125
the shift is manifested in several recent trends. These trends include creating and
sustaining physical complexity and connectivity within river corridors by deliberately reintroducing large wood (US Bureau of Reclamation 2016) in forested
regions or beaver in the northern hemisphere (Pollock et al. 2015). Another trend in
river management is mandating water quality standards that can maintain aquatic
life as well as provide human drinking water (e.g., US Environmental Protection
Agency, EU Water Framework Directory). A third trend involves removing dams or
modifying dam operations (Bednarek 2001; Grant 2001; Stanley and Doyle 2003;
O’Connor et al. 2015). Creating space for rivers to adjust to changing water and
sediment inputs by setting back or notching levees and altering grade-control structures (Florsheim and Mount 2002; Moritsch 2017; Dutch Room for the River
Programme, www.ruimtevoorderivier.nl) is a fourth trend in river management.
Finally, becoming more conscious of the need to accept and embrace complexity,
connectivity, and change within river corridors is a relatively recent shift in river
management (Ward et al. 2001; Elosegi et al. 2010).
In Asia, Africa, and Latin America, however, enormous numbers of large dams
are rapidly being built or are currently planned for construction. In the Mekong
River basin, for example, seven large dams are under construction and an additional
133 are proposed (Kondolf et al. 2014). In the Amazon River basin, 151 new dams
are proposed for the Andean portion of the western Amazon (Finer and Jenkins
2012). The budgets for large dams tend to be systematically biased below actual
costs (Ansar et al. 2014). Governments and some international aid agencies view
large dams favorably because the dams are believed to provide clean or green energy
with minimal use of fossil fuels and because they are large projects that attract
major funding and investors and can create a sense of national achievement and
pride. In reality, construction of these dams is perpetuating the same devastation
wrecked on river ecosystems in high-income countries during the twentieth century
because the basic designs and operating regimes have varied little with respect to
preserving riverine connectivity or complexity. High-income countries that have
benefited economically from past dam construction can provide the research that
might be used to modify traditional dam design, but such research is not being
widely used. The rapid pace of traditional dam construction is especially disappointing given the numerous alternative means of generating energy, from microhydro power plants (Paish 2002) and within-channel turbines (Vermaak et al. 2014)
to solar, wind, and biofuels. However, if rivers are viewed as simple channels to
convey water downstream, rather than as ecosystems, then it does not matter much
when or how the water is conveyed or whether it flows downstream at all.
Protecting river ecosystems remains a substantial challenge even in high-income
countries with extensive legislation, standards, and programs designed to protect
and restore rivers. An example comes from the increasing use of stream mitigation
banking in the United States. Stream mitigation banking gives developers the option
to offset construction impacts to streams by purchasing credits generated by forprofit companies that restore degraded streams (Lave et al. 2008). This is an unfortunate trend for several reasons. First, the requirements for establishing a stream
mitigation credit market in a given region are not specified. Second, different
4.6 Changing Perceptions of River Health and Naturalness
the shift is manifested in several recent trends. These trends include creating and
sustaining physical complexity and connectivity within river corridors by deliberately reintroducing large wood (US Bureau of Reclamation 2016) in forested
regions or beaver in the northern hemisphere (Pollock et al. 2015). Another trend in
river management is mandating water quality standards that can maintain aquatic
life as well as provide human drinking water (e.g., US Environmental Protection
Agency, EU Water Framework Directory). A third trend involves removing dams or
modifying dam operations (Bednarek 2001; Grant 2001; Stanley and Doyle 2003;
O’Connor et al. 2015). Creating space for rivers to adjust to changing water and
sediment inputs by setting back or notching levees and altering grade-control structures (Florsheim and Mount 2002; Moritsch 2017; Dutch Room for the River
Programme, www.ruimtevoorderivier.nl) is a fourth trend in river management.
Finally, becoming more conscious of the need to accept and embrace complexity,
connectivity, and change within river corridors is a relatively recent shift in river
management (Ward et al. 2001; Elosegi et al. 2010).
In Asia, Africa, and Latin America, however, enormous numbers of large dams
are rapidly being built or are currently planned for construction. In the Mekong
River basin, for example, seven large dams are under construction and an additional
133 are proposed (Kondolf et al. 2014). In the Amazon River basin, 151 new dams
are proposed for the Andean portion of the western Amazon (Finer and Jenkins
2012). The budgets for large dams tend to be systematically biased below actual
costs (Ansar et al. 2014). Governments and some international aid agencies view
large dams favorably because the dams are believed to provide clean or green energy
with minimal use of fossil fuels and because they are large projects that attract
major funding and investors and can create a sense of national achievement and
pride. In reality, construction of these dams is perpetuating the same devastation
wrecked on river ecosystems in high-income countries during the twentieth century
because the basic designs and operating regimes have varied little with respect to
preserving riverine connectivity or complexity. High-income countries that have
benefited economically from past dam construction can provide the research that
might be used to modify traditional dam design, but such research is not being
widely used. The rapid pace of traditional dam construction is especially disappointing given the numerous alternative means of generating energy, from microhydro power plants (Paish 2002) and within-channel turbines (Vermaak et al. 2014)
to solar, wind, and biofuels. However, if rivers are viewed as simple channels to
convey water downstream, rather than as ecosystems, then it does not matter much
when or how the water is conveyed or whether it flows downstream at all.
Protecting river ecosystems remains a substantial challenge even in high-income
countries with extensive legislation, standards, and programs designed to protect
and restore rivers. An example comes from the increasing use of stream mitigation
banking in the United States. Stream mitigation banking gives developers the option
to offset construction impacts to streams by purchasing credits generated by forprofit companies that restore degraded streams (Lave et al. 2008). This is an unfortunate trend for several reasons. First, the requirements for establishing a stream
mitigation credit market in a given region are not specified. Second, different
4.6 Changing Perceptions of River Health and Naturalness