TWIN PILLARS OF STREAM SYSTEM INTEGRITY (GRAPHIC): “There are many factors that influence stream degradation. There is not a single smoking gun. Sure, impervious area is the main culprit. But you can trash a stream just as badly by deforestation of the riparian zone as you can by paving over the headwaters with a mall,” stated Dr. Chris May, a Washington State local government leader
Note to Reader:
Rich Horner and Chris May are the Washington State researchers who correlated changes on the landscape to the consequences for streams. In the mid-1990s, their findings were transformational. Their work shook the foundations of traditional engineering practice. Horner and May provided us with a science-based framework for balancing use and conservation of land.
The Partnership for Water Sustainability in British Columbia calls the Horner and May framework the Roadmap for (Protecting or Restoring) Stream System Integrity. We must stay true to the science if we hope to make a difference. The problem is the gap or disconnect between what communities know what they should do versus what they continue to do. That is an ever-present challenge.
Hydrology is the Engine that Powers Ecological Services
“In November 2015, release of Moving Towards “Sustainable Watershed Systems, through Asset Management” launched an educational process built around the twin pillars concept. Alignment with Asset Management for Sustainable Service Delivery: A BC Framework, released a year earlier through Asset Management BC, is the context for including asset management in the title,” explains Kim Stephens, Partnership Executive Director.
“The educational goal is to encourage local governments to reframe how they look at urbanizing watersheds, and then connect the dots between drainage infrastructure and stream health. What happens on the land does matter to streams. Getting an unfunded liability under control is their incentive for moving from awareness to action.”
What Happens on the Land Does Matter!
“EAP, the Ecological Accounting Process, is the culmination of a 25-year journey. This began with seminal research by Chris May, Richard Horner, and others at the University of Washington in the 1990s.”
“They correlated land use changes with the impacts on stream condition, identified four limiting factors, and ranked them in order of consequence from an ecological perspective. Their work provided us with the Roadmap for Protecting Stream System Integrity. We must stay true to the science if we hope to make a difference.”
“In British Columbia, we built on this science-based understanding with the concept of the twin pillars of stream system integrity. The Water Balance Accounting pillar addresses changes in hydrology on the land draining to the stream. The Ecological Accounting pillar addresses loss of riparian integrity within a stream corridor.”
“Linkage of the two pillars should be the over-arching goal of a Sustainable Funding Plan for the Drainage Service. Because it determines eligibility for senior government grants, alignment with Asset Management for Sustainable Service Delivery: A BC Framework provides local governments with the incentive to go down this path.”
Mimic the natural Water Balance
In the 1990s, Richard Horner and Chris May had a clear message for land use and drainage practitioners: changes in hydrology, not water quality, must be the primary focus of their efforts. If one gets the hydrology right, water quality typically follows takes care of itself in a residential development.
“When we started the research project, one of the hypotheses was that it was all about water quality and that everything bad was the result of bad water quality. But we found that it is the changes in hydrology that rip apart streams,” stated Chris May in an interview.
For two decades, Chris May had a leadership position in Washington State local government – first with the City of Seattle and then with Kitsap County. The latter was his living laboratory. Because he was Director of the Surface & Stormwater Division, Chis May could put science into practice. Chris May retired from local government in 2020.
“We also found that the loss of riparian and watershed land cover has a real impact before water quality does. And you do not see the acute impacts of water quality problems until you get into the higher levels of urban development and impervious area.”
“Salmon that were coming back to restored streams were dying before they spawned. Decades later, that finding led to work on the pre-spawn mortality issue. Now the research shows that it is actually the wear from tires that kills the fish.”
“Unless and until land development practices mimic the natural water balance, communities cannot expect to restore the biological communities within streams. Simply put, hydrology hits first and hardest – one could pour an equivalent volume of distilled water into a stream, and the consequences for stream health would be the same as if it was urban runoff,” Richard Horner reiterated.
EAP is a BC Strategy for Community Investment in Stream Systems
The Synthesis Report is a distillation of over 1000 pages of case study documentation into a storyline that is conversational and written for a continuum of audiences that includes land use practitioners, asset managers, stream stewards, and local government decision-makers.
To Learn More:
Download and read a copy of the entire Synthesis Report on EAP, the Ecological Accounting Process, A B.C. Strategy for Community Investment in Stream Systems (2022), the 4th in the Beyond the Guidebook series of guidance documents.
