Spatio-temporal analysis of hydropower projects with terrestrial environmentally sensitive areas of Nepal

Hydropower project construction is increasing, which can affect the terrestrial environment. Hydropower projects located in environmentally sensitive areas have higher environmental impacts, so I analyzed the spatiotemporal interaction between hydropower project locations and terrestrial environmentally sensitive areas of Nepal to visualize the probable environmental impacts. Most of the existing projects lie on the hill; however, future projects are moving northward. Among the 12 eco-regions of Nepal, hydropower projects are located in 10 eco-regions. Hydropower projects were found to interact with more than half of the biodiverse areas of the country (28 out of 45), and more than ve thousand megawatts of hydropower projects are located completely inside these biodiverse areas. The study suggests that the interaction between hydropower projects and environmentally sensitive areas might increase in the future. Hydropower projects should avoid environmentally sensitive areas such as biodiverse areas and protected areas as much as possible to minimize the impacts. Rapid hydropower development is a necessity in countries such as Nepal, so further studies on the effects of hydropower projects on environmentally sensitive areas as well as improvement of the quality of the environmental assessment of the projects are necessary for environmentally friendly development.


Introduction
Renewable energy is expected to have lower environmental impacts than fossil fuel consumption; however, there might be impacts on biodiversity and the environment during the construction and operation of renewable energy projects [1,2]. Hydropower is one of the major sources of renewable energy, supplying 16.4% of the world's electricity from all sources in 2016 (www.worldenergy.org, accessed on 2 August 2019), and its construction is increasing in the Himalayan region, including Nepal [3][4][5][6][7] as well as other parts of the world [8][9][10].
Studies on various parts of the world show that hydropower projects can severely affect the environment and biodiversity [2,[11][12][13][14][15]; however, most of them focused on the detrimental effects of hydropower projects on sh diversity, richness, migration, and their important habitats [11,12,14,[16][17][18]. The few studies that are conducted on the effects of hydropower projects on the terrestrial environment suggest that hydropower projects might affect terrestrial biodiversity and faunal species [16]. However, these studies mainly focused on direct impacts due to dams and inundation on forests [19], montane birds [20], and migration of caribou [21]. There are inadequate studies on the effects of hydropower project development on environmentally sensitive areas such as biodiverse areas and protected areas. Hydropower projects have a large number of structures, such as dams, tunnels, canals, powerhouses, internal project roads, access roads, camps, and transmission lines (hydropower project components including associated and auxiliary structures) [22], and most of these structures cause habitat fragmentation, which affects terrestrial faunal species and biodiversity in environmentally sensitive areas [23][24][25][26][27][28]; therefore, studies related to hydropower project distributions in environmentally sensitive areas are necessary.
Nepal has a high potential for hydropower projects (total 83,000 MW, technically feasible 45,610 MW and nancially feasible 42,133 MW), and the requirement of electricity is increasing (up to 15,000 MW installed capacity will be required in 2030) [29]. In Nepal, approximately 95% of electricity [30] and more than 99% of renewable electricity are currently produced from hydropower projects (www.doed.gov.np, accessed on 6 September 2018). To overcome the shortage of electricity in the country [7] and to meet the increasing demand for electricity, the government of Nepal planned to accelerate hydropower project development and adopted the National Energy Crisis Reduction and Electricity Development Decade-related Action Plan in 2016, which helped to increase the construction of hydropower projects.
The location of the hydropower project is an important parameter for assessing the environmental impacts [18,31]. Likewise, the spatial approach is important for estimating the impacts of hydropower projects, and the distribution of hydropower projects can be insightful for estimating the probable impacts [32,33]. Therefore, I spatially analyzed the potential interactions between current and future hydropower projects with environmentally important/sensitive areas.
Hydropower projects that interact with species-rich areas (biodiverse areas) and protected areas have higher environmental impacts [18,32]. Therefore, my objective for this study is to analyze the numbers and capacities of existing, underconstruction and proposed hydropower projects within geographic regions, ecoregions, and important terrestrial habitats (environment protection area, protected areas, important birds and biodiversity areas and key biodiversity areas) of Nepal.

Study area
Nepal, situated in the Central Himalaya region, has an area of 147,181 sq. km and is located in latitudes 26° 22' to 30° 27' N and longitudes 80° 40' to 88° 12' E [34]. There are 12 national parks (IUCN category II), one wildlife reserve (IUCN category IV), one hunting reserve (IUCN category VI), six conservation areas (IUCN category VI) and 13 buffer zones (IUCN category VI), and the country's 23.39% area is protected under these areas [35]. Most of these protected areas are distributed in northeast and southern areas, and a few protected areas are located on the hill [36,37] (Figure 3). Additionally, the Chure Environment Protection Area (hereafter CEPA) extends from west to the east of the entire country, covering 12.78% of the area of the country, which is designed for the protection of the fragile Siwalik region, especially from landslides, soil erosion, sand, and boulder extraction, and deforestation (www.chureboard.gov.np, accessed on 6 September 2018) ( Figure 3).
The country has a variety of biodiversity due to vast variations in altitude from 67 masl (meters above sea level) to 8848 masl Mount Everest [34]. Nepal has divided into three geographic regions: northern areas with a low population density that contain the Himalayas up to height 8848 m called mountains; midrange areas with moderate population density having a gorgeous mountain, high peaks, hills, valley, and lakes called hills; and densely populated lowlands with at terrain called terai [38]. The eastern part of Nepal has one of the biodiversity hotspots, the Eastern Himalayan Biodiversity hotspot [39], which also makes it important from a global conservation viewpoint.

Data sources
The data and maps for the study were collected from secondary sources from 16 August to 15  Data extraction I considered the license boundary of the project issued by the DoED (for government projects that do not require a license, the coordinate listed on the DoED website was considered) as the location of hydropower projects, as most of the project structures are located inside the license boundary. Although most previous studies on hydropower projects' impacts focus on the number of dams [11,14,16,19,40,41], there are debates about whether single large or several small hydropower projects have higher environmental impacts [8,18,33,[41][42][43][44][45]. Therefore, I considered both the numbers and total capacity of hydropower projects for this study. For this study, projects with a capacity of one megaWatt (MW) or more were considered because projects with a capacity less than one MW do not require environmental study based on installed capacity [46], are localized and managed at the local level, and are expected to have minimal environmental impacts.
For the study, I considered different categories of hydropower projects, such as existing projects (projects that have undergone commercial operation), underconstruction projects (projects whose feasibility and environmental study have been completed, and acquired construction licenses from DoED, and include one government underconstruction project), and proposed projects (projects that have received survey licenses and are in the study phase, projects whose study is completed and have applied for construction licenses, and government projects in the study phase as well as the study completed but have not gone to the construction phase). I did not consider projects that applied for the survey license as they are in the preliminary stage, and permission for the study has not been issued by the government.
I studied the geographical and eco-regional distribution of the project to show which areas have the highest number and capacity of the projects. In Nepal, the IBA and KBA areas overlap. The IBA, KBA, and protected areas were merged and named PIKs (short form for protected areas, IBA, and KBA) or biodiverse areas ( Table 3) because most of the protected areas are found to be IBA and KBA, and vice versa in Nepal. The 27 IBA and KBA and 33 protected areas (including buffer zones) were located in the country; combining them, a total of 45 PIKs or biodiverse areas were included in the analysis. The Chure Environment Protection Area (CEPA) data had been merged into a single layer from the given KMZ le, and due to its unique nature (it is not included in IUCN categories, it is designated to protect the fragile environment and established under different act than other protected areas), it was separately analyzed.

Analysis
Altogether, 608 hydropower projects with a total capacity of 35.98 GW were considered in the analysis. The current installed capacity of existing projects was found to be 1.01 GW (73 projects), 162 projects (5.00 GW capacity) were underconstruction, and 373 projects (29.97 GW capacity) were proposed. I used ESRI Arc Map 10.3 GIS software for spatial analysis [47]. The maps were converted into Modi ed UTM 84 using the project tool, as most Nepal's data are in this projected coordinate system. As eco-regions have global data, I clipped them by the Nepal administrative boundary to select the data related to Nepal. I conducted most of the spatial analysis between hydropower projects and environmentally important areas (PIKs and CEPA) using selection and eld calculators in ArcMAP 10.3. The ndings are expressed as percentages and as numbers.
