The use of infiltration field tests for groundwater artificial recharge

 When using surface infiltration as a method of recharge, infiltration testing is considered an important additional data input along with other hydrogeologic data into the recharge decision. As part of an investigation into the potential for groundwater recharge, two desert basins in Jordan (Wadi Madoneh and Wadi Butum) were investigated to determine the possibility of recharge using floodwater retention structures. For each area, short-duration (up to 7-h) infiltration tests were conducted to estimate surface infiltration capacity of the upper soil layers in order to present to the authorities preliminary information which could be used along with other factors to aid in the selection of the best site for a pilot recharge project. Given the highly fractured rock formations that constitute the underlying aquifers in the two areas, it was assumed that the upper alluvium layers are the limiting factors in transmitting water to target aquifers. The infiltration tests conducted to estimate the recharge characteristics of the recharge sites yielded test results that indicated a representative infiltration rate of 0.44 m/day for the Wadi Madoneh site and 0.197 m/day for the Wadi Butum site. The data input was used subsequently with other decision factors to select the most promising site for the pilot project. Received: 9 January 1998 · Accepted: 27 April 1998     

Monitoring the grazing resources of the Badia region, Jordan, using remote sensing

In this paper we discuss how low spatial resolution (1 km) ERS ATSR-2 and NOAA AVHRR satellite data were used to map and monitor changes in the grazing vegetation of the Badia region of Jordan. This area is typical of many arid zone grazing areas, comprising sparse vegetation and highly reflective soils. These two factors were found to severely limit the usefulness of satellite-derived vegetation indices that are frequently used to map and monitor vegetation in more temperate areas. Furthermore, the relationship between vegetation indices and percentage vegetation cover was found to be site-specific, thus reducing their application for large-scale vegetation monitoring. As an alternative, a hybrid geometric optical/empirically based model was developed for the area. This was based on the illumination geometry and reflectance values from the red and near-infrared scattergram of the satellite images. The output of the model was a series of maps indicating percentage vegetation cover for different dates and these were used to construct maps showing areas of vegetation change. Strong correlations (r²=0.837) were found between estimates of percentage vegetation cover derived from the model, and measurements made at a series of 16 field sites in the area. The use of geometric optical models based on satellite imagery improves the ability to map areas of grazing vegetation in arid areas such as the Badia and provides a good alternative to the use of vegetation indices.     

The exploitation of an arid landscape by a pastoral society: the contemporary eastern Badia of Jordan

The paper reconsiders the use of arid landscapes as a resource by pastoral societies in the light of recent socioeconomic developments, using Bedouin livestock herding in the Jordanian Badia as a case study of a pastoral system in transition. The paper argues that in the contemporary Badia context, landscape is exploited by users in a wide variety of ways, and for the acquisition of both tangible and non-tangible resources. The study concludes that the modernization and commercialization of livestock production in the Badia does not necessarily imply a diminishing of ties between herder and land resources, and suggests instead that the process of modernization in livestock production may in fact generate a wider spectrum of options for its exploitation.     

Effect of extreme rainfall events on the water resources of the Jordan River

As a response to climate change, shifting rainfall trends including increased multi-year droughts and an escalation in extreme rainfall events are expected in the Middle East. The purpose of this study is to evaluate the potential impact of these shifting trends on stream flow in the Jordan River and its tributaries. We use a non-homogeneous hidden Markov model to generate artificial daily rainfall simulations which capture independently shifting trends of increased droughts and escalated extreme. These simulations are then used as input into a hydrological model calibrated for the upper catchments of the Jordan River to compare the impact on stream flow and water resources between the different rainfall scenarios. We compare the predicted baseflow and surface flow components of the tested watersheds, and find that while an increase in extreme rainfall events increases the intensity and frequency of surface flow, the over all flow to the Jordan River, and the characteristics of the baseflow in the Jordan River system is not largely impacted. In addition, though it has been suggested that in the case of a multi-year drought the karstic nature of the aquifer might lead to more intense, non-linear reductions in stream flow, here we quantify and show the conditions when annual stream flow reduce linearly with rainfall, and when these relations will become non-linear.     

The Major Gulf of the Aqaba Earthquake, 22 November 1995 – Maximum Intensity Distribution

The major earthquake of 22 November 1995, with a moment magnitude M_W = 7.1 and a local magnitude M_L 6.2, was the beginning of a seismic swarm that occurred in the central part of the Gulf of Aqaba. During this swarm, thousands of earthquakes occurred with local magnitude ranging between 2 and 6.2 from 22 November 1996 to 31 December 1997, when 2089 earthquakes were detected and/or analyzed by the Jordan Seismological Observatory (JSO). The major earthquake strongly affected the near shoreline cities (Figure 1). The maximum observed intensity on these cities was VIII on the modified Mercalli intensity (MMI) scale. A questionnaire was distributed in the main cities of Jordan one week after the major earthquake. The results of this investigation, which demonstrated the observed intensity distribution for Aqaba city, shows a relationship between local conditions, such as geological foundations and topographical characters, and the extent of the destruction. This conclusion was supported by the maximum peak ground acceleration (PGA) measurements inside Aqaba and Eilat cities. From the results of this questionnaire compiled inside Jordan, and other reports and readings compiled from other nearby countries outside Jordan, a preliminary regional iso-intensity map for this major earthquake of 22 November 1995 is presented in this study.     

