My Journey to Understanding River Health

Jason Rainey
Wednesday, May 6, 2015
The Yuba River in California where Jason first began his exploration of what makes a healthy river
The Yuba River in California where Jason first began his exploration of what makes a healthy river
Photo by Jason Rainey

Ten years ago, I stood with others in a circle at the South Yuba River, in my home watershed in Northern California. The fragrance of burning sage mixed with the earthy smell of the pine forest, and the soft rhythm of a hand drum could be heard through the steady roar of the river in full winter flow. Led by an elder, we were participating in an age-old indigenous “First Salmon Ceremony” to welcome the annual return of salmon to the river of their birth, to spawn and pass on. The ceremony concluded with the elder raising a small basket of “salmon medicine” and asking the youngest in the circle to step forward. My daughter, not yet a year old and bundled around my chest, was given the honor of sprinkling the medicine into the water, to let the “salmon people” know that the humans were ready for their return from the ocean to give themselves and “heal” the rivers. You see, we were many miles upstream from a dam; the imparted wisdom was that without their native salmon, this river was unhealthy, or more specifically, in need of healing.

That morning began a journey for me to discover new ways of defining, assessing and understanding river health. Influenced by river science, indigenous wisdom, and my own direct experiences with rivers, I offer several perspectives on how to gauge river health.

River health can be impaired by any number of human transgressions or natural phenomena, including industrial and agricultural pollution, land conversion within the watershed (such as deforestation, and urbanization), over-fishing and changes in water flow patterns (water withdrawals, dams and diversions, scheduling river flows according to electricity demands).  The cumulative impact of any one of these environmental insults is daunting. For example, dams and their reservoirs now intercept more than a third of river flows as they head toward the sea, a seven-fold increase since 1950. Dams trap more than 100 billion tons of nutrient-rich sediment that would otherwise have replenished farms, deltas and coastal zones. A number of major rivers are so heavily dammed and diverted that they no longer reach the sea for all or part of the year, including the Colorado, the Indus, the Yellow and the Nile. 

And yet, not every dammed or polluted river is on death’s door. A related truism is that a river need not be “pristine” to be healthy. Even in the most remote and unaltered landscapes and river systems, “pristine” is now an unattainable (atmospheric mercury deposition across the globe, and human-driven climate variability come to mind) and ultimately unhelpful measuring stick. River health should not be viewed as a state to attain, but a dynamic and variable process to allow. Fundamentally, a healthy river is one that has resilience and the ability to self-recover from natural and human-caused disturbances. Thus, an ecologically healthy river will have certain components that allow the river to maintain its functionality, including the following physical elements: 

  • A natural flow, which is the base upon which all other river functions rely. “Natural” flows are, of course, unique to each river, and depend on interactions between climate, topography, geology, vegetation cover, etc. Variability in the quantity, timing and frequency of river flows – over seasons and through years – is natural, and the most crucial element of a healthy river. The plants, fish and wildlife of a river system – which includes its adjacent riparian, floodplain and delta ecosystems – evolved based on natural flow and variability. If that’s lost, the food web unravels and biodiversity can decline.
  • Sediment and nutrient transport (abetted by natural, dynamic flows) are important components of a healthy river, and are responsible for creating floodplains, sandbars and deltas, and nourishing the river channel and life that depends upon it. Excessive erosion is a sign of an unhealthy river that’s out of equilibrium.

Water flow and material transport lead us to another key concept of river health, what river scientists refer to as connectivity. Connectivity moves in all directions: healthy rivers have linear connectivity (in other words, materials flow downstream, fish can migrate upstream), lateral connectivity (high flows allow the river to spread into the floodplains, nourishing lands and recharging water tables) and underground interactions (shallow groundwater filters into the river course, called hyporheic connectivity).

Next time you’re beside a river, try to see these river functions playing out in real time. Allow your imagination to fill in the details not visible to your eye, or not visible in the present moment: the line of woody debris up on the bank might signal the last big flow event; when might that have occurred? Is it obvious to your eyes (and informed imagination) that the components of connectivity and sediment transport have been impaired by upstream “management” of the river flow? Can you diagnosis river health with this view?

The world below

Next, we need to peer below the surface. Even an unhealthy river can cast a lot of misleading beauty. Our eyes take in sunlight reflecting on surface ripples that sparkle like jewels. That seemingly universal beauty has a lot to do with what initially draws us to rivers. But the true composition of the water, and the life and processes under the surface, cannot be ascertained from a view from the riverbank. 

