The Journey of a Water Droplet

Posted by Nina Lester Finley December 30, 2014

The Journey of a Water Droplet

WOW. My first semester at Whitman is already over. My year began in Brazil and took me all over the place, from Ecuador and Peru to the San Juan Islands and the great state of Idaho. It's hard to believe I started this blog just one year ago!

One of my greatest adventures has been starting at a new school, Whitman College, as a super-sophomore transfer student. In the two-and-a-half years since I graduated from high school I've attended five different colleges! I feel lucky to have finally settled into Walla Walla as my home for the next three years.

Many of my recent blog entries have been based on the weekly excursions I took with my Introduction to Environmental Studies class, which acquainted me with my new surroundings in eastern Washington.

For my last blog of 2014, I would like to take you on a journey of a water droplet, from the headwaters of Mill Creek in the Umatilla National Forest all the way to the Walla Walla sewage treatment plant. After all, there isn't much that is more central to our lives or our connection with place than water.

My Whitman adventure began in the sweltering sunshine of September, during Walla Walla's hottest autumn on record. I knew my Environmental Studies class was going to be a great one when we had to climb over a No Trespassing sign for our hike. (Not to worry, the government official in charge hopped over right next to us.)

As a water droplet, you fall onto the trees of the Umatilla National Forest as rain or snow and trickle your way downhill into Mill Creek. Then you may be siphoned off into the drinking-water pipe at this low diversion dam.

The diversion dam is equipped with a mossy concrete fish ladder for returning steelhead (anadromous rainbow trout) and salmon.

Our professor Bob got up on a stump pedestal to demonstrate the aesthetic value of this native white wildflower with the poetic name, pearly everlasting.

We hiked through lithosol meadows and huckleberry patches on the 36 city-owned square miles of the Mill Creek watershed.

A ranger from the United States Forest Service explained the extreme care taken by the city of Walla Walla to prevent forest fires, from removing fuel (downed wood and dead grass) to thinning out the less fire-resistant tree species.

These fire-resistant tamaracks are allowed to remain in sparse stands that don't touch one another. Walla Walla takes such strict precautions because the ash from a forest fire would be disastrous for the city's unfiltered water supply.

Here's the Environmental Studies gang enjoying a sunshiny meadow at the top of our hike.

I found one small gray bird! Maybe its body contains a droplet of water that will end up in some Whitman student's water bottle next week.

Flash forward a couple weeks and here we are in the Water Treatment Plant. Here's the end of that pipe that began all the way up in the mountains at the Mill Creek diversion dam. Because the altitude drops 300 meters from the dam to the treatment plant, the city is able to produce electricity from a "micro-hydro" operation pictured here.

The water is sterilized with ozone produced from regular oxygen in these machines I call Lightning Tanks. They are possibly the most awesome thing ever.

After treatment the water must pass rigorous tests for low microbial content and low turbidity (cloudiness). Here's a colony of bacteria growing on an agar in the treatment plant's on-site microbiology lab.

We were shivering in 20 degree Fahrenheit weather as we toured the city's reservoirs, water towers, and deep-basalt well.

The rest of our day was spent exploring the portion of Mill Creek which is not diverted for drinking-water treatment. Here, Mill Creek flows through a series of little red homes for elves. (Our professor told us these elf homes are actually debris-capture devices, but you and I know better.)

Mill Creek then reaches another fork in the river. Based on decisions made by the Army Corps of Engineers, water can flow through this concrete gravity dam and through the city of Walla Walla, or it can be diverted to flow into the man-made reservoir (and birding sanctuary) known as Bennington Lake.

Here is Bennington Lake in all its frozen glory. The water level was looking quite low, which is good for flood control but not great for recreational uses like hiking and boating. The water levels aren't always low, though. Our professor told us about a time several years ago when the water rose to within feet of the top of the earth-rock dam from which this photo was taken; the parking lot and bathroom were all submerged!

Walking on that earth-rock dam in the freezing wind was not fun.

The water that isn't diverted to Bennington Lake continues on through downtown Walla Walla in the "concrete box" portion of Mill Creek, pictured here. The channelized creek looks more like a public park wading pool (with a fast current) than a river.

Flash forward again and we arrive here, the Wastewater Treatment Plant. The droplet of water that rained upon the Mill Creek Watershed, produced microhydro electricity, and underwent ozone sterilization has been soiled by the city in any number of ways -- in a toilet bowel, shower or sink, through a human body or that of a cat or dog, perhaps for an experiment in a Whitman College organic chemistry lab. Finally it ends up here, where it goes through settling tanks, microbial digestion, aeration and filtration.

The wastewater is disinfected with UV radiation and chlorine. Depending on the time of year, it's released back into Mill Creek (downstream of the city) or used for irrigation of regional crops. The solid portions of the wastewater, known as biosolids, are used as fertilizer.