Geomorphology of the eastern Badia basalt plateau, Jordan

The eastern Badia of the Hashemite Kingdom of Jordan is a landscape developed predominantly on late Tertiary and Quaternary basalt lava flows, which vary in age between 8.9 million and 0.1 million years. Pyroclastic deposits are associated with remnant volcanic cones. There is limited, seasonal rainfall. Natural vegetation regenerates during cool, damp months. Slopes, which range from concave to convex forms and have varying relief, can be related to different basalts and the time since emplacement. Much of the ground surface is mantled with boulders. In many places the continuity of boulder cover produces a desert pavement. Clasts show differing degrees of burial or exhumation, depending on the surrounding topography. Water and sediment movement are important to landscape development. Much sediment is deposited in pans, which evolve at topographic lows. The pans, known locally as Qa, vary in form depending on drainage network development. Transitional forms, known as Marab, develop where wadis widen out and sediments are deposited along ephemeral channels. Groundwater is significant, with three aquifers beneath much of the eastern Badia. Recharge of the upper aquifer is predominantly on the footslopes of the Druze Mountains, with north to south flow. Groundwater extraction has resulted in the expansion of agriculture, with consequent changes in soil and water quality.     

Dating desert pavements – First results from a challenging environmental archive

Desert pavements are widespread landforms of arid environments. They consist of a monolayer of clasts at the surface, associated with an underlying unit of eolian fines. In some situations, buried desert pavements can be observed, which is interpreted as a change in the environmental conditions. Therefore, it is believed that desert pavements represent important paleoenvironmental sediment archives, especially for arid environments, where natural archives of past environments are rare. To better understand the formation process of desert pavements and to enable the paleoenvironmental interpretation of these valuable sediment archives, reliable chronologies are of crucial importance. Thus, OSL dating was applied to samples from well-developed desert pavements in two different study areas, the Cima Volcanic Field, eastern Mojave Desert, USA, and the desert of northeastern Badia, Jordan. To test the suitability of the sediments for OSL dating, the luminescence characteristics of the fine- and coarse-grain quartz fraction are described and compared. Finally, first OSL ages are presented.     

The Wasatch Environmental Observatory: A mountain to urban research network in the semi-arid western US

The 2085 km² Jordan River Basin, and its seven sub-catchments draining the Central Wasatch Range immediately east of Salt Lake City, UT, are home to an array of hydrologic, atmospheric, climatic and chemical research infrastructure that collectively forms the Wasatch Environmental Observatory (WEO). WEO is geographically nested within a wildland to urban land-use gradient and built upon a strong foundation of over a century of discharge and climate records. A 2200 m gradient in elevation results in variable precipitation, temperature and vegetation patterns. Soil and subsurface structure reflect systematic variation in geology from granitic, intrusive to mixed sedimentary clastic across headwater catchments, all draining to the alluvial or colluvial sediments of the former Lake Bonneville. Winter snowfall and spring snowmelt control annual hydroclimate, rapid population growth dominates geographic change in lower elevations and urban gas and particle emissions contribute to episodes of severe air pollution in this closed-basin. Long-term hydroclimate observations across this diverse landscape provide the foundation for an expanding network of infrastructure in both montane and urban landscapes. Current infrastructure supports both basic and applied research in atmospheric chemistry, biogeochemistry, climate, ecology, hydrology, meteorology, resource management and urban redesign that is augmented through strong partnerships with cooperating agencies. These features allow WEO to serve as a unique natural laboratory for addressing research questions facing seasonally snow-covered, semi-arid regions in a rapidly changing world and an excellent facility for providing student education and research training.     

Erosion risk assessment and sediment yield production of the King Talal Watershed, Jordan

 King Talal Dam (KTD) watershed is the most important one in Jordan. At its outlet lies the KTD (80 MCM capacity) which serves irrigation purposes in the Jordan Valley. However, the dam suffers from accelerated annual sedimentation. Therefore, this study is directed to assess the erosion risk over the watershed, and to simulate actual annual sediment yield at the dam in order to devise the appropriate conservation practices. Generalized assessment was first conducted over the watershed on the basis of drainage texture, rainfall erosion index (R), and the ratio p²/P. As a result, the watershed is divided into zones of severe, high (gullying), high (overland flow) and low erosion risk. Sediment yield at the dam was evaluated by a simulation model. For model validation the simulation results were compared to the measured values over 12 years period, and a good agreement was obtained in some of the years. The simulation results allow us to assess the application of two practical conservation practices: terracing and plantation of trees. Received: 18 November 1997 · Accepted: 18 May 1998     

Monitoring soil moisture dynamics using satellite imaging radar in northeastern Jordan

This paper describes how synthetic aperture radar (SAR) data from the European Environmental Remote Sensing (ERS) satellite series were used to derive estimates of near-surface soil moisture for seasonally vegetated and bare soil surfaces in the area of the Jordan Badia Research and Development Programme (BRDP). Data were acquired between March 1995 and April 1998, covering both wet and dry seasons. A surface scattering model was calibrated using field data: first to understand how soil moisture affects the SAR signal and, secondly, to predict the response of the SAR signal to changes in volumetric soil moisture. Good agreement between predicted and observed estimates was obtained. Model inversion allowed soil moisture predictions to be made that were deemed realistic in terms of soil moisture values.