Negev Highlands Research Articles

Pilot studies on high recovery BWRO-EDR for near zero liquid discharge approach

A hybrid process combining reverse osmosis and electrodialysis has been shown to be effective in recovering 97–98% of brackish water as product water with chloride levels of 200 mg/L or less. Potential for scaling on the brine side of the electrodialysis unit was prevented by acidification, operating the electrodialysis in a reversal mode (EDR), and a side loop crystallizer which prevented buildup of scaling components. Settlers, inline microfiltration, and side-loop ultrafiltration kept suspended solids from returning to the EDR unit. This process was demonstrated in a series of more than eighty batch experiments of 1.5 to 1.8 m 3 of RO concentrate of raw brackish groundwater from the Negev Highland, Israel. Each batch could be processed within a single day. The feed-water was concentrated from 0.3% to over 10% TDS super-concentrate while producing the water that could be recycled to the RO permeate. This super-concentrate from the EDR unit was further concentrated in a wind powered WAIV unit that brought final brine TDS to > 30%, and showed promise as a method to recover mineral byproducts such as magnesium salt. Initial economic estimates show that this hybrid process is competitive with conventional RO and other enhanced recovery processes for inland desalination requiring use of evaporation ponds .

Lichen Colonization on Cobbles in the Negev Desert Following 15 Years in the Field

Rock slabs were placed from 1991 through 2006 at the bottom of a north- (NFS) and a south-facing (SFS) slope of a first order drainage basin in the Negev Desert Highlands, Israel (P = 95 mm) where natural cobbles have >95% cover of endolithic and epilithic lichens. Periodic measurements of rain, dew and chlorophyll content took place. Lichen cover and the regeneration time were aspect-dependent. Lichen cover was 98% and 61% at NFS and SFS, respectively, while the lichen's recovery time was respectively ∼45 and ∼80 years. The fast regeneration time may have important implications regarding weathering and soil formation.

Radiocarbon Results from the Iron IIA Site of Atar Haroa in the Negev Highlands and their Archaeological and Historical Implications

In this article, we present a set of radiocarbon measurements from Atar Haroa, a site that belongs to the early Iron IIA Negev Highlands settlement system in southern Israel. The results place activity at the site in the 9th century BCE, with a possibility that it was founded in the 10th century BCE, probably in the second half. The Atar Haroa measurements seem to indicate that the early Iron IIA phase in the ceramic typology of Israel lasted until the mid-9th century BCE—somewhat later than previously suggested. These new data shed light on several issues related to the history of southern Israel in the late 10th and 9th centuries BCE.

The Use of Torpor in Reproductive Female Hemprich’s Long‐Eared Bats (Otonycteris hemprichii)

We investigated the patterns of torpor use and body temperature (T(b)) in reproductive Hemprich's long-eared bats (Otonycteris hemprichii; body mass approximately 20 g) in the central Negev Desert highlands. We hypothesized that T(b) regulation in female O. hemprichii during reproduction is shaped by a trade-off between the energy and temperature requirements of embryo and pup growth and the mother's own need to use torpor and passive rewarming to save energy and water. We predicted that patterns of torpor use change during pregnancy but change little if at all during nursing. We used radio telemetry to track, find the roosts of, and measure the skin temperatures of eight pregnant and 15 nursing bats during the years 2002-2004; we measured roost temperature (T(r)) using temperature data loggers. Before field data collection, we simultaneously measured skin temperature and T(b) in three female bats in the laboratory and derived field body temperatures (T(bf)) from these data. Female bats often used both deep and shallow daily torpor during the first two trimesters of pregnancy, with T(bf) frequently dropping as low as 15 degrees C. Pregnant females used only shallow torpor during the last trimester of pregnancy, perhaps to permit faster growth of the embryo. During nursing, the bats used only shallow torpor, with T(bf) always >29 degrees C, possibly to facilitate milk production. T(bf) of pregnant and nursing bats varied with daily oscillations in T(r). Passive rewarming was not evident before the animals exited their roosts to forage.

