Podatność naturalna i specyficzna wód podziemnych na obszarach rolniczych

Abstract

Intrinsic and specific groundwater vulnerability in the agricultural areas.A b s t r a c t. The main aim of the work was to evaluate intrinsic and specific vulnerability of groundwater. An assessment of intrinsic vulnerability to groundwater pollution was elaborated on the basis of the original DRASTIC method. An assessment of specific vulnerability to groundwater pollution by nitrate was elaborated by two independent methods. First method – Nitrate Vulnerability Index (NV) was an adaptation of DRASTIC method, second was based on the quotient of nitrate loads (LN) and recharge rate (R), and expected nitrate concentration (NO3exp) were computed in this method. The results were presented in the relation to four homogenous regions called hydrozones: upland, top of the upland, plain and valley. The results of the DRASTIC method indicated on higher vulnerability of the aquifer in the plain (average IPZ = 155) and lower in the upland (IPZ = 125). The results of both specific vulnerability methods confirmed high vulnerability of the aquifer in the upland unit (the nitrate concentration in the range of 10–25 mg/dm3 in 25% of the unit area; average NV = 94) and lower in the plain area (the range of 0–5 mg/dm3 in the 47% /of unit area; average NV = 81). The resultspresent a high difference between intrinsic and specific vulnerability mainly caused by agricultural activity in the upland.