An analysis of the geographic and eco-regional distribution of hydropower projects was conducted to determine the number and capacity of projects found in each region. For the hydropower projects' distribution with respect to CEPA and PIKs, the number and capacity of the projects whose project area interacted with the CEPA and PIKs areas as well as the number and capacity of hydropower projects that were completely within them were spatially analyzed using the ArcMAP. As the areas of PIKs vary greatly (less than one sq. km. to more than 7,000 sq. km), the hydropower project number and capacity were analyzed while considering the areas of the PIKs as the number and capacity of hydropower projects per 100 sq. km of the area (named the number density and capacity density, respectively) and compared them among various PIKs. During the analysis, if one project was located in two or more regions/areas, its capacity and number were considered in both regions/areas.
The data analysis was conducted in Microsoft Excel with the help of add-in 'STATISTICIAN (version 2.00.01.81)'. First, I analyzed the data normality of the capacity of projects whose project area interacted with environmentally sensitive areas (PIKs and CEPA) using the Shapiro-Wilk test, as it was most appropriate to test the normality [48,49]. The data was not found to be normally distributed. In addition, the number of projects whose project area interacted with PIKs and CEPA is discrete variables (count). Therefore, I used the Kruskal-Wallis H test to assess the differences in the number and capacity of existing, underconstruction, and proposed projects in environmentally sensitive areas (PIKs and CEPA) because this test is appropriate for nonnormal and discrete data [50,51]. In addition, I used linear regression to analyze the trends of the interactions between hydropower project locations and PIKs and CEPA to assess future interactions.

Results
Geographic and eco-regional distribution of hydropower projects The highest number of all hydropower projects was found in the hill; however, the highest capacity of all hydropower projects was found in the mountain. The highest number and capacity of existing projects were located on the hill. Although the highest number of underconstruction and proposed projects were located on the hill, the highest capacity of the underconstruction and proposed projects was located in the mountain (Figure 1). Details are given in Table 1.
Out of 12 eco-regions of Nepal, hydropower projects were located in 10 eco-regions except for Upper Gangetic Plain Moist Deciduous Forests and Lower Gangetic Plain Moist Deciduous Forests. The highest capacity of the projects was located in Himalayan subtropical broadleaf forests; however, the highest number of projects was located in eastern Himalayan broadleaf forests. Although the highest capacities of the existing and proposed projects were found in Himalayan subtropical broadleaf forests, the highest capacity of underconstruction projects was located in Eastern Himalayan subalpine conifer forests.
While no existing and underconstruction projects were located in the Rock and Ice region, nine proposed projects with a total capacity of 566.95 MW were located in the eco-region (Figure 2). Details are given in Table 2 Hydropower projects and environmentally important/sensitive areas There were signi cant differences in the number (χ 2 = 15.4, df = 2, p = 0.0005) and capacity (χ 2 = 22.83, df = 2, p < 0.0001) of existing, underconstruction and proposed projects that were located in the environmentally sensitive areas (PIKs and CEPA) of Nepal. There was no signi cant difference between existing and underconstruction projects that were located in environmentally sensitive area interms of the number (χ 2 = 2.07, df = 1, p = 0.1503) and capacity (χ 2 = 3.17, df = 1, p = 0.075). However, the proposed project number (χ 2 = 6.39, df = 1, p = 0.0115) and capacity (χ 2 = 10.21, df = 1, p = 0.0014) in environmentally sensitive areas were signi cantly higher than those in underconstruction projects (Supplementary Table S1 and Figure 3).
No hydropower projects were found to be located completely within the CEPA. The total of 19 hydropower projects (total capacity 3,481.87 MW) interacted in the CEPA, and their capacity (R 2 = 0.75) and numbers (R 2 = 0.59) increased from existing to proposed projects: four existing projects (total capacity 45.02 MW), two underconstruction projects (total capacity 62 MW), 13 proposed projects (total capacity 3,374.85 MW) were in the CEPA (Supplementary Table S1 and Figure 3).
Out of the 45 PIKs, 275 hydropower projects (45.23% of the number of projects) had a capacity of 17,994.24 MW were found to be partially or fully located in 28 (62.22% of the number of PIKs) PIKs. The percentage of hydropower projects that partially and fully overlapped with PIKs increased from existing and underconstruction projects (40%) to the proposed project (47%). The overall number (R 2 = 0.925) and capacity (R 2 = 0.893) of hydropower projects in the PIKs increased from existing projects to proposed projects: 29 existing projects (330.83 MW capacity) and 67 underconstruction (3,167.03 MW capacity) to 179 proposed projects (3,496.38 MW capacity). Among those 275 projects, a total of 150 hydropower projects with a capacity of 5,103.98 MW was found to be located completely within the PIK area, and their number (R 2 = 0.93) and capacity (R 2 = 0.99) were also found to be increased from existing to proposed projects: 16 existing projects (132.03 MW capacity) and 37 underconstruction (1,685.37 MW capacity) to 97 proposed projects (3,286.58 MW capacity) ( Figure  3).
