Estimation of non-point source pollution load in core area of Zhangjiakou Winter Olympic Games

Evaluating the non-point source pollution load is imperative for the water environment safety of the core area of the Zhangjiakou Winter Olympic Games. Using the export coefficient modeling approach, along with the digital elevation model, the 2015 land use remote sensing data, and the 2007–2016 statistical yearbook data, the non-point source pollution output load and spatial distribution were calculated, and the contributions of different types of pollution loads were analyzed. The results were as follows: (1) From non-land use factors pollution source, the annual output of pollution load of TN, COD, TP and NH₄⁺-N were 1,154.25~17,540.39 kg, 2,114.76~34,552.41 kg, 51.29~842.54 kg and 34.40~514.88 kg, respectively. (2) Under different land use types, the output of pollution load of TN, COD, TP and NH₄⁺-N were 33,372.94, 21,453.45, 512.82 and 1,129.78 kg, respectively. (3) The agricultural population life and cultivated land were the major sources of pollution for the output of non-point source pollution loads. (4) The spatial distribution of pollutant output load was uneven. In addition, the output of the upper sub-basin and the downstream sub-basin of Donggou was relatively high. Furthermore, the output load of sub-basin in the middle and lower reaches of the Taizicheng River was relatively high.