Denver Water: Adapting to Climate Change — a water utility’s approach

March 24, 2015


My new sounds: Jim Lochhead.MP3 — Brent Gardner-Smith on #SoundCloud #ColoradoRiver

March 21, 2015


A tale of two tunnels: How the Moffat Tunnel conquered the divide

February 26, 2015

Originally posted on Mile High Water Talk:

The water tunnel is the pilot bore next to the famous railroad tunnel, pictured here in 1956. The water tunnel runs parallel to the famous railroad tunnel, pictured here in 1956.

A tale of two tunnels: How the Moffat Tunnel conquered the divide 

The Moffat Tunnel changed the way Denver Water provided a reliable water supply to its earliest customers.

By Steve Snyder

This week, 9News and History Colorado provided a historical perspective on the Moffat Tunnel. Eighty-seven years ago, that tunnel changed the way railroad travelers traversed the Continental Divide. But the Moffat Tunnel would provide groundbreaking implications when it came to water delivery as well.

In the early 1920s, the Denver Water Board (as Denver Water was called then) was a fledgling utility searching for additional water to serve a growing city. The water provider had already secured additional water rights from Colorado’s West Slope, but getting that water over the Continental Divide and into existing infrastructure was problematic. Necessity would soon meet innovation.

View original 249 more words


Do you know your snowpack?

February 25, 2015

Originally posted on Mile High Water Talk:

Do you know your snowpack?

9 facts about Colorado snowpack: what it is, why it’s important and how we tell how much of it we have.

By Steve Snyder

You may have seen this map from the Natural Resources Conservation Service of Colorado. It shows how much snowpack we have in Colorado this year compared to normal. But what is normal? For that matter, what is snowpack, and what does it have to do with our water supply? Our Denver Water experts answer these questions and more in the slideshow below:

View original


“Conservation has been successful and will be an integral part of meeting our future water needs” — Jim Lochhead

February 10, 2015
Cheesman Dam spilling June 2014 via Tim O'Hara

Cheesman Dam spilling June 2014 via Tim O’Hara

From The Denver Post (Bruce Finley):

Maybe it is projects such as replacing 10,000 toilets in Denver Public Schools. Maybe it is Denver Water’s ceaseless “Use Only What You Need” campaign. Or maybe residents seeing scarcity are self-motivated. Whatever the reasons, water use in metro Denver has dipped to 40-year lows.

The total amount residents used in December decreased to 3.19 billion gallons, and in January to 3.36 billion gallons — down from previous winter highs topping 4 billion gallons, utility officials said.

The last time December use dropped this low was in 1973 when Denver had 350,000 fewer people.

“Our customers are responding. … Conservation has been successful and will be an integral part of meeting our future water needs — along with reuse and new supply,” Denver Water manager Jim Lochhead said.

The low use this winter continues a trend of declining water use despite a growing population. Denver residents use 82 gallons a day per person for all indoor and outdoor purposes, utility data show. That’s down from 104 gallons in 2001 and puts Denver ahead of other Western cities that are counting on conservation to avoid running dry.

Water supply has become more of a challenge around the West, with population growth and droughts projected to be more frequent and severe. The crisis in California, where mountain snowpack lags at 25 percent of normal, prompted Interior Secretary Sally Jewell to meet with Gov. Jerry Brown last week to hash out relief.

Farmers use the most water, by far, for food production — an 85 percent share in Colorado. Yet it is city dwellers who are making the greatest strides in water conservation.

Denver Water leaders last week declared a new target for 1.3 million customers: 30 gallons a day for indoor use.

The overall water conservation effort relies on a widening strategy: rebates for those who switch to water-saving appliances, tiered water rates that encourage using less, summer lawn-watering restrictions, and a rule that all new development must include soil “amendments” so that soil retains more water.

Water bills still are relatively low. Denver Water charges about $455 a year for households using less than 115,000 gallons, compared with $1,283 in Arapahoe County and $890 in Colorado Springs.

The recent low use likely resulted partly from citywide conservation projects, utility officials said — including the replacement of toilets in 140 public schools with low-flow models designed in Japan.

Denver Public Schools field supervisor Jeff Lane said current toilets use 3.5 gallons per flush while the Toto toilets use 1.25 gallons. That’s expected to save the city 65.9 million gallons a year.

So far, district crews have replaced 3,200 toilets, Lane said this week at Colfax Elementary. The rest should be done by 2018.

Less water coursing through 4-inch iron and clay sewer lines could complicate the effort, Lane said. “It could get caught up.” But Denver Water officials said they’ve investigated and that, as long as lines are in good condition, there shouldn’t be a problem.

Denver Water pays DPS rebates of $90 per toilet. DPS officials said they’ll also sell old brass parts, $2 a pound, to help finance the switch.

The reduced water use also is attributed to Denver Water “messaging” using billboards, television and utility bills. Last month, bills contained blurbs touting the 30-gallon target. “Each person in an average single-family house should use roughly 30 gallons inside per day, or better yet, shoot for less!”

This is “something to aspire to,” Lochhead said.

Water bill blurbs also exhorted residents to “rethink your fixtures,” consult with neighbors because “understanding how others conserve will help you, too,” and replace portions of lawns with low-water shrubs.

A widening awareness of water supply challenges also appeared to be motivating residents to use less. “Whether it is a drought in Colorado or the West,” Lochhead said, “water availability is becoming a more familiar topic for many people.”

More conservation coverage here.


Draining Antero Reservoir: Where will all that water go?

January 7, 2015

Originally posted on Mile High Water Talk:

Crews work on excavating Antero Dam this past October as part of the rehabilitation project that began in 2013.  Crews work on excavating Antero Dam this past October as part of the rehabilitation project that began in 2013.

Draining Antero Reservoir: Where will all that water go?

And 9 more facts about rehabbing Denver Water’s 100-year-old Antero Dam

This summer, Denver Water will empty Antero Reservoir to clear the way for significant repairs to the 100-year-old dam. Draining Antero is a major undertaking; the reservoir holds about 20,000 acre-feet of water, enough to supply approximately 50,000 households for one year in the Denver metro area. And such a project is bound to raise questions about the dam, the water supply and the impact on recreational fishing. Here are the answers to questions we thought Coloradans might ask:

1. So what’s wrong with the dam?

Antero Dam is fully operational, but it’s old. The dam has been in service for 100 years, and this rehab project will help ensure that…

View original 750 more words


Water reuse: “It’s not a question of ‘Can we do it?’ We can do it” — John Rehring #COWaterPlan

November 23, 2014

Reverse Osmosis Water Plant

Reverse Osmosis Water Plant


From The Denver Post (Bruce Finley):

Colorado water providers facing a shortfall…are turning to a long-ignored resource: wastewater.

They’re calculating that, if even the worst sewage could be cleaned to the point it is safe to drink — filtered through super-fine membranes or constructed wetlands, treated with chemicals, zapped with ultraviolet rays — then the state’s dwindling aquifers and rivers could be saved.

Colorado officials at work on the first statewide water plan to sustain population and industrial growth recognize reuse as an option.

“We need to go as far and as fast as we can on water-reuse projects,” Colorado Water Conservation Board director James Eklund said.

But there’s no statewide strategy to do this.

Other drought-prone states, led by Texas, are moving ahead on wastewater conversion to augment drinking-water supplies.

Several obstacles remain: huge costs of cleaning, legal obligations in Colorado to deliver water downstream, disposal of contaminants purged from wastewater, and safety.

Local water plans recently submitted by leaders in five of Colorado’s eight river basins all call for reuse, along with conservation and possibly capturing more snowmelt, to address the projected 2050 shortfall.

Front Range utilities will “push the practical limit” in reusing water, according to the plan for the South Platte River Basin, which includes metro Denver. The Arkansas River Basin plan relies on reuse “to the maximum potential.”

Western Slope authorities in the Gunnison, Yampa and Colorado river basins contend Front Range residents must reuse all available wastewater as a precondition before state officials consider new trans-mountain projects.

The emerging Colorado Water Plan, to be unveiled Dec. 10, remains a general guide, lacking details such as how much water is available. Nor does this 358-page draft plan specify how much of Colorado’s shortfall can be met by reuse.

Water industry leaders urge an aggressive approach. Colorado officials should determine how much water legally can be reused and analyze how this could boost supplies, WateReuse Association director Melissa Meeker said in a letter to the CWCB. Colorado’s strategy “should be crafted to encourage innovation and creativity in planning reuse projects.”