Among the PIKs, the highest number of hydropower projects was found to be located in the Annapurna Conservation Area; however, the number density (number of projects per 100 sq. km of the PIK areas) of hydropower projects were highest in the Lantang Buffer Zone (Table 3 and Supplementary Table S1). The highest capacity and capacity density of hydropower projects (capacity of projects per 100 sq. km of the PIK areas), were in the Makalu Barun Buffer Zone (Table 3 and Supplementary Table S1). Among existing projects, the highest number of projects were in the Annapurna Conservation Area; however, Mai Valley Forests had the highest number density of the operated projects. The highest number, capacity, and capacity density of underconstruction projects were in the Gaurishankar Conservation Area; however, the highest number density of underconstruction projects was in the Lantang Buffer Zone. The highest number of proposed projects was found to be in the Annapurna Conservation Area. Nevertheless, the highest number density, capacity, and capacity density of the proposed projects were in the Makalu Barun Buffer Zone. Details are given in Table 3 and Supplementary Table S1.

Discussion
While hydropower projects are considered green development, they have several environmental problems [2,9,11,12]. Large hydropower projects have severe adverse regional environmental impacts due to secondary impacts such as deforestation, regional development, and disturbance to wildlife [18,41,52].
Similarly, the cumulative effect of several hydropower projects in an area also has several adverse environmental impacts [8,14,33,42]. Likewise, noise can affect wild fauna even if the infrastructure does not directly affect it [20,53]: blasting during tunnel excavation and other project construction activities of a large project or several smaller projects might severely affect to a large geographical extent. Therefore, a large number of hydropower projects, large capacity or both in an area suggest the higher adverse impacts of hydropower projects on that area.
Hydropower projects and their associated structures might have substantial impacts on terrestrial biodiversity, especially in remote locations. Hydropower projects in remote locations need to construct a long transmission line, access roads and electricity line for construction power. In intact remote areas, these structures might have detrimental ecological impacts [23]. My study suggests that although most of the existing projects' capacity is found in the hill, future projects' capacity is shifting northwards toward remote mountains and even in fragile rock and ice eco-regions. In addition, the number of projects in the mountain is increasing from existing to the proposed project, suggesting the northward shifting of projects. As the northern region of Nepal is fragile, less populated, and biodiverse with many protected areas [34,[36][37][38] (Fig 3), future projects might have a higher impact on the terrestrial environment.
The ndings of this study are consistent with the impacts of the rapid development of hydropower projects in other countries of the Himalayan areas on forests [19], montane birds [20], sh [3], and the overall environment [5,54], suggesting that hydropower projects severely affect the natural ecosystem of the Himalayas. This study shows that subtropical and temperate eco-regions are probably the most severely affected by hydropower projects, as there are a higher number and capacity of hydropower projects in these areas, which is similar to another study conducted in the adjoining Himalayan area that suggests hydropower projects predominantly affect subtropical and temperate forests [16].
As PIKs are an important basis for biodiversity conservation and are helpful for mitigating global biodiversity loss [55][56][57], the impact on these areas might signi cantly affect conservation efforts. In this study, a considerable number and capacity of hydropower projects are located in natural and fragile areas such as CEPA and PIKs, which is similar to the study conducted in the adjoin Himalayan area as well Andean Amazon areas [15,16]. These hydropower projects are expected to affect terrestrial biodiversity due to habitat fragmentation. Habitat fragmentation decreases species abundance and sometimes causes the disappearance of species [19,31,[58][59][60][61]. Although few existing projects with less capacity are in environmentally sensitive areas, the number and capacity of hydropower projects are found to increase signi cantly in the future and are expected to have severe impacts on the environment. In addition, the number and capacity of hydropower projects located completely inside the PIKs are also increasing, suggesting more threats in the future.
More than half of the biodiverse areas (PIKs) of Nepal are affected by hydropower projects, and approximately 40% of the existing projects and underconstruction projects and approximately 48% of the proposed projects are located in PIKs, which is higher than that in the Amazon region [52]. The hydropower project number density in most PIKs is higher than that in nearby Indian Himalayas, which suggests only 0.16 hydropower projects per 100 sq. km [19]. Both the highest number density (in the Langtang Buffer Zone) and capacity density (in the Makalu Barun buffer zone) of hydropower projects are located in the Eastern Himalayan biodiversity hotspot. These PIKs are mostly affected by proposed projects that suggest possible higher impacts in the future on the sensitive region if the developments are not managed. In addition, hydropower projects located in environmentally sensitive areas of Nepal do not comply with approved environmental reports [30], which can aggravate the problem.
All of the proposed projects might not result in implementation; however, they have a higher probability of implementation because the project proponent has invested in license and feasibility studies, and the projects look feasible from desk study. Studies show that infrastructure development in natural areas signi cantly affects faunal species and biodiversity [61,62]. Hence, it is important to study the distribution of hydropower projects to determine the effect on terrestrial biodiversity if they undergo construction and to assess the future trends of probable impacts of hydropower projects on terrestrial biodiversity. As hydropower development faces various environmental challenges, social con icts, seismic hazards, and political challenges, risk analysis is suggested to minimize such challenges and attract investment [7,63,64]. Hydropower projects located in environmentally sensitive areas can have higher environmental con ict, and this study suggests that such con ict will increase in the future in Nepal. Therefore, regulators should formulate policies to minimize such con icts for sustainable hydropower development.
Despite some environmental concerns, renewable energy is the basis for sustainable development as well as the energy security of a country [65,66]. Although hydropower projects have the greatest impact on the environment among renewable energy sources [67], hydropower projects are the only energy resource that can generate electricity on a large and small scale in various parts of the country and replace fossil fuel consumption in Nepal [7]. In addition, hydropower projects are necessary for national development [65], so their construction is necessary and urgent for countries such as Nepal. To minimize the environmental impact of hydropower projects, environmental studies are conducted before the implementation of the projects; however, these studies are not su cient to analyze the impacts of these projects in Nepal or in other countries [68][69][70][71]. As environmental studies are short-term analytical studies that depend on scienti c evidence and information, a lack of information degrades the quality of environmental studies [32,72]. As managed hydropower project development helps to achieve sustainable development [7,9,44,73] and a signi cant number and capacity of hydropower projects are located in environmentally sensitive areas, it is necessary to conduct further studies to analyze the impact of the projects on terrestrial biodiversity to determine the ways for sustainable development of hydropower projects with minimal compromise on the environmental quality and biodiversity.

Conclusion
Studies in other parts of the world also suggest that a higher number of projects or larger capacity of projects in environmentally sensitive areas have higher adverse impacts in these areas [14,16,18,31,45,52]. The interaction between hydropower project locations and terrestrial environmentally sensitive areas suggests that hydropower project development in Nepal might adversely impact important terrestrial habitats, and the impact might have worsened in the future. It also gives the idea of highly probable affected regions and important terrestrial habitats by providing the relative distribution of hydropower projects and capacity. As the development of hydropower projects in such critical habitats might have severe impacts on terrestrial biodiversity, development should be carefully planned, and policy should be formed to avoid these areas as much as possible. In the case of the development of hydropower projects in PIKs, the appropriate terrestrial biodiversity management plan should be included in environmental studies of hydropower projects and strictly implemented to minimize threats. As the development of hydropower projects is inevitable and necessary in Nepal, research on hydropower projects' impact on terrestrial biodiversity and its mitigation is crucial, along with improving the quality environmental assessment of hydropower projects to minimize such threats.   Koshi Tappu  WR_IKBA  --------21 Koshi Tappu -Buffer Zone  WRBZ_IKBA   --------22  Krishnasar  CA  --------23 Langtang  --------30  Parsa  NP_IKBA  --------31 Parsa -Buffer  Zone  NPBZ_IKBA   --------32  Phulchoki  Mountain  forests  IKBA   --------33  Rampur valley  IKBA  --------34  Rara  NP_IKBA  --------35 Rara -Buffer Zone NPBZ_IKBA  Ecological regions of Nepal and hydropower project distribution Data Sources: www.doed.gov.np, www.maps.tnc.urg/gis_data.html, www.nationalgeoportal.gov.np