Conferences and Workshops

Every other year WREP hosts a conference or workshop related to water resources or watershed science and policy. 

Water management and climate change in northern Arizona, Summer 2011

This one-day workshop consisted of technical presentations by climatologists and water management experts. Afterward, discussion groups were convened to discuss several inter-related questions: 

  1. What are the significant perceived challenges to water resource management in light of climate change?
  2. What planning/management approaches will enable us to cope with uncertainties regarding future climate?
  3. What kinds of scientific knowledge are most useful in facilitating water resource management during increased climate variability?


  • Tree Rings and Water Resource Management in the Southwest. Connie Woodhouse, School of Geography and Development, University of Arizona. Download.
  • Downscaled Regional Climate Modeling for the Southwest. Christopher Castro, Department of Atmospheric Sciences, University of Arizona. Download
  • USGS Global Change: Impacts on Water Resources, and Climate Change Programs Nationally and in the Southwest. Don Bills, Geological Survey (USGS), Arizona Water Science Center. Download.
  • Approaches For Integrating Climate Change Into Water Resources Planning. Levi Brekke, Hydraulic Engineer, Bureau of Reclamation, Denver, Colorado. Download.
  • Tree-rings, gages and climate models: Salt River Project’s new methodology for water resources planning and reservoir management on the Salt-Verde watershed. Jon Skindlov, Water Resource Operations, Salt River Project, Phoenix. Download

Discussion Group Process and Outcomes

Experts in climate change science and water management moderated breakout sessions and guided the conversation through a series of follow-up questions and subtopics (below):

How can policy-makers and management agencies encourage the public to focus on behaviors that will promote sustainable watersheds?


Discussion group members felt that we need to improve knowledge of the hydrologic cycle and how human management has affected watersheds and landscapes in Arizona. It was also suggested that the complex interaction between riparian vegetation and water level fluctuation is poorly understood by the general public; improved dissemination of information about these processes could prove helpful.

Discussion group members suggested that outreach efforts by management agencies should focus on water users (and not on legislators), and that these same water users may provide useful feedback to management agencies. Water users may be able to provide multiple water management variables for input into models of Arizona's watersheds from the “grassroots” level. The discussion group members also recommended that newer and more sustainable technologies should be made available to both private and community water users.

How can we improve the communication of scientific issues to better inform watershed management?

Discussion groups were concerned that there was inadequate funding for climate research, and that an additional financial investment in climate modeling and improved communication/public outreach would better inform watershed management in the face of climate change. Discussion group members frequently brought up the need for readily available, easy-to-interpret, downscaled climate projections. Specifically, they indicated that there is a need for precipitation projections that are specific to Arizona, and that this information must be made available and relevant to the general public. In addition, discussion group participants felt that care must be taken to effectively communicate data generated from models and projections to the general public, and that the overarching message of climate change and variability should be communicated, if at all possible, in a non-political and non-biased manner. Participants in the discussion groups also felt that improved knowledge of watershed processes and issues related to climate change would better allow water users to adjust to any “acute” changes in water availability that may occur in the future.

What methods and practices can be used to maintain sustainable watersheds in the face of climate change?

Discussion group participants felt there was a need to control the rise of water demand in Arizona. An example of this type of pro-active management has been set by AZ state parks, which have seen a dramatic reduction in water-use since the implementation of a 2004 water conservation initiative. Discussion group participants suggested that water suppliers and users can employ strategies emphasizing flexibility to mitigate possible problems with variable future water supplies, especially if climate changes trigger drought events are sporadic and severe in nature. 

Is it more important to plan for population growth and/or for sustainable water use in Arizona?

Participants felt that by making per capita changes in water use habits, quality of life could be sustained in the face of climate change. To this end, it is important for water agencies to promote more sustainable per capita water use practices (for example, reduced shower times, infrequent watering of lawns). In addition, sustainable water-use practices and management strategies should be encouraged and implemented for all demographics and regions of Arizona. This last idea is particularly relevant to ongoing changes to the ways land is used in Arizona: for example, conversion of agriculture land to industrial/residential, increased importance of sustainable power generation, etc.
Participants suggested that Arizona should consider monitoring private groundwater wells, which historically have not been monitored, at least in terms of withdrawal volumes. Participants also suggested that it would be useful to monitor, assess and summarize groundwater-aboveground water fluctuations---both for regional aquifers and for the state’s entire water allocations.

How will projected regional climate changes for Arizona influence timing of water replenishment and recharge events?

Participants felt that more sporadic, unpredictable and dramatic precipitation events will require changes to water agencies’ existing ability to catch precipitation and control groundwater recharge. It was recommended that water agencies expand their storage options so that they can provide additional water during extended drought periods. In the face of the challenges posed by climate change, participants felt that flexibility and coordination across multiple-agencies in terms of planning and management would be necessary to accommodate all Arizona stakeholders. The discussion group participants also suggested that it will be necessary to implement “system thinking” to address entire watershed-related issues; that is, the water management needs to be treated as a single, integrated issue, not as a series of disconnected “problems.” Participants noted that we must also improve the public’s understanding of water use issues, particularly with regard to watershed use and management and engage the public regularly during the decision-making process.

