As gov­ern­ments and non-state actors strive to min­i­mize glob­al warm­ing, a pri­ma­ry strat­e­gy is the decar­boniza­tion of pow­er sys­tems which will require a mas­sive increase in renew­able elec­tric­i­ty gen­er­a­tion. Lead­ing ener­gy agen­cies fore­cast a dou­bling of glob­al hydropow­er capac­i­ty as part of that nec­es­sary expan­sion of renew­ables. While hydropow­er pro­vides gen­er­al­ly low-car­bon gen­er­a­tion and can inte­grate vari­able renew­ables, such as wind and solar, into elec­tri­cal grids, hydropow­er dams are one of the pri­ma­ry rea­sons that only one-third of the world’s major rivers remain free-flow­ing. This loss of free-flow­ing rivers has con­tributed to dra­mat­ic declines of migra­to­ry fish and sed­i­ment deliv­ery to agri­cul­tur­al­ly pro­duc­tive deltas. Fur­ther, the reser­voirs behind dams have dis­placed tens of mil­lions of peo­ple. Thus, hydropow­er chal­lenges the world’s efforts to meet cli­mate tar­gets while simul­ta­ne­ous­ly achiev­ing oth­er Sus­tain­able Devel­op­ment Goals. In this paper, we explore strate­gies to achieve the need­ed renew­able ener­gy expan­sion while sus­tain­ing the diverse social and envi­ron­men­tal ben­e­fits of rivers. These strate­gies can be imple­ment­ed at scales rang­ing from the indi­vid­ual project (envi­ron­men­tal flows, fish pas­sage and oth­er site-lev­el mit­i­ga­tion) to hydropow­er cas­cades to riv­er basins and region­al elec­tri­cal pow­er sys­tems. While we review evi­dence that project-lev­el man­age­ment and mit­i­ga­tion can reduce envi­ron­men­tal and social costs, we posit that the most effec­tive scale for find­ing bal­anced solu­tions occurs at the scale of pow­er sys­tems. We fur­ther hypoth­e­size that the pur­suit of solu­tions at the sys­tem scale can also pro­vide ben­e­fits for investors, devel­op­ers and gov­ern­ments; evi­dence of ben­e­fits to these actors will be nec­es­sary for achiev­ing broad uptake of the approach­es described in this paper. We test this hypoth­e­sis through cas­es from Chile and Ugan­da that demon­strate the poten­tial for sys­tem-scale pow­er plan­ning to allow coun­tries to meet low-car­bon ener­gy tar­gets with pow­er sys­tems that avoid damming high pri­or­i­ty rivers (e.g., those that would cause con­flicts with oth­er social and envi­ron­men­tal ben­e­fits) for a sim­i­lar sys­tem cost as sta­tus quo approach­es. We also show that, through reduc­tion of risk and poten­tial con­flict, strate­gic plan­ning of hydropow­er site selec­tion can improve finan­cial per­for­mance for investors and devel­op­ers, with a case study from Colombia.