Table 1.

Impacts of hydropower dam construction illustrated by average changed values of five indices of the buffer zones for different global regions

Region	Global		Africa		Asia		Europe		North America		South America
△GDP (Million dollars)
Zone 1 (<5 km)	−6,021,947	−19%	19,063,010	78%	−10,991,470	−28%	48,748,587	303%	37,872,421	659%	−18,183,144	−53%
Zone 2 (5 to 20 km)	−8,731,524	−27%	5,705,802	23%	−9,250,586	−24%	12,032,548	75%	30,547,340	532%	−18,622,539	−54%
Zone 3 (20 to 50 km)	−7,381,805	−23%	−7,673,398	−31%	−9,356,665	−24%	8,488,121	53%	15,990,569	278%	−12,002,126	−35%
NAHD (0 to 50 km)	−7,570,664	−23%	−5,399,154	−22%	−9,357,101	−24%	9,422,390	59%	18,392,903	320%	−13,056,998	−38%
Reference Zone (50 to 60 km)	32,326,438		24,433,029		38,767,215		16,102,404		5,746,072		34,614,073
△Urban (km2)
Zone 1 (<5 km)	−2.52 ×10−08	−49%	−3.78 × 10−08	−64%	−4.38 × 10−08	−52%	3.12 × 10−08	941%	4.96 × 10−08	87%	−3.06 × 10−08	−97%
Zone 2 (5 to 20 km)	−2.05 × 10−08	−40%	1.17 × 10−08	20%	−3.16 × 10−08	−38%	1.55 × 10−08	467%	1.97 × 10−08	35%	−2.54 × 10−08	−80%
Zone 3 (20 to 50 km)	−1.68 × 10−08	−33%	−2.83 × 10−08	−48%	−1.69 × 10−08	−20%	1.55 × 10−08	468%	9.15 × 10−09	16%	−2.49 × 10−08	−79%
NAHD (0 to 50 km)	−1.74 × 10−08	−34%	−2.24 × 10−08	−38%	−1.94 × 10−08	−23%	1.57 × 10−08	472%	1.11 × 10−08	20%	−2.50 × 10−08	−79%
Reference Zone (50 to 60km)	5.14 × 10−08		5.93 × 10−08		8.34 × 10−08		3.32 × 10−09		5.68 × 10−08		3.17 × 10−08
△NTL (DN)
Zone 1 (<5 km)	1.0	54%	1.3	65%	0.6	26%	0.5	61%	−0.4	−47%	1.6	87%
Zone 2 (5 to 20 km)	0.2	9%	0.1	4%	−0.2	−8%	0.4	45%	−0.5	−58%	0.5	28%
Zone 3 (20 to 50 km)	0.1	7%	−0.1	−3%	−0.2	−10%	0.4	51%	−0.2	−20%	0.5	24%
NAHD (0 to 50 km)	0.2	8%	0.0	−1%	−0.2	−10%	0.4	50%	−0.2	−26%	0.5	26%
Reference Zone (50 to 60 km)	1.9		2.0		2.4		0.9		0.9		1.9
△Pop (Person/km2)
Zone 1 (<5 km)	−2.4	−16%	27.5	49%	−3.2	−15%	−5.2	−210%	4.1	32%	−4.1	−43%
Zone 2 (5 to 20 km)	−5.2	−35%	4.1	7%	−5.8	−27%	0.5	21%	2.3	18%	−7.4	−77%
Zone 3 (20 to 50 km)	−6.9	−46%	−25.2	−45%	−9.0	−42%	1.9	77%	−2.5	−19%	−6.2	−65%
NAHD (0 to 50 km)	−6.6	−45%	−20.3	−36%	−8.5	−40%	1.6	66%	−1.7	−13%	−6.4	−66%
Reference Zone (50 to 60 km)	14.8		56.1		21.4		2.5		13.1		9.6
△NDVI (index number)
Zone 1 (<5 km)	−0.004	−34%	−0.003	−53%	−0.005	−35%	−0.006	−47%	−0.002	−11%	−0.004	−38%
Zone 2 (5 to 20 km)	−0.002	−15%	−0.004	−73%	−0.003	−26%	−0.003	−22%	0.001	4%	−0.001	−9%
Zone 3 (20 to 50 km)	−0.001	−4%	−0.002	−35%	−0.001	−8%	−0.001	−9%	0.000	−1%	0.000	0%
NAHD (0 to 50 km)	−0.001	−6%	−0.002	−40%	−0.001	−11%	−0.002	−12%	0.000	0%	0.000	−1%
Reference Zone (50 to 60 km)	0.013		0.005		0.013		0.014		0.021		0.011

Note that the table indicates the average changed values of five indices in different sizes of buffer zones (Zones 1 through 3) in NAHDs and a reference zone in five global regions. It also shows their relative proportions to the changes in the respective reference zones. Globally, these recently constructed dams were linked with reduced economic production, population, and greenness of areas within 50 km of the dams. While recently constructed dams were associated with increased GDP in North America and urban areas in Europe, they were related with decreased economy (reflected by GDP and urban land) and population for the Global South (Africa, Asia, and South America) and greenness for Africa. Furthermore, as distance increases from the construction site to 50 km (from Zone 1 to Zones 2 and 3), while population decreased more, NTL increased less and urban land and greenness decreased less, with GDP declining the most in the area of 5- to 20-km distance to the construction site.