Investigating and understanding the responses of runoff and nitrogen loading to climate and land use change is particularly important for future water resources management. In this article, the Soil and Water Assessment Tool (SWAT) was used to simulate runoff and nitrogen loading in the middle reaches of the Fenhe River. The model was calibrated by the SWAT calibration and uncertainty procedure (SWAT-CUP) to achieve the accuracy of simulating runoff and nitrogen loadings. Furthermore, 20 climate change scenarios and 7 extreme land use change scenarios were set up and run on the calibrated model. The results showed that runoff and nitrogen loading decreased when temperature increased and increased with increasing precipitation. Runoff was more sensitive to changes in precipitation (±10%) than temperature (±2 °C), while nitrogen loading showed the opposite pattern. When the two climatic factors changed in the same direction, the combined effect was larger than either factor alone, whereas the change in the opposite direction produced a weaker effect. The changes produced by different extreme land use scenarios on runoff and nitrogen loading were significantly different and were more obvious during the flood season than in the non-flood season. The results of this study provide a useful guide for water resource managers.

Spontaneous combustion gangue hill has attracted great attention due to serious environmental pollution and terrible geological disasters. However, the rich thermal resources inside are often ignored. In order to control the spontaneous combustion of gangue hill and utilize the internal waste heat resources, this project studied the combined treatment effect of 821 gravity heat pipes, laid 47 sets of temperature monitoring devices, evaluated the storage of waste heat resources and proposed different waste heat utilization methods. The results show that: (1)The positions of spontaneous combustion are all located on the windward slope. The highest temperature is in the range of 6m~12m underground, exceeding 700 ℃. (2) The single-tube experiment of gravity heat pipe shows that the effective temperature control radius is 2m. The cooling effect is obvious in the range of 3m~5m underground.However, the temperature rises at the depth of 1 m underground. (3) After 90 days of treatment of the gravity heat pipe group, the temperature at the depths of 3m, 4m, 5m and 6m in the high temperature zone dropped by 56℃, 66℃, 63℃ and 42℃ respectively. The maximum temperature drop exceeds 160℃. The average temperature drop in the middle and low temperature areas is between 9°C and 21°C. (4) The concentration of harmful gases (CO, SO2 and H2S) decreases by more than 90%. The hazard level is greatly reduced. (5) The amount of waste heat resources contained within ten meters of the spontaneous combustion gangue hill is 7.83E13J. Waste heat resources can be used for indoor heating and greenhouse cultivation. And, under the temperature difference of 50 °C, 100 °C and 150 °C, the electric energy generated by the heat through the thermoelectric conversion device in the high temperature zone of the gangue hill is 4056.8 kW•h, 7468.2 kW•h and 10603 kW•h, respectively.

Spontaneous combustion gangue hill has attracted great attention due to serious environmental pollution and terrible geological disasters. However, the rich thermal resources inside are often ignored. In order to control the spontaneous combustion of gangue hill and utilize the internal waste heat resources, this project studied the combined treatment effect of 821 gravity heat pipes, laid 47 sets of temperature monitoring devices, evaluated the storage of waste heat resources and proposed different waste heat utilization methods. The results show that: (1) The positions of spontaneous combustion are all located on the windward slope. The highest temperature is in the range of 6m~12m underground, exceeding 700 ℃. (2) The single-tube experiment of gravity heat pipe shows that the effective temperature control radius is 2m. The cooling effect is obvious in the range of 3m~5m underground. However, the temperature rises at the depth of 1 m underground. (3) After 90 days of treatment of the gravity heat pipe group, the temperature at the depths of 3m, 4m, 5m and 6m in the high temperature zone dropped by 56℃, 66℃, 63℃ and 42℃ respectively. The maximum temperature drop exceeds 160℃. The average temperature drop in the middle and low temperature areas is between 9°C and 21°C. (4) The concentration of harmful gases (CO, SO2 and H2S) decreases by more than 90%. The hazard level is greatly reduced. (5) The amount of waste heat resources contained within ten meters of the spontaneous combustion gangue hill is 7.83E13J. Waste heat resources can be used for indoor heating and greenhouse cultivation. And, under the temperature difference of 50 °C, 100 °C and 150 °C, the electric energy generated by the heat through the thermoelectric conversion device in the high temperature zone of the gangue hill is 4056.8 kW·h, 7468.2 kW·h and 10603 kW·h, respectively.