Northwestern Coastal Zone Research Articles

Integrated Impact of Olive Mill Wastes and Semi-Circular Bunds on Soil Properties and Rainwater Harvesting Efficiency in Egypt’s Northwestern Coastal Zone

ABSTRACT The productivity of olive in the northwestern coastal zone of Egypt is significantly constrained by drought and low organic matter in the soil. This study addresses these challenges by exploring the synergistic effects of olive mill wastes (OMW) application and micro-catchment water harvesting techniques on soil properties, runoff, moisture storage, and rainwater harvesting efficiency. Field experiments were conducted over two winter seasons, employing different micro-catchment structures (semi-circular and triangular bunds) and OMW applications. The results revealed that the integration of semi-circular bunds with OMW application (T4) substantially increased rainwater harvesting efficiency by 67.7% and 46.4% in the first and second seasons, respectively. Additionally, T4 and T5 exhibited reduced runoff by 47.8% and 41.3% in the first season and 49.4% and 38.9% in the second season, respectively. T4 significantly enhanced soil organic matter, soil macronutrients (N, P, and K), and micronutrients (Fe, Mn, Zn, and Cu) compared to the control (T1). The study highlights the effectiveness of T4 in improving soil moisture, reducing soil erosion, and enhancing soil fertility. This integrated approach involving OMW application within a semi-circular bund as a water harvesting system proves to be a promising strategy for sustainable olive cultivation in arid conditions.

Changes in Coastal Landforms from the Poonaryn Peninsula to the Malwathu Oya (Aruvi Aru) Estuary, Northwestern Coastal Zone (NWCZ) of Sri Lanka

Changing coastal landforms are constantly occurring due to wind, waves, sea currents, tidal fluctuations, and human interference. This paper makes a special effort to ensure the correct usage, management and utilization of these landforms, which will benefit society through economic growth. A variety of peculiar coastal landforms have formed between the Poonaryn Peninsula (9°36'10.23"N, 80°03'16.74"E) and Malwathu Oya (Aruvi Aru) estuary (8°46'30.22"N and 79°56'12.85"E), which are approximately 120 km long coastal stretch. The Poonaryn Peninsula extends from Pallikuda Beach to Kalladi Yutha Kovil (9°35'53"N, 80°3'10"E). The peninsula stretches northwest to southeast, covering dunes with a maximum elevation of 17 meters. The selected study location is favourable for the coastal environment, and the coastal environment can be defined as the area lying at the interface between land and Mannar Bay, Palk Bay and a part of the Jaffna Lagoon. This area includes non-barrier delta estuaries with seasonal rivers and bar-built perennial delta estuaries. The zone of shallow water within which waves can move sediment and the area landward of this zone, including beaches, low coastal dunes and vegetation cover, are affected to some degree by the direct or indirect effects of waves, tides, winds and currents. The coastal environment itself may extend inland for many meters or kilometers. These processes make it possible to identify several coastal habitats, such as mangroves, salt marshes, covered and covered dunes, beaches, barrier beaches and spits. Lagoons, riverine estuaries, brackish water bodies, water holes, and marshes. When considering biodiversity, local and migratory avifauna, beach mangroves, seagrass beds, tidal creek system are very important for tourist attraction. Additionally, fishery harbours, boat landing sites, traditional fisheries (beach seines, koodo fishing), etc., and tourism were established in the northwestern coastal stretch owing to enticing coastal processes and landforms in the area for correct usage, management and utilization for enormous benefits of the fishing society, the environment and the economy.

