Vulnerability of groundwater to pollution from agricultural diffuse sources: a case study.

Kumluca, near Antalya in Turkey, is an important plain with its intensive agricultural activities employing greenhouses. The chemical fertilizer application practices caused excessive increases of the nitrogen, phosphorus and salinity within groundwater. A study has been initiated to assess the present state of the groundwater pollution problem of Kumluca Plain. A total of nine measurement and sampling stations have been selected to represent different depths groundwater table, different types of agricultural activities and different soil types. The magnitudes of the parameters: temperature, salinity and conductivity, nitrate, nitrite, ammonia, orthophosphate and fecal coliform were determined for groundwater. Soil samples collected from the stations have been analyzed for several parameters such as texture, total salinity, total nitrogen, and total phosphorus. The measurement and analyses results of the groundwater showed wide spatial variations depending on factors such as the quality of irrigation water, depth groundwater, soil characteristics, type and age of agriculture and hydrology. Groundwater vulnerabilities to pollution have been analyzed using the SEEPAGE Model approach. Furthermore the soil, aquifer and groundwater characteristics, which will be utilized to establish "cause" and "effect" relationships in future, have been clarified.