摘要:

Groundwater recharge in arid regions is intermittent and usually occurs as a result of flood flow transmission losses in dry wadi channels. Hydrograph characteristics play a dominant role in determining the amount of channel abstraction in relation to the width of the wetted perimeter and the time of inundation, and the subsequent groundwater recharge. Large variations in the magnitude of channel losses result mainly from the diversity in inflow volumes. The magnitude of groundwater recharge in relation to bed transmission losses is dependent on flood volume and duration, soil moisture content and physical soil profile characteristics. Runoff volume and duration are the dominant factors influencing the cumulative infiltrated volume and recharge to shallow water tables. Taking into consideration the influence of various hydrological and channel characteristics, several regression equations are suggested to estimate the transmission losses from a wadi bed and the groundwater recharge.

ISSN:0262-6667    

DOI:10.1080/02626669309492661

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Le logiciel TraPhyC-BV a été élaboré pour extraire des données des modèles numériques de terrain, les composantes de l'hydrologie: réseau de drainage, réseau hydrographique, sous-bassins versants et caractéristiques hydrogéomorphométriques intervenant dans le fonctionnement du bassin versant. A différentes échelles d'observation, le réseau hydrographique étudié présente une structure très variable. On a fait appel à la géométrie fractale pour identifier des relations “grandeur mesurée/jauge de mesure” afin de quantifier l'arborescence et détecter des propriétés invariantes d'échelle.

ISSN:0262-6667    

DOI:10.1080/02626669309492662

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The Khulais plain lies within a typical arid area in western Saudi Arabia. Groundwater occurs within two aquifers in the area: the alluvium of the wadi system, and the sandy layers of the Cretaceous-Tertiary sedimentary succession. Detailed field investigations and laboratory analysis helped in determining the aquifer properties for each of the water-bearing units. Groundwater movement has been thoroughly studied, and distribution maps prepared to explain the variations in transmissivity, permeability, porosity and specific yield. An attempt has been made to estimate volumes of groundwater flow towards the plain. This study presents a first attempt towards determining groundwater availability in the Cretaceous-Tertiary succession of this part of the world.

ISSN:0262-6667    

DOI:10.1080/02626669309492663

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Des mesures physico-chimiques et hydrochimiques ont été réalisées sur un site expérimental équipé de sept forages (26 à 100 m de profondeur) dans des granites fissuré, et de sept piézomètres (1 à 3 m) dans des colluvions et des altérites. Il a été possible de différencier ces deux milieux d'un point de vue hydrochimique et d'en déduire leur degré de connexion et leurs conditions d'alimentation.

ISSN:0262-6667    

DOI:10.1080/02626669309492664

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A field study of erosion processes and local responses was carried out at representative sites of major soil groups in the Niger delta. The soils at these sites varied widely from plastic silty clays to silty sands of varying relative densities. Information on soil type, stratification and state of compaction together with tidal velocity distribution and pool level variation in river channels was used to establish predominant mechanics of erosion. The influence of vegetation on bank stability is dependent on the stage of growth of the vegetation, the relative location of the vegetation in the bank area, the bank steepness and its height. Although bamboo trees and raphia palms on lower parts of channel banks impede flow, thus aiding sedimentation, they may not be effective in checking bank recession. The difficulty of achieving an effective bank protection with raphia palms can be overcome by an improvement in bank protection design layout along the line of a filter which preferentially allows water to escape from the mesh. An upper bank protection may not be effective if low bank areas are scoured as this results in overhangs which readily fail. Consequently, bank protection measures must cover the entire bank profile.

ISSN:0262-6667    

DOI:10.1080/02626669309492665

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626669309492666

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626669309492667

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626669309492668

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626669309492669

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0262-6667    

DOI:10.1080/02626669309492670

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor