AUTHOR=Amwele Hilma Rantilla , Kgabi Nnenesi Anna , Kandjibi Liisa Indileni 

TITLE=Sustainability of Groundwater for Irrigation Purposes in Semi-arid Parts of Namibia

JOURNAL=Frontiers in Water

VOLUME=Volume 3 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/water/articles/10.3389/frwa.2021.767496

DOI=10.3389/frwa.2021.767496

ISSN=2624-9375

ABSTRACT=Groundwater quality data from 1137 boreholes in 10 regions of Namibia were assessed for Sodium Adsorption Ratio (SAR), Kelly’s Ration (KR), Sodium Percentage (Na%), Magnesium Adsorption Ratio (MAR), Total Hardness (TH), Soluble Sodium Percentage (SSP), Potential Salinity (PS), Electrical Conductivity (EC) and Total Dissolved Solids (TDS) to determine the suitability for irrigation. The groundwater was classified as follows: SSP as fair and poor; PS as not suitable for irrigation; EC very high; TDS as slightly moderate and unsuitable for agricultural purpose; and Na% as doubtful and unsuitable. The results was due to higher concentrations for regions such as Erongo region EC, TDS, SO42-, Cl-, Ca2+ and K+; Hardap region  Cl-, Ca2+ and K+; Karas region SO42-, Cl- and K+; Kavango and Khomas regions K+; Kunene Cl- and K+; Ohangwena region Mg2+  and K+; Omaheke and  Otjozondjupa regions SO42-, Mg2+ and K+; Zambezi region SO42-, Cl-, Ca2+ and K+ that exceeded the FAO guideline for irrigation water quality. Other water quality criteria had inverse groundwater classification such as SAR as excellent and good water in all regions; in 70% of the regions MAR classified as recommended for irrigation; KR as groundwater safe for irrigation and TH classified groundwater as soft water.