bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rainfall interception by a young Acacia auriculiformis (a. cunn) plantation forest in West Java, Indonesia: Application of Gash's analytical model
Authors: Bruijnzeel L. A. , Sampurno Swami Prem , Wiersum K. F. 
Published: February 2007

AbstractMeasurements are reported of rainfall, throughfall, stemflow, and derived interception losses made on a daily basis during two consecutive rainy seasons in a 4–5 year old and rapidly growing plantation forest of Acacia auriculiformis in a humid tropical environment. During the first observation period throughfall, stemflow, and interception loss amounted to respectively 81, 8, and 11 per cent of gross precipitation, whilst corresponding values for the second observation period were 75, 7, and 18 per cent. All three components correlated strongly with amounts of daily rainfall, but slopes of linear regression equations differed significantly between seasons for each component. Such differences are thought to reflect a 20 per cent increase in foliar mass as well as a certain instrumental bias introduced by the use of a fixed grid of throughfall troughs that differed between seasons. Tests did not reveal any effects of differences in rainfall characteristics although the two observation periods differed markedly in this respect.Although the present results fell within the (lower part of the) range reported for other sites in Southeast Asia application of Gash's analytical model suggested the results obtained during the second observation period to be anomalous. The model was tested with data from the second halves of the two observation periods, using parameters derived from the corresponding first halves. Discrepancies between estimated and observed losses were +9·4 and −14·3 per cent for the two periods respectively. The bulk of the interception loss consisted of evaporation from a saturated canopy (69–80 per cent) and of evaporation after rainfall had ceased (25 and 15 per cent for the two periods respectively). Although the results were encouraging it would seem that a major difficulty in applying the analytical model to the humid tropics lies in obtaining a reliable estimate of the evaporation rate from a saturated canopy.
The effects of hydrological factors on river suspended solids contamination from a colliery in South Wales
Authors: Bird S. C. 
Published: February 2007

AbstractSuspended solids contamination caused by runoff below a working colliery in the Upper Clydach catchment in South Wales, U.K., was investigated in relation to hydrological controls. Field studies over a 16 month period found that concentrations below the colliery ranged from 4 to 8028 mg 1−1. Simple correlation and linear regression analysis of spot and storm event samples taken below the colliery gave a correlation coefficient of 0·39 between flow and suspended solids concentration. Because of the lack of explained variance, a multiple linear regression model of within‐storm concentrations was derived using four selected independent variables. X1 the time relation of the sample to the storm peak; log X2 the stormflow at the time of sampling; log X3 the baseflow at the time of sampling; and log X4 an index of the storm intensity. Analysis of the entire dataset gave an R2 of 0·34. When the results from three atypical events were excluded however, the R2 value improved to 0·65. Beta coefficients indicated that rising limb conditions (X1) and intense storms (log X4) along with dry antecedent conditions (log X3) represent the worst combination of hydrological factors for producing suspended solids contamination.
Bromide as a conservative tracer for soil‐water studies
Authors: Levy B. S. , Chambers R. M. 
Published: February 2007

AbstractThe assumption that potassium bromide is a conservative tracer for soil‐water studies was tested in a series of batch sorption experiments. Sorption experiments were conducted on soil samples collected from the O, E, and A horizons of the Albemarle soil series near Charlottesville, VA. The experiments were conducted under conditions of differing bromide concentration and filter treatments. Bromide concentrations in soil‐solution mixtures were measured through time using an Orion bromide‐specific electrode. An analysis of variance of results showed no significant sorption of bromide through time under any concentration level or filter treatment (α = 0·01). No sorption of bromide between different soil horizons could be determined. This work clearly indicates that bromide is conservative under the conditions examined.
A tipping bucket flowmeter for roadside gully runoff
Authors: Hollis G. E. , Ovenden J. C. 
Published: February 2007

AbstractA tipping bucket flowmeter designed for the measurement of inflows to roadside gully pots is described. It is braced within the pot above the liquor and the runoff is fed to it via a glass fibre funnel and a hose. Whilst it can be calibrated to only 0·71 s−1, it is very effective at low flows and has a number of advantages over the well known Institute of Hydrology Gully Meter. Its use at Redbourn, Hertfordshire for roads on highly permeable soils shows that for both rainfall and artificial irrigation the ‘losses’ are very large and highly variable even within a single housing estate road.
Modelling pipeflow contributions to stream runoff
Authors: Jones J. A. A. 
Published: February 2007

AbstractRunoff from natural soil pipes has been shown to be a significant contributor to stream discharge in parts of upland Wales. Attempts have been made to model pipeflow contributions using both theoretical and empirical approaches, but little progress has yet been made towards producing generally applicable models of complete pipeflow systems.The paper identifies some of the problems of devising general models with reference to data from the Maesnant Experimental Catchment. The data suggest that in‐pipe travel times are more important here than inferred elsewhere, and that neither simple hydraulic models nor kinematic wave theory can adequately explain the patterns of response. In particular, stormflow tends to begin first at the network outfall and even peak discharge often occurs at the outfalls before the headward zones.
Solute concentrations in the lower niger river and the source rock contribution
Authors: Martins O. 
Published: February 2007

AbstractWater quality analyses for the Niger River for the 1980/81 hydrological year are presented. The samples were collected from the main river at Lokoja, and from two main tributaries, the Kaduna and the Benue Rivers.Different water types were distinguished by the concentrations of major ions. The type Ca > Na > Mg > K ‐ HCO3 > SO4 > Cl was represented at all stations during at least part of the year. Chloride was found to dominate the sulphate ion in the Kaduna and Niger, while the Benue maintained a higher concentration of sulphate relative to chloride all year round.Distinct patterns of seasonal variation in the ion concentrations were observed, particularly for the samples collected at Lokoja. Low ion concentrations were prominent during periods of high discharge, while low flow periods coincided with high dissolved ion concentrations.The contribution of rainwater to the total dissolved solids in the river waters was assessed indirectly using rainwater chemistry data from the Gulf of Guinea. The estimated rainwater contribution to the Lower Niger amounts to 5.15 mg 1−1.Geochemical weathering calculations involving reactions of the four major minerals of granitic rocks ‐ anorthite, biotite, albite, and K‐feldspar ‐ with carbon dioxide and water, can account for the average water composition of the Lower Niger. The proportion of the ionic components was also related to the occurrence of the respective element in the minerals.
Sources and sinks of nutrients in a New Zealand hill pasture catchment I. Stormflow generation
Authors: Cooke James G. , Dons Tony 
Published: February 2007

AbstractThe processes of stormflow generation were studied in a hill pasture catchment near Hamilton, New Zealand. Although rainfall was relatively evenly distributed throughout the year, stormflow was highly seasonal and over 65 per cent occurred during the winter. Three main processes contributing to stormflow were identified which could be related to soil type and physiographic position. On gleyed soils derived from rhyolitic colluvium, saturation overland flow was the dominant process. Hydrographs from ‘Whipkey’ throughflow troughs also indicated that there was a subsurface response (saturated wedge) from this soil type. On steeper convex slopes, more permeable soils were derived from weathered greywacke. The presence of ephemeral springs on the hillslopes and direct observation during storm events indicated that storm runoff was generated as return flow from this soil.It was noted that nitrate concentrations from subsurface sources were 5–10 times higher than surface runoff. This difference in concentration was utilized in a chemical mixing equation which partitioned stormflow sources. This was compared with the stormflow predicted from rain falling on to saturated areas. There was good agreement between the two models for winter‐spring events with respect to the volumes of surface runoff predicted, however the saturated areas model underestimated total stormflow.The results of the study are briefly discussed in terms of the potential for water quality management.
Sources and sinks of nutrients in a New Zealand hill pasture catchment III. Nitrogen
Authors: Cooke James G. , Cooper A. Bryce 
Published: February 2007

AbstractA study was made of the nitrogen (N) inputs to, and exports from, a stream draining a pasture catchment near Hamilton, New Zealand, in order to plan measures for minimizing N losses to natural waters.An estimated 7 kg N ha−1was exported from the catchment during 1981 of which 86 per cent was in reduced forms (Kjeldahl‐N, TKN) and the remainder as nitrate‐N (NO3‐N). Virtually all of the reduced N inputs came from saturated overland flow whereas NO3‐N inputs were dominantly subsurface derived. The TKN exported by individual storm events could be predicted (R2= 0.97) from peak flow and from the peak flow rate in the seven days preceding the storm. A TKN balance for eight events showed that except for large floods (return period approximately a year) the stream system was a net sink for TKN. During large floods, scouring of the organic rich seepage areas resulted in the stream system itself being a net source of TKN.Microbial assays for nitrification and denitrification activity indicated that the main nitrate source was the well‐aerated greywacke and ash soils and that the permanently saturated seepage zones were a significant nitrate sink. An in‐stream nitrate addition experiment showed that up to 20mg N m−2h−1was removed from the stream. Simultaneous measurements ofin situdenitrification activity demonstrated that only about 1 per cent of this removal could be accounted for by denitrification. It was inferred that plant uptake was responsible for the remainder.Retention of near‐stream seepage areas is suggested as a measure for minimizing NO3‐N export, whilst removal of stock from seasonally saturated areas during periods of saturatior should reduce soil loss and hence TKN inputs to the stream.
Finite element computation of shape factors for Kirkham's piezometer tube method for hydraulic conductivity of saturated soil
Authors: James McD. , Brown B. , Hodgson Martyn P. 
Published: February 2007

AbstractThe Kirkham piezometer tube method of measuring hydraulic conductivity of saturated soil uses a numerical constant (shape factor) to account for the relative geometrical parameters of the cavity and the soil domain. Published shape factors have mostly been determined using an electrical analogue. In this paper the application of the finite element method to shape factor determination is considered. Convergence is studied and methods of extrapolation evaluated. A determination is made of the size of finite region required to represent adequately the radially unbounded domain assumed for the piezometer method. Computed shape factors were found to be in good agreement with analogue data.
Groundwater recharge in arid regions: Review and critique of estimation methods
Authors: Gee Glendon W. , Hillel Daniel 
Published: February 2007

AbstractArid‐site recharge, while generally low, can be highly variable. Recharge under similar climate and soil conditions but with different plant cover and topography can vary from zero to more than the annual precipitation. Simple estimates of recharge based on fixed fractions of annual precipitation are misleading because they do not reflect the plant and soil factors controlling recharge. Detailed water balance models, successful for irrigated agriculture, fail to predict evapotranspiration accurately under conditions where plants suffer seasonal water stress and cover is sparse. Recharge, when estimated as a residual in water balance models, may be in error by as much as an order of magnitude. Similar errors can occur when soil water flow models are used with measured or estimated soil hydraulic conductivities and tension gradients. Lysimetry and tracer tests offer the best hope for evaluating recharge at arid sites, particularly in siting waste disposal facilities, where reliable recharge estimates are needed. Quantification of drainage using lysimetry over several years under a given set of soil, plant, and climate conditions for a specific site can provide a basis for calibrating models for recharge prediction. Tracer tests using such long‐lived tracers as 36Cl or perhaps stable isotopes (180, deuterium) can provide qualitative estimates of recent recharge at a given site.
Assessing the influence of environmental parameters on the hydrological cycle
Authors: Yan‐Nian Yu , Yiao‐Mei Zhu , Yi‐Chun Xie 
Published: February 2007

AbstractHuman activity is exerting an increasing influence on the hydrological cycle. In order to avoid adverse impacts and to establish optimum conditions for the water balance, it is necessary to understand the role of environmental parameters in influencing the hydrological cycle. Work is currently in progress in China to study the relationships between environmental parameters and the hydrological cycle to provide a basis for planning future development.
A weighing lysimeter in a regenerating eucalypt forest: Design, construction, and performance
Authors: Reyenga W. , Dunin F. X. , Bautovich B. C. , Rath C. R. , Hulse L. B. 
Published: February 2007

AbstractA 36 tonne monolithic weighing lysimeter (3.7 m diameter and 1.5 m deep) was installed in Kioloa State Forest near Batemans Bay, New South Wales, Australia, to provide a continuous record of water use from a regenerating natural eucaplyt community, five years old at installation. The resolution is equivalent to 0.05 mm of evaporation and provides hourly information for diurnal variation of forest evaporation. The sensitivity of 14 ppm compares favourably with those reported for other lysimeters, similar in magnitude, in the U.S.A.Design criteria for selecting, isolating and suspending a sample community ‘in situ’ with an electro‐mechanical balance are outlined. Procedures adopted during installation are described with emphasis placed on precautions taken to minimize disturbance and to avert possible changes in character of the isolated natural community. Lysimeter performance was assessed both in terms of its accuracy and its operation as a remote facility with infrequent attention.
Interception loss from eucalypt forest: Lysimeter determination of hourly rates for long term evaluation
Authors: Dunin F. X. , O'Loughlin E. M. , Reyenga W. 
Published: February 2007

AbstractAnalyses of the response by a weighing lysimeter in Kioloa State Forest during and after rainfall provided values of interception loss rate. The derived rates for time scales between 0.1 and 1.0mm h−1 were generally similar throughout storm events to losses determined from throughfall and stemflow observations. During post‐rainfall periods of canopy drying, enhanced rates of lysimeter evaporation were consistent with micrometeorological determinations of the partitioning of available radiant energy, based on atmospheric gradients of humidity and temperature.Interception losses from the eucalypt forest, deduced from the lysimeter response, varied between 10 and 15 per cent of gross rainfall in three consecutive 12 month periods whereas the corresponding rainfall ranged between 590 and 1530 mm yr−1. Daytime losses accounted for about two‐thirds of total interception loss with a similar fraction occurring during rain periods.Storage capacity of the evergreen forest canopy was inferred to be 0.35 mm. Hourly loss rates during rainfall ranged up to 0.8 mm h−1 but with decreasing mean values and variability with increasing time scale resulting in a monthly mean value computed for the total number of hours of rain of approximately 0.1 mm h−1. A preliminary analysis of loss rate in terms of storm windspeed and rainfall intensity explained about half of its variation in statistically derived relationships. Improved time resolution of the order of seconds was considered a prerequisite to the physical understanding of turbulent transport from saturated canopies.The small value of interception storage capacity was considered in relation to that for pine forest as a basis for explaining observed differences in interception behaviour between eucalypt forest and coniferous plantations in the same area. Large differences in interception losses between the Kioloa site and evergreen forest in the South Island of New Zealand and also eucalypt forest in Western Australia were attributed to dissimilar meteorological conditions at the various sites.
Modelling long term stream acidification trends in upland wales at plynlimon
Authors: Whitehead P. G. , Reynolds B. , Hornung M. , Neal C. , Cosby J. , Paricos P. 
Published: February 2007

AbstractHistorical reconstructions and predictions of streamwater acidification are presented for moorland and afforested catchments in the Welsh Uplands at Plynlimon. MAGIC (Model of Acidification of Groundwater In Catchments) is validated by application to an afforested catchment. MAGIC is used to illustrate that atmospheric deposition is primarily responsible for stream acidification but that conifer afforestation can enhance stream acidity. The historical trends determined by the model illustrate that long‐term acidification has been present since the turn of the century and will continue unless either deposition levels are reduced significantly or liming is undertaken on a major scale.
A unique flood event in an arid zone
Authors: Walter Michael O. 
Published: February 2007

AbstractArid regions generally lack surface water records for developing flood characteristics for hydraulic design purposes. Consequently good records of floods, particularly large ones, are a data asset to arid zone hydrology.A large rainfall and runoff event which occurred on 23 April 1985 has been fully recorded on Wadi Ghat, a 597 km2 catchment in southwest Saudi Arabia.Maximum point rainfall intensity was 115.4 mm hr−1. The peak discharge was 3200 m3 s−1. Point rainfall has an expected frequency of occurrence in excess of once every 200 years. The peak discharge is expected to occur on an average once in 143 years.
Sea‐salt induced streamwater acidification
Authors: Langan S. J. 
Published: February 2007

AbstractThe paper describes three episodes of short‐lived streamwater acidification for a remote site in southwest Scotland. During the third of these storms stream pH decreased from 5.5 to 4.4. The apparent mechanism for acidification is one of ion‐exchange within the catchment soil following precipitation inputs heavily laden with sea‐salt. Verification of such a process is provided by a series of soil experiments. Comparison of data from three catchments under differing land‐use indicates the additional role land management can play in streamwater acidification.
A terrain‐based watershed information system
Authors: Band L. E. 
Published: February 2007

AbstractA framework for a watershed information system is presented in which the topology of the drainage basin is closely followed in the data structure. The topography is partitioned into a set of subcatchments and hillslopes that are organized around the drainage network, automatically extracted and defined from standard digital elevation data. A set of recursive algorithms perform the actual topographic feature extraction and synthesis into a full basin model, and also serve as the basis for processing registered information. The techniques are particularly well suited to support and parameterize distributed components runoff models as full hydrologic connectivity throughout the basin is explicitly defined. Full scale flexibility in terms of the representation of the topography and aggregation of physical units is achieved by the recursive nature of the data stucture, allowing straightforward translation between scales and the investigation and choice of the appropriate scale for various hydrologic applications.
Soil hydrophobic effects on infiltration and catchment runoff
Authors: Burch G. J. , Moore I. D. , Burns J. 
Published: February 2007

AbstractAfter dry summers or drought, eucalypt forest soils at two sites in southeastern Australia developed hydrophobic or non‐wetting surface characteristics that reduced infiltration, measured using a sprinkling infiltrometer. At one site the development of hydrophobic conditions caused the rainfall to runoff conversion efficiency of a forested catchment to increase from 5 per cent to 15 per cent. Under non‐hydrophobic conditions at this site, grassland always generated more runoff than forest. However, one major rainfall‐runoff was recorded at a time of highly hydrophobic forest soil conditions and this storm generated greater runoff on the forested catchment than the grassland catchment.At the second site forest soils have naturally highly conductive surface layers because of a dense network of macropores and pathways for preferential flow. Hydrophobic conditions produced by drought caused soil water movement to be confined to only a few of the larger macropores exposed to surface ponded water. Even so, infiltration rates remained relatively high so that the impacts of hydrophobic soils were not translated into increased catchment runoff as at the first site.
Field measurement and associated controlling factors for ground water seepage in a piedmont impoundment
Authors: Bruckner Amy E. , Hornberger George M. , Mills Aaron L. 
Published: February 2007

AbstractKnowledge of groundwater seepage to and from lakes can be an important component of scientific investigations involving water and geochemical budgets. Measurements of groundwater seepage at Lake Anna, a man‐made lake in central Virginia, show that inflow to the lake occurs even under dry summer conditions. Seepage rates were found to be correlated with the elevation of the near‐shore water table, which responded rapidly to rainfall events in the fractured rock terrane in which Lake Anna is located. Seepage rates did not decline uniformly with distance offshore. This result contrasts with those for lakes underlain by relatively homogeneous porous media where measurements generally confirm the prediction that seepage rates drop off exponentially with distance from shore. The along shore variability of seepage rates in Lake Anna was related to a topographic index that is used to describe drainage from hillslopes. This suggests that seepage in impoundments such as Lake Anna may be strongly controlled by drainage pathways that pre‐date the lake.