WAIV - Wind aided intensified evaporation for brine volume reduction and generating mineral byproducts

In this study bench pilot WAIV units (∼ 1 m2 evaporation area loaded on 0.17 m2 footprint) were operated on two different desalination brines (RO and ED) as well as on a mineral brine concentrate under arid conditions of the Negev Highlands. The evaporation rate with the WAIV unit on these feeds often gave evaporation rates per footprint that were 10-fold or greater than the pan evaporation rate obtained from the local meteorological station at Sde Boker. Desalination brines were concentrated up to 23% TDS when operating on ED concentrate. The evaporation from the WAIV unit demonstrated enrichment in the magnesium ion compared to the calcium and the sodium ion, including over a two-fold enrichment of magnesium relative to calcium as would be expected by the equilibrium solubilities of the different minerals. Despite precipitation of minerals, there is not a large buildup of deposit on the flexible evaporation surface, and this helps establish the feasibility for recovering minerals from the desalination brine by using WAIV unit. For the ED-RO hybrid desalination process which provided one of the feeds to the WAIV unit, WAIV capital costs will only be about 5.5% of the annualized desalination costs (CAPEX and OPEX).

Spatial evaporation patterns within a small drainage basin in the Negev Desert

Summary Although important, data regarding the spatial distribution of evaporation are scarce. With the development of a small reference atmometer (RAM), studying the spatial distribution of evaporation was made more feasible and consequently carried out at the hilltops (TOP), wadi beds (WADI) and along the northern (NF), southern (SF), eastern (EF) and western (WF) aspects within a second order drainage basin in the Negev Desert Highlands during June 2004 to May 2006. Evaporation rates showed high variability in accordance with season and aspect following the order: TOP > SF ⩾ EF ⩾ WF > WADI > NF. The data showed (a) an increase in evaporation with elevation; (b) that the average evaporation rates of the stations located at the slopes and the wadi beds were respectively ∼14% and ∼23% lower than that of the hilltop stations; (c) that while insignificant differences characterized the eastern and the western aspects during summer and winter, significant differences characterized the northern and the southern aspects, and (d) that the ratio obtained between the northern and southern aspects is significantly different from that calculated based on direct-beam shortwave radiation. The findings were explained by the effects of sun and wind upon evaporation, with each factor explaining up to ∼45–50% of the results. The findings are in agreement with the dense vegetation at the north-facing footslope and at the wadi bed, and may have important implications towards the understanding of microorganism and plant distribution as well as geomorphological and pedological topics such as weathering rates and soil forming processes.

Establishment of a constructed wetland in extreme dryland

The project was set to construct an extensive wetland in the southernmost region of Israel at Kibbutz Neot Smadar (30 degree 02'45" N and 35 degree 01'19" E). The results of the first period of monitoring, summary, and perspectives are presented. The constructed wetland (CW) was built and the subsequent monitoring performed in the framework of the Southern Arava Sustainable Waste Management Plan, funded by the EU LIFE Fund. The specific aims were: (1) To end current sewage disposal and pollution of the ground, the aquifer, and the dry river bed (wadi) paths by biologically treating the sewage as part of the creation of a sustainable wetland ecosystem. (2) Serve as an example of CW in the Negev highlands and the Arava Valley climates for neighboring communities and as a test ground for plants and building methods appropriate to hyper arid climate. (3) Serve as an educational resource and tourist attraction for groups to learn about water reuse, recycling, local wildlife and migrating birds, including serving the heart of a planned Ecological-Educational Bird Park. This report is intended to allow others who are planning similar systems in hyper arid climates to learn from our experience. The project is located in an extreme arid desert with less than 40 mm of rain annually and temperature ranges of -5 degree C to +42 degree C. The site receives 165-185 m3 of municipal and agricultural wastes daily, including cowshed and goat wastes and winery outflow. The CW establishment at Neot Smadar was completed in October 2006. For 8 months, clean water flowed through the system while the plants were taking root. In June 2007, the wetland was connected to the oxidation pond and full operation began. Because of seepage and evaporation, during the first several months, the water level was not high enough to allow free flow from one bed to the next. To bed A, the water was pumped periodically from the oxidation pond (Fig. 1) and from there flowed by gravitation through the rest of the system. The initial results of the monitoring are promising. In nearly all measurements, the system succeeded as expected to reduce levels of contaminants at least to the level acceptable for irrigating fruit trees and often to the level of unlimited irrigation. The introduction of the plants in the system and their physiological performance were evaluated and were found to correlate well to the quality of water in the various beds. It should be said at the outset that evaluation of the performance of a CW system is a long-term process. Thus, the main aim of this report is to present the problems, difficulties, preliminary results, and concepts concerned with the first stage of establishment of CW in an extremely dry region. The CW system was designed to dispose of municipal and agricultural wastes in a way that not merely reduces pollution, but adds to environmental quality by creating accessible parkland for local residents and tourists. Several factors affected the performance of the system at the initial stages of operation: ecological balance between microbes and plants, big seasonal variations, seepage and evaporation reduced the flow in the initial operation of the system. Despite the initial difficulties, the quality of water coming out the system is acceptable for irrigation. The CW can function well under extreme dryland conditions. The oxidation pond was the major source of evaporation and bad odors. Therefore, alternatives to the oxidation pond are needed. Cost effectiveness of the system still has to be evaluated systematically.

The cooling efficiency of urban landscape strategies in a hot dry climate

This paper describes a climatic analysis of landscape strategies for outdoor cooling in a hot-arid region, considering the efficiency of water use. Six landscape strategies were studied, using different combinations of trees, lawn, and an overhead shade mesh. The effects of these treatments were tested during the summer season in two semi-enclosed courtyards located at an urban settlement in the arid Negev Highlands of southern Israel. Compared to a non-vegetated exposed courtyard, which on average reached a maximum air temperature of 34 °C in mid-afternoon, a similar courtyard treated with shade trees and grass yielded a daytime temperature depression of up to 2.5 K, while shading the courtyard with a fabric shading mesh, counter-intuitively, caused a relative increase of nearly 1 K. Unshaded grass was found to cause only a small air temperature depression and had the highest water requirement. However when the grass was shaded, either by the trees or by the shade mesh, a synergic effect produced greater cooling as well as a reduction of more than 50% in total water use. The “cooling efficiency” of these strategies was calculated as the ratio between the sensible heat removed from the space and the latent heat of evaporation, with the latter representing the amount of water required for landscape irrigation. This measure is proposed as a criterion for evaluating landscape strategies in arid regions, where water resources are scarce.

Possible Role of Pectin-containing Mucilage and Dew in Repairing Embryo DNA of Seeds Adapted to Desert Conditions

Repair of damage to DNA of seed embryos sustained during long periods of quiescence under dry desert conditions is important for subsequent germination. The possibility that repair of embryo DNA can be facilitated by small amounts of water derived from dew temporarily captured at night by pectinaceous surface pellicles was tested. These pellicles are secreted during early seed development and form mucilage when hydrated. Seeds of Artemisia sphaerocephala and Artemisia ordosica were collected from a sandy desert. Their embryos were damaged by gamma radiation to induce a standard level of DNA damage. The treated seeds were then exposed to nocturnal dew deposition on the surface of soil in the Negev desert highlands. The pellicles were removed from some seeds and left intact on others to test the ability of mucilage to support repair of the damaged DNA when night-time humidity and temperature favoured dew formation. Repair was assessed from fragmentation patterns of extracted DNA on agarose gels. For A. sphaerocephala, which has thick seed pellicles, DNA repair occurred in seeds with intact pellicles after 50 min of cumulative night dew formation, but not in seeds from which the pellicles had been removed. For A. ordosica, which has thin seed pellicles, DNA repair took at least 510 min of cumulative night dewing to achieve partial recovery of DNA integrity. The mucilage has the ability to rehydrate after daytime dehydration. The ability of seeds to develop a mucilaginous layer when wetted by night-time dew, and to repair their DNA under these conditions, appear to be mechanisms that help maintain seed viability under harsh desert conditions.

Subsistence practices in an arid environment: a geoarchaeological investigation in an Iron Age site, the Negev Highlands, Israel

The Negev Highlands (southern Israel) is an arid zone characterized by settlement oscillations. One settlement peak occurred in the early Iron Age IIA (late 10th and early 9th centuries BC). The most conspicuous structure in many sites of this period is an oval compound comprised of an internal courtyard surrounded by rooms. Two hypotheses for the function of these oval compounds are that they served as Israelite fortresses which guarded the southern border and routes of the Solomonic kingdom, or that they represent local agro-pastoral groups. In order to gather more information regarding the subsistence practices conducted in these oval compounds, we carried out a small-scale excavation at the site of Atar Haroa. We focused on sediment sampling and used several geoarchaeological, as well as isotopic, techniques in order to identify macroscopic and microscopic remains related to animal husbandry and crop agriculture. The remains identified from the archaeological sediments were compared with modern reference materials collected from abandoned Bedouin camps. The excavation included two half rooms and several test pits in the courtyard of the oval compound, featuring one Iron Age occupation level composed of gray sediments and relatively small amounts of pottery, bones and macro-botanical charred remains. Micromorphological, mineralogical, dung spherulite and isotopic analyses carried out on the gray occupational sediments from the rooms show that they originate from wood ash and dung, both used as fuel. Similar analyses of the gray sediments in the courtyard show that they originate only from degraded livestock dung. Phytolith analyses show that the gray anthropogenic sediments have similar concentrations of phytoliths as in control (yellowish) sediments and in the dung of winter free-grazing desert livestock and lichen-grazing black dwarf Bedouin goats. Phytoliths indicative of cereal crops are completely absent in the archaeological dung remains, indicating that cereal crops were not processed by the site inhabitants. Based on ethnographic and archaeological parallels, and on the presence of grinding stones and absence of sickle blades in the excavated rooms, we infer that the inhabitants at the oval compound at Atar Haroa subsisted on livestock herding and bought or exchanged cereal grains. Our results support the hypothesis that the inhabitants at the oval compound at Atar Haroa were desert-adapted pastoralists, rather than garrisoned soldiers.

Critically Endangered Arabian leopards Panthera pardus nimr in Israel: estimating population parameters using molecular scatology

The Critically Endangered Arabian leopard Panthera pardus nimr faces severe reduction in population size and is on the brink of extinction. This situation is, to a large extent, a result of human activity. The small populations of this subspecies are restricted to a few areas in the Arabian Peninsula, Israel and Jordan. Information required for conservation of this subspecies, including reliable population estimates and the range of individuals, is currently unavailable. To estimate population size and assign gender to individuals in the population in Israel we used molecular markers in leopard DNA extracted from scats collected in intensive surveys throughout the Judean Desert and the Negev Highlands. This non-invasive mode of sampling, combined with the availability of high-resolution markers (microsatellites) and sex-specific DNA-sequences, was successful in identifying both individuals and gender. The results indicated the existence of a male and two females in the Judean Desert, and four males and one female in the Negev Highlands. Although the non-invasive procedure we used may underestimate the leopard's true population size, continuous monitoring of population size and sex composition of this small population using scatology is a key component for the management of this species. These data, especially if used in conjunction with similar data from other countries within the subspecies' range, will assist in the establishment of conservation plans for the Arabian leopard.

Geomorphic changes leading to natural desertification versus anthropogenic land conservation in an arid environment, the Negev Highlands, Israel

The Negev Highlands in southern Israel are currently under an erosive regime causing degradation of soil and vegetation; a process which has often been attributed to land mismanagement and overgrazing caused by the local Bedouin population. To estimate the anthropogenic role in the erosional processes in the Negev Highlands, two similar drainage basins were selected and studied, one undisturbed with almost no human impact and the other with intensive human modification including the establishment of Roman to Early Islamic agriculture. Field observations and luminescence dating indicate that during the Late Pleistocene glacial period (OIS 4 and 3) deposition of fluvio-loess sediments, with minor erosion cycles, occurred in the Negev Highlands. Severe erosion started during OIS 2 and continued into the Holocene. As the climate shifted during the termination of the Pleistocene to the present interglacial phase, higher rain intensity generated the incision of gullies and channels into the fine-grained alluvial sediments of the previous phase, causing extended soil erosion and reducing the natural biomass and the agricultural potential. Establishment of runoff-harvesting farms in the 3rd century interrupted the Holocene natural erosion and gully incision, and led to the redeposition of up to 3.5 m of fine alluvial loess sediments originating from Late Pleistocene loess sections. This accumulation is not related to any late-Holocene pluvial climatic phase and is solely the result of farming. We conclude that since the end of the Pleistocene a dynamic change in the soil/rock ratio related to the long-term process of adjustment of the geomorphologic system to the Holocene climate has been taking place within the drainage basins in the Negev Highlands. The fluvio-loess sediments deposited in the region during OIS 4 and 3 have been eroding since the latest Pleistocene throughout the Holocene. This process causes degradation of the biomass and agricultural potential and leads onto natural desertification of the region. The historical intervention by establishment of runoff-harvesting agriculture, which as a by-product resulted in the accumulation of redeposited loess sediments, counteracted the natural trend of soil erosion. This was in fact a land-conservation act, applied by the ancient farmers in the semi-arid regions of the Middle East deserts. This activity and its geomorphic consequences are in contrast to the well-documented land degradation trend generated by recent anthropogenic impact on marginal lands elsewhere. In any case, the human impact, either contributing to land degradation or to soil conservation, is super-imposed on the natural long-term trend leading toward desertification.

