Table 2. Fragmentation of the Andean tributaries of the Amazon by existing and proposed hydropower dams.

River network length and longest continuous river reach (km) are based on river lengths in HydroSHEDS (48). For fragmentation metrics, the Mainstem and Tributary Connectivity scores follow the approach of Dynesius and Nilsson (54). The DCI follows Cote et al. (16) and Grill et al. (17), where 100 equals full connectivity.

Basin	River network length (km)	Longest continuous mainstem river reach (km)	Longest reach (km)—existing dams	Longest reach (km) —existing and proposed dams	Mainstem connectivity— existing dams	Mainstem connectivity —existing and proposed dams	DCI— existing dams	DCI—existing and proposed dams
Caquetá	46,871	2216	2216	2216	100.0%	100.0%	100	99.60
Putumayo	21,165	1952	1952	1952	100.0%	100.0%	100	100
Napo	17,999	1108	1108	981	100.0%	88.5%	92.63	82.01
Marañón	61,619	1656	1551	1135	93.7%	68.5%	82.40	28.17
Ucayali	59,747	2463	2376	1879	96.5%	76.3%	79.68	32.65
Madre de Dios	48,324	1417	1417	1346	100.0%	95.0%	97.09	53.49
Beni	20,103	1260	1260	767	100.0%	60.9%	97.18	39.13
Mamoré	42,010	2048	2048	1427	100.0%	69.7%	99.56	61.16