Concepts

The River Culture Concept, with its 5 tenets on (i) acknowledging the value of hydrological rhythms, (ii) adapting human use practices to the natural flow regime, by learning from and improving on (iii) traditional ecological knowledge or (iv) biological adaptive strategies (landscape bionics), and (v) considering the hydrographical basin as the basic unit for all territorial and land/water use policies (“bassin de responsabilité”) places the relationships between humans and their einvironment into the foreground, which can be summarised as “learn from the river, live with the river, love the river” (Wantzen et al., 2016).

The changing flow and water level patterns of all natural water bodies on earth represent a strong evolutionary selective driver, a force shaping physical habitats, and a biogeochemical engine. They open windows of opportunity and of susceptibility, and they create a spatiotemporal mosaic of different successional states of ecosystems in river-floodplain ecosystems, allowing the sequential coexistence of different life strategies at the same site. There are no two identical hydrological years following each other, but hydrology follows overarching patterns, allowing a certain predictability and adaptations. The River Culture Concept has widened the scope of the hydrology-organism interactions by integrating the human beings and their cultural adaptations, but also the process of learning from adaptive patterns by non-human species into river management schemes. It also refers to the non-rational human-river relationships such as emotions, spiritual relationships, inspiration by the riverine nature, and physical and mental health, in order to create a "psychology of care" for the river.

Hydronexialism (Wantzen, 2025) is a holistic approach to face the policrisis of sociohydrosystems by combining knowledges and techniques from all adequate scientific and social fields. Scientific disciplines such as hydrology, sociology, ecology etc. are considered as a toolbox providing options for problem-solving. Critically checked (peer reviewed or probabilistic) information from research and practical experienced is combined by teams of nexialists who collaborate to find the most efficient and adaptive solution to a given problem. For example, a dam removal project to restore passability for migratory fish and other ecosystem services, may fail its targets (despite being technically excellent), if it was not supported by the people that are directly concerned by the project (example: interuption of the French dam removal program after protests following the Selune dam removals). Hydronexialists delve into the valuescapes of all concerned stakeholders (human and non-human) and are able to co-develop solutions, communicating them within the team and among the team and the participating parties.

The word GAINARD is an anagramm of the word DRAINAGE and alludes to the verb “to gain”. The inversion of the term “drainage” and its transformation into a “gaining process” in the name is fully intentional.  Its overall idea is to gain water and to redistribute it better, acknowledging (and employing) the natural processes and mechanisms in the water cycle. Being organized along the flow patterns in the landscape, beginning with rainfall, groundwater formation and spring sources, and ending with the confluences of rivers to the sea, GAINARD provides a chain of Nature-based-Solutions employing the principles of Ecohydrology (Zalewski et al. 2002), reinforcing the natural processes (Environmental Flows (Arthington et al. 2018), acknowledging the natural environmental flow regime, and the River Culture Concept (Wantzen et al. 2016), harmonizing humans and rivers by learning processes from nature and traditional ecological knowledge.

Practically speaking, this includes:

• Facilitation of infiltration of rain water into the soils by removing surface sealing
• Removal of drainage pipes and ditches, evtl replacing them by temporary storage wetlands, avoiding artificial retention ponds (“mega-bassines”)
• Increase of the protected, water-“producing” area in the headwaters by replanting natural vegetation in large buffer zones, beginning at the uppermost point of a subcatchment. Tiered protection/use schemes need to be developed and employed for these zones.
• Removal of flow obstacles such as culverts and dams and replacement by low-head sills (??? seuils) that deviate excess flood water into lateral floodplain wetlands. (water sowing)
• Construction of lateral floodplain wetlands with a high natural hydrologial buffer capacity, i.e. absorbing large amounts of floodwater and releasing it during rainless periods.
• Restoration of lateral floodplain wetlands bydike relocation/removal
• De-straightening of rectified stream/river planforms to increase land/water interactions
• Construction of open, “multiple use floodplains” in the rural-urban gradient and in cities. These should be able to absorb and release large amounts of water, and at the same time serve as carbon sinks, water purification units and harbor biodiversity (but be protected against invasive and nuisance species, esp. mosquitoes) by adequate management.
• Replanting riparian woody vegetation to improve shading of rivers and lakes, to reduce heating up of the water
• Creation of hydrological and thermal refuges for heat-sensitive species along the whole river continuum. These refuges need to be conceptualized to avoid predation by native / invasive species and sufficiently long supply of food resources in adequate quantities.
• Development of a decision support system (with adequate criteria) to prioritize entire rivers or long river sections to be restored, avoiding a fragmentation of habitats
• Develop specific education projects on how to deal with water, appreciate the value of water (beyond its market price) and respect and take care of water and aquatic ecosystems and their respective cultural values.