Ancient standards of volume: negevite Iron Age pottery (Israel) as a case study in 3D modeling

Hand-made cylindrical vessels unearthed in excavations of Iron Age IIA sites in the Negev Highlands constitute the largest and most dominant ceramic assemblage of simple-shaped vessels found in Israel. The volumes and linear dimensions of these vessels were analyzed based on computer 3D models reconstructed according to their drawn profiles. This analysis revealed the rules that could have been employed by the ancient potters in order to produce vessels of given volumes. These rules demonstrate the human ability to reveal approximate (but inherent) geometric relationships between form and volume and deploy them in everyday life.

Permanent Quaternary hyperaridity in the Negev, Israel, resulting from regional tectonics blocking Mediterranean frontal systems

Although various episodes of wet Quaternary climates have been suggested in studies of the Negev Desert, here we demonstrate that Reg soils, developed on flat alluvial surfaces and sensitive to minor changes in precipitation, indicate that the southern Negev has been permanently hyperarid at least since the middle Pleistocene. The wetter episodes were restricted to the northern Negev, currently mildly arid. Gypsic-saline Reg soils that de- veloped on stable surfaces during .200 k.y. in the southern Negev are cumulative and polygenetic, but none exhibits even the weakest development of calcic horizons. Under current climate conditions in the Negev, calcic soils are widespread in areas with rainfall .80 mm yr 21 . The fact that the hyperarid (,50 mm yr 21 ) southern Negev lacks any calcic horizons indicates that it never experienced an average rainfall of $80 mm yr 21 during the middle-late Pleistocene, whereas the northern Negev was wetter. This Negev dichotomy is explained by the main physical features controlling rainfall over the Negev, i.e, the southward-decreasing depth of the atmospheric boundary layer with distance from the Mediterranean, and the altitude of the central Negev Highland (1000 m). The interaction between these two features often prevents the passage of rain clouds into the southern Negev. The Holocene and Pleistocene gypsic-salic soil distribution across the Negev closely matches the current circumstances. We suggest that hyperaridity has prevailed over the southern Negev since the last stages of the uplift of the central Negev Highland in the late Pliocene-early Pleistocene.

On the Periphery of an Agricultural Hinterland in the Negev Highlands: Rekhes Nafha 396 in the Sixth through the Eighth Centuries C.E.

Next article No AccessOn the Periphery of an Agricultural Hinterland in the Negev Highlands: Rekhes Nafha 396 in the Sixth through the Eighth Centuries C.E.*Benjamin Adam SaidelBenjamin Adam SaidelEast Carolina University, Greenville, North Carolina Search for more articles by this author East Carolina University, Greenville, North CarolinaPDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Journal of Near Eastern Studies Volume 64, Number 4October 2005 Article DOIhttps://doi.org/10.1086/498382 Views: 20Total views on this site Citations: 2Citations are reported from Crossref © 2005 by The University of Chicago. All rights reserved.PDF download Crossref reports the following articles citing this article:Ruth Shahack-Gross, Elisabetta Boaretto, Dan Cabanes, Ofir Katz, Israel Finkelstein Subsistence economy in the Negev Highlands: the Iron Age and the Byzantine/Early Islamic period, Levant 46, no.11 (Apr 2014): 98–117.https://doi.org/10.1179/0075891413Z.00000000034I. Taxel Luxury and common wares: socio-economic aspects of the distribution of glazed pottery in Early Islamic Palestine, Levant 46, no.11 (Apr 2014): 118–139.https://doi.org/10.1179/0075891413Z.00000000036

Gully incision as a key factor in desertification in an arid environment, the Negev highlands, Israel

