Perspectives on River Restoration

posted by Guest Blogger on Monday, October 10, 2022

Will Gaskin, Water Resources Designer with RDG Planning & Design

instruction time at stream

As a Water Resources Designer with RDG Planning & Design, I work on a variety of projects related to our surface waters. My work really boils down to infrastructure that protects Iowa waterways from further harm or improves their existing condition, with the occasional building saved or community amenity added as a bonus.  

work crew

Part of why I enjoy working in this field is the unique circumstances related to every project. The River Restoration Toolbox Training offered through Iowa Rivers Revival outlines foundational processes in riverine systems, guiding principles for design, and common engineering solutions to create some consistency in the field of river engineering. It was also a great opportunity to share experiences among practitioners and develop our working vocabulary to better communicate with contractors and clients. Questions from class participants led to thoughtful discussion among the whole group. I participated in both Level 1 and 2 courses this year. The breadth of knowledge that Nate Hoogeveen and George Athanasakes, the class instructors, shared was immense. What a pleasure it is to be in a room filled with river people. 

stream bankRDG is currently leading a major stream restoration project in Ankeny, which will require us to fully redesign over a mile of degrading stream. The ability to utilize the principles of Natural Channel Design and the Iowa DNR Restoration Toolbox is critical for our design to rely on stream geometry and pattern rather than excessive armoring. The days of dumping riprap into our streams should be behind us. The more engineers we can get in the River Restoration Toolbox Training, the more attractive, accessible, and healthy our streams will be.  

crew at stream

team at stream

more work at stream

Rai Tokuhisa, Water Resources Engineer for the City of Clive

Rai Tokuhisa working on a stream bank

Welcome to Friday morning! It’s the first day after my Level 2 Training in the Iowa DNR’s River Restoration Toolbox. The air is brisk—downright cold, if I’m honest. I’m hesitant to admit that I’ve completely lost my cold tolerance, but my fears are assuaged when I get to the site. I just spent four days learning RiverMorph enchantments from Nate and George, and I’m about to learn construction tips from Nick. I’m relieved to note that they’re all in fleece and flannel, too (so I feel like less of a weenie). 

The site is a swath of park nestled in a residential section of Clive, Iowa. We are in Phase 2 of construction; the upper reach of the stream has already been raised and underpinned with rock riffles and toe-wood. Folks from Clive Public Works–the finest operations crew in the whole metro area–are scattered about. They’re getting ready to clear the stations they’ll be working on today while Nate, George, Nick, and I review cross-sections of interest. The cross-sections are slices of the intended design, plotted against a survey from the current buildout. They help the team compare how our current work matches up with the conveyance needs for the channel. I scribble this communication tip down for future reference: 


Cross-sections are also one of the views my brain has been chewing on for the last couple of days in Toolbox training. My recent ‘coursework’ gave me a taste of the iterative process between sediment transport requirements and the stream power provided by the design channel. In class, we measured our existing stream and sediment moving through it. Then, we used a bunch of math to figure out a more stable configuration to pass the same flows and particles. In the real world, we’d move design from the model to paper and then we’d get to bust out our Tonka trucks and make it real…  

I come back to the present moment, where Nick is telling me about the tolerances on these structures. He says we need to be within a tenth of a foot in the vertical on the placement of each half-ton boulder. It’s a funny juxtaposition going from classroom language of ‘shear stress’ and ‘hydraulic capacity’ to the construction site, where it becomes ‘how to pin logs in place with big rocks to keep the water where we want it’. I sketch a note about methods for locking the wood in a log-and-rock riffle, pretending that the cold shiver in my hands is adding to the artistry.  


The project will open up the views to the water’s edge and give the channel the profile and pattern she hydraulically demands. She’s a flashy thing—the product of a watershed that’s predominantly impervious. Her volatile nature is a hallmark of intense upstream development. Fickle creatures like her are half the reason I’m here. The other half is for the people (present and future). My Toolbox training experience marries the two.  

The lecture slides are available publicly, so it’s less about performing the calculations and more about unpacking my experience of the stream from the tidy box of idealized equations. Toolbox training is like learning to cast a new spell—the fundamental magic of fluid mechanics takes on a different life when you pull it out of the test flume and get it onto the ground. Today that unpacking looks like: How does the stream ‘prove’ to me that she’s still constricted? What are the ways we lose cross-sectional area during construction and how do we adjust for it? 

Stream restoration certainly isn’t nascent in Iowa, but Iowa is still building its repertoire of practices and skilled contractors. Since we’re still learning, I value my time with Nate and George. I also appreciate the depth of conversation and case studies that come up when you put a bunch of stream nerds in a room for four days. Learning like this keeps me fluent in the language of wizards.  

A single municipal employee doesn’t get to cast spells on their own. Instead, I get to revel in the magic that is caring for our waterways in concert on these cold, October mornings.  

Rai Tokuhisa

Rai Tokuhisa is the water resources engineer for the city of Clive, Iowa. Rai’s roots are in the Southern Iowa Drift Plain. After a sabbatical to the youngest land on earth (Hawai’i), they are excited to learn all of the fun things that happen in the Des Moines lobe. Rai likes the weather, dogs, textiles, food sovereignty, gender-neutral pronouns, and all the ways they can mālama ka ‘aina.  

Rai needs you to know that that Iowa Rivers Revival is hosting contractor training for streambank stabilization methods on November 4, 2022.

Will Gaskins As RDG's Water Resources Designer, Will Gaskins enriches communities through stormwater enhancements, flood reduction, water quality improvements and the planning and design of recreational areas. Working alongside a diverse group of experienced design professionals, Will focuses on a variety of project types, contributing to work that enhances communities across the country. (Updated: A former version of this article stated Will Gaskins as a Water Resources Engineer)  

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