Rivers In Israel Research Articles

Cost–benefit analysis of full and partial river restoration: the Kishon River in Israel

ABSTRACTRestoration of rivers is important because they provide many ecosystem services. However, full restoration is costly, and with limited resources, the priority of the different elements of a restoration plan needs to be considered. In this article the benefits of separable restoration components were analyzed for the Kishon River in Israel. The proposed restoration plan contained four segments: riverbed cleaning, ecological restoration, accessibility, and sports facilities. We used non-market valuation to estimate benefits and found the full restoration programme to pass the cost–benefit test, but partial restoration to be more efficient. Based on these conclusions, different funding alternatives are discussed.

The value of rehabilitating urban rivers: the Yarqon River (Israel)

Rehabilitating the good ecological status of rivers in urban catchments can represent a wise decision since it can enhance the provision of valuable ecosystem services, such as aesthetic appreciation. The higher prices of houses located closer to rivers are a reflection of the willingness of households to pay for access to such service. The main objective of this study was to apply a hedonic pricing analysis to estimate the benefits generated by this ecosystem service due to the rehabilitation of the Yarqon River in Israel. During the last two decades, several projects and actions, such as the discharge of tertiary-quality effluents, have increased the quantity and quality of the river's water and improved its ecological state. Using a sample of 883 houses in the Tel-Aviv Metropolitan Area and selecting a mixed log-level functional form (R2 = 0.808), it was found that an increase of 1% in the distance to the Yarqon caused a 0.12% decrease in the price of a house. Finally, benefits are estimated and compared with the rehabilitation costs, showing that, even if no other ecosystem services are considered, the rehabilitation can prove to be beneficial to society.

Rehabilitating rivers and enhancing ecosystem services in a water-scarcity context: the Yarqon River

After the creation of the state of Israel in 1948, the increase in urban and agricultural water demand and the increased flow of poorly treated sewage had a severe impact in one of the most ecologically important rivers in Israel, the Yarqon. The attempt to reverse this situation began with the creation of the Yarqon River Authority in 1988. In the last 20 years, the authority has implemented or collaborated in several projects that have significantly contributed to enhancing the provision of ecological services. This article aims to analyze the case of the pollution and subsequent rehabilitation of aquatic ecosystem services in the Israeli water-scarcity context.

TILAPIA AUREA (STEINDACHNER) AND THE STATUS OF TILAPIA NILOTICA EXUL, T. MONODI AND T. LEMASSONI (PISCES, CICHLIDAE)

ABSTRACT In West Africa from Senegal through the Middle Niger to the Chad basin, in the lower Nile and in Israel and beyond the Jordan River as far as the Asraq marshes, is found a species of Tilapia which, until 1951 (Jordan Valley) and 1954 (Middle Niger), was confused with T. nilotica. The earliest name for it is T. aurea (Steindachner) and the type locality is here designated as Senegal. In West Africa and the Nile, and in at least one of the coastal rivers of Israel, it coexists with T. nilotica, but there is no firm evidence for the existence of a natural population of T. nilotica in the Jordan Valley and beyond. Elsewhere, T. nilotica seems to be more abundant than T. aurea. The affinities of T. aurea may be with T. mossambica, which exists without T. nilotica in the eastward-flowing rivers of Africa, but this species has a finer dentition in jaws and pharynx and a characteristic hypertrophy of the jaws and snout in the breeding male.

The Nile Soft-shell Turtle, Trionyx triunguis, of Israel and Turkey: Two genetically indistinguishable populations?

Whereas the Nile Soft-shelled Turtle, Trionyx triunguis, used to be found in most of the east Mediterranean rivers, today only three major subpopulations remain: two in Turkey and one in Israel. The management of small subpopulations should rely on their genetic relatedness, and so this study examined the AFLP and cytochrome b genetic diversity of 58 T. triunguis specimens from the Alexander River in Israel and from Dalaman’s Lake Kükürtlü in southwestern Turkey. The four selective primer pairs for AFLPs yielded 339 distinct loci. We found the populations to be highly polymorphic (>88%) and the level of gene diversity (He) relatively low (0.11). Indeed, using our methods, the two populations were found to be genetically identical (I=1.0). Our study further demonstrates a high identity of the mitochondrial gene cytochrome b DNA sequence with a Liberian (West Africa) specimen of T. triunguis. These results support previous preliminary genetic studies and observations which showed that this species travels around in the Mediterranean Sea. However, we suggest that the results are evidence of previous large populations and of past connections with the African populations, and that the dams on the Nile are probably preventing this gene flow today.

Comparative analysis of algal biodiversity in the rivers of Israel

Abstract Comparative analysis of algal communities in the rivers of Israel was completed to highlight the influence of environmental variables on biodiversity. The study revealed that 671 species of algae and cyanobacteria belonging to nine taxonomic divisions were present during 2002–2009 in the Yarqon, Alexander, Hadera, Qishon, Oren, Lower and Upper Jordan, and Zin rivers. The species richness of each river was evaluated by taxonomic structural comparison, geobotanical, hierarchical cluster analysis, and the degree of relatedness for different levels of taxonomic resolution. The analysis revealed close similarity of the Upper Jordan and Oren rivers. The average taxonomic distinctness index showed that the Yarqon, Oren, Upper Jordan, and Qishon communities were partly degraded due to permanent environmental disturbances. The variation in taxonomic distinctness index showed that the Alexander, Yarqon and Hadera communities were formed not only due to anthropogenic factors but also through long-term climatic impact. The most abundant indicator species inhabit low streaming and standing alkaline waters of medium salinity and low to medium organic pollution. The statistical approaches allowed discrimination between climatic and anthropogenic factors that impact upon the riverine biodiversity in semi-arid environments. Analysis shows the influence of anthropogenic factors was strongly modulated by climatic impacts causing a marked decease of species richness from north to south.

Detection of Spatial and Temporal Influences on Bacterial Communities in an Urban Stream by Automated Ribosomal Intergenic Ribosomal Spacer Analysis

The Yarqon is the largest urban river in Israel, and is a slow-flowing stream whose water originates mostly from wastewater treatment plants. Thus, its microbial community is expected to be heavily impacted both by anthropogenic factors and by seasonal temporal variation. In order to identify the main factors that influence the bacterial community, and their spatial-temporal variation, 50 samples were collected representing five different time points and eleven locations. Samples were analyzed for biotic and a-biotic parameters and the bacterial populations were analyzed by Automated Ribosomal Intergenic Spacer Analysis (ARISA). Bacterial richness and diversity were calculated and compared across samples. Canonical Correspondence Analysis (CCA) showed that ARISA clustered the samples according to temporal variation. Molecular fingerprinting analysis provided a snapshot of the microbial community and showed good correlation with geochemical parameters, despite the rapid changes of the Mediterranean environment and the anthropogenic impact. Molecular fingerprinting methods based on natural fragment length polymorphisms may therefore represent a supplementary approach for stream monitoring, alongside physico-chemical measurements.

Algal communities of the Hadera River (Israel) under dramatic niche changes

Abstract The Hadera River is the most polluted among the Mediterranean coastal rivers of Israel due to abundant E. coli, high concentrations of heavy metals and nutrients, and high temperatures. In 2003–2008 we found 191 species of algae and cyanobacteria belonging to seven taxonomic divisions. The upper reaches were dominated by cyanobacteria and exhibited levels of toxic pollution. Downstream, the ecological niches of algal communities dramatically changed: upper stream diversity first increased and then decreased due to the influx of rainwater in the tidal zone during winter. On one hand, seasonal dynamics show that in winter, inorganic contamination was reduced because of dilution by the influx of rainwater, but, on the other hand, organic pollution increased from agriculture. Down the river, diversity increases and the community composition undergoes considerable change. In summer, algal blooms indicate a reduction of stress and aid in the river’s self-purification. The WESI indices and RPI show steady year-round stressful conditions for algal photosynthesis with increasing instability in the river. Perpetuation of the current situation would disturb the self-purification capacity of the river ecosystem through destruction of biotic components. Statistical analysis (CCA) reveals the impact of wastewater as the most important stress factor for the Hadera River ecosystem, which is an exceptionally strong example of self-purification.

Diversity and ecology of algae from the Lower Jordan River, Israel

The Lower Jordan River stretches from the outlet of Lake Kinneret till the Dead Sea and is one of the most polluted rivers in Israel. In order to estimate the aquatic ecosystem of the northern part of the Lower Jordan River we used algal communities as biological indicators in the rainy and dry seasons of 2005 and 2007. We found 152 species of algae and cyanoprokaryotes from seven taxonomic divisions, which were mostly dominated by diatoms accompanied by the greens, blue‐greens and euglenoids. The xanthophycean species Heterococcus viridis, a red freshwater alga Audouinella hermannii, and a cyanobacterium Microcrocis marina were found for the first time in Israel. In the ecological analysis we revealed groups of freshwater algae according to pH, salinity, and saprobity as well as temperature, streaming and oxygenation. Quantitative information on the relationship between species and environmental variables was obtained using CCA analysis, emphasizing the major seasonal parameters. The extent of association of species with the environmental variables vector allowed us to determine the bio‐sensors and bio‐indicators, which may be relevant for monitoring of pollutants in the Lower Jordan River. The combination of bio‐indicational methods and statistics were effective in the determination of the main factors influencing algal diversity, as well as in revealing the indicators or bio‐sensing species for the most important environmental variables.

EXAMINATION OF WATER QUALITY FROM THE YARQON RIVER (CENTRAL ISRAEL) USING THE GLASS SLIDE METHOD TO DEFINE ALGAL VEGETATIVE ACTIVITY ( IN VITRO )

The provision of uniform, artificial substrates for periphytic colonization has a long history, and it is the most widespread of all the techniques applied to study algal periphyton activity. The Yarqon River is one of the largest coastal rivers in Israel. An experiment for the determination of algal vegetative activity in the artificial pools, using the glass method, from the Yarqon River stations was conducted during the period from 8.11.06 till 6.12.06. During the experiment we revealed the colonization's speed of substrates and the activity of self-purification processes at different stations of river. The artificial colonization of substrates by algae during the rainy period takes about 2-3 weeks. Chlorophyll, which was used as a trophic marker, revealed ultra-oligotrophic or oligotrophic levels in pool I. At pools II and III levels were either oligo-mesotrophic or eutrophic. These results corresponded to the gradient of organic matter in each experimental pool.The algal diversity found on glass slides represented about 10-15 species for each pool. During the experiment, cells from pool I were about 1-2.5 µm 3 , and at pool Ii cells were about 0.1-1.4 µm 3 . The increase of the ecosystem's entropy is indicative of environmental stress. This criterion, which is based on diversity dynamics, cell counts, and biomass may be used for monitoring the quality of water and aquatic ecosystems in the rivers of Israel.

Algal communities in the polluted lower Jordan River, Israel

The lower Jordan River stretches from the outlet of Lake Kinneret to the Dead Sea (190 km meandering distance) and is one of the most polluted rivers in Israel. In order to estimate the aquatic ecosystem of the northern part of the lower Jordan River (between the outlet of Lake Kinneret and Hussein Bridge), we used algal communities as biological indicators to monitor pollution levels in two seasons, rainy and dry (November 2005 and May 2007). In two different seasons, we found 152 species of plankton and periphyton from 7 divisions, which were mostly dominated by diatoms (Bacillariophyceae) accompanied by green algae (Chlorophyta) and blue-green algae (Cyanoprokaryota), and euglenoids (Euglenophyta). In the ecological analysis we revealed groups of freshwater algae according to pH, salinity, and saprobity as well as temperature, streaming, and oxygenation.

Persistent organic pollutants and sedimentary organic matter properties: A case study in the Kishon River, Israel

The Kishon River, the second largest coastal river in Israel, has been severely polluted for several decades. Sediments from upstream and downstream sites of the river were analyzed, lipid-extracted and evaluated for phenanthrene uptake. Total polycyclic aromatic hydrocarbon (PAH) concentration in downstream sediments was 299 μg kg −1, consisting mostly of petrogenic-derived PAHs. Downstream sedimentary lipids were found to be dominated by fresh and decomposed petroleum-derived n-alkanes. The total PAH concentration in upstream sediments was 173 μg kg −1, consisting mostly of pyrogenic-derived PAHs, whereas lipids from these sediments were mostly vegetation-derived. Spectroscopic data suggested an exceptionally high aromatic content in downstream humic acid, which originated from PAHs attached to its structure. Sorption data suggested that upstream sedimentary cuticle-derived lipids function as a sorption domain, while downstream sedimentary lipids, consisting of shorter-chain-length petroleum-derived alkanes, compete with phenanthrene for sorption sites.

A 2.5-Year Genotoxicity Profile for a Partially Restored Polluted River

This study evaluates water genotoxicity of the Kishon River, the most polluted river in Israel that is under restoration. Water samples were collected every other month (January 2001-May 2003) from five sites, and genotoxicity was assayed by the alkaline comet assay using a fish hepatoma cell line (RTH-149). Genotoxicity in the Kishon River was reduced during 2002 as compared to the previous year. The results further revealed fluctuations in genotoxicity levels at all sites throughout the studied period with variations for the same month during consecutive years and seasonality. In general, summer samples were more genotoxic than winter samples. In the vast majority of the 75 water samples, all four parameters for genotoxicity that were employed revealed significant higher genotoxic levels than the controls. Comet percentage values in Kishon River samples were, on average, 1.8-2.4 times higher than controls. Damage score, comet tail length, and cumulative tail length values were 2.2-3.1, 2.4-3.7, and 2.4-3.7 times higher than controls, respectively. The Histadrut Bridge and Haifa fishing harbor (3.0 m depth) emerged as the most polluted sites, whereas Kiryat Haroshet was the least contaminated. Results call for a long-term genotoxicity follow-up plan at the Kishon River in order to assess the possibly evolving chronic genotoxicity state.

Genotoxicity of the Kishon River, Israel: the application of an in vitro cellular assay

The alkaline comet assay, a sensitive method for DNA strand breaks and alkali labile site detection in individual cells, was employed here as an ecotoxicological monitoring tool for evaluation of genotoxicity in the Kishon River, Israel. This river, the most polluted river in Israel, has recently elicited major public concern with regard to cancer incidences in people who have dived there over many years. Five water samples were collected every odd month throughout the year 2001, from four localities. The comet assay was employed on fish hepatoma cell line RTH-149. Cells were exposed for 2 h, in triplicate, to Kishon water: medium (1:1) samples that were pre-adjusted for pH and salinity percentage levels. Three DNA damage parameters (comet percentages, score of damage, and cumulative tail lengths of the comet), revealed significantly higher genotoxic values in Kishon water-treated cells as compared with the controls (up to 2.4, 3.2, and 3.6-fold, respectively). Part of the sampling sites revealed higher genotoxicity than other polluted sites. The results of this study demonstrate that the comet assay with RTH-149 cells can be successfully applied to a variety of aquatic samples revealing freshwater, marine and estuary conditions. The method found to be fast, sensitive, and suitable for monitoring programs.

Nutrient pollution at the lower reaches of Mediterranean coastal rivers in Israel

This study represents the first attempt to evaluate the nutrient load introduced into the coastal waters by the rivers along the Mediterranean coast of Israel. Measurements of nutrient concentrations (phosphate, ammonium, nitrate, nitrite, silicic acid) at two or three stations along the lower river reaches (11 rivers) were carried out annually from 1990 up to 1998. Combining the nutrient concentrations with the monthly riverine discharges we assessed the nutrient load. In general, most of the coastal rivers contain high nutrient contamination level, compared to the criteria adopted by NOAA (USA) for coastal river estuaries. The high degree of contamination is attributed to extreme low natural flow combined with the discharge of domestic and industrial wastes, and with agriculture runoff. In terms of nutrient concentrations, the Kishon River is the most polluted, followed by the Soreq, Poleg and Alexander Rivers. The preliminary estimate is that the coastal rivers transport between ~2000 to 6000 tons of dissolved inorganic nitrogen (DIN) and between ~250–800 tons of dissolved inorganic phosphorus (DIP) to the sea. An additional 3500 and 3000 tons of DIN and DIP, respectively, are supplied through the Kishon River. The load of the Poleg River is unknown (no discharge data) but expected to be significant based on nutrient concentration measured. The total load of the coastal rivers constitutes a major component among the other land-base point sources such as the Gush Dan outfall. Our estimate probably represents minimal values, as it does not include diffused input of agricultural runoff nor the riverine particulate and dissolved organic nutrient loads (which are unknown).

Restoration of the rivers in Israel's coastal plain.

Israel's chronic water shortage has aggravated problems of river pollution, as almost no dilution of inadequately treated wastewater takes place. Since the early 1990s, large investments were made to build new wastewater treatment plants, designed to produce effluents of secondary quality or better. Consequently, it became of interest to examine the possibility of using tertiary treated effluents as a water source for rehabilitation of aquatic habitats. A survey of water quality in clean and polluted segments of Israel's coastal rivers was initiated, including analyses of riverbed sediments. Although many segments are still heavily polluted, there are examples of measurable improvement in water quality, which should lead to better sediment quality. It is argued that sediments serve both as a memory bank of past pollution events and as an ongoing source of anaerobic and toxic compounds, such as sulfides and ammonium compounds. Their chemical compositions are, therefore, of much importance for river restoration processes and monitoring.