Recharging the Freshwater Coastal Aquifer of Sidi Kirayr Area Using Sustainable Infiltration Trenches

Egypt is considered an arid country and depends mainly on the Nile River and groundwater reservoirs to supply water for drinking and various uses. The northwestern coastal zone is one of the regions that rely heavily on groundwater and rainwater for drinking and irrigation. As a result of changes in climate and the rise in sea level, the increase in seawater intrusion is growing. Furthermore, groundwater exploitation and increased pumping of some wells installed in this area have a negative impact on the amount of water in the region’s subterranean reservoirs. One of the approaches suggested for managing freshwater lenses floating on top of seawater from saltwater intrusion in this region is to recharge the aquifer lenses with fresh water. This can be done either by injection wells or by use of groundwater mounds, i.e., infiltration trenches. Due to the expected higher cost operation of injection wells, it is interesting to study the recharge of freshwater lenses through the use of groundwater mounds. Studies have been carried out in the past on the Sidi Kirayr area in terms of recording the water table levels and the amount of rainfall before and after the rainy season. However, we propose using an environmentally sustainable economic solution to recharge the underground reservoirs through the use of rainwater instead of letting it run off into the sea. In this respect, an infiltration trench is designed to recharge the aquifer in the Sidi Kirayr area. Two design types for the trench are proposed, with the geometrical calculations of the appropriate dimensions. The trenches are suggested north and south of the asphalt road in the area of Sidi Kirayr, providing that the trenches can be recharged by rainfall or surplus water when being available from other sources.

EVALUATION OF RAINFED AGRICULTURE MANAGEMENT PRACTICES AS AN APPROACH FOR SUSTAINABILITY IN NORTHWESTERN COAST (NWC), EGYPT

Sustainable development can be possible in rainfed agriculture by integrated approach of soil management measures. Soil quality in the form of a quantitative index is used as an indicator of environmental quality and sustainability. Twelve farms selected to achieve the targets of the present investigation (six farms under traditional rainfed agriculture system and six farms under rainfed with supplemental irrigation) at Northwestern Coastal Zone (NWCZ). These farms varied in land use and management practices concerning fertilization practices, tillage system, crop type and cultivated period. This study selected some soil indicators vis-à -vis soil physicochemical properties of the selected farms of studied areas at NWCZ. The rating of soil quality index (SQI) and relative of soil quality (RSQI) values in this study were higher towards to rainfed agriculture with supplement irrigation farms than in traditional rainfed farms. In addition, most of the values of soil quality change (∆RSQI) were moderately increase (class II) and most of these farms were under traditional rainfed management. The results of cumulative rating index CRI showed a negative correlation and significant relationship with RSQI (R2=0.82, p<0.05). concerning the impacts of soil quality on productivity, the relationship between relative yield (Ry %) and RSQI was positive significant correlation (R2=0.78, p<0.05). Also, CRI showed negative significant correlation with Ry% (R2=0.81, p<0.05). Moreover, the highly soil quality class I, highly sustainability, low changes in soil quality and highly crop yield observed was in the farms under rainfed with supplemental irrigation system and good fertilization practices (NPK+organic manure). So, this study recommended to expansion rainfed with supplemental irrigation management system and add suitable dose of NPK application with manure along scientific lines to encourage crop yields that can be achieved on a sustainable basis, but it need a long time to reach class I quality and highly sustainable status.

Integrated TEM and 2DERI techniques to delineate groundwater bearing zones in fractured carbonate rocks at the upstream portion of wadi Halazeen, Northwestern Coast, Egypt

