Editing IPCC:AR6/WGII/Chapter-12 (section)

==== 12.5.3.2 Main Concepts and Approaches ====

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Adaptation in the water sector includes a broad set of responses to improve and transform, for example, water infrastructure, ecosystem functions, institutions, capacity building and knowledge production, habits and culture and local-national policies ( [[IPCC:Wg2:Chapter:Chapter-4#4.6|Section 4.6]] ).

Most adaptive water management approaches in CSA centre around extending the water supply side, including large infrastructure projects. However, ‘hard path’ interventions are now strongly contested because negative effects exacerbate local water conflicts ( [[#Carey--2012|Carey et al., 2012]] ; [[#Boelens--2019|Boelens et al., 2019]] ; [[#Drenkhan--2019|Drenkhan et al., 2019]] ), potentially leading to increasing water demand, vulnerabilities and water shortage risks ( [[#Di%20Baldassarre--2018|Di Baldassarre et al., 2018]] ), thereby limiting adaptive capacity ( ''high confidence'' ) ( [[#Ochoa-Tocachi--2019|Ochoa-Tocachi et al., 2019]] ). More integrated approaches focus on multiple uses of water storage with shared stakeholder vision, responsibilities, rights and costs, as well as risks and benefits, and often integrating water and risk management ( [[#Branche--2017|Branche, 2017]] ; [[#Haeberli--2017|Haeberli et al., 2017]] ; [[#Drenkhan--2019|Drenkhan et al., 2019]] ). In this chapter, a feasibility assessment was carried out for six major dimensions of multi-use water storage for the entire CSA (Table 12.11). While geophysical and economic aspects allow for the implementation of water storage projects under a multi-use approach, the institutional, social and environmental dimensions pose a major barrier ( [[#12.5.3|Section 12.5.3]] ). Further demand-oriented approaches focus on incentives for the reduction of water use through changes in people’s habits, efficiency increase and smart water management ( [[#Gleick--2002|Gleick, 2002]] ). These are promoted in some regions, such as in CA and NWS (e.g., Colombia, Ecuador and Peru), to foster a sustainable water culture ( [[#Bremer--2016|Bremer et al., 2016]] ; [[#Paerregaard--2016|Paerregaard et al., 2016]] ).

Major emphasis has been placed on NbS, that is, catchment interventions that are inspired and supported by nature and leverage natural processes and ecosystem services to contribute to the improved management of water. NbS potentially enhance water infiltration, groundwater recharge and surface storage, contribute to disaster risk reduction and can replace or complement grey (i.e., conventionally built) infrastructure that is often socioenvironmentally contested ( [[#WWAP--2018|WWAP, 2018]] ). Some examples include the reactivation of ancestral infiltration enhancement systems in the Peruvian Andes (NWS) ( [[#Ochoa-Tocachi--2019|Ochoa-Tocachi et al., 2019]] ), the use of erosion control structures in the Bolivian Altiplano (SAM) ( [[#Hartman--2016|Hartman et al., 2016]] ) and the potential improvement of drinking water quality and flood risk reduction in urban areas of CSA ( [[#Tellman--2018|Tellman et al., 2018]] ) ( [[#12.5.5.3.2|Section 12.5.5.3.2]] ). Additionally, NbS in combination with ecosystem and community-based adaptation potentially generate important co-benefits, including increasing water security and the attenuation of social conflicts in Chile (SWS) ( [[#Reid--2018|Reid et al., 2018]] ), water conservation in coastal Peru (NWS) and flood protection in Guyana (NSA) ( ''medium confidence: medium evidence, medium agreement'' ) ( [[#Spencer--2017|Spencer et al., 2017]] ). However, the evaluation of implementation success of NbS is often hampered by limited evidence on actual benefits ( [[#WWAP--2018|WWAP, 2018]] ).

In recent years, the inclusion of IKLK in current adaptation baselines has attracted increasing attention, particularly in regions with a high share of Indigenous Peoples (NWS, SAN, SWS, NSA) ( ''high confidence'' ) ( [[#Reyes-García--2016|Reyes-García et al., 2016]] ; [[#Schoolmeester--2018|Schoolmeester et al., 2018]] ; [[#McDowell--2019|McDowell et al., 2019]] ). One example is the adapted use of agrobiodiversity when dealing with more frequent and intense tidal floods in the Amazon delta (NSA) ( [[#Vogt--2016|Vogt et al., 2016]] ). In another context, IKLK has been considered for the evaluation of water scarcity and GLOF risks in Peru (NWS) ( [[#Motschmann--2020b|Motschmann et al., 2020b]] ). Additionally, local citizen science-based initiatives ( [[#Buytaert--2014|Buytaert et al., 2014]] ; [[#Tellman--2016|Tellman et al., 2016]] ; [[#Njue--2019|Njue et al., 2019]] ) can support the production of multiple forms of knowledge with flexible and extensive data collection. Important questions centre around how to integrate IKLK and other types of knowledge from the early planning stages on, to achieve enhanced or transformational adaptation building on co-produced knowledge ( [[#Kates--2012|Kates et al., 2012]] ; [[#Klenk--2017|Klenk et al., 2017]] ). NbS combined with community engagement and integration of diverse knowledge can foster transformational adaptation of social-ecological systems ( [[#Palomo--2021|Palomo et al., 2021]] ).

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