Tafna Basin Research Articles

Macroinvertebrate-hosted sclerobiont assemblage from the Upper Miocene Clypeaster-rich beds of the Djebel Murdjadjo (Oran, northwestern Algeria)

ABSTRACT Sclerobiont communities from Messinian Clypeaster-rich beds at Terziza (Djebel Murdjadjo, NW Algeria) are described. Endobionts are exclusively composed of domichnial structures of polychaete annelids (Caulostrepsis isp. Maeandropolydora isp. and Trypanites isp.), clionid sponges (Entobia geometrica, E. retiformis and Entobia isp.), and endolithic bivalves (Gastrochaenolites torpedo and Gastrochaenolites isp.). Among sclerozoans, epibionts are represented by barnacles, bryozoans, juvenile oysters, serpulids, and vermetid gastropods (with attachment scar Santichnus mayorali). Host organisms include Ostrea lamellosa, Clypeaster, and Pecten. The studied assemblage is ascribed to the Trypanites ichnofacies, indicating nearshore, high-energy deposition influenced by storm events, and post-mortem bioerosion. Clypeaster-rich beds mark the initial Mediterranean marine transgression on the southern flank of the Murdjadjo horst, characterised by three distinct phases. The bioerosion pattern parallels that of the Tafna basin, suggesting uniform environmental evolution during the Early Messinian.

Artificial Neural Networks vs Long Short-Term Memory Prediction of Solid Flow in Tafna Basin (North-West Algeria)

Artificial Neural Networks vs Long Short-Term Memory Prediction of Solid Flow in Tafna Basin (North-West Algeria)

Record of Late Neogene seismites in turbidite deposits of the Tafna Basin (NW Algeria)

The wide variety of soft-sediment deformation structures (SSDS) developed within deposits of the same age may hinder the interpretation of their origin. Some types of SSDS may appear similar though have different trigger mechanisms, while others may result from a specific mechanism. Furthermore, the development of particular SSDS may be influenced by several synchronous or semi-synchronous factors. This study deals with the recognition of SSDS trigger mechanisms with respect to lithological and deformational features of the deposits concerned. Turbidite deposits of late Neogene age in the Hadjret El Gat area (Tafna Basin) contain different types of SSDS associated with (1) slope processes (e.g., slump folds) and induced overburden pressure, coupled with broken beds and overloading structures, and (2) liquefaction and fluidisation phenomena, leading to the development of load structures, ball-and-pillow structures, water-escape structures and syndepositional faults. These two mechanisms of SSDS formation in the study area are thought to result from seismically-induced triggers. Recognition of a vertically-repeated, sandwich-like arrangement of deformed and undeformed layers along with the SSDS features ("trapped" within beds) suggests that these internally-deformed beds are seismites, the first recognized in the Tafna Basin of NW Algeria. Large earthquakes may trigger seismic waves energetic enough to deform strata and induce the development of SSDS. This hypothesis is supported here by tectonic evidence, given deposition of the Tafna Basin strata in the convergence zone between Africa and Eurasia, active since the late Neogene.

Ichnological analysis and depositional setting of late Miocene marginal marine deposits from the Tafna Basin (northwestern Algeria)

Abstract The late Miocene marginal marine deposits of the Sikkak area (Tafna Basin, northwestern Algeria) encompass moderately diversified invertebrate trace fossils preserved mainly as epichnia. The present study documents for the very first time the trace fossils occurring in this area, where 16 ichnotaxa, dominated by post-depositional domichnial, repichnial and fodinichnial components, are reported: ? Bifurculapes isp., Diplocraterion isp., Helminthoidichnites isp., ? Kouphichnium isp., ? Megagrapton irregulare , Ophiomorpha annulata, Ophiomorpha cf. nodosa , Oravaichnium isp., Palaeophycus isp., Planolites cf. beverleyensis , Planolites montanus , Ptychoplasma isp., Skolithos isp., S. linearis , Thalassinoides isp. and T. suevicus . The main producers of the studied trace fossils are arthropods (crustaceans, limulids, insects), annelids (polychaetes, phoronids) and bivalves. These traces are commonly associated with sedimentary structures that are caused by hydrodynamics, suggesting high-energy conditions and opportunistic colonization within a marginal marine environment (i.e. backshore to foreshore), and corresponding to the Skolithos ichnofacies. The crustacean trace ? Bifurculapes and the limulid trackways Kouphichnium are reported herein for the first time in Algeria. Sedimentological data suggest an imbricated sandstone channel within a marginal marine setting and subaerial exposures indicated by mud-cracks. The foraminiferal assemblage, dominated by shallow marine species, therefore suggests a Tortonian age for these deposits.

The Effect of Beneficial Autochthonous Microorganisms (Bams) on the Chemical Quality of Agricultural Soils and Olive Production in the Wilaya of Tlemcen (Western of Algeria)

Abstract Beneficial Autochthonous Microorganisms (BAMs) are a multi-purpose technology that has already been used in Latin America and Southeast Asia but is still unknown in Africa and particularly Algeria. The aim is to examine the effect of BAMs on agricultural soils and olive fields. The study was carried out in two degraded olive fields located in the Oued Tafna basin west of Tlemcen (The Semi-arid region in Western Algeria). The objective is to evaluate the effectiveness of BAMs on the chemical characteristics of the soils, particularly in terms of organic matter (MO), pH, electrical conductivity (EC), total limestone (CaCO3), moisture, organic carbon (C) and olive production and its weight. Statistical analysis (Independent Test) between all groups (treated and controls) showed a significant difference, in conductivity (EC) where we recorded “0.214±0.03μs /cm “ in treated soils vs. “0.198±0.029μs/cm “ in control soils a different statistical significance was recorded for the other parameters, however, it was observed that there is a relative increase in these parameters in the soils of the treated groups such as carbon (C): “2.85±1.06%” organic matter (MO): “4.91± 1.83%”, “pH=7.81±0.225”, “CaCO3 27.76±4.99% and a decrease in humidity “15.11±3.77%” compared to control soils. The results of statistical analyses (Mann-Whitney Test and Suite Test) of olive production showed a clear alternation (every other year) in fruit production in the control group and a positive effect of BAMs on olive production in the treated group, with a slight increase of production (19 kg in 2019 vs. 30 kg in 2020), but without any significant difference regarding the weight of the fruit between the two sessions. However, a highly significant difference “p=0.00<0.001” in fruit weight was noted between the treated groups “3.908g” and “5.70g” and the control ones “4.40g “ and “5.00g” in 2019 and 2020 respectively. The use of MAB is an interesting technique to restore the chemical properties of degraded soils, and increase olive tree production. To achieve more reproducible results (in terms of quantity and quality), sufficient doses of these BAMs and periodicals must be added to provide a good nutritional supplement and reduce farmers’ use of pesticides and mineral fertilizers.

A comparative assessment of meteorological drought in the Tafna basin, Northwestern Algeria

A comparative assessment of meteorological drought in the Tafna basin, Northwestern Algeria

Spatio-temporal trends of hydrological components: the case of the Tafna basin (northwestern Algeria)

Abstract Climate change is expected to increase in the future in the Mediterranean region, including Algeria. The Tafna basin, vulnerable to drought, is one of the most important catchments ensuring water self-sufficiency in northwestern Algeria. The objective of this study is to estimate the evolution of hydrological components of the Tafna basin, throughout 2020–2099, compared to the period 1981–2000. The SWAT model (Soil and Water Assessment Tool), calibrated and validated on the Tafna basin with good Nash at the outlet 0.82, is applied to analyze the spatial and temporal evolution of hydrological components over the basin throughout 2020–2099. The application is produced using a precipitation and temperature minimum/maximum of an ensemble of climate model outputs obtained from a combination of eight global climate models and two regional climate models of the Coordinated Regional Climate Downscaling Experiment project. The results of this study show that the decrease of precipitation in January, on average −25%, ranged between −5% and −44% in the future period. This diminution affects all of the water components and fluxes of a watershed, namely, in descending order of impact: the river discharge causing a decrease −36%, the soil water available −31%, the evapotranspiration −30%, and the lateral flow −29%.

Bioerosion in Ostrea lamellosa shells from the Messinian of the Tafna basin (NW Algeria)

Bioerosional trace fossils (borings) are reported for the first time in Algeria. Three ichnotaxa observed in the shells of Ostrea lamellosa from the lower Messinian (upper Miocene) deposits of the Tafna basin (NW Algeria) are described. The ichnotaxa are Entobia cf. geometrica, Gastrochaenolites cf. torpedo and Trypanites isp.. Ostrea lamellosa shells are encrusted by balanid barnacles which are bored by Trypanites isp.. The ichnoassemblage is assigned to the Trypanites ichnofacies. Besides the bioerosion and encrustation described herein, specimens permitted the identification of the different phases of the Messinian transgression across the Souk el Khemis shoal.

Future climatic and hydrologic changes estimated by bias-adjusted regional climate model outputs of the Cordex-Africa project: case of the Tafna basin (North-Western Africa)

This study investigates climatic and hydrologic changes of the Tafna basin, by using ten outputs of precipitation and temperature from RCMs of the Cordex-Africa project. Different methods of bias-correction (LS, LOCI, DM and VS) are compared to correct the bias of precipitation and temperature datasets to observations. The suitable method, DM, reduces the bias to 1.27 mm for precipitation and 0.06 and 0.7°C for minimum/maximum temperature, respectively. The bias-corrected precipitation and temperature datasets are introduced into the SWAT model, calibrated and validated on the Tafna basin with good Nash criteria (NSEoutlet = 0.83). The discharge is over or under-estimated without bias-correction of RCM outputs, which highlights the necessity of applying bias-correction before using RCM outputs from Cordex-Africa for hydrological applications. The results show that the precipitation and discharge decreases, and temperature increases are more important with RCP 8.5 than with RCP 4.5, especially in the last decades of the 21st century.

Future climatic and hydrologic changes estimated by bias-adjusted regional climate model outputs of the Cordex-Africa project: case of the Tafna basin (North-Western Africa)

This study investigates climatic and hydrologic changes of the Tafna basin, by using ten outputs of precipitation and temperature from RCMs of the Cordex-Africa project. Different methods of bias-correction (LS, LOCI, DM and VS) are compared to correct the bias of precipitation and temperature datasets to observations. The suitable method, DM, reduces the bias to 1.27 mm for precipitation and 0.06 and 0.7°C for minimum/maximum temperature, respectively. The bias-corrected precipitation and temperature datasets are introduced into the SWAT model, calibrated and validated on the Tafna basin with good Nash criteria (NSEoutlet = 0.83). The discharge is over or under-estimated without bias-correction of RCM outputs, which highlights the necessity of applying bias-correction before using RCM outputs from Cordex-Africa for hydrological applications. The results show that the precipitation and discharge decreases, and temperature increases are more important with RCP 8.5 than with RCP 4.5, especially in the last decades of the 21st century.

The Dynamics of Suspended Particulate Matter in the Oued Nachef (Tafna Basin, Algeria): Typology of Flood Events and Contribution to Sediment Transport

This article focuses on the study of sediment transport during flood events in the Oued Nachef watershed that feeds the Mefrouche dam. To understand the sediment dynamics in this watershed, ANRH data on instantaneous water discharges and the respective concentrations of suspended particulate matter were used. This enabled the selection of some of the largest flood events over a 24-year period in order to establish the log-log relationships between sediment load (concentration and flux) and water discharge. However, the discharge-concentration relationships revealed hysteresis phenomena that enabled a flood typology to be established and classified into seven categories, thus showing very different transfer dynamics in relation to flood events. The results showed that Category 6 floods presenting hysteresis in the form of a figure of eight exported almost 44% of the suspended particulate matter load while representing just 29% of the flow discharge.

Reports of Baetidae (Ephemeroptera) species from Tafna Basin, Algeria and biogeographic affinities revealed by DNA barcoding.

