摘要:

AbstractA precise photogrammetric technique was used to determine the microtopography of seven 2.6 m × 1.2 m experimental units located on a hillslope. Surface elevations were determined with an accuracy of better than 1 mm, from which contours at 2mm intervals were interpolated. These contour plots were then manually interpreted to define depressions and associated storage volumes. Analysis of the results highlighted the complex variability of depression storage over the hillslope, for example there being little relation between depression storage volumes and unit slope. This study also highlights the sampling problem for the measurement of depression storage on natural surfaces, which appears not to have been formally recognized previously, and also emphasizes the practical difficulty of achieving depression storage estimates with coefficients of variation less than ten per cent to 50 per cent, much of this variability being due to problems of interpretation rather than measurement of the surface

ISSN:0885-6087    

DOI:10.1002/hyp.3360030102

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

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 km2catchment in southwest Saudi Arabia.Maximum point rainfall intensity was 115.4 mm hr−1. The peak discharge was 3200 m3s−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 ye

ISSN:0885-6087    

DOI:10.1002/hyp.3360030103

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

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 acidif

ISSN:0885-6087    

DOI:10.1002/hyp.3360030104

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractLaboratory and field experiments demonstrated that solid state pressure transducers are accurate and reliable devices for frequent measurements of soil suction. However, each transducer had to be individually calibrated before use and a hanging column procedure designed for this purpose is described. Analysis showed that each transducer had a linear response and that environmental conditions such as temperature had minimal influence. Twenty four tensiometers with pressure transducers were intalled in a forest soil to test their operation and their output was monitored by a data logger. An example of soil suction results measured during four storms is given to demonstrate their stability and their rapid response. The transducers were found to perform accurately and were only affected by temperatures below 0°C

ISSN:0885-6087    

DOI:10.1002/hyp.3360030105

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractLarge land areas in Sweden are planned to be planted with high producing, short rotation forest stands of willow in the beginning of the 1990s. Since willow is a highly hydrophilic species, this new land use may have strong implications on water resources. To assess these implications, evaporation ofSalix viminalisand Salix viminalis x caprea stands in lysimeters was analysed with the simple, yet physically realistic KAUSHA model. Parameter values for the Lohammar equation were deduced (b= 100 m3kg−1,kmax= 0.01 m s−1), believed to be applicable to other sites. Simulated evaporation during the 1980 growth season for a normal stand with a production of 12 tonnes of dry matter per hectare per season was 526 mm, of which 375 mm was transpiration, 56 mm interception evaporation, and 95 mm soil evaporation. For an optimally irrigated 20‐tonnes stand, the total evaporation was 584 mm, of which 430 mm was transpiration. As a comparison, Penman open water evaporation was 430 mm. To avoid soil water stress in the 20‐tonnes stand, 140 mm was needed as irrigation, equivalent to 25 per cent of the mean annual precipitation. Since intensively cultivated willow plantations seemed to be using much water, it was concluded that introduction of this agri‐forestry practice must be carefully planned to make use of this property, e.g. in biological filters or in reclaiming water‐

ISSN:0885-6087    

DOI:10.1002/hyp.3360030106

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractSix stations along the Rhône River from the Rhône Glacier to Lake Geneva were sampled by continuous flow centrifuge for recovery of suspended sediment. The samples were taken four times in the year in both 1982 and 1983. In addition, the mouth of the river was sampled in a like manner every two weeks during 1982 until August 1983. Concentration of sediment and composition did not vary as a function of depth or location across the river. Concentrations varied in time and as a function of flow and samples showed both increasing concentration in suspension and an increase in the proportion of finer particles moving downstream from source to mouth. Only slight variations in texture could be observed down the river as a function of time and appeared to relate to freezing and melting of the Rhône and other headwater glaciers as the primary sediment source. Little variation was observed annually in the texture and composition of the sediment at the river mouth despite large changes in concentration between the high flow summer and low flow winter discharges. These findings are consistent with a well‐mixed system in which the suspended sediments are directly related to the primary supply of material from the glac

ISSN:0885-6087    

DOI:10.1002/hyp.3360030107

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractPermian evaporite deposits have been extensively dissolved beneath the perimeter of the Southern High Plains in the Texas Panhandle. Hydrologic and geochemical data were collected from six test wells to determine hydrogeochemical processes involved and the source and flow paths of ground water moving in salt‐dissolution zones. Geochemical similarities and hydraulic‐head relationships indicate that ground water dissolving halite and anhydrite moves downward from aquifers in post‐Permian formations and follows flow paths influenced by topography. Holocene salt‐dissolution rates probably are lower than Tertiary and Pleistocene rates owing to regional changes in physiography and climate that probably decreased the amount of recharge to salt‐dissolution zones. Present as well as palaeohydrologic ground‐water velocities and salt‐dissolution rates are probably less beneath the Southern High Plains than in adjacent, peripheral salt‐dissolution zones because of lower hydraulic conductivities and lower hydraulic‐head gradients. Salinities in peripheral salt‐dissolution zones are low (67 000 to 95 000 mg L−1) despite high solubility of halite, reflecting relatively open circulation of ground water. In interior salt‐dissolution zones beneath the Southern High Plains, ground‐water circulation is low and water composition tends t

ISSN:0885-6087    

DOI:10.1002/hyp.3360030108

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0885-6087    

DOI:10.1002/hyp.3360030109

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0885-6087    

DOI:10.1002/hyp.3360030110

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0885-6087    

DOI:10.1002/hyp.3360030111

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY