"Engineering Wetlands and Rivers for Climate Resiliency" - An Interview with Rachel Kamman of Kamman Hydrology and Engineering

"Engineering Wetlands and Rivers for Climate Resiliency" - An Interview with Rachel Kamman of Kamman Hydrology and Engineering

By En-Ya Zhang (MSS Intern, Terra Linda High School)

Rachel Kamman is a hydrologist whose specializes in hydraulic and hydrodynamic analysis. Her consulting practice, Kamman Hydrology and Engineering, is based in San Rafael, and focuses on the protection and restoration of wetlands and estuaries. Her talk, "Engineering Wetlands and Rivers for Climate Resiliency," was February 5, 2020, in Room 207, at Terra Linda High School. (320 Nova Albion Way)


1. What inspired you to start looking into rivers and wetlands and how they can be engineered to become more climate resilient?

The focus of my work is on river and wetland restoration, which requires planning and design for the future. Climate change became a part of our vision for the future.
Initially the goal was to provide protections for natural resources. Now we recognize that both our communities and our natural resources will need to adapt to survive in the changing world.     

2. What kind of projects does Kamman Hydrology and Engineering take on? Do you mainly focus on wetlands and rivers surrounding the Bay Area?

I no longer work through Kamman Hydrology & Engineering, I am now an independent consultant. 
My work continues to focus on large scale ecological restoration projects.
I work throughout the state, though most of my work is on coastal river, estuary and beach systems.   

3. What do you believe is the most difficult aspect of engineering bodies of water so that they will be able to adapt more easily to climate change?

The most difficult aspect of engineering for climate change is securing the space in the landscape needed for adaption.  
Humans and our communities have gotten accustomed to living where we choose on the lands, and engineering the conditions to support their needs.  We have drained, leveed and filled lands to accommodate housing.    
Landscapes, and their ecological communities, adapt to climate changes by moving spatially (up and down hill, and expanding and contracting laterally). 
For natural systems to adapt to climate change, communities must provide that space. This giving up of developed lands is the most difficult aspect of engineering for climate change.  The difficulty lies more in community planning than in engineering design.    

4. Does engineering these ecosystems have any negative effects on the species inhabiting them? If so, what measures can be taken in order to prevent these drawbacks?

Any human disturbance to lands can have adverse impacts on resident species.  To protect resident wildlife, and optimize design to provide a high level of ecological services, I always have biologists and ecologists working with me as an integrated part of the design team.   

In addition, we time our work to minimize impacts to breeding and use, we carefully clear wildlife from the area prior to work, monitor for wildlife during work and often restore and protect sites nearby in advance of our work to mitigate for the disturbance and loss of habitat during construction.  These mitigation measures are required by state and federal water, fish and wildlife protection laws.  Regulators, representatives from these agencies, advise on and review designs in an effort to maintain these protections.   

5. In general, what do you think is the most effective approach to engineering rivers and wetlands so that they have higher resistance to climate change?

I believe the most effective approach is to step back from the edges of these systems, and restore their capacity for natural adaption to climate change.  This means removing community infrastructure, and restoring floodplains along river banks, and low lying coastal shorelines to provide the space needed for landscape climate adaption.  This increases the resilience of both communities and natural systems to climate change.  Land is needed for climate adaption.  
This has a dual benefit which is also necessary for successful climate adaption.  Wetlands have a capacity for carbon storage comparable to rain forests.    

6. What do you think is currently the biggest threat to local reservoirs?

The biggest threats to local reservoirs in Marin County are groundwater withdrawals and fire.  
Environmental protection regulations require maintenance of minimum flows to sustain fish populations is our creeks.  The more private well owners withdraw water, the more water must be released from reservoirs to sustain minimum flows.  This reduces the volume of water available for public distribution.   Fire in watersheds supporting reservoirs is a threat because following a burn fine sediments are easily mobilized into the system which adversely impact water quality.