The increasing reliance on groundwater as supplementary water resource for the decreasing rainfall in the Northwestern Coastal Zone of Egypt (NWC) makes groundwater exploration and aquifers characterization in that area of particular importance. A representative locality for the conditions under which groundwater occurs in NWC is the upstream portion of Wadi Halazeen, which lies some 37 km to the west of Mersa Matruh city. In the present work, integrated Transient electromagnetic (1DTEM) and two-dimensional electrical resistivity imaging (2DERI) has been conducted to explore and characterize the groundwater of Miocene aquifer in the upstream portion of Wadi Halazeen. A total of 25 TEM soundings along with 5 normal and reciprocal profiles of 2DERI were measured. The lithological data of the borehole has been used to parameterize the inversion of the geophysical data. In order to maximize the reliability of the inversion results, the acquired data is subjected to some processing such as smoothing, editing and removing depending on TEM sounding significance plus computing reciprocal error of 2DERI measurements. The inversion results of both geophysical methods indicated that the geoelectrical succession consists of five layers along with the surface weathered layer (Dolomitic limestone, Sandy limestone, limestone, marly limestone and clay). The results indicated also that facies change is a common feature characterizes most of the layers. This feature controls groundwater occurrence within the fifth layer where the lithological composition of this layer changes from fractured limestone to marly limestone to marl and clay. Groundwater exists in a channel-like zone of fractured limestone and marly limestone which extends from south to north in the study area. Generally, the groundwater salinity of the study area and neighboring groundwater wells tapping the fractured Miocene aquifer are range between 2900 and 4268 ppm, while the groundwater of DRC5 well which lays in the watershed area has a relatively lower salinity value (1482 ppm) where it receives large recharge related to annual precipitations and surface runoff water than area of outside basin boundary divides. Integration of the results of 1DTEM and 2DERI delivered plausible information about the groundwater occurrence in fractured carbonate rocks.

Initial effect of shifting from traditional to no-tillage on runoff retention and sediment reduction under rainfall simulation

Context Low precipitation and soil erosion are critical threats to sustainable agricultural development in the north-western coastal zone of Egypt. Conservation tillage may offer a good opportunity to mitigate these threats; however, switching from traditional tillage to conservation tillage causes initial challenges such as soil compaction and erosion. Aims This study was designed in order to assess the effects of various tillage practices on soil bulk density, volumetric water content, runoff rate, runoff initiation time, soil loss, sediment yield rate and wheat (Triticum aestivum L.) yield in a cultivated basin area. Furthermore, to investigate the efficacy of various rainfall intensities in generating runoff in a micro-catchment area. Methods Under rainfall simulation, five rainfall intensities (14, 21, 30, 36, and 45 mm h−1) and three tillage practices (contour tillage, CT; traditional tillage, TT; and no tillage, NT) were investigated. Key results Under various rainfall intensities, the CT treatment significantly reduced surface runoff compared with the TT and NT treatments. For the 30 mm h−1 rainfall intensity, the CT treatment decreased sediment yield rate by 58.7% and 49.4% compared with NT and TT treatments, respectively. Furthermore, the CT treatment significantly increased precipitation use efficiency by 11.8% and 19.9% compared with TT and NT treatments, respectively. Additionally, the CT increased grain yield by 12.3% more than TT and 21% more than NT. Conclusions and implications Consequently, it is preferable to encourage farmers to use CT practices when transitioning from traditional tillage to conservation tillage. Moreover, soil compaction and smoothing may contribute to enhance the generated runoff on the micro-catchment area.

A portable rainfall simulator to evaluate the factors affecting soil erosion in the northwestern coastal zone of Egypt

Soil erosion and the resulting sedimentation constitute major natural hazards that increase land degradation in the Mediterranean region. Understanding the behavior of soil erosion is of particular importance to control the degradation of productive soils. Therefore, a portable field rainfall simulator was designed to provide rainfall intensities in the range of 14 to 80 mm h−1. The simulator was tested in terms of Christiansen uniformity coefficients that ranged from 89 to 94% for the three full-jet nozzles used in this study, with median diameters ranged from 0.836 to 2.113 mm, showing an appropriate degree of accuracy. Furthermore, kinetic energy values ranged from 12.7 to 18.9 J m−2 mm−1, showing similarity to the natural rainfall occurs in the Mediterranean regions under conditions of low rainfall intensity. The applicability of the rainfall simulator in the dynamic processes of erosion characteristics was investigated in the northwestern coastal zone of Egypt. Five rainfall intensities (14, 21, 30, 36, and 45 mm h−1) were evaluated in three repetitions at three uncultivated sites having slope gradients of 5, 9, and 12%, forming 45 simulated rainfalls. The changes of sediment yield and runoff rate for the 45 simulated rainfalls were quantified. Altogether, the results indicated that runoff and sediment yield rates were substantially different between the rainfall intensities of 14 and 45 mm h−1 than those obtained between any other pairs of intensities under all soil gradients. Summing up the findings, the proposed rainfall simulator in this study can be used in future soil erosion studies.

