تقييم جودة المياه الجوفية في جنوب طرابلس و ملاءمتها لمري باستخدام مؤشر جودة مياه الري (IWQI)‎

الملخص EN

Groundwater represents one of the main constraints to develop successful sustainable agricultural activity in Libya.

good management and proper planning of this resource requires knowledge of water quality to reduce the problems which may face the users of that resource.

this study aims to identify the chemical composition of groundwater in the south of Tripoli area and to assess the quality of groundwater for irrigation purposes.

in order to achieve the objectives of this study, 31 samples of groundwater were collected from wells scattered around southern tripoli during July of 2016.

many chemicals analyze were conducted on these samples to estimate the electrical conductivity(ec), ph and the concentration of some dissolved ions which included sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl-), bicarbonate (HCO3-) and sulfate (SO42-).

The adjusted percentage of absorbed sodium (SARo) was also determined.

the five-parameters irrigation water quality index was used.

These parameters included EC, Na+, Cl-, HCO3-, and SARo.

the inverse distance weighted to the power 2 was used to obtain the maps of the spatial distribution of chemical properties and irrigation water quality index.

the results showed that the values of the electrical conductivity were high in the middle of the study area and decreased at its east and west, and the spatial distribution pattern was very similar to the spatial distribution of sodium and chloride ions.

the results also indicated that the average relative abundance of dissolved anions as expressed in units of (meq/l) were 65.8, 20.4, and 13.8% for Cl-, SO42-, and HCO3-, respectively.

The average relative abundance of dissolved cations was 49.3, 28.1, 21.7 and 0.9% for Na+, Mg2+, Ca2+, and K+, respectively.

the irrigation water quality index values ranged between 41.2 and 76.6.

the spatial distribution map of the irrigation water quality index also showed that 62% of the area of the study area was classified as having moderate restrictions and limitations for use for irrigation purposes, and that 37.5% were classified as having high restrictions and limitations.