Assessing Temporal and Spatial Variations of Groundwater Quality (A case study: Kohpayeh-Segzi)

Document Type : Research and Full Length Article


1 Faculty of Natural Resources, University of Tehran, Karaj

2 Faculty of Natural Resources, University of Tehran, Karaj,

3 Watershed Management, University of Tehran and member of Young Researchers Club of Kurdistan.


Assessing the quality of groundwater is important to ensure the sustainable
safe use of these resources. However, describing the overall water quality condition is
difficult due to the spatial variability of multiple contaminants and the wide range of
indicators (chemical, physical and biological) that could be measured. Therefore, in this
case study, some water quality parameters including Na, Mg, Cl, K, and pH, SAR, TDS,
Th, Co3, HCo3, So4, Ca and EC of 34 wells and 16 qanats have been monitored and
analyzed in a 15 year period. After collecting data, the main affecting factors on water
quality of wells and qantas were determined separately by factor analysis test. Zoning
maps were generated in Arc GIS on the basis of most important effective factors. Dry and
wet years were determined based on rainfall data and 7-year moving average. Finally, the
temporal trend of principal factors was depicted and water quality variations of wells and
qantas were compared. Believing that sodium and chlorine are the most important
parameters for water quality of wells and qanats, water quality of wells during dry years
is downgraded as the results show. In initial wet year period, water quality is extremely
improved but thereafter it is degraded. Results also show that water quality variation in
qanats is negligible.