BackgroundThe Mediterranean basin is known to be the cradle of many endemic species. Within mayflies (Insecta, Ephemeroptera), North African species belonging to the family Baetidae remain poorly known and, traditionally, affinities to European fauna were proposed. Recent studies, based on molecular reconstructions, showed closer relationships to Mediterranean islands fauna.New informationBaetidae were sampled from North-West Algerian wadis (Tafna basin) and involved in COI barcoding reconstructions. Seven species were identified. The subgenus Rhodobaetis is represented by Baetis atlanticus known previously from Macaronesian islands, Europe and Morocco and the Maghrebian endemic Baetis sinespinosus. Specimens, previously identified as Cloeon cf. dipterum, correspond to Cloeon peregrinator and, until now, only reported from Macaronesia. Besides the confirmation of endemicity of some species, such as Procloen stagnicola and B. sinespinosus, our molecular study showed quite original results for relationships between European, insular and Algerian species. Baetis maurus stood out as a North African endemic sister clade to an Iberian clade. Furthermore, we found clear interspecific distances between Algerian and European clades for A. cf. sinaica and B. cf. pavidus, suggesting the presence of cryptic species in Algeria. However, additional studies are needed, as, for the moment, no clear morphological characters were found to separate the different clades and support them as valid species.

Applications of a SWAT model to evaluate the contribution of the Tafna catchment (north-west Africa) to the nitrate load entering the Mediterranean Sea.

An elevated nitrogen concentration in water is one of the main problems affecting water quality in Mediterranean rivers. The objectives of this study were (1) to evaluate the contribution of the Tafna catchment to the nitrate load entering the Mediterranean Sea, (2) to quantify the impact of agriculture on the nitrate concentration in water bodies, (3) to evaluate nitrate loads entering groundwater, and (4) to quantify the role of reservoirs in nitrate retention. A SWAT model was applied during the period 2003 to 2011. The discharge calibration was based on a previous study by Zettam et al. (2017). NSE efficiencies ranged from 0.421 to 0.75, R2 ranged from 0.25 to 0.84, and PBIAS ranged from 3.68 to 39.42. The simulations of monthly nitrate loads were satisfactory in the upstream sampling stations, with NSE between 0.48 and 0.65 and R2 between 0.63 and 0.68. The PBIAS was satisfactory in all the sampling stations (- 36.30 to 10.42). In the downstream sampling stations, the calibration of the monthly nitrate loads was unsatisfactory (NSE ranged from - 0.26 to 0.21 and R2 ranged from 0.02 to 0.25). Fertilisation was the main N input in the catchment, while the main N output was plant uptake. The Tafna River carried an annual average of 37 to 85.5tNyear-1 into the Mediterranean Sea. The simulation also showed that reservoirs in the Tafna basin contain a large quantity of nitrates, i.e. 62% on average of the total amount of nitrates transported annually by the Tafna River.

Analyzing Trend and Variability of Rainfall in The Tafna Basin (Northwestern Algeria)

Northwest Algeria has experienced fluctuations in rainfall between the two decades 1940s and 1990s from positive to negative anomalies, which reflected a significant decline in rainfall during the mid-1970s. Therefore, further analyzing rainfall in this region is required for improving the strategies on water resource management. In this study, we complement previous studies by dealing with sub basins that were not previously addressed in Tafna basin (our study area located in Northwest Algeria), and by including additional statistical methods (Kruskal–Wallis test, Jonckheere-Terpstra test, and the Friedman test) that were not earlier reported on the large scale (Northwest Algeria). In order to analyse the homogeneity, trends, and stationarity in rainfall time series for nine rainfall stations over the period 1979–2011, we have used several statistical tests. The results showed an increasing trend for annual rainfall after the break detected in 2007 for Djbel Chouachi, Ouled Mimoun, Sidi Benkhala stations using Hubert, Pettitt, and Buishand tests. The Lee and Heghinian test has detected a break at the same year in 2007 for all stations except Sebdou, Beni Bahdel, and Hennaya stations, which have a break date in 1980. We have confirmed this increasing trend for rainfall with other trend detection methods such as Mann Kendall and Sen’s method that highlighted an upward trend for all the stations in the autumn season, which is mainly due to an increase in rainfall in September and October. On a monthly scale, the date of rupture is different from one station to another because the time series are not homogeneous. In addition, we have applied three tests enabling further results: (i) the Jonckheere-Terpstra test has detected an upward trend for two stations (Khemis and Hennaya), (ii) Friedman test has indicated the difference between the mean rank again with Khemis and Hennaya stations and the Merbeh station, (iii) according to the Kruskal-Wallis test, there have been no variance detected between all the rainfall stations. The increasing trend in rainfall may lead to a rise in stream flow and enhance potential floods risks in low-lying regions of the study area.

Thirty years after: an update to the mayflies composition in the Tafna basin (Algeria)

Thirty years after the first Ephemeroptera checklist (excluding Baetidae) of the Tafna basin (North-west Algeria) involved in an ecological study, new sampling investigations in 12 of the 48 sites prospected allowed us to record 12 taxa including six Baetidae taxa. The aim of the present study is to analyze and discuss the current diversity and distribution of Ephemeroptera. The results highlighted that more than half of the Ephemeroptera fauna previously mentioned has been depleted, with the loss of filtering and burrowing species. The mayfly fauna was mostly dominated by the family Baetidae (83%). Baetis (Rhodobaetis) sp. and Baetis pavidus were the most common taxa, with a large spatiotemporal distribution; other baetid species include Acentrella sinaica and Baetis maurus, two rheophilic species with strict ecological requirements and a distinct seasonality, as well as two limnophilic species Cloeon cf. dipterum and Procloeon stagnicola. Conductivity and habitat integrity seem the most influencing parameters to explain the current distribution and abundance of Ephemeroptera, especially Baetidae. Moreover, specific richness variability is related to conductivity and altitude.

The impact of climate change on groundwater resources in northwestern Algeria

Algeria lies in one of the most vulnerable regions facing climate change impacts during the twenty-first century. Northwestern Algeria has experienced a persistent decline in annual rainfall associated with the significant increase in temperature during the twentieth century. This variability has been accentuated since the 1980s and has had a significant impact on water resources. The primary motto of the current study is to measure the impact of climate change on groundwater resources using time series of rainfall and runoff data measured in the Tafna Basin (7245 km2) of Algeria. The application of meteorological drought indices and statistical test of Pettitt shows that a rainfall regime modification occurred around the seventies. This modification reveals a decrease of rainfall between 8.21 and 38.85% according to the stations, with an average of 17.85%. The average recession coefficients obtained by Maillet’s exponential model varies between 8.90.10 and 17.06.10−2 day−1 either side of 1987, with an average increase of 45.45% and highlight a much faster drainage of the aquifers supplying the baseflow after 1987. A shortening of 1 to 11 days with an average of 6 days of the duration of the recession after 1987 was highlighted. The average water volumes mobilized by the aquifers fluctuated between 11.38 and 3.62 hm3 before and after 1987, with an average decrease of − 69.06%. These results show a decrease in the water volumes mobilized by the aquifers after 1987 and suggest a considerable decline of groundwater resources under the influence of climate change.

Origin, distribution, and behaviour of rare earth elements in river bed sediments from a carbonate semi-arid basin (Tafna River, Algeria)

The behaviour and sources of rare earth elements (REE) in river sediments were investigated at ten stations and two dams of the Tafna basin (Northern Algeria) during contrasting hydrological conditions and using a combination of normalisation procedures, REE anomalies, various REE ratios, and multivariate statistical analysis. The ranking and REE concentrations were in the range of other carbonated areas. The classical fractionation of the heavy REE(HREE) erosion pattern, evidenced from upstream to downstream by the La/Yb or Sm/Yb ratios, was disturbed by the presence of dams, which retained the light REE (LREE) in particular. The hydrological conditions, particle size, and geochemical characteristics controlled the REE patterns. The LREE were associated with clay minerals and HREE with coarse silts, whereas carbonate and particulate organic carbon (POC) did not influence the transport downstream. The total concentration of REE in sediments was not strongly affected by anthropogenic inputs from various sources (industrial activities, and domestic or medical wastes). Indeed, some LREE enrichment and anomalies were detected at a few stations and locally for Gd, Tb, and Yb. However, the anthropogenic contribution can partially be hidden by dilution due to particle erosion. High flow increased the LREE and MREE enrichment and LREE/HREE fractionation in some places due to erosion processes and anthropic influences (dam releases and local wastes inputs). Middle REE (MREE) and HREE were the most extractable elements unlike LREE (which are the most concentrated), particularly during high water conditions. Finally, the REE demonstrated the impact of natural processes (hydrological, geochemical, and physical) and some anthropogenic disturbances (waste inputs, fertilisers, and dams). This might inspire to develop such investigations in other similar semi-arid basins undergoing various pressures. The use of local bedrock as a reference and a set of geochemical and statistical tools, is recommended.

Assessment of groundwater quality in a semiarid region of Northwestern Algeria using water quality index (WQI)

The present paper aims at determining the status and trends of groundwater quality of 12 aquifers situated in Northwestern Algeria, especially under conditions of last drought that has affected the region using water quality index (WQI) over a period of 4 years. Multivariate statistical methods have been used jointly with conventional graphical methods, to classify the samples according to plausible levels of groundwater evolution. The computed WQI values range from 67 to 588 and therefore can be categorized into four categories: “good water” to “water unsuitable for drinking.” Overall, 36% of groundwater sites sampled in the study area had good water quality, while 53% were poor. Unfortunately, 6% of the samples indicate “very poor water quality” and 5% represent water “unsuitable for drinking purposes.” Results show that the majority of groundwater of Tafna basin fell under good water quality. Groundwater of poor and medium quality characterizes the majority of the studied aquifers of Macta basin. The result showed that the water quality at monitoring station “Ain Skhouna” fell under good water quality (Chott Chergui aquifer). Results also show that groundwater of Coastal Oranais basin showed poor water quality, very poor at some monitoring stations of Mléta Plain aquifer. It has been demonstrated that the water of some aquifers has degraded under water scarcity conditions and will continue to degrade given the ongoing and projected development in the study area. The analysis reveals that the water of some aquifers needs treatment before it is used for human consumption. The influence of salt water on the some freshwater aquifers in the study area needs special attention in terms of monitoring and for sustainable management.

Quantification and study of monthly variation of suspended sediment loads in Tafna basin – Algeria

Abstract The magnitude of the phenomenon is disproportionate in semi-arid or in temperate climates. Thus Algeria is one of the most affected countries by this phenomenon and its consequences. To enable a rapid response to the request of engineers and managers to quantify sediment transport at the outlet of a watershed, a simple, easy tool to implement was developed. The principle adopted is based on hydrometric data sets from gauging stations with seasonal and annual time steps to define a suitable method for estimating sediment production. The sediment study was conducted by analysing the daily flows. Pierre du Chat station at the outlet of the Tafna basin served as an application. The obtained results are entirely satisfactory because the correlation coefficients of model Qss = f(Q) range between 72 and 95%. This method, once refined can be generalized to all watersheds in northern Algeria.

Status and trends of water quality in the Tafna catchment: a comparative study using water quality indices

Water quality indices (WQIs) are necessary for resolving lengthy, multi-parameter, water analysis reports into single digit scores; different WQIs have been developed worldwide which are greatly differing in terms of mathematical structures, the numbers and types of variables included, etc. The aim of this paper is to evaluate trends of water quality in Tafna basin with a comparison of 10 WQIs perceived as the most important indices for water quality assessment. The results show that there is an appreciable difference between indices values for the same water sample. The results also show that water quality categorization for sampling stations in the Canadian Council of Ministers of the Environment WQI (CCMEWQI) and British Columbia WQI (BCWQI) was found to be ‘marginal’ for all sampling stations, except Hammam Boughrara reservoir and Mouillah wadi where it was found to be ‘poor’. For the Aquatic Toxicity Index, it was found to be ‘totally unsuitable for normal fish life’ for all stations and ‘suitable only for hardy fish species' for Mouillah wadi and Boughrara reservoir. The results show that this transboundary catchment always needs strategies for more effective pollution control management. Future use of WQIs in this way should prove a valuable tool for environmental planning decision-makers in tracking water quality change.