Denver Water Research Articles

Denver Water Celebrates New Northwater Treatment Plant

Denver Water Celebrates New Northwater Treatment Plant

The impact of urban tree shade on residential irrigation demand in a semi-arid Western U.S. City

This research examines how shade offsets residential landscape irrigation demand in a semi-arid city in the western United States. Using over 40,000 customer records from Denver Water, the relationship between residential irrigation and quantities of turf, tree canopy, and shade was studied, controlling for other factors related to the vegetation, parcel, and residence. LiDAR and imagery were used to model turf and tree canopy area and daily hours of shade falling on turf. Simultaneous Autoregression determined that each additional hour of daily building and tree shade falling on turf was associated with 18,672 and 11,683 fewer liters of irrigation per growing season, respectively, for the average parcel (turf area = 476 m2), equating to reductions of 39.2 and 24.5 liters per m2 per growing season for a single hour of shade. These numbers, incorporating spatial spillovers, suggest that for landscapes with both trees and turf—the dominant pattern in many Western US cities— mature trees could potentially be arranged to produce enough shade to reduce water demand of underlying turf by an amount equal to, or even greater than, the trees' irrigation demand. This benefit was not found for shorter and younger trees, which have higher irrigation rates per unit area.

Futuristic Water Lab Enhances Colorado Educational Hub

Denver Water's water quality laboratory is part of an innovative, forward‐thinking learning center created by Colorado State University (CSU). Students of all ages visiting the center will experience a range of scientific disciplines in action.

Autonomy Is Key to Revitalizing Water Utilities

Allentown, Pa.; Bayonne, N.J.; Flint, Mich.; Newark, N.J.; and Jackson, Miss., are a few of the communities that have had serious water issues involving an underfunded utility in need of critical intervention. That intervention came, and it arrived in a variety of forms. In Allentown a public–public arrangement with the independent authority, Lehigh County Authority, turned things around. In Bayonne a public–private partnership sparked a recovery. Flint, Newark, and Jackson required massive infusions of public dollars and outside management to address the emergencies in the short term. In these and other communities, revenues have been diverted to other municipal needs, or rates have been held artificially low for years because of political resistance or interference. The common denominator for failing or distressed utilities is being embedded in municipal government and managed by elected political officials—mayors, city councils, and boards—who view water rate increases as taxes and thus a political “root canal.” Because charging more for service is not generally popular, political leaders have every incentive to defer or oppose rate increases until they leave office. Embedded utilities are not permitted to operate as independent enterprises, so they are not always able to make financial decisions that are based on public health and business or infrastructure needs. This has meant that many American communities have not adequately invested in infrastructure. AWWA's 2012 report, Buried No Longer, estimated the investment gap or needs at a trillion dollars. The US Environmental Protection Agency estimates that cost to be just under half a trillion dollars. This is a case of government failure—local government, primarily. Recently, I spoke to a utility manager in the capital of a midwestern state who told me they have not had a rate increase in 11 years. At 2%, 3%, or 4% annual inflation rates, the financial hole gets deep very fast. When I asked why, he responded, “The mayor does not support rate increases.” Politically depressed water rates and revenue stifle capital planning and development. Meanwhile, water infrastructure continues to slowly degrade. Seth Siegel, in his critique of the drinking water sector, Troubled Water: What's Wrong With What We Drink, argued to “keep mayors away from water.” Siegel explained that “to improve decision-making, the counterproductive connection between water utilities and municipal government needs to be decoupled.” Political mismanagement and neglect may be the unified field theory of public utility failure, and it deserves serious research. Indeed, a 2019 study in AWWA Water Science by Jennifer Biddle and Karen Baehler found that “autonomy matters” (https://doi.org/10.1002/aws2.1140). This quantitative study focused on 22 US managers from water utilities across the country. The researchers found that there was an overarching sentiment that utility performance improved with insulation from political interference, and utilities with organizational autonomy possess greater decision-making power and flexibility in spending. Removed from direct municipal control and political influence, independent water utilities may focus intently on water service delivery. According to one mid-Atlantic participant in the study, “The city was always very, very reluctant to spend money on infrastructure replacement, renewal upgrades, you name it. They didn't want to want to raise the rate.” There are alternative models of governance. Louisville Water is a separate corporation owned by the city, which preserves independence and pays dividends to the municipality. In addition to Lehigh County Authority mentioned earlier, Denver Water is a fine utility and part of an independent authority from the city. Washington, D.C., (DC Water) has improved immensely since becoming a separate authority. Massachusetts General Law (Part I, Title VII, 40N, Section 1) provides for the adoption by towns of an independent political subdivision to operate water and sewer systems modeled after Boston's Enabling Act of 1977. Another model to consider is the investor-owned utility regulated by a public utility commission. Seth Siegel points out, “De-linking water utilities from mayoral politics, though, need not lead to unaccountability.” Local officials can appoint board members or commissioners of these independent authorities, ideally for fixed terms, ensuring autonomy to provide effective management of the assets entrusted to them. Not all embedded utilities fail, but most failed utilities are embedded in municipal government. Autonomous utility governance is the key to a revitalization of the water sector. Author's note: The views expressed herein are entirely the author's and not those of AWWA. G. Tracy Mehan III is executive director of government affairs in AWWA's Washington, D.C., office; [email protected].

The influence of precipitation on the energy footprint of Denver's water supply: A 20-year analysis and implications for climate change

Denver Water serves 1.5 million people in the metropolitan area of Denver, Colorado, USA. Relying on runoff from mountain watersheds, its water supply is obviously sensitive to precipitation, but so is its energy footprint. We analyzed Denver Water's annual energy use and water use alongside local precipitation over a 20-year period from 1995 to 2014. Energy use generally trended opposite to precipitation: In dry years the system used more energy than in wet years, even when the energy use was normalized by water volume. The data suggest that the system needs to compensate for less precipitation by expending more energy, presumably by supplying water from more distant or more energy-intensive water sources. A regression model indicates that a 1 cm decrease in annual precipitation equates to 275,000 kWh of additional energy use and that typical interannual variability in precipitation accounts for 11% of Denver Water's energy footprint. The analysis highlights implications for altered energy footprints as water utilities respond to new precipitation patterns in a changing climate.

Denver Water Ensures a Sustainable Future With Its Northwater Treatment Plant

Key TakeawaysDenver Water's project to upgrade part of its water system involves building a new treatment plant, installing new pipeline, and redeveloping the existing treatment plant.Good stewardship through commitment to protecting the environment, serving current and future populations, and exercising fiscal responsibility is woven into the Northwater Treatment Plant project.The Envision sustainability assessment framework, along with pursuit of the Envision Gold Award, has helped Denver Water achieve its project objectives.

Comparison of coupon and pipe rack studies for selecting corrosion control treatment

AbstractThis study directly compared the data obtained from coupon studies and flow‐through pipe rack studies from two sources in the Denver Water system. The pipe rack study was completed over multiple years using harvested lead service lines. The coupon studies were completed in about 2 months using pure lead coupons. Orthophosphate at 2 mg/L was found to reduce lead concentrations by about 81% in the pipe racks, whereas 74%–81% was observed in the coupons. At an orthophosphate dose of 1 mg/L lead concentrations were reduced by 62%–65% in the pipe loop and by 55%–75% in the coupons, pH at 8.8 reduced lead by 45%–60% in the pipe racks and by 27%–48% in the coupons. The pipe racks were able to give insights into the transition from one condition to another, which is time‐based and dependent on existing pipe scales. Both types of demonstration studies produced similar conclusions about treatment options. The pipe rack was more representative of conditions in the distribution system while the coupon studies were performed in a fraction of the time.

Building Type, Housing Density, and Water Use: Denver Water Data and Agent‐Based Simulations

AbstractThis study examined simulated changes in total (and outdoor) water demand with increased dwelling units per unit area (DUUA) for seven building types (BTs) in the Denver Water service area. We utilized the Denver Water Demand Model — a spreadsheet tool that uses inputs such as BT, population, household size, number of units, etc. — to develop an “agent‐based” simulator to permit scenario analyses of future water use for different mixes of BTs. We examined household “movement” for new residents from lower density to higher density classifications. Increased residential density can be achieved through multiple pathways. For instance, a family could move from a large single‐family (LSF) unit to a single‐family home with a smaller lot footprint (SSF). Or, a family could move into a multi‐family housing development from a SSF. Our results suggest uneven, nonlinear efficiency gains in water use with increased density, depending on the specific BT movements. Simulation outputs indicate that the greatest gains in water savings per unit change in DUUA can be achieved with short movements over the lowest density classes (e.g., LSF to a SSF). In addition, results suggest that increasing irrigation efficiency (less water applied per unit area irrigated) may decrease total residential water demand by 5% to 25% over baseline; efficiency of irrigation may prove to be as effective, if not more, at reducing residential water demand as increasing housing density.

From Domination of the Environment to Stewardship: A Historical Look at Denver Water's Public Communication 1933–2018

When most people think about the water coming from their kitchen faucets, they seldom consider where the water originates and how transporting it to their homes has environmental impacts. Utilities that supply water know the complexity of their systems, but from their position as a “utility,” they view their job as supplying safe water to their customers, not necessarily stewarding the environment. Consequently, when building large projects like dams, canals, and tunnels, utilities regard environmental disruption as a necessary byproduct of serving growing cities with water. Representations of these projects often replicate the “man conquering nature” frame, praising these engineering marvels for their defiance of nature. Denver Water, the utility that serves almost 1.5 million people on the arid eastern slope of the Colorado Rockies, has produced films describing its complex system since the early 20th century, and these films reveal an evolution of values from dominating nature to actively stewarding the environment. This paper reports on a grounded theory analysis of films produced by Denver Water between 1933 and 2018 examining how the films frame human relationships to the natural environment. The results reveal that the films increasingly express stewardship ideals over those of domination, with recent public communication actively advocating for environmental causes. The paper concludes by suggesting that we can learn important lessons from Denver Water about ethical organizational action for environmental stewardship.

Denver Water and the Lean Methodology: Enhancing Stakeholder Input for Major Infrastructure Design

Key TakeawaysSo that employees are empowered to assess workplace issues and implement a continuous‐improvement framework, Denver Water adopted the Lean methodology in 2011.With its goal of renewing or replacing aging infrastructure, Denver Water designed Northwater Treatment Plant as a key element in its North System Renewal Program.Denver Water held Lean‐supported workshops to glean input from its key stakeholders, including several of its operational departments.Lean workshops led to rightsizing of treatment plant capacity and multiple improvements in operational and management strategies for enhanced system resilience.

Canada Days

It has been 152 years since Canada took its first step toward independence from England and 37 years since it achieved full independence. Canada Day, which is July 1 each year, marks the day on which Canadians celebrate and honor the historic beginning of their independence. On July 1, 1867, Canada's Constitution Act was enacted and Canada began the process of separating from the British Empire. First, some readers of this column may not realize that there are five AWWA Sections in Canada and that collectively they serve AWWA members living in Canada's 10 provinces and three territories. In total, one out of 10 AWWA members lives in Canada. Canadian AWWA members have been an important part of AWWA for over 100 years—2016 marked the 100th anniversary of the original Canadian Section. It is interesting to note that at first the entire country of Canada was one enormous AWWA Section called the Canadian Section. After 51 years of being a single Section, in 1967 (a century after Canada's Constitution Act took effect), the waterworks professionals in Quebec received Section status. Then on Jan. 1, 1971, the Canadian Section reorganized and three new AWWA Sections came into existence—Atlantic Canada, Ontario, and Western Canada. Finally, on Jan. 1, 1973, the British Columbia Section was inaugurated, making it the youngest of the five Canadian Sections we know today. This year, 2019, has had several events celebrating Canada's success. Perhaps, although no one can be fully sure, they began in January when the AWWA board of directors held its annual winter board meeting in British Columbia, Canada. Maybe that was the sign of things to come. In June at ACE19 in Denver, Colo. (the home of AWWA's headquarters), Canada and Canada's water professionals had three first-time successes, which I am calling Canada Days. Let's start with June 11. For 15 years AWWA has conducted a “Best of the Best” tap water taste test. Drinking water utilities compete fiercely at the Section level, and the best-tasting drinking water from each Section is eligible to compete for the Best of the Best title at ACE each year. For the first time ever, the bragging rights that accompany the honor of being the Best of the Best went to a Canadian utility—the Town of The Blue Mountains (Ontario Section). While I did not have the privilege of judging the competition this year, I have to say that with a name like that, I am not surprised that it has great-tasting water. And look at the picture I've included of Reg Russwurm, the director of infrastructure and public works, as he lifts the Best of the Best trophy high, just like a Stanley Cup champion. But as if that wasn't enough, Canada was not done with its victories. AWWA also conducts a taste test called the People's Choice. In this competition, ACE19 attendees select their favorite water and, as with the Best of the Best, for the first time ever a Canadian water utility won the People's Choice award. This time it was EPCOR (City of Edmonton in the Western Canada Section) that demonstrated its liquid prowess. I can tell you from personal experience that EPCOR's water tastes great, almost like it comes from a glacier, and that is because … it does. Two days later, on June 13, Canada had another first. This was the day that the Toronto Raptors—the only NBA team in Canada—won the NBA finals in six games. Just as with the drinking water taste test firsts, this was the first time a Canadian basketball team had ever won the NBA championship. Three consecutive victorious first-ever Canada Days— a double win on drinking water taste by Town of The Blue Mountains and EPCOR at ACE19, followed two days later by the Raptors’ NBA championship. And who knows—maybe this all happened because the AWWA board of directors met in British Columbia. Happy Canada Day.

Storage for One More Century

Since its completion more than a century ago by a previous owner, Denver Water’s Antero Dam has experienced seepage problems, forcing the utility to limit the storage capacity of the associated res...

Improbable Denver

Improbable Denver

Open Channel -- Less Than 1

Sometimes it is wise to listen to your own advice. I have spent a significant amount of time over the past year talking about lead in water, how it gets there, what utilities are doing to protect their customers, and what customers can do if they have concerns. And then it occurred to me that I had no idea if there was lead in my family's drinking water. So I did what I have suggested, over and over, to others – I called my water utility. Turns out that my utility, Denver Water, has a program where it will test customers' tap water free of charge. It is a new program, and I was the first customer.

SU‐F‐T‐533: Study of Dosimetric Properties of Cadmium Free Alloy Used in Compensator Based IMRT

Purpose:To study the dosimetric properties of cadmium free alloy which is used in compensator based IMRT.Methods:A mixture of 30% of lead,52% of bismuth and 18% of tin was used to prepare alloy. We prepared slabs of different thicknesses ranging from 0.71 cm to 6.14 cm. Density of alloy was measured by Archimedes’ principle using SI‐234 Denver instrument and water as buoyant liquid. Transmission, linear attenuation coefficient (µ), tissue phantom ration (TPR), beam hardening, surface dose (Ds), percentage depth dose (PDD) and effect of scatter were measured and analyze for different field size and different thickness of compensator for 6 MV photon beam. Measurements were carried out at 100 cm SSD and 160 cm SSD.Results:Density of alloy was found to be 9.5456 gm/cm3. Melting point of alloy is 90–95 °C. For a field size of 10×10 cm2 µ was 0.4253 cm‐1 at 100 cm SSD. Calculated TPR was found to be within 3 % of measured TPR. Ds was found to be decreasing with increasing thickness of compensator. 1cm, 1.98 cm and 4.16 cm thick compensator slab decreased surface dose by 4.2%, 6.1% and 9.5% respectively for a field size of 10×10cm2 at 100 cm SSD. As field size increases Ds increases for a given compensator thickness. This is due to increase in amount of scattered dose from wider collimator opening. For smaller field size, PDDs are increased from 3.0% to 5.5% of open beam PDDs as compensator thickness increases from 1 cm to 6.14 cm at a depth of 10 cm in water. For larger field size variation in PDDs is not significant.Conclusion:High degree of modulation can be achieved from this compensator material, which is essential in compensator based IMRT. Dosimetric properties analyzed in this study establish this alloy as a reliable, cost effective, reusable compensator material.

Seasonal and spatial variability of nitrosamines and their precursor sources at a large-scale urban drinking water system

Nitrosamines are considered to pose greater health risks than currently regulated DBPs and are subsequently listed as a priority pollutant by the EPA, with potential for future regulation. Denver Water, as part of the EPA's Unregulated Contaminant Monitoring Rule 2 (UCMR2) monitoring campaign, found detectable levels of N-nitrosodimethylamine (NDMA) at all sites of maximum residency within the distribution system. To better understand the occurrence of nitrosamines and nitrosamine precursors, Denver Water undertook a comprehensive year-long monitoring campaign. Samples were taken every two weeks to monitor for NDMA in the distribution system, and quarterly sampling events further examined 9 nitrosamines and nitrosamine precursors throughout the treatment and distribution systems. NDMA levels within the distribution system were typically low (>1.3 to 7.2ng/L) with a remote distribution site (frequently >200h of residency) experiencing the highest concentrations found. Eight other nitrosamines (N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitroso-di-n-propylamine, N-nitroso-di-n-butylamine, N-nitroso-di-phenylamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosomorpholine) were also monitored but none of these 8, or precursors of these 8 [as estimated with formation potential (FP) tests], were detected anywhere in raw, partially-treated or distribution samples. Throughout the year, there was evidence that seasonality may impact NDMA formation, such that lower temperatures (~5–10°C) produced greater NDMA than during warmer months. The year of sampling further provided evidence that water quality and weather events may impact NDMA precursor loads. Precursor loading estimates demonstrated that NDMA precursors increased during treatment (potentially from cationic polymer coagulant aids). The precursor analysis also provided evidence that precursors may have increased further within the distribution system itself. This comprehensive study of a large-scale drinking water system provides insight into the variability of NDMA occurrence in a chloraminated system, which may be impacted by seasonality, water quality changes and/or the varied origins of NDMA precursors within a given system.

XERISCAPING: A GREENING APPROACH FOR FACING WATER-SCARCITY IN ARID CITIES The case of Egypt

There is no doubt that green spaces provide the urban environments with an important asset, however the water-scarcity issues that is facing many urban settlements, Egypt is one of these places that is not only suffering from the rareness of green spaces, but the water scarcity issues as well, these issues have arose to the surface in the last several years forced the municipality's supply of these green spaces to decline dramatically. Xeriscaping is one of the methods that is used to challenge such scarcity, it is a method of gardening that doesn’t sacrifice beauty to conserve water, Xeriscaping (zer-i-scaping) is a water conservation technique that first originated in 1981 by the Denver water department. It is a 7 step landscaping method which aims at using drought-tolerant plants among a series of other steps to protect the environment. Water scarcity is a spreading phenomenon that affects all sectors of the community and threatens the sustainability of the resources. The “Water consumption versus water scarcity” reality in Egypt emphasizes the importance of following procedures for water conservation, and this could be tackled through a water-wise practice such as “Xeriscaping”. This paper summarizes the significance of Xeriscaping, its major characteristics; it aims at forming a framework which could be considered a counter measurement technique to mitigate the water scarcity phenomenon which is crippling the Egyptian economy.

United in Orange and Walking on Water

As the modern‐day gladiators took to the field in Rutherford, N.J., for Super Bowl XLVIII, emotions were high ‐ and water demand was plummeting. LaFrance provides us with a quarter‐by‐quarter analysis of Denver's water demand during the Super Bowl.

Project outcomes: Evaluating predicted benefits for field force mobilization

A year into launching a production mobile workforce automation system, Denver Water reviews benefits that were not quantified with its initial analysis and presents compelling reasons for continuing to build on the system. This article is part three of a series about this experience. The first article, in the August 2012 Journal (Assessing Options and Costs Versus Benefits of a Mobile Work Management Solution), outlined the start of the journey to build this application with a focus on creating a compelling yet conservative cost‐benefit analysis (CBA) for a new mobile work management system. The second article, in the November 2012 Journal (Information Technology Projects and Business Engagement: New Strategies), focused on how system adoption and end‐user satisfaction were achieved through an agile software development process.

The Path of a Conservation Trailblazer

Liz Gardener, a forerunner in the field of water conservation, has spent the past 35 years raising people's awareness about the need to use water efficiently. She gave birth to Denver Water's conservation program in 1986 and nurtured it to maturity. Through AWWA, which she joined that same year, she reached out to other trailblazers and helped to build a nationwide community of conservation champions. Her contributions to water use efficiency are recognized by water utilities and water conservation experts throughout North America. She recently talked with former Journal AWWA editor Nancy Zeilig Lively about her career and her commitment to wise water use.