摘要:

This paper examines spatial and temporal heterogeneity of the surface, subsurface and vertical drainage components within and between three sites in a 25.7 ha tropical rainforest catchment. Our analysis indicates that saturation overland flow depends on the relationships between temporal variations in rainfall intensity, the upper soil store capacity, and the spatial variation of saturated hydraulic conductivity in the subsoil below 20 cm. This results in saturation overland flow occurring throughout storms on the upper slopes, but being confined to rainfall intensity peaks in the lower, incised area during the post-monsoon “transitional” season. Regression models indicate that rainfall pulse shape is an important factor determining the proportion of the upper soil store capacity occupied by water. This in turn controls within site differences in specific runoff components between storms. Piezometers showed an almost instantaneous rise and lag to peak times as short as 24 minutes, irrespective of location on the upper slope site. This is attributed to the high rainfall intensities and soil moisture status that prevail in this area.

ISSN:0303-6936    

DOI:10.1080/02626668109490858

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Temperature is arguably the most significant single determinant of water quality but data are collected at comparatively few locations and are rarely subjected to systematic analysis. This paper details two different methods suitable for water managers engaged in predicting river temperatures on an operational basis over a wide range of time scales. Firstly, simple linear regression equations are presented for estimating annual and monthly river temperatures to an acceptable level of accuracy using air temperatures only. Secondly, it is shown how an empirical equation can be fitted to short term observations of river temperature in order to represent the characteristic seasonal and diurnal cycles.

ISSN:0303-6936    

DOI:10.1080/02626668109490859

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Recent work in on-line hydrological forecasting has utilized the Kalman-Bucy filter for state (discharge) forecasting. One drawback of using these algorithms has been restrictions related to the size of the state vector due to computation and computer limitations; resulting in limiting hydrological applications to small headwater catchments. Forecasts of headwater catchments are of limited use to agencies such as the US National Weather Service which routinely have catchments with between 10 and 100 forecast points. This paper sets forth the methodology that allows forecasting of large systems by partitioning the system into subsystems where the filtering of subsystems is performed in parallel. The interactions between the partitioned subsystems are accounted for by supplementing the noise processes. An added institutional advantage to the partitioning approach is the ability for forecasting agencies to set up local forecast centres that are coordinated through a regional centre. This is especially important in large river basins which experience localized flooding on tributary streams. Often regional forecast centres are more concerned with the main river and ignore (or their models do not have the ability to forecast) localized flooding.

ISSN:0303-6936    

DOI:10.1080/02626668109490860

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Rainfall depths and water levels in rivers have been systematically recorded in France since the middle of the nineteenth century. These long observation records can be used for completing recent records of discharges of rivers on plains. The homogeneity of a long series must first be verified and the reliability of the double mass method established. A long, reconstructed series of mean daily discharge at a site proposed for a dam, is used in different cases, according to the available longstanding data record. The generated series are directly usable to work out the dimensions of storage and flood control reservoirs and to develop real time forecasting models. The cost of computerized storage of historical data is negligible compared with the cost of the investments for which they will be used.

ISSN:0303-6936    

DOI:10.1080/02626668109490861

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

On 11 August 1979, the Machhu-2 earth dam, situated about 6 km upstream of the town of Morvi in the Saurashtra region of India, collapsed under the onrush of an unprecedented volume of water. An 8–10 m high flood wave rolled down Machhu valley, entirely submerging Morvi and nearby villages. This flash flood caused the deaths of thousands of people and totally destroyed urban and rural property downstream of the dam. The heavy rainfall of August 1979 over and around the Machhu basin has been analysed by both depth-area-duration and depth-duration methods. Important aspects of heavy rainfall distribution such as: analysis of past severe rainstorms, maximum point rainfall of different return periods, and probable maximum precipitation, were also studied. This study has shown that this event was not the most severe rainstorm in this region. Possibly, the antecedent conditions of the Machhu basin played a significant role in generating the flood volume which caused the earth flanks of the dam to give way.

ISSN:0303-6936    

DOI:10.1080/02626668109490862

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Snowmelt runoff, primarily from mountains, contributes about 75% of the water supply in the western United States. Snow and related hydrological data have been collected from remote mountain sites for more than 40 years primarily through manual methods. An automated data collection system called SNOTEL (forsnow telemetry) is being installed. A portion of the system passed an operational test early in 1979, and installation of the entire system of approximately 500 automated data sites is expected to be complete by November 1980. Sensors to measure snow water content, accumulated precipitation, and temperature are standard at each SNOTEL site. The automated sensors will eliminate the need for manual measurements at more than 500 of the 1600 data sites in the snow data network. The SNOTEL communication system uses meteor trails to transmit data from the remote sites to a master station. The system, which operates in near real time, is capable of collecting and transmitting data from as many as 1000 remote sites and from as many as 16 digital or analog sensors at each site.

ISSN:0303-6936    

DOI:10.1080/02626668109490863

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626668109490864

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626668109490865

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626668109490866

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0303-6936    

DOI:10.1080/02626668109490867

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor