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23 July 2009 @ 08:43 pm
Water Bureau Field Day  
A couple of months ago, Kate told me that July 23 would be "a surprise." We got in the car this morning and drove across town to... a big industrial-looking parking lot full of giant trucks and earth-moving machines. "The hell?" I said.

Turns out she'd signed us up for the Portland Water Bureau's annual Field Day. In other words, we went on a field trip. It was fun and we learned a lot about how the water we drink (and use for so many other things) gets from the Bull Run watershed to our tap. If you have the opportunity to go next year, I'd recommend it. It's free.

Me being me, I couldn't help but take extensive notes, which I present for your edification below.

Started off with a talk by the head of the Bureau and the Chief Engineer - we all got bright orange hard hats, reflective vests, and a safety lecture - it felt like Take Your Citizens To Work Day at the Water Bureau

Water is absolutely vital to life but we usually don't see the infrastructure that brings it to us

4 C's of water: Clean, Cold, Constant, and Cheap - taking water from different levels of the dam to select the right temp for people & fish - colder = deeper - they take surface water during the winter to "bank" cold deep water for the summer

Portland's Water Event Station (WES) is a mobile system to provide tap (fire hydrant) rather than bottled water to events like Bridge Pedal

Portland does have a seasonal drought - since June 23 we have been in "drawdown" where we're taking more water from Bull Run reservoirs than is coming in - most years we don't have to use groundwater from the Columbia wellfield to supplement, but sometimes we do - groundwater is also used when heavy rain or other events cause turbidity (dirt in the water) in Bull Run reservoirs

Water conservation: Benson bubblers are on timers and now have flow reducers (40% of previous usage) - most decorative fountains recirculate - these add up to a tiny fraction of 1% of total water usage - Benson bubblers are symbolic of Portland - there are only 2 outside of Portland: Maryhill and Sapporo

Portland's system is completely unfiltered - water doesn't really move very fast in the pipes so what sediment does come in from Bull Run settles in the pipes and must sometimes be flushed out (UDF = Uni-Directional Flush) - system is full of loops, can set valves and flush any given section of pipe with fire hydrant water

Federal LT2 standards against cryptosporidium will require burying/covering reservoirs and (unless we can get a waiver) treating the water with either UV ($90 million) or filtration ($400 million) - chief engineer has a clock on his desk counting down to the LT2 deadline

Bull Run is unique because it has never been logged, inhabited, or used for recreation - only one protected by Presidential Proclamation - New York State has some fine reservoirs but they're surrounded by houses and people water-ski on them

Boarded a bus for our selected tour "Maintenance and Construction" - our tour guide: Kelly Mulholland (!) - no relation to Willam Mulholland of Chinatown fame

There's a lot of standing around a hole waiting for something to happen - "Authentic shovel-leaning experience"

You have to have perfect trust in the backhoe operator - so many ways to die - one of the most dangerous jobs in the city - even dumping the dirt into the truck can be done well or badly

Water hammer is a hazard to big pipes - valves must be opened slowly and in sequence to prevent damage down the line

Ductile iron has some magnesium, will bend a little, vs. cast iron which just cracks if bent

Some cast-iron mains from the early 1900s are in great shape - mains from the 1940s are in worse shape because their iron was made with lower-quality higher-sulfur coal

pH balance: you don't want too much acid because it leaches lead out of brass fittings, but more acid makes the chlorine more effective against microorganisms - it's a tradeoff like so many things - modern brass is made without lead

What's that valve you just took out of the hole? Just a piece of scrap some previous Water Bureau worker threw in the hole as fill, years ago

Former bank being converted to a gym - have to bring everything up to code - old 2" domestic water line being converted to fire service and new 1" domestic line being installed - fire & domestic water used to be separately metered & billed - today there's just a remotely-monitored backflow meter to check that you are not using fire water for domestic purposes - meter is buried in dirt with a "remote-read gun" port (black circular plastic thing with cross) in the sidewalk above it

Paint marks on the street use an agreed color code (blue = water, etc.) - water, sewer, gas, electricity, cable TV, telephone - each utility is responsible for locating (marking) its own lines before anyone starts work, based on records & metal detectors - both can be inaccurate - "Every day with a backhoe downtown is like Christmas - you never know what you'll get" - City to property owner: "Does your basement extend under the sidewalk?" Owner: "No." Backhoe: "Yes."

They take out dirt, send it to the dump, where they pull out the concrete etc. and re-use much of it - they re-fill with gravel rather than dirt because dirt turns into mud - vaults are used (vs. direct burial) to protect electronics or when frequent access is needed - a CV or CIV (small Cast-Iron Valve cover) marks a pipe going down to a buried gate (valve) that is opened/closed with a key (T-shaped wrench)

Many of the other people on the tour are PSU students in the interdisciplanry "Capstone" program - one is a water bureau employee (customer service) who wants to learn about other parts of the department

Uni-Directional Flush: test and close valves to send the flow down the target stretch of pipe to a fire hydrant - onto the street and down the storm drains - a "dechlorinating diffuser" on the hydrant to keep chlorine out of streams, bad for fish - UDF dislodges pebble-sized "rocks" of old sediment - first flush is pretty ugly brown - doesn't generally affect customers except for a loss in pressure, but if there are unknown closed gates (valves) they can cut off water to a block without meaning to - they don't send out letters because they don't know for sure who will be affected - they don't do UDF when we are using groundwater (pumped, therefore expensive) or when it's raining (storm drains already taxed) or freezing

Portland has very low losses (3-4%) - it's a very nice place for pipes, non-acid soil and not much freezing - in some parts of Australia the pipes are buried in sand and they lose up to 17%

Each valve has a "gate card" that says which way to turn it (on/off) and how many turns - before doing a UDF they verify this info for each gate in the area and mark what they've done in chalk on the underside of the CV

Portland's water is entirely gravity-fed from Bull Run except for a few parts of the West Hills - pumping is expensive (other water bureaus spend 20-30% of their budget on energy) - we could get 100% of our water from groundwater but we don't like to because pumping it up is costly

I wonder about people driving by and seeing 20 people in fluorescent vests and hard hats staring into a hole - thinking "must be a big problem" or "what a waste of tax dollars"

Very nice lunch at Sabin Hydro-Park - sandwiches from Grand Central, your tax dollars at work - Hydro-Park is not a water park, it's a community park, playground, and garden on Water Bureau property - there are 7 of them, offering parks to neighborhoods that lacked them - maintenance and liability issues are kind of hairy, the Water Bureau owns the land but isn't really in the park business - 2 water towers here - is the water pumped up into them? Actually no, it's gravity-fed from Bull Run, which is even higher than this hill - these towers store water for the neigborhood and provide backup pressure, also they moderate pressure changes in the main supply - also provide a site for cell antennas and microwave dishes

Cell phones make the water bureau more efficient - crews can now talk to each other and to local businesses directly, rather than going through dispatch - but there's a loss of tracking & accountability

Kind of cool to be driving around Portland in a big tourist bus - can see stuff from up here that's invisible from Corolla level

Watching a live tap into an 8" water main for a new subdivision - big honkin' drill, very slow - drill goes thru a valve - when hole is done, withdraw drill and close valve - cut-out circle is called a "coupon"

The 4 C's are NOT: Cloudy, Crunchy, Colorful, and Coagulated

In addition to coordinating with other utilities and property owners, also have to deal with dept of transportation, Tri-Met, etc for any traffic disruptions

New 4" water main is just a fraction of an inch too long - haul it out of the hole and cut it down - shower of sparks, and smoke coming out the other end of the pipe - cut-off circle is still hot to the touch half an hour later

Doing a live tap avoids disruption for customers and water quality issues (disturbing sediment in the pipes by turning water off and on again)

Putting in a new bioswale near PDX - water mains need to be lowered to go under swale, meters and fire hydrants also need to be moved to new curb line - have to do this work so that road can be re-opened so that traffic can go through here so that another road can be closed - everything depends on everything else

Taking out a fire hydrant attached to a 12" main - very glad to dig down and find a valve, it was just marked on the map as a T - if it had been a T they would have had to shut down the main (supplying a big stretch of Columbia Blvd) - as is they can just close and cap the valve, no shutdown required - don't want to start that work today, though, it would mean the bike path would be torn up on the weekend - nice to see so much consideration for the citizens

 
 
 
Timapparentparadox on July 24th, 2009 04:14 am (UTC)
The 4 C's are NOT: Cloudy, Crunchy, Colorful, and Coagulated

But, maybe C4 is!
(Deleted comment)
Luke McGuffholyoutlaw on July 24th, 2009 06:00 am (UTC)
I'm glad you took extensive notes! This was fascinating.
Allanallanh on July 24th, 2009 02:57 pm (UTC)
Kewl.
joyce scrivnerserendipoz on July 25th, 2009 05:13 am (UTC)
Thanks for the field trip notes!

My father was a civil Engineer, and we lived for four years in Australia while my father was an advisor to the snowny mountains Hydro Scheme. Lots of weekends we'd take off for field trips to look at dam sites (all stages of construction) and power stations and tunnels and such. Your travels reminded me.

Thank you!

Joyce