Cleaning up wastewater to the point it can be reused as drinking water long has been technically feasible. Water already is recycled widely in the sense that cities discharge effluent into rivers that becomes the water supply for downriver communities.

Cleaning systems

In 1968, utility operators in Windhoek, Namibia, a desert nation in Africa, began cleaning wastewater and pumping it into a drinking-water system serving 250,000 people.

Denver Water engineers in the 1980s pioneered a multiple-filter cleaning system at a federally funded demonstration plant. From 1985 to 1991, Denver Water used wastewater to produce 1 million gallons a day of drinking water, which proved to be as clean as drinking water delivered today.

Delegations of engineers from Europe and the Soviet Union visited.

“There was a sense we were ahead,” said Myron Nealey, a Denver Water engineer who worked on the project.

But utility leaders scrapped it, partly out of fear that customers would object to drinking water that a few hours earlier might have been flushed from a toilet. They also were struggling to dispose of thousands of gallons a day of purged contaminants — a super-concentrated salty mix that must be injected into deep wells or buried in landfills. [ed. emphasis mine]

So Denver Water has focused instead on recycling wastewater solely for irrigation, power-plant cooling towers and other nonpotable use. An expanding citywide network of separate pipelines distributes this treated wastewater — 30 million gallons a day.

“Reuse is definitely a way to maximize the use of the water we have,” said Jim Lochhead, manager of Denver Water and former natural resources director for the state.

“We’re in the exploration stage of trying to analyze what are the options for various types of reuse,” Lochhead said. “What’s the most effective? What’s the least costly? What’s the most secure?”

Meanwhile, drought and population growth in Texas have spurred construction of water-cleaning plants at Wichita Falls and Big Spring. Engineers have installed water-quality monitoring and testing systems sensitive enough to track the widening array of pathogens, suspended particles and hard-to-remove speciality chemicals found in wastewater.

A Texas state water plan calls for increasing reuse of wastewater eightfold by 2060. The New Mexico town of Cloudcroft is shifting to reuse as a solution to water scarcity. And California cities hurt by and vulnerable to drought, including San Diego, are considering wastewater conversion for drinking water.

Costs can be huge, depending on the level of treatment. Water industry leaders estimate fully converted wastewater costs at least $10,000 per acre-foot (325,851 gallons).

By comparison, increased conservation, or using less water, is seen as the cheapest path to making more water available to prevent shortages. The most costly solution is building new dams, reservoirs and pipelines that siphon more water from rivers.

Colorado also faces legal constraints. The first-come-first-serve system of allocating water rights obligates residents who rely on diverted water from rivers to return that water, partially cleaned, to the rivers to satisfy rights of downriver residents and farmers.

However, much of the Colorado River Basin water diverted through trans-mountain pipelines has been deemed available for reuse. Western Resource Advocates experts estimate more than 280,000 acre-feet may be available. In addition, water pumped from underground aquifers — the savings account that south Denver suburbs have been tapping for decades — is available for reuse.

Indirect reuse

While nobody in Colorado has embarked on direct reuse of treated wastewater, Aurora and other cities have begun a form of indirect reuse that involves filtering partially treated wastewater through river banks. This water then is treated again at Aurora’s state-of-the-art plant. Cleaned wastewater then is blended with water from rivers to augment municipal supplies.

The most delicate challenge has been dealing with safety — making sure engineered water-cleaning systems are good enough to replace nature’s slow-but-sure settling and filtration.

While industry marketers focus on semantics to try to make people feel more comfortable — rejecting phrases such as “toilet to tap” to describe reuse — engineers are honing the systems.

They envision early-detection and shut-off mechanisms that quickly could stop contaminants left in water from reaching people. They aim for filtration and other advanced treatment sufficient to remove the multiplying new contaminants found in urban wastewater. Cleaning water increasingly entails removal of plastic beads used in personal-care products; mutating viruses; resistent bacteria; synthetic chemicals such as herbicides; ibuprofen; birth control; anti-depressants; and caffeine.

“That’s the whole job of treatment and monitoring, to remove pathogens and other contaminants to where it is safe to drink,” said John Rehring of Carollo Engineers, a Denver-based expert on water reuse.

“It’s not a question of ‘Can we do it?’ We can do it,” he said. “And because of growing affordability and public acceptance, we’re starting to see it implemented.”


Follow

Get every new post delivered to your Inbox.

Join 1,151 other followers

%d bloggers like this: