# Hydropower Functional Zoning with Crowdsourced Geospatial Data: A Case Study in Sichuan Province
## 3 Results
### Hydropower Functional Zoning Results  
The various geomorphic types in Sichuan Province include plains, terraces, hilly areas, and mountainous areas. Among them, the mountainous areas occupy the largest area (74%) and are mainly distributed in the southern regions of Qinghai-Tibet Plateau and the southwest Hengduan Mountain region in northwestern Sichuan Province, with an average elevation of 3000-5000 m. Hills, plains, and terraces are the second largest areas (accounting for 12%, 7%, and 7%, respectively). These areas are mainly distributed in basin areas in Eastern Sichuan Province (Figure 6a).  
The relative-humidity index represents the spatial-distribution characteristics of climatic differences. Sichuan Province generally belongs to humid and over-humid areas (57% and 41%, respectively), accompanied by local semi-humid or semi-drought areas (2%) (Figure 6b).  
Figure 5: Distribution of hydropower-engineering construction area (**a**) and affected zones (**b**) in Sichuan Province.  
Figure 6: Distribution patterns of level 1 zoning indexes in Sichuan Province. (**a**) Landform type; (**b**) relative humidity; (**c**) runoff depth; (**d**) level 1 zoning results.  
Runoff depth, divided into five types based on natural breaks, was also used to characterize water resources (Figure 6c). The distribution of the runoff depth was basically consistent with the landform distribution. The average runoff depth in the western mountainous regions was about 102 mm, whereas it was 710 mm in the eastern basin areas.  
By considering the landform, relative humidity, and runoff depth, the distribution of 12 river basins (Figure 3) in Sichuan Province was divided into 17 level 1 ecological functional zones (Figure 6d). In this work, the level 1 ecological functional zones emphasize the aquatic- and terrestrial-ecosystem-coupling relationship and also reflects the characteristics of the river basin in Sichuan Province. The naming of the zones reflects geological and hydrological characteristics. Level 1 ecological functional zones were defined based on the name of the river basin, the location, and landform features, as well as the names and codes of different level 1 ecological functional zones.  
The vegetation coverage in 75% of the regions exceeded the value of 0.8. Regions with poor vegetation coverage were mainly distributed in high-altitude regions in the western mountains and in urban areas on the eastern plains (Figure 7a). The percentages of the construction land and the cultivated land were basically consistent with the vegetation coverage. In the western mountains, there were relatively low degrees of agricultural and urban disturbances. The construction land was mainly concentrated in the Chengdu Plain (Figure 7c), and agriculture was mainly concentrated in the eastern hills (Figure 7b).  
Based on the level 1 zones and considering the vegetation coverage, the percentage of cultivated land area, and the percentage of farmland area, Sichuan Province was ultimately divided into 27 level 2 ecological functional zones (Figure 7d). Level 2 zoning emphasizes the human-land-coupling relationship. The level 2 ecological functional zones were named \"name of level 1 zone,\" with the land-use type and the name and code of the different ecological functional zones.  
Figure 7: Level 2 zoning indexes and results in Sichuan Province. (**a**) Vegetation coverage; (**b**) percentage of cultivated land area; (**c**) percentage of construction-land area; (**d**) level 2 zoning results.  
With a focus on the affected zones of hydroelectric-development and hydropower-construction areas, the research area was divided into 53 level 3 aquatic ecological functional zones based on level 2 zoning. The detailed indexes are shown in Figure 8.