Water quality can be seen through relatively simple tests of pH, nutrient concentrations, dissolved oxygen and total suspended solids, for example, and can reveal a lot about the health of a river, especially when sampled over long periods of time. I worked for a time with a local river advocacy and watershed science organization that now has over 12 years of water quality data (taken monthly, from more than 30 locations along the river), with all of the data collected by volunteers from the community. Beyond the incredible service they provide in guiding actions to improve river health, those people have developed new ways of seeing their river. 

Taking river health assessments a step further, collecting samples of underwater bug life (the jargon is “Benthic Macro Invertebrates,” or BMIs if you’re in deep) can tell stories of river health that range from oxygen levels in the water column (stoneflies, for example need highly oxygenated water) to the rates of water flow changes (caddisflies, which build little shells made of small stones, get stranded and crushed under the weight of their “shells” if water levels drop unnaturally fast). Aquatic insects are excellent indicators of river health, which is why there’s been a growing movement of rapid river assessments anchored by surveying the bug life underwater. And these creatures are fascinating and fun to get to know!  

Beyond serving as indicators, aquatic insects are also a key underpinning of the food web of a river system. Healthy rivers, by definition, support a diversity of productive habitats that in turn support numerous plant and animal species. Riffles, pools, side channels, tributary junctions and root zones of riparian trees – as well as the saline-freshwater mixing zones in estuaries – are all different river habitats, necessary for supporting species diversity and even the different life-phases of a single species. 

Seeing rivers through a different lens

Above all, I’ve come to understand that “healthy rivers” are defined, more than anything, by the degree to which a society is able to “see” them for what they are, and through multiple lenses and perspectives. It takes real attention and time to see even a single river fully; as Heraclitus pointed out about 2,500 years ago, you cannot step twice into the same river. 

Ancient Greek wisdom about change as the one great constant in the cosmos brings me back to the wisdom of the indigenous elders. After that “First Salmon Ceremony,” I accepted an invitation and committed to meeting regularly with members and leaders of the Maidu tribe. In one of the early meetings, their perspective on this subject of healthy rivers was as clearly articulated as it was foreign to my science-trained mind. Referencing this jewel of a Yuba River, distinguished with “Wild & Scenic” designation and adored by half a million visitors a year, they said something like this: 

The river is sick, and it has been a long time. It’s the Salmon People that kept it clean since the beginning – they clean the gravels and they organize the rest of the river community and keep it in balance. And they won’t come back under these conditions, and not just because of that dam downstream. The Salmon People are in council out in the ocean, waiting for an indication that the humans are healed and ready to receive them. You see, we have to heal the human relationships and our relationship to the land and the water. Only then can we heal the waters, call back the salmon and restore the health of the river. The healing action comes when we work together. When we heal each other and the wounds we’ve inflicted in the past, then we will have healthy rivers again.  

Protecting rivers from the wounds inflicted from new dam development requires a much greater literacy and scientific understanding among decision-makers (and first, by the rest of us) of how rivers function, and why that matters for local and planetary ecology and the society we’ve built on the backs of rivers. Tapping into long-held local wisdom, in whatever river basin or region of the world you call home, is a fine starting place for expanding your understanding of “river health” and seeing where those currents take you. 

Ways Forward for River Health

As the current global dam boom progresses, International Rivers is increasingly working to document cumulative impacts of multiple dams, and seeking basin-wide solutions to protect basic functions of rivers. Our broad model of what changes we are pressing for include:

  • The evidence of planetary-scale impacts from river change is strong enough to warrant a major international focus on understanding the thresholds for “river change” in the world’s major basins, and for the planet as a whole system.  
  • In the meantime, dams should become an option of last resort for managing water and generating electricity. Governments and other actors should adopt state-of-the-art river basin planning and integrated resource planning processes and follow highest social and environmental standards for their water and energy sector projects. 
  • No more dams should be built on the mainstream of rivers, which play a crucial role for the sustainability of freshwater ecosystems.
  • Local communities have been the guardians of freshwater ecosystems for generations. Their voices need to be heard and respected in the protection and management of rivers. River basin projects need to be based on demonstrable public acceptance, including the free, prior informed consent of indigenous peoples for projects on their lands.
Jason Rainey recently stepped down as International Rivers’ executive director to move back to his home watershed.