Olympia has always been defined by its relationship to the water. Local waters have shaped our city’s history, culture, and quality of life. One of our greatest potential treasures, however—Moxlie Creek—runs through town buried in a large concrete pipe. By restoring and daylighting Moxlie Creek through downtown Olympia we have an opportunity to bring back a living waterway, benefiting both people and nature.
A healthy stream flowing into Budd Inlet will provide habitat for salmon, birds, and other wildlife. Unlike engineered systems, natural aquatic ecosystems are productive, resilient, and maintenance free. In turn, a beautiful living can attract economic development.
Moxlie Creek begins as a series of springs in Watershed Park. Indian Creek flows a couple of miles from Bigelow Lake through culverts and on the surface, much of it parallel to the Woodland Trail. The two streams combine under the name Moxlie Creek. The stream then flows underground in a concrete culvert through town directly into East Bay where it has a critical impact on what happens there. It’s an underground estuary, which opens up a world of opportunity.
A History of Buried Waterways Across the Country
Moxlie Creek is typical of what happened to streams around the country as cities grew. There are hidden waters under many cities. For example, 66 percent of streams in Baltimore, 85 percent in Detroit, and 73 percent in Philadelphia have been buried. Buried streams are in New York City; Washington D.C.; Oakland, California and Portland, Oregon. These streams were buried to prevent flooding and to make more room for new buildings. But more development and more impervious surfaces prevented water from infiltrating into the ground and channeled more stormwater into the now-buried streams than they could handle. Urban areas that flood today are often where streams have been enclosed and can no longer handle the “rain bombs’ that are becoming more frequent.
Daylighting is Revitalizing Cities
American Rivers has published a white paper about daylighting and provides several case studies where it improved water quality, mitigated flooding and revitalized economies and communities.
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In Napa, California, restoring the Napa River has helped to create $1 billion in investments in hotels, restaurants and commercial spaces.
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Kalamazoo, Michigan uncovered 5 blocks of Arcadia Creek and redeveloped the area with city bonds and private businesses into a thriving area with an amphitheater over the creek that hosts summer events.
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Daylighting Dolph Creek in Portland, Oregon replaced an old nightclub and parking lot with 2 apartment buildings, an affordable senior apartment complex and 14 condos along the creek.
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Closer to home, Thornton Creek in Seattle transformed from a parking lot into an urban park offering wildlife habitat with a creek, trails and surrounding apartments.
Arcadia Creek in Kalamazoo, MI – Before and After (7canyonstrust.org)
Dolph Creek in Portland, OR – Before and After (7canyonstrust.org)
Thornton Creek in Seattle – Before and After (7canyonstrust.org)
What could Moxlie Creek look like if Olympia decided to invest in its downtown?
The Hidden Waters blog offers a fascinating look at the early history and current condition of the creek through maps and photos. Here is a map of its hidden course under city streets.
Here’s an AI generated image of a daylighted Moxlie Creek in a section of Chestnut St where the creek is currently entombed in concrete pipe. The AI image allows us to see one imagined version of a beautiful natural Moxlie Creek that also generates upscale development.
Moxlie Creek – Before and After ???? (hiddenwatersblog.wordpress.com & RLKramer)
The Economic Benefits of a Daylighted Stream for Olympia
Streams have great economic value. Here is another example: the highest rental properties in San Luis Obispo, California—the five star places—back up onto a stream that runs through the center of town. There’s great economic value in natural beauty.
Other cities have proven that daylighting projects revive neighborhoods, attract investment and restore pride of place. Imagine a future downtown Olympia where families can walk along a green corridor, students can learn science outdoors, and visitors can see firsthand how Olympia honors its environment.
Daylighting’s economic impact goes beyond the obvious benefits of an attractive downtown. It also provides “cost effective alternatives to ongoing culvert maintenance and by keeping stormwater out of combined sewer systems, thereby reducing water treatment costs. ” (White paper – Executive Summary)
In Olympia, where sea level rise promises more incidents when stormwater from intense rainstorms will overwhelm LOTT and Olympia’s sewer system, this would be particularly valuable. A daylighted Moxlie Creek would be a one-time cost that would require minimal maintenance compared to the cost of continually having to repair deteriorating culverts and sewer pipes or upgrade LOTT’s capacity.
The Environmental Benefits of a Daylighted Stream
There are other values as well that in some cases represent incalculable potential. The most obvious is the hyporheic zone, the region of sediment and porous space beneath and alongside a stream bed, where there is mixing of shallow groundwater and surface water and a proliferation of biota. In a pipe, there is no hyporheic zone.
With a daylighted Moxlie Creek, Budd Inlet will see an increased abundance of marine species including a wide variety of diving ducks that will utilize the richness of life. Because hyporheic zones are the beginning of the food web, we will ultimately see an increase in other species including flat fish and shell fish that might someday be harvested for food.
Large numbers of salmon used to pass through this section of Moxlie Creek to spawn upstream in what’s now Indian Creek. Amazingly, some still do get through the pipe, albeit in small and arguably unsustainable numbers. Improving passage, water quality and primary production will ultimately result in more fish surviving to spawn. Imagine sitting at a table in a fancy restaurant adjoining a stream eating perfectly seared salmon in a cream sauce, watching salmon swim by.
A Healthy Estuary Generates Many Other Environmental Benefits
In an estuary, fresh water, being lighter than salt water, flows out on the surface drawing salt water in beneath and creates persistent mixing patterns. Nutrients entering the system are consumed by marine plants called algae, especially free-swimming algae called phytoplankton.
When working properly, phytoplankton create not only aquatic dissolved oxygen but at least half of the earth’s atmospheric oxygen. Phytoplankton are also the primary producers, the base of the food web. Virtually all life in the sea depends on phytoplankton.
The natural control on phytoplankton abundance is the grazers or herbivores. These herbivores are mostly tiny crustaceans called copepods. Copepods represent a larger biomass than any other animal. After consuming phytoplankton, they are in turn consumed by everything from herring to whales. Copepods settling to the bottom are the world’s largest carbon sink, remediating about 1/3 of all human contributions to atmospheric carbon!!
A natural estuary is characterized by a long shallow run-out. The tide flowing in and out through a vast network of tide flats and channels twice each day brings herbivores well up into the system where they can control the production of phytoplankton.
Daylighting Moxlie Creek would make all this happen. Keeping it confined to a pipe will prevent it from happening. It’s basic oceanography. Physical parameters shape chemical and biological parameters.
How to Make it Happen
The American Rivers white paper has four recommendations. It asks for more scientific research and comprehensive monitoring to maximize results, a standardized daylighting database, the removal of policy barriers that fail to recognize the full benefits of restoring small streams, and raising awareness to increase community involvement and reconnect people to the waters that sustain us.
At the local level, this article will hopefully encourage readers to envision Moxlie Creek in a renewed downtown Olympia, and to let the City Council know the benefits of daylighting Moxlie Creek. Contact them at citycouncil@ci.olympia.wa.us
Harry Branch is a retired vessel captain who writes about urban estuaries at garden bay blog
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