Wastewater Reuse for River Recovery in Semi-Arid Israel

Most of the water has been captured in the rivers of Israel and they have turned into dry river-beds which deliver only sporadic winter floods. In a semi-arid country where literally every drop of water is used, reclaimed wastewater is the most feasible water source for river recovery. Two topics are addressed in this paper: water quality management in rivers where most of the flowing water is treated wastewater, and the allocations of reclaimed wastewater required for the recovery of rivers and streams. Water quality management must consider that the main source of water to the river has a pollution loading which reduces its capability to absorb other pollution impacts. The allocation of treated wastewater for the revival of rivers may not affect negatively the water balance of the region; it may eventually improve it. An upstream bruto allocation of 122 MCM/year of wastewater for the recovery of 14 rivers in Israel may favor downstream reuse of this wastewater, resulting in a small neto allocation and in an increase of the water resources available to the country. The discharge of effluents upstream to revive the river followed by their re-capture downstream for irrigation, implies a further stage in the intensification of water reuse.

Wastewater reuse for river recovery in semi-arid Israel

Most of the water has been captured in the rivers of Israel and they have turned into dry river-beds which deliver only sporadic winter floods. In a semi-arid country where literally every drop of water is used, reclaimed wastewater is the most feasible water source for river recovery. Two topics are addressed in this paper: water quality management in rivers where most of the flowing water is treated wastewater, and the allocations of reclaimed wastewater required for the recovery of rivers and streams. Water quality management must consider that the main source of water to the river has a pollution loading which reduces its capability to absorb other pollution impacts. The allocation of treated wastewater for the revival of rivers may not affect negatively the water balance of the region; it may eventually improve it. An upstream bruto allocation of 122 MCM/year of wastewater for the recovery of 14 rivers in Israel may favor downstream reuse of this wastewater, resulting in a small neto allocation and in an increase of the water resources available to the country. The discharge of effluents upstream to revive the river followed by their re-capture downstream for irrigation, implies a further stage in the intensification of water reuse.

The Dead Sea, The Lake and Its Setting

I cannot think of a subject more befitting the description of interdisciplinary research with societal relevance than the study of the Dead Sea, a terminal lake of the Jordan River in Israel and Jordan. The scientific study of the Dead Sea is intimately connected with politics, religion, archeology, economic development, tourism, and environmental change.The Dead Sea is a relatively closed geologic and limnologic system with drastic physical changes often occurring on human timescales and with a long human history to observe these changes. Research in this unique area covers diverse aspects such as active subsidence and deformation along strike‐slip faults; vertical stratification and stability of the water column; physical properties of extremely saline and dense (1234 kg/m3) water; spontaneous precipitation of minerals in an oversaturated environment; origin of the unusual chemical composition of the brine; existence of life in extreme environments; use of lake level fluctuations as a paleoclimatic indicator; and effects on the environment of human intervention versus natural climatic variability. Although the Dead Sea covers a small area on a global scale, it is nevertheless one of the largest natural laboratories for these types of research on Earth. These reasons make the Dead Sea a fascinating topic for the curious mind.

Very high rates of bedload sediment transport by ephemeral desert rivers

GEOMORPHOLOGISTS have thought for some time that rates of sediment transfer might differ markedly in ephemeral and perennial rivers, and have used this idea to explain both the changing character of sedimentary successions and the morphology of rivers in sub-humid or semi-arid areas that have experienced significant shifts in climate during the Quaternary period1−5. But until now there has been a lack of suitable field data to confirm this suggestion, mainly because floods in arid zones are infrequent and unpredictable. Here we present bedload sediment transport data for an ephemeral river in Israel, which show it to be, on average, as much as 400 times more efficient at transporting coarse material than its perennial counterparts in humid zones. This suggests that existing predictive sediment transport equations24, developed and calibrated exclusively with data obtained in perennial rivers, are inadequate for application to rivers in arid environments. It also suggests that areas that are at risk of shifting from sub-humid to semi-arid conditions as a result of prospective global changes in climate may suffer severe sedimentation problems.