Downtown Perspective: Deep Dark

Musty smells emanated from dark tunnel in the underbelly of Downtown SLO as a group of SLO City staff and City Council began a tour of “Deep Dark”. Led by our city’s biologist Freddy Otte, the team donned waders and respirator masks as they flicked on flashlights and began the trek up San Luis Creek from Mission Plaza. I was fortunate to be one of the individuals on this journey and after 31 years of wondering what lay beneath our city streets and businesses I found my answer. I had ideas of what we would find on this tour and in some regards my expectations were correct and in others, I was completely surprised. The tour completely changed the way I saw the water flowing through Mission Plaza.

Freddy Otte: City of San Luis Obispo Biologist

Following the tour I needed to sit down with Freddy and his interns Ali Coblentz and Liya Klingenberg to discuss what we witnessed down there. The image of a hypodermic needle spinning in an eddy of water was just too strong for me to be able to walk away from that tour and not have questions of them. For the complete interview listen below as we delve into what life is like as a city biologist and the strategies in place to start cleaning up our watershed.

The day after the tour I witnessed a man letting his daughter play in the water in a swimsuit and two alarms went off for me. First, the water is absolutely not safe for children to be swimming in. Second, that is habitat for endangered steelhead fish populations. When I asked Freddy what can be done to raise awareness and help protect the water, his response was that we need to start talking about the issue of cleaning up our “one water”. Take a listen to the complete interview online and learn more about the one water concept. In short, think twice before touching water that you don’t know is clean and make every effort you can to keep junk out of our water. It is, after all, one of the greatest assets of our beloved Mission Plaza and Downtown SLO.

Quick Facts:

  • Freddy Otte: Freddy is the city’s biologist and at a young age was intrigued by fish and the ecosystem we share with them. Freddy has since made it his life ambition to work to help them thrive in their native waters.
  • Ali Coblentz and Liya Klingenberg: Both are interning with Freddy and are a part of a program known as Civic Spark. In their work with Freddy they are getting real world experience collecting samples, analyzing data and developing strategies to improve the local watershed.
  • The local watershed starts on the western side of the Cuesta grade and extends all the way to Avila Beach, along the way the water collects debris, bacteria and other pollutants that eventually affect the waters of our coast line.
  • As the water enters the tunnel under the city known as Deep Dark, the Total Daily Load for fecal coliform is approximately 200 units (pushing the acceptable TDL guidelines). By the time the water exits the tunnel and flows into Mission Plaza the TDL is 100,000 units. To put this in perspective, the desired concentration of fecal coliform for swimming activity is 200 units or less and the permissible level is less than 1,000. To drink the water there can be no presence of fecal coliform.
  • Sources of contaminants upstream include pigeons nesting in the tunnel and human waste from transients encamped along the stream. (The same humans that are using hypodermic needles to find a high and using the stream as a toilet.)

Graffiti riddles the walls of the tunnel while pigeons, bats and other creepy crawlies move through the darkness.

Occasional glimpses at the world above shine down into the darkness but the overall sense of the tour is of darkness and moving water.












Links to valuable information to continue your study of our stormwater programs.

City of San Luis Obispo:

Regional Quality Control Board:

California Stormwater Program: