A New Approach for the Assessment of Groundwater Quality and Its Suitability for Irrigation: A Case Study of the Korba Coastal Aquifer (Tunisia, Africa)

Abstract

BSTRACT: Groundwater is the main source of water in Mediterranean, water-scarce, semiarid regions of Tunisia, Africa. In this study of the Korba coastal aquifer, 17 water wells were studied to assess their suitability for irrigation and drinking purposes. Assessment parameters include pH, salinity, specific ion toxicity, sodium adsorption ratio, nutrients, trace metals pollutants, and fecal indicators and pathogens. Results indicate that salinity of groundwater varied between 0.36 dS/m and 17.4 dS/m; in addition, its degree of restriction is defined as "none", "slight to moderate", and "severe" for 18, 23, and 59% of the studied wells, respectively. To control salts brought in by irrigation waters, the question arises as to how much water should be used to reach crop and soil requirements. To answer this question, a new approach that calculates the optimum amount of irrigation water considering the electrical conductivity of well water [ECw], field crops, and the semiarid meteorological local conditions for evapotranspiration and rainfall is developed. This is applied to the authors' case study area; barley and lettuce were selected among the commonly grown crops because they are high-and low-salinity tolerant, respectively. Leaching requirements were found to be independent of the crop selected, and depend only on the season, that is, 250 to 260 mm/month in the driest season, with a minimum of 47 mm/month though all seasons. A high bacteriological contamination appears in almost all samples. However, if disinfected and corrected for pH, all the well waters can be used for animal farming (including livestock and poultry), although only 29% could be used for human consumption. Water Environ. Res., 84, 673 (2012).

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“…For exam ple, we could have investigated more deeply the influence of agricultur al activities (fertilizers and/or agrochemicals), but in the involved countries agricultural activities have different forms and different influ ence on biodiversity. In Tunisia for example, the presence of agricultural areas have a great impact on the coastal aquifer and salt habitats consid ered in the study (El Ayni et al 2012), in France the majority of agricul tural areas in the gulf of Marseille consists in traditional agricultural landscapes, which have an important role for the conservation of the plant species; in Italy the situation is in between (Tieskens et al, 2017). Moreover, except for Lebanon, we could not gather any informa tion on the quantity and quality of the fertilizers and agrochemicals used in the agricultural areas.…”

Hydrochemical assessment of water quality for irrigation: a case study of the Medjerda River in Tunisia

“…However, even water with considerably high salt concentration can be used for irrigation without endangering soil productivity, provided selected irrigation management. The key point is how to maintain existing salt balance in plant root zone (El Ayni et al 2012). In addition, the increase in salinity of surface waters stems from the discharge of high salt concentrations of waste effluents (Chapman 1996;Thilagavathi et al 2012).…”

Applicability Assessment of Natural Waters in Irrigation of Agricultural Land on the Example of the Vakhsh River and Its Tributaries

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