摘要:

The Duhamel superposition integral is used to obtain some exact solutions for unit hydrograph applications. These equations and numerical examples are used to show that oscillations will occur in an S-curve when the time step is less than the excess rainfall duration if the measured hydrograph differs from a hydrograph that would be obtained by solving a linear differential equation with time-independent coefficients. The implications of this result with regard to the calculation of the instantaneous unit hydrograph (IUH) are discussed.

ISSN:0262-6667    

DOI:10.1080/02626668509490997

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Groundwater temperature at an arbitrary depth and at an arbitrary point is determined not only by heat transported by conduction but also by advection caused either by infiltration of rain, snowmelt or irrigated water, or by seepage from surface water bodies. Therefore, characteristic changes of groundwater temperature are observed in recharging and discharging areas within a groundwater flow system. The changes may be one-, two-, or three-dimensional, depending on individual situations. Since heat is a conservative quantity in the subsurface environment, groundwater temperature can be used as a tracer to reveal the regional structure of a groundwater flow system. A case study showing the importance of groundwater temperature in a regional groundwater survey is presented taking Nagaoka plain, Japan, as an example. The groundwater temperatures were measured in observation wells with diameters of 65 to 250 mm and depths of 20 m or more. Marked seasonal changes in temperature depth profiles showing advective effects in the horizontal direction from the Shinano River, and in the vertical direction from upper and lower aquifers, were observed. The temperature depth profiles were classified into six types. The distribution of these types does not contradict the regional structure of the groundwater flow system revealed by the potential distribution. As groundwater temperature is an easily measureable element in a hydrological survey, the method described in the present paper is appropriate for a field study in an uninstrumented groundwater basin.

ISSN:0262-6667    

DOI:10.1080/02626668509490998

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

En se référant à la distribution spatiale des gouttes de pluie selon la dimension, dont la loi se précise actuellement, on calcule les puissances de chutes de pluie de diverses intensités. Compte tenu des incertitudes sur les paramètres, les valeurs associées de l'énergie totale de ces chutes de pluie ne diffèrent pas significativement de celles fournies par les formules simplifiées couramment utilisées dans les indices d'érosivité.

ISSN:0262-6667    

DOI:10.1080/02626668509490999

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Vegetation debris dams occur on average every 27 m of channel in a drainage basin in the New Forest, Hampshire, England, and within less than 12 months 36% changed position or were destroyed and 36% changed character. Such dams significantly affect the timing of flood peaks as they are routed through the channel network; their significance has been demonstrated by preliminary analysis of hydrograph travel times by measurements in a reach at different flow stages, and by measurements before and after dam clearance. There was a difference in travel time of over 100 minutes for the situation with and without dams for a discharge of 0.1 m3s−1but a difference of only 10 minutes for a discharge of 1.0 m3s−1along the same 4028 m channel reach.

ISSN:0262-6667    

DOI:10.1080/02626668509491000

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Annual evaporation (E) is often determined using the water balance approach, E = P—Q, because precipitation (P) and runoff (Q) are easily obtainable for most parts of the world. From a regional perspective, P and Q are point observations, containing information pertaining both to the regional trend and to the local environment. Trend surface analysis provides a simple method to filter out the local element, permitting a regional estimation of evaporation. This technique was applied to northern Ontario in Canada where a limited P and Q data network covers a vast domain. The resulting estimated evaporation pattern, obtained as a difference between P and Q trend surfaces, is partially compatible with a manually constructed map published by the Government. Discrepancies arise where the data sources are different or inadequate. One major advantage of this method is that, given additional information, the macro-scale estimates of evaporation can be updated easily and objectively.

ISSN:0262-6667    

DOI:10.1080/02626668509491001

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The intended performance of hydraulic structures such as dams built on soluble rock or soil foundations may depend upon rates of dissolution caused by water seeping through joints, fissures or granular zones. Previous papers by one author and collaborators have defined the rates of dissolution for soluble rocks by means of a simple equation: dM/dt = K A (Cs—C)θ. This relationship may be used as an aid to prediction of enlargement of joints and fissures in rocks, settlements of granular foundation strata, the deterioration of filters, risks to shallow but intensely loaded foundations, and durability of underground storage caverns in soluble rocks. The relationship requires a knowledge of the solution potentials of groundwater associated with these features of engineering structures. They in turn require an understanding of the relevant hydrochemistry and hydrology which is discussed in this paper.

ISSN:0262-6667    

DOI:10.1080/02626668509491002

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

For a leaf-shaped basin geometry, the governing equations of flow are solved analytically by using the method of characteristics for prediction of the basin runoff. The flow model is based on kinematic wave theory and employs a diverging-converging model to represent the geometry of a leaf-shaped basin. Solutions are presented for both equilibrium and partial equilibrium conditions. In many solution domains explicit analytical solutions are obtained for constant rainfall excess. Considering two examples, the predictive potential of the proposed flow model is examined. The surface runoff hydrographs predicted by using the method of characteristics are compared with those of a finite difference method.

ISSN:0262-6667    

DOI:10.1080/02626668509491003

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626668509491004

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626668509491005

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626668509491006

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor