter minimum of about 5.8°C and a summer maximum of 12.S°C. After harvesting, the winter minimum stream temperatures in all trials were unchanged as topography exerts the major control over incoming solar radiation. The largest rises in mean summer stream temperatures, up to 5.5°C, were in the catchments that had been clearcut and burnt before planting. The maximum stream temperature recorded was 22.8°C in a clearcut catchment with no riparian reserve. Summer stream temperatures in this catchment were up to 11°C higher than in an adjacent control catchment. Summer stream temperature rises in catchments with riparian reserves were less than 1.5°C.Seven years after harvesting, stream temperatures were dropping towards pre‐treatments levels in only two of the six treated catchments as revegetation of the riparian areas occurred and the plantations became established.As these small headwater streams discharge into streams with flows one or two orders of magnitude larger, the increases in summer stream temperatures will be rapidly dissipated. However, the cumulative impact of harvesting many small headwater catchments that discharge into a larger stream could have a noticeable effect on stream temperature if intact riparian reserves were not retained in both headwater and main streams.
Accuracy of kinematic wave and diffusion wave approximations for space‐independent flows with lateral inflow neglected in the momentum equation
Authors: Singh V. P. 
Published: February 2007

AbstractError equations for the kinematic wave and diffusion wave approximations with lateral inflow neglected in the momentum equation are derived under simplified conditions for space‐independent flows. These equations specify error as a function of time in the flow hydrograph. The kinematic wave, diffusion wave and dynamic wave solutions are parameterized through a dimensionless parameter γ which is dependent on the initial conditions. This parameter reflects the effect of initial flow depth, channel‐bed slope, lateral inflow and channel roughness when the initial condition is non‐vanishing; and it reflects the effect of bed slope, channel roughness and acceleration due to gravity when the initial condition is vanishing. The error equations are found to be the Riccati equation. The structure of the error equations in the case when the momentum equation neglects lateral inflow is different from that when the lateral inflow is included.
Multiple flow direction algorithms for runoff modelling in grid based elevation models: An empirical evaluation
Authors: Holmgren Peter 
Published: February 2007

AbstractWhen pathways for groundwater flow are defined in grid based elevation models, the grid structure creates some obstacles as it only allows for eight flow directions. Earlier algorithms have used arbitrarily designed flow distributions, which have resulted in either too diverging or too converging flow patterns. This study defines a computationally simple distribution function, where the converging nature (x) can be altered. A material of reference flow distributions was produced through simulation in four elevation models. The distribution function was tested for different values on x, against the reference. The results show a stable correlation pattern between the tested function and the reference. Optimum values on x were found, which suggest that the flow distribution from a grid cell should be weighted with the slope gradient raised to the power of 4–6.
Interactions between groundwater and surface water in a virginia coastal plain watershed. 2. Acid—base chemistry
Authors: Kuebler O'Brien Anne , Eshleman Keith N. , Pollard John S. 
Published: February 2007

AbstractAn intensive study was conducted on the biogeochemical processes controlling the acid‐base chemistry of Reedy Creek, a wetland‐influenced coastal plain stream located near Ashland, Virginia. In the context of the hydrological processes determined by Eshleman et al., the present research sought to: (1) identify the sources and sinks of anthropogenic and organic acidity within the watershed, (2) determine the seasonal and spatial variability in the stream base flow chemistry, (3) determine the episodic variability in stream stormflow chemistry and (4) quantify a watershed sulphate budget for the 1990 water year. Sulphate is the primary acidic anion in groundwater and surface water at the Reedy Creek watershed. Dissolved organic carbon (DOC) and anion deficit data suggest that organic acids are less important than sulphate in contributing acidity to the stream. In groundwater sampled from wells installed along two transects perpendicular to the stream, sulphate concentrations were higher and alkalinity lower in the groundwater in the hill‐slope than in the stream. Sulphate concentrations and alkalinity observed in groundwater in the wetland were usually between those of the hillslope and stream. These data suggest that the wetland is a sink for sulphate and acidity; sulphate reduction may be an important mechanism for generating alkalinity in the wetland. The DOC concentrations were higher in the stream and wetland groundwater than in hillslope groundwater. No consistent spatial patterns in sulphate concentrations were observed in surface water chemistry under base flow conditions. Anion deficit, DOC and the sum of base cation concentrations were usually higher at upstream sites than downstream sites. At all sites, sulphate concentrations were higher and alkalinity lower in winter and spring than during summer and autumn. Calculated anion deficits were lower in winter and spring than during summer and autumn, reflecting an increase in the contribution of organic acidity during the growing season. Seasonality was not observed in DOC concentrations. Stream discharge was found to be positively correlated with base flow sulphate concentrations and inversely correlated with alkalinity. A sulphate mass balance indicated that approximately 30% of the estimated 24.9kg SO2−2/ha yr wet atmospheric input was exported from the watershed as sulphate in stream runoff in the water year 1990.
Dissolved organic carbon dynamics in two streams draining forested catchments at loch ard, Scotland
Authors: Grieve Ian C. 
Published: February 2007

AbstractDissolved organic carbon (DOC) was measured at four or eight hour intervals between mid‐1989 and mid‐1991 in two catchments in west central Scotland. The experimental catchment had been recently clear‐felled and the control remained under forest. The amount of DOC varied during individual storm events following the stream hydro‐graph. Maximum variations were found in the summer half‐year and in the clear‐felled catchment. There was also evidence of the exhaustion of DOC in the later events of a sequence. Differences between the catchments were related to catchment characteristics and to land‐use change. The reduced magnitude of variation in DOC with discharge in the control stream was due to the influence of a wetland area through which the stream flowed. The mean DOC concentrations were similar in the two streams and annual exports were 15 g m−2 from the control and 16g m−2 from the felled catchment. The stream draining the clear‐felled catchment had greater high flow DOC concentrations in the summer half‐year, probably due to the effect of greater mean summer temperatures on DOC release and of the greater supply of organic debris in the stream channel.
Major ion variation and efflux related to discharge in a mafic piedmont province watershed
Authors: Rose Seth 
Published: February 2007

AbstractMajor‐ion variability related to discharge was analysed in a forested 187 km2 mafic Piedmont Province watershed using statistical (both parametric and non‐parametric), graphical (box‐plots) and curve‐fitting (log concentration‐log discharge) techniques. Baseflow alkalinity and base cation concentrations show systematic temporal variations as a result of the influx of additional water that occurs during the late autumn to early spring. Regression analyses indicate that storm‐related discharge and baseflow generated during periods of water surplus are characterized by similar dilution slopes. Mass balance estimates indicate that the additional water, which comprises storm/recession discharge and base‐flow from late autumn to early spring, is between about 30 and 80% as concentrated as summer low‐flow.The thick clay‐rich soil mantle represents a key control on solute concentrations in that it stores water for periods of time sufficient for a high degree of water‐mineral interaction to occur. Hence solute‐discharge relationships (C = aQb, where b is typically < 0) are characterized by relatively low slope values and there is ample acid neutralizing capacity throughout the range of discharge. Owing to the predominance of amphibolite, solute efflux related to rock weathering from the Falling Creek watershed is much greater than other more felsic locations within the region. Statistical analyses (Mest and the non‐parametric Mann‐Whitney‐Wilcoxon test), along with accompanying box‐plot representations, provide a useful method of describing systematic annual hydrochemical variation within streamflow. These methods are particularly effective for those instances in which a long‐term data set exists, but is limited to relatively few sampling periods per year.