Soil erosion control and wheat productivity are improved by a developed ridge-furrow and reservoir tillage systems

ABSTRACT Soil erosion and drought are significant environmental hazards for crop production in the northwestern coastal zone of Egypt, leading to increased soil resources degradation. In-situ rainwater harvesting techniques by changing the micro-topography of soil via tillage practices can increase runoff retention and improve soil productivity. In this study, field trials were conducted on a sandy loam soil to determine the effects of four tillage systems [integrated ridge-furrow tillage (RFT), integrated reservoir tillage (RT), conventional tillage (CT), and No tillage (NT)] on soil bulk density, volumetric water content, runoff, soil loss, precipitation use efficiency, and winter wheat yield during two growing seasons under-rainfed conditions. The results indicated that tillage systems significantly affected soil properties, precipitation use efficiency and wheat yield in the order of: RFT > RT > CT > NT. Compared with the CT, the mean runoff with the developed RFT and RT was significantly decreased by 55.4% and 40.3%, respectively. Meanwhile, the precipitation use efficiency increased by 18.1% and 9.5%, respectively. By taking into account the stability of soil productivity along with environmental protection, it is suggested that the RFT and RT are the tillage systems that can efficiently increase the availability of soil water and, consequently, wheat yield.

Environmental assessment of radioactivity levels and radiation hazards in soil at North Western-Mediterranean Sea coast, Egypt

The present work aims to obtain adequate knowledge about the natural radioactivity levels and the related radiation hazard at the northwestern coastal zone of Egypt as part of the Egyptian regulations and nuclear law. Thirty-eight soil samples of different geologic formations were collected and analyzed using gamma spectrometer equipped with hyper-pure germanium (HPGe) detector. The mean activity concentrations of 238U, 226Ra, 232Th and 40K in all soil samples are 29.40, 25.18, 11.22 and 159.16 Bq kg−1, respectively. Those activity concentrations are below the soil world average. The activity concentrations of 238U are found to be higher than that of 226Ra and 232Th. The spatial patterns of the activity concentrations of these radionuclides were also presented using the geographical information system (GIS). Radiation hazard indices were assessed through the calculation of radium equivalent activity (Raeq) Bq kg−1, external and internal hazards (Hex, Hin), absorbed dose rate (ADR) nGy h−1 and annual effective dose (AED) mSv year−1. The average values of ADR and AED are 25.41 nGy h−1 and 20 μSv year−1, respectively. These values are below the soil world average of 59 nGy h−1 and the effective dose limit of the public radiation exposure of 1 mSv year−1.

QUANTIFY IMPACT OF WIND EROSION ON ORGANIC MATTER CONTENT UNDER MANAGEMENT PRACTICES, WADI EL RAML, NWCZ, EGYPT

Wind soil erosion is one of the land degradation processes in North Western Coastal Zone (NWCZ) of Egypt. It was assessed under condition of wheat crop grown on a sandy loam soil in Wadi El Raml in 2018/2019. Three tillage treatments of no-tillage (NT), minimum tillage (MT) and conventional tillage (CT) were assessed with or without organic manuring (30 m3 ha-1) combined with or without mulching (with rice straw covering 60% of soil surface).The aim of the study was assessment the impact of wind erosion on wheat yield and soil organic matter content (SOM) under different tillage practices under rainfed agriculture at Wadi El Raml in NWCZ. The highest bulk density was associated with NT. Losses (kg m-2 y-1) of about 275, 221 and 173 were shown in the CT, MT and NT treatments, respectively.The erodibility average values andloss of OM and TN were highest in the bare soil. Soil loss materials for the bare soil was higher than for the cultivated soils, which gave their the highest loss of 275 kg m-2y-1with non-manured non-mulched CT and the lowest of 16 kg m-2y-1for the manured and mulched NT. The highest wheat yield was obtained with manured and mulched CT. The results of this study showed that the use of 30 m3ha-1of organic manure and 60% of the coverage with rice straw in each cultivation type led to improving the soil content of organic matter and reducing soil loss by erosion by wind. This study emphasized the benefits of conservation tillage, such as improving bulk density as a guide to soil quality, which keeps it from degradation, as happens with conventional tillage. The study also recommended the use of conservation tillage in cultivated cereal crops for more than one season under rainfed conditions in Egypt to increase the content of soil organic matter, thus increasing crop productivity compared to the traditional tillage system to achieve sustainable agricultural production inNWCZ of Egypt.

Evaluation of Environmental Pollution and Microbial Treatment of Shallow Groundwater in El Omayed Area, Egypt.

In the last few years, the northwestern coastal zone of Egypt has been affected by many stresses that impact its water resources, leading to undesirable consequences related to water quantity and quality. This paper aims to evaluate the possible contamination sources of shallow aquifers in the El-Omayed area, Egypt, that are causing its deterioration; this was achieved through an integration of hydrochemical and isotopic techniques, an assessment of the undesirable consequences of potential toxic metals (PTMs) on human health risk as a result of direct water consumption, and finally, the application of biological treatment in the remediation of some metal contamination. The chemical composition, environmental isotopes (δ18 O and δ2 H), and microbial analyses were analyzed from 13 collected water samples. Approximately 20% of the groundwater samples were classified as fresh water, and the rest were classified as slightly saline to moderately saline. Stable isotopes proved the contribution of the El Sheikh Zoied canal (which is mainly recharged from the Nile system) as a recharge source. The toxicity of PTMs (Cd, Cu, Co, Cr, Pb, Zn, B, and Fe) was evaluated on the basis of their exceedance values. It was proven that the majority of the groundwater samples were contaminated, which might be attributed to natural and anthropogenic actions in the study area; however, according to human health risk exposure assessment calculations, there is no human cancer risk posed via ingestion of drinking groundwater. The total bacterial count was determined for all water samples; autochthonous microorganisms were capable of removing heavy metals in the polluted water sample. The bacterial strain M52, which was identified by 16S rRNA sequencing as Stenotrophomonas rhizophila, showed the best results, by removing 75% and 65% of the initial concentrations of Fe and B, respectively. The results indicate that this bacterial strain may be useful and represents an environmentally friendly method to remove pollutants and heavy metals from contaminated water. Integr Environ Assess Manag 2020;16:461-471. © 2020 SETAC.

Distribution of rare earth elements in surface sediments of the western Gulf of Thailand: Constraints from sedimentology and mineralogy

To understand the modern sedimentation and land-sea interaction processes in the Asian margin seas, we analyze rare earth element contents (REE, i.e., La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and grain sizes, detrital minerals from 158 surface sediment samples collected from the western Gulf of Thailand (GoT). The results reveal that the REE contents ranged from 25.42 μg/g to 201.21 μg/g, with an average value of 137.21 μg/g, and that the GoT is characterized by higher accumulations of LREE relative to HREE, together with negative Eu anomalies. Based on the spatial distribution characteristics of REE contents, δCe and δEu, the western GoT can be classified into three geochemical provinces. The Province I covers the northern and northwestern coastal zones of the GoT, including the entire upper GoT; its coarse size fraction and distribution pattern of hornblende- and quartz-dominated minerals caused REE contents to be the lowest, and these sediments were mainly derived from the rivers around the upper GoT, including the Chao Praya River and the Kea Klong River. The Province II is located in the central GoT and has the highest REE concentrations due to finer sediment composition and higher contents of zircon, authigenic pyrite, and biogenetic limestone. The Province II has two accumulation centers around Samui Island and Koh Chang Island, with REE spatial distribution influenced by the seasonal setting and mixed derived from multiple provenances around the GoT. The Province Ш is located in the lower GoT, close to Malaysia. The sediment type in this region is similar to that of Province I except for different detrital mineral compositions, especially the presence of siderite that is responsible for higher REE contents. The sediments in this region exhibits similar distribution patterns to those of terrestrial materials from the Malaysian peninsula such as that from the Kelantan River. The transportation processes of sediments in this region are mainly controlled by the coastal current.

An analysis of the developmental differences in Borneo’s Southeastern and Northwestern Coastal Zones

In this research, Landsat TM images were used to extract the land use information for Borneo’s coastal zones (0 to 35 km) during three time periods (1990, 2000, and 2010). Then, in combination with the DEM and shoreline types, the developmental differences under the influences of the geographical boundaries of the Borneo coastal zones were examined from such perspectives as the spatial distribution characteristics of the land development, sea-land gradient variation characteristics, and comparative analyses of the different regions. The results indicated that the geographic boundaries, as well as the different countries, had great influences on the development of the coastal zones. The regions with the most active development in Borneo’s coastal zones were mainly located in the estuary bay, onshore with land on both sides, and the near-shore alluvial plain with DEM < 50 m. The northwestern coast zone showed relatively flat topography, and was close to an important international waterway. Therefore, the development in this area was found to be more intense than in the southeastern coastal zone, and which was characterized by a long developmental history. On one side of the geographical boundary, the development was also found to differ among the different countries. Malaysia was observed to be dominated by industrial plantations. Meanwhile, the industrial plantations, agriculture, and aquaculture in Indonesia were significantly increased, which was closely linked with the national economic policies. Furthermore, the development of Borneo’s coastal zones has led to vegetation degradation towards a constant inland development, plantation enlargements, agricultural development, and cleared and burnt areas, which have resulted in the land use transfer of 22,000 km2 of forest land within the 0 to 35 km range.

Contribution des petits ruminants au revenu du ménage dans la zone agroécologique côtière du nord-ouest de l’Egypte

L’étude a été menée dans la zone côtière du nord-ouest de l’Egypte afin d’explorer l’importance économique relative de la production de petits ruminants. Sur la base des ressources en eau, la zone d’étude a été divisée en trois sous-zones agro­écologiques (ZAE): a) la zone pluviale (ZP) à l’ouest, b) la zone sèche (ZC) au centre, et c) la zone irriguée (ZI) à l’est. La collecte des données a été effectuée au moyen d’enquêtes de terrain, à l’aide d’un questionnaire testé au préalable. La productivité a varié de 20,8 à 25,4 kg, et de 18,9 à 20,9 kg, respectivement chez les ovins et les caprins. La productivité des ovins et des caprins a été plus faible dans la ZC que dans les ZP ou ZI (p &gt; 0,05). La production des petits ruminants a été rentable dans les différentes ZAE. Les rendements sur capi­tal investi dans la production ovine ont été de 22,3, 17,9 et 14,4 %, respectivement dans les ZI, ZP et ZC. Les données correspondantes pour la production caprine ont été respecti­vement de 16,5, 16,7 et 16,7 %. La contribution de l’élevage au revenu du ménage a varié de 40,8 à 71,6 % dans les ZAE. La comparaison des revenus provenant des cultures et du bétail dans la ZC a révélé que, alors que l’élevage représentait 71,6 % du revenu net total, la contribution des cultures n’a été que de 2,5–5 %. Dans le secteur de l’élevage, la contribu­tion des petits ruminants a été la plus élevée (63,4 %). Aider les agriculteurs à prendre conscience des avantages finan­ciers des petits ruminants peut les convaincre de considérer ces derniers comme une meilleure alternative à la produc­tion agricole en termes de génération de revenus. Ces résul­tats pourront probablement influer sur leur décision concer­nant l’allocation de leurs ressources limitées à des alternatives concurrentes.

Flash flood risk assessment applying multi-criteria analysis for some northwestern coastal basins, Egypt

ater resources are increasingly a constraint on economic and social development in Egypt. Coping with the water scarcity in the North Western Coastal zone Basins (NWCB) requires good management for the flash floods. This requires an accurate estimation for the hazard degrees and flood risk. Multi Criteria Analysis (MCA) describes any structured approach used to determine overall preferences among alternative options, where the options accomplish certain or several objectives. The maximizing of water use in arid zones, like NWCB, is a highly important issue due to the damage, danger and other hazards associated to it to human life, properties, and environment. MCA techniques were tested and evaluated for the purpose of flash flood risk assessment, hydromorphological parameters for sample catchments in NWCB, were used in this analysis. Drainage network and watershed boundaries of NWCB shape file was created using TOPAZ (Topographic Parameterization) technique from the 90 m Digital Elevation Model (DEMs). These data are used in Watershed Modeling System (WMS) package to automatically delineate basin boundaries and define stream networks. Thirty four basins in NWCB were delineated for the study of the risk assessment of flash floods. Cluster analysis, depending on 10 estimated hydro-morphological parameters, classifies the NWCB into three groups. Ten chosen hydro-morphological parameters have their direct effect on flash flooding were used for estimating hazard scale depending on the MCA procedures. The proposed risk scale assumed category three for the high Weighted Standardized Risk Factor (WSRF) of five basins, while the category two (moderate WSRF) represents the middle sector of NWCB (19 basins). The class one represents 10 basins (low WSRF). Field measurements are highly recommended to verify the results of MCA procedure used in this paper.

Assessing causes of quality deterioration of groundwater in Puttalam, Sri Lanka, using isotope and hydrochemical tools

ABSTRACTExtensive extraction of groundwater has resulted in deterioration of the groundwater quality in the Puttalam area in the northwestern coastal zone of Sri Lanka. This situation led us to carry out the present comprehensive study based on environmental isotopic (18O, 2H, 3H) and geochemical evaluation to understand the root cause for water quality deterioration. The isotopic data suggest that the surface water and shallow groundwaters are subjected to intensive evaporation and, as a result, increase in their salinity. Deep groundwater of the area is mostly recharged by direct infiltration of rainwater and at few places by nearby surface water bodies. The salinity increase of deep groundwater depends on the specific hydrogeological zones and would be due to dissolution of salts which are precipitated in soil through the seawater spray over the time, dissolution of minerals in geological matrix and leaching of salts from salterns. The quality of the deep groundwater is relatively good in the granitic gneiss zone and nearby areas outside the sedimentary aquifer. There is no evidence from isotope and hydrogeochemical evaluation for seawater intrusion into groundwater in the Puttalam area.

Distribution of major and trace elements in surface sediments of the western Gulf of Thailand: Implications to modern sedimentation

In this study, we analyze major and trace elements (SiO2, Al2O3, Fe2O3, CaO, K2O, MgO, Na2O, TiO2, P2O5, MnO, Cu, Pb, Ba, Sr, V, Zn, Co, Ni, Cr, and Zr) and grain size of 157 surface sediment samples from the western Gulf of Thailand (GoT). On the basis of the space distribution characteristics, the study area can be classified into three geochemical provinces. Province I covers the northern and northwestern coastal zones of the GoT, including the whole upper GoT and thus the sediments from the rivers in the area. It contains high contents of SiO2. Province II is located in the middle of the GoT and has similar geochemistry composition as the South China Sea (SCS). It contains sediments that are characterized by higher contents of Na2O, TiO2, Ba, Cr, V, Zn, Zr, and Ni. Province Ш is located in the lower GoT, close to Malaysia. Major and trace elements in this area showed complex distribution patterns, which may be due to terrestrial materials from Malay rivers combining with some sediments from the SCS in this province. The results also indicate that grain size is the controlling factor in elemental contents, and that the hydrodynamic environment and mineral composition of the sediments play an important role in the distribution of these elements. The anthropogenic impact of heavy metal introduction (especially Cr, Zn, Cu, and Pb) can be seen in surface sediments from the nearshore region of Chantaburi province and north of Samui Island.

Impact of ridge–furrow water harvesting system on faba bean (Vicia faba L.) production under rainfed conditions in Matrouh, Egypt

In the North Western Coastal Zone (NWCZ) of Egypt, low rainfall results in poor crop production. Different techniques should be examined to enhance the crop yield productivity and increase the water use efficiency. The ridge–furrow water harvesting system (RFWHS) is examined under the rainfed conditions in the NWCZ of Egypt over the two growing seasons of 2012/2013 and 2013/2014. Two ridge:furrow ratios of 120:60 and 60:60cm ridge:furrow were used and compared to the conventional cultivation in a flat plot. The RFWHS was combined with different plant densities produced from three different row spacing (i.e., 20, 30, 60cm). The faba bean yield was highly influenced by the ridge:furrow ratio, the seed yield was increased by 47% and 128.2% when the 60:60cm ridge:furrow ratio was used as compared to the conventional cultivation in the first and second seasons, respectively. The row spacing of 30cm apart produced the highest seed yield of 491.1kg/ha in the first season and 261.3kg/ha in the second season as compared to 20cm and 60cm row spacing. The water use efficiency followed the same pattern as that of seed yield; it was the highest for the 60:60cm ridge:furrow ratio and the highest for the 30cm row spacing. It is concluded that the RFWHS can be used effectively in increasing faba bean production and maximizing water use efficiency in limited rainfall areas.

Hydrologic factors controlling groundwater salinity in northwestern coastal zone, Egypt

The aim of this article is to assess the main factors influencing salinity of groundwater in the coastal area between El Dabaa and Sidi Barani, Egypt. The types and ages of the main aquifers in this area are the fractured limestone of Middle Miocene, the calcareous sandstone of Pliocene and the Oolitic Limestone of Pleistocene age. The aquifers in the area are recharged by seasonal rainfall of the order of 150 mm/year. The relationship of groundwater salinity against the absolute water level, the well drilling depth, and the ability of aquifer to recharge has been discussed in the present work. The ability of aquifer to locally recharge by direct rainfall is a measure of the vertical permeability due to lithological and structural factors that control groundwater salinity in the investigated aquifers. On the other hand, the fracturing system as well as the attitude of the surface water divide has a prime role in changing both the mode of occurrence and the salinity of groundwater in the area. Directly to the west of Matrouh, where the coastal plain is the narrowest, and east of Barrani, where the coastal plain is the widest, are good examples of this concept, where the water salinity attains its maximum and minimum limits respectively. Accordingly, well drilling in the Miocene aquifer, in the area between El Negila and Barrani to get groundwater of salinities less than 5000 mg/l is recommended in this area, at flow rate less than 10 m3/hr/well. In other words, one can expect that the brackish water is probably found where the surface water divide is far from the shore line, where the Wadi fill deposits dominate (Quaternary aquifer), acting as a possible water salinity by direct rainfall and runoff.

Méthode d’évaluation des perceptions et des représentations locales sur un échantillon ciblé de la faune et de la flore de la côte ouest de Madagascar

Method for evaluating perceptions about animals and plants among the inhabitants of the northwestern coastal zone of Madagascar. The evaluation of global perceptions about animal and plant species by villagers living in protected area including fragmented dry forests has been conducted in the northwestern coastal zone of Madagascar. The methodology used in field conditions is presented and discussed in relation to possible integration of the results into localized botanical and zoological surveys, which have been conducted during the same period.