Use of the Macromodel DNS/Swat to Calculate the Natural Background of Tn and Tp in Surface Waters for the Rac Parameter

Abstract

Total nitrogen (TN) and total phosphorus (TP) get into surface waters from both natural and anthropogenic sources. Anthropogenic sources have been relatively well recognised but the natural emmission of nutrients into the rivers, in the case of many catchments, remains a mystery. The paper describes the possibility of using a tool, the Macromodel DNS/SWAT (Discharge Nutrient Sea/Soil and Water Assessment Tool), to estimate the concentration and load of natural background (Natural Pollutant Concentration-NPC and Natural Pollution Load-NPL) for TN and TP and thus to specify the previously developed method of river absorption capacity-RAC. A variant scenario was developed allowing for a "virtual" change in the use of the area of an analysed catchment. This allowed the simulation of the amount of TN and TP in the waters of the main river, the Warta, in a situation where there was no anthropogenic phenomenon in the area. NPC and NPL results were obtained for six calculation profiles located on the central Warta main stream. On this basis, the total absorbency of the Total River Absorption Capacity-RACT River was calculated. The obtained results indicate an increasing pollution of the analyzed river on subsequent Surface Water Bodies (SWB). The values of RAC and RACt parameters for both TN and TP were reduced between the opening and closing profiles of the analyzed catchment by 2651 t/y (TN) and 86 t/y (TP), respectively. K e y w o r d s : Natural background; Total nitrogen; Total phosphorus, RAC parameter, Macromodel DNS/SWAT.

Estimation of nutrient loads with the use of mass-balance and modelling approaches on the Wełna River catchment example (central Poland)

“…Although estimates according to both methods were based on a similar concept, the differences reached 30% and 80% for TN and TP, respectively. In the case of NBS, an attempt was made to recreate nutrient concentrations from the pre-human period, using coefficients on the natural background in undisturbed catchments 17 according to the mass-balance method, and creating a variant scenario in a modelling approach where the entire catchment area was covered by forestry without any human activities 47 , 60 . As for ATS, which was combined in a single scenario along with NBS in the modelling simulations (A5), the data on pollutant atmospheric deposition was taken into consideration.…”

“…In the next two scenarios (A2 and A3), concerning urban and agricultural land use, their surface areas (5 663 ha and 192 917 ha, respectively) were successively replaced by the forest land use. This procedure was based on the assumption that the forest is the primary type of land use for this catchment area 47 . In order to completely eliminate the influence of these areas, the nutrient loads from the relevant surface area occupied by forest land use were subtracted, in order to estimate the contribution of urban and agricultural land (L URB and L AGS , respectively).…”

Estimation of Nutrient Loads With the Use of Mass-balance and Modelling Approaches on the Wełna River Catchment Example (Central Poland)

“…In the next two scenarios (A2 and A3), concerning urban and agricultural land use, their surface areas (5 663 ha and 192 917 ha, respectively) were successively replaced by the forest land use. This procedure was based on the assumption that the forest is the primary type of land use for this catchment area [42] . In order to completely eliminate the in uence of these areas, the nutrient loads from the relevant surface area occupied by forest land use were subtracted, in order to estimate the contribution of forest and agricultural land (L URB and L AGS , respectively).…”

From the source to the reservoir and beyond—tracking sediment particles with modeling tools under climate change predictions (Carpathian Mts.)

“…To achieve the goal of the study, i.e., to track sediment particles from their source to the deposition area, the DNS (Discharge Nutrient Sea) digital platform (Macromodel DNS) has been used as a modeling tool. The Macromodel DNS, developed at the Institute of Meteorology and Water Management-National Research Institute (Instytut Meteorologii i Gospodarki Wodnej-Państwowy Instytut Badawczy, IMGW-PIB) (Wilk et al 2018b;Wilk and Orlińska-Woźniak 2019), provides an interactive platform allowing for integration of the SWAT (Soil and Water Assessment Tool) module (version 2012) (Arnold et al 2012;Abbaspour et al 2015) with other modeling tools (modules) to track different processes of the sediment/contaminant transport in a catchment (Wilk et al 2018a;Szalińska et al 2020Szalińska et al , 2021Orlińska-Woźniak et al 2020a). The RR catchment module has been created in the SWAT module (Fig.…”