## 4 Conclusions  
The study presented an investigation on the impacts of climate change-land use variation on water resources of Multan city, Punjab, Pakistan, based on an evaluation of  
Figure 14: Spatial variability in arsenic concentration. past climate and land-use changes. Multan, having an arid climate, is pronounced part of lower Bari Doab, which lies to the south of Punjab plains. The following conclusions can be summarized:  
1. Results show significant variation in temperature indices, and a regular increment has been observed in minimum temperature indices, which increased significantly over the last 40 years. However, the increment in maximum indices was not regular and varied from year to year. A noticeable decrease in mean annual relative humidity and increase in wind speed were observed over the last four decades;
2. The urban land extended from 130.03 km\({}^{2}\) (45.44%) by 2000 to 155.49 km\({}^{2}\) (55.33%) by 2020. Conversely, the dense vegetation decreased from 31.80 km\({}^{2}\) (11.11%) by 2000 to 12.2 km\({}^{2}\) (4.27%) by 2020, while the light vegetation reduced from 112.94 km\({}^{2}\) (39.47%) to 105.40 km\({}^{2}\) (36.83%) by 2020. An increase in temperature and urbanization (improvious cover) has reduced the rate of infiltration and increased runoff inflows to the river;
3. The evaluated results from HEC-HMS revealed that the transition of rainfall into runoff increases with time. On 31 August 2017, the whole catchment basin's outlet discharge point recorded a maximum surface water runoff of 959.6 m\({}^{3}\)/s, with 306 mm of rainfall. This indicates that infiltration was minimal and that most of the rainfall was converted to surface runoff. Consequently, the groundwater is depleting rapidly due to an imbalance between discharge and recharge of the groundwater;
4. The depth of the water table is declining at the rate of 0.2 m per year. Water quantity and water quality are also deteriorating due to unplanned land-use changes and open dumping of domestic and industrial effluents. At some spots, arsenic concentration was found beyond the WHO threshold, creating health issues for the citizens of Multan. Therefore, climate and land-use changes are both deteriorating water distribution and water quality. Moreover, the effects of urbanization were found more prominent and more critical in the study area. Conceptualization, M.A. ; methodology, M.A. and P.G.A.N. ; software, M.A. ; validation, M.A. and P.G.A.N. ; formal analysis, M.A. ; investigation, M.A. ; resources, M.A. ; data curation, M.A. ; writing--original draft preparation, M.A. ; writing--review and editing, P.G.A.N. ; supervision, Y.W. ; project administration, Y.W. ; funding acquisition, Y.W. All authors have read and agreed to the published version of the manuscript. This research has been supported by the Natural Science foundation of Guangdong Province of China (Grant No. 2022A1515011200), Science and Technology Planning Project of Guangdong Province of China (Grant No. STKJ2021129). National Centre for Environmental Prediction (NCEP) observed daily predicators and Global Climate Model (GCM) daily predicators were downloaded from the site, Government of Canada ([[http://climate-scenarios.canada.ca/?page=pred-hacm3](http://climate-scenarios.canada.ca/?page=pred-hacm3)]([http://climate-scenarios.canada.ca/?page=pred-hacm3](http://climate-scenarios.canada.ca/?page=pred-hacm3)); accessed on 20 September 2020). Historical daily observed maximum and minimum temperature, precipitation, and other climate variables, such as air humidity and wind speed, were collected from Pakistan Metrological Department (PMD). Data for depth to the water table were collected from the Punjab irrigation department. Digital Elevation Model (DEM) and Landsat data were downloaded from the earth explorer, USGS ([[https://earthexplorer.usgs.gov](https://earthexplorer.usgs.gov)]([https://earthexplorer.usgs.gov](https://earthexplorer.usgs.gov)); accessed on 20 September 2020) site. Financial support and data sources are gratefully acknowledged.