Calibration and validation of water flow model in soil using sensor technology

Tok vode u tlima ključan je proces koji utječe na njenu količinu i kvalitetu. S obzirom da je transport onečišćivača u tlu usko povezan s kretanjem vode vrlo je važno na pravilan način procijeniti navedene procese u stvarnim (poljskim) uvjetima. Cilj ovog rada je kalibrirati i validirati model toka vode u nesaturiranoj zoni tla na temelju podataka o količini vode u tlu i vodnog potencijala tla. Istraživanje je provedeno na tri lokacije u drugoj zoni vodozaštite grada Zagreba. Terenskim opažanjima (TDR tehnologija) i laboratorijskim analizama (HYPROP-FIT) eksperimentalno su određeni hidraulički parametri tla koji su prvi korak u određivanju toka vode. Za primjenu numeričkih simulacija korišten je HYDRUS-1D program kojim je simulirana volumna količina vode u tlu i vodni potencijal. Radom se izvršila kalibracija modela toka vode pri čemu su korištene optimizirane, inverzno dobivene vrijednosti hidrauličkih parametara. Rezultati istraživanja varirali su ovisno o hidrauličkim parametrima tla te klimatskim parametrima (temperatura, oborine i evapotranspiracija). Statističkom analizom podataka potvrđeno je da je model uspješno validiran i kalibriran.Water flow in soils is a key process that affects its quantity and quality. Given that the transport of pollutants in the soil is closely related to the water flow, it is very important to properly assess these processes in real (field) conditions. The aim of this paper is to calibrate and validate the water flow model in the unsaturated soil zone based on soil water content and pressure head data. The research was conducted at three locations in the second water protection zone of Zagreb city. With the field observations (TDR technology) and laboratory analyzes (HYPROP-FIT) we experimentally determined the hydraulic parameters of the soil, which is the first step in determining the water flow. HYDRUS-1D program was used for the numerical simulations, which determined soil water content and pressure head. The calibration of the water flow model was performed using optimized, inversely obtained values of hydraulic parameters. The results of the research varied depending on soil hydraulic properties and climatic parameters (temperature, precipitation and evapotranspiration). Statistical analysis of the data confirmed that the model was successfully validated and calibrated