Gully incision has been eroding the alluvial sediments and loess soils deposited and developed along the valleys in the arid and semiarid regions of Israel. This phenomenon is critical in the arid regions of the Negev Highlands where the agricultural fields, the main floral biomass and the areas which have the highest grazing value, are limited to narrow valleys filled with redeposited loessial sediments. The headcut migration and gully development in the region were studied between 1990 and 2001 in three representative drainage basins (Zipporim, Revivim and Sekher). During flood events, the runoff penetrates the alluvial cover of the valleys, forming vertical headcuts, which gradually retreat up the valley. The runoff is channeled into narrow gullies, preventing the floodwater from spreading over the whole width of the valley. The change in irrigation efficiency along the valleys is reflected in a sharp estimated drop of 70–90% in the floral biomass, causing the reduction of the range value by 83–99%. During the monitoring time interval (1990–2001), the linear gully retreat in the study area ranged between 12.3 and 250 m an average rate of 1.12–22.7 m year − 1 for each gully head. The process is accompanied by erosion of soil, which has high agricultural and range value. The total soil losses in these sites ranged between 800 and 9000 m 3 at an average rate of 81–818 m 3 year − 1 for each gully head, which is equivalent to 121–1227 Mg year − 1 . During the monitoring period, approximately 0.11–0.87 ha of land lost its agricultural and range value in each basin under study, at an average rate of 0.01–0.079 ha year − 1 . Since the Byzantine period (1400 BP), approximately 6.5 ha, which is 10% of the land that had high agricultural and range value in the Zipporim valley, lost its value due to gully erosion. No recovery effects of the gully channels were found in the nearby region. The soil erosion is generated by a long-term natural dynamic change in the soil / rock ratio evolving within the drainage basins through time since the termination of the last glacial phase. The loessic sediments, originally deposited within the drainage basins during the late Pleistocene glacial stage, are being removed under the present Holocene climate in several erosion stages. This ongoing phenomenon is causing degradation of soil and biomass and is severely reducing the agricultural and range potential of the region. These parameters indicate that an ongoing process of desertification is active in the arid environment of the Negev Highlands, and is advancing in proportion to the headcut retreat rates in the region. The soil erosion and headcut retreat have been active in the Negev Highlands for the last few millennia. If these processes continue in the future, the Negev Highlands region will lose its agricultural potential within a few millennia. However, the fact that the ancient inhabitants of the region implemented successful long-term land conservation techniques already 3000 years ago, implies that a sustainable land management policy can be adapted to the Negev Highlands, as well as to other semi-arid regions in the Middle East.

Analysis of Byzantine mortars from the Negev Desert, Israel, and subsequent environmental and economic implications

Mortar of different types and compositions was widely known and used in the ancient world, and became widespread throughout the Roman and Byzantine Empires. In many cases lime was used in it as a binder and for better plasticity. This paper discusses two mortar samples from a building in the Negev Highlands, Israel, their analysis under scanning electron microscope (SEM) and with X-ray diffraction (XRD), and the environmental implications in terms of energy consumption in the production process of lime in the Byzantine period.

Khirbet en-Nahas, Edom and Biblical History

This paper deals with a recent publication of the finds from the copper production centre of Khirbet en-Nahas (Levy et al. 2004). It argues that the site should be associated with the late Iron I and early Iron II sites of the Beersheba Valley and the Negev Highlands and thus has no bearing on the history of early Edom. It also casts doubt on the dating of the Khirbet en-Nahas fort to the 10th century BCE.

Khirbet en-Nahas, Edom and Biblical History

This paper deals with a recent publication of the finds from the copper production centre of Khirbet en-Nahas (Levy et al. 2004). It argues that the site should be associated with the late Iron I and early Iron II sites of the Beersheba Valley and the Negev Highlands and thus has no bearing on the history of early Edom. It also casts doubt on the dating of the Khirbet en-Nahas fort to the 10th century BCE.

Angle and aspect dependent dew and fog precipitation in the Negev desert

Knowledge regarding dew and fog precipitation in relation to angle and aspect may be of great importance to plant photosynthesis and to rock dwelling microorganisms, especially in arid land where water is highly limited. Measurements of dew and fog were carried out periodically during the fall of two years (1989, 1992) at a hilltop in the Negev Desert Highlands, Israel. Measurements were carried out using velvet-like cloths (6×6×0.15 cm) attached to the center of different angle sides of 5 pairs of wooden boxes (50×50×10 cm) and to the top of an additional pair (10×10×5 cm) that served as a control (horizontal surface). The sides of each pair of boxes had angles of 30, 45, 60, 75 and 90° facing north, east, south and west. Whereas fog showed an advective pattern of precipitation, with windward aspects receiving higher amounts, that was not the case with dew. When the dew values received in the different aspects within each angle were grouped together, surfaces at 30, 45, 60, 75 and 90° received 99.8 (SE±11.9), 78.2 (SE±17.9), 42.0 (SE±18.3), 33.8 (SE±10.8), and 25.6 (SE±9.7) percent of the amounts condensed on the horizontal surface, respectively. A positive linear relationship characterized the dew amounts with cos ( θ). The data also showed an increase in dew duration with west>north>south>east. The data thus imply that aspect and angle may play an important role in controlling dew and fog availability.