Who can Arizona model to improve future watershed issues in face of climate change uncertainties?

Participants discussed other groups (tribes, countries, geographic regions) that have a successful history of dealing with drought and water shortages. It was suggested that some of these groups might serve as a “model” for Arizona to follow as climate change reduces water availability with the state. Several key ideas/questions emerged during this discussion. (1) Are there water management lessons to be learned from the pre-colonial societies of the Southwest? (2) Could a distant community serve as a model for water use in Arizona? Australia and South Africa were suggested as potential model communities and both have strict government regulation of per capita water use. (3) Are there local communities that could serve as templates for water management strategies? Swales, Arizona, and the Navajo Nation were both suggested as having exceptional water management policies.
It was noted that there is variability between major population areas within Arizona, but that these diverse areas need to be managed under one, unified water management plan, as compared with current, separate water-management regimes. Participants also suggested that there is a need for improved lines of communication among scientists, policy makers and stakeholders. As things stand, there appears be a “disconnect” between public perception of water management issues and the actual problems faced by management agencies.

What are easily tangible regional problems and/or solutions for water management?

Discussion group participants suggested looking to solutions already being employed at community and grassroots levels. Key ideas that emerged during this discussion focused on recapturing water that may be “lost” under current management practices. In particular, participants suggested that increased emphasis should be placed on (1) small-scale storm water catchments (for example, water barrels) that will allow precipitation to be harvested for local use and (2) water conservation/sustainable infrastructures (for example, permeable pavements) that may improve ground water recharge during precipitation events.

How can we integrate climate change variability and natural climatological processes into watershed management?

Discussion groups felt that riparian habitats in Arizona represent a key link in understanding the interface between temperature, precipitation, and water management. An awareness of the need for ecological sustainability may also raise awareness of the need for “cultural” sustainability---that is, the need for users and management agencies to implement water conservation strategies. It was also suggested that scientists and management agencies should identify critical thresholds for Arizona's watersheds, and manage the watersheds with the overarching goal of maintaining these levels. Discussion group members suggested that changes could be made to existing infrastructure to facilitate water storage and redistribution to accommodate the variable precipitation projections under regional climate change models.

How extensive are Arizona’s water resources?

Participants stated that water resources are likely being depleted at a rate that cannot be sustained. Participants were particularly concerned about the management of groundwater (aquifer) resources in Arizona and felt that we need to improve our understanding of aquifer use and aquifer recharge. In addition, participants rpeatedly expressed concern that there is a lack of understanding of the nature of this depletion and the problems that depletion will eventually pose for water management in Arizona. Concern was expressed over “aquifer injections”: in particular, how does artificial input of treated wastewater in to the aquifer affect biological process and natural filtration? Discussion group participants suggested that it is necessary to improve the monitoring of withdrawals from the aquifer and that that Arizona must enter into an era of state-level, long-term water planning.

Financial support for this conference was provided by the U.S. Bureau of Reclamation and University of Arizona’s CLIMAS.

Panel of national, state, and local experts address reclaimed water issues, December 5, 2011

The Reclaimed Water forum provided a public presentation for five experts in reclaimed water from the national, state, and local levels to present scientific knowledge around reclaimed water and to field questions from the public. The presentations by each panel members addressed the human health risks, regulatory framework and treatment methods for reclaimed water. Following a presentation by each panel member, panel members addressed questions from the audience.

Panel presentations

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The first presentation was by Brad Hill, Utilities Director for the City of Flagstaff. He addressed an overview of the best management practices for reclaimed water treatment and use from an international scale to a local scale. Over 90% of water re-use occurs in just four states in the U.S., and Arizona is one of those states, re-using 205, 000 acre-feet/year. Flagstaff stands as a leader even in Arizona, as 20% of the municipal water use is from reclaimed water, and is used for a range of uses, including: irrigation, construction, industry, and amenity lakes. Water treatment occurs at two facilities, the Wildcat Hill facility and the Rio de Flag facility, which together, treat a capacity of 10 MGD (million gallons per day). Hill’s presentation closed by advocating for re-use, not disposal of reclaimed water.

Following Brad Hill was Dr. Shane Snyder, who is a professor at the University of Arizona and co-director at the Laboratory for Emerging Contaminants. Opening his talk, he posed the question: “when does wastewater just become water?”, and suggested that we are all “swimming in a sea of chemicals”. He presented the results of his research, which involves sensitivity analysis on compounds of emerging concern (CEC’s). Of 62 compounds researched across the country, they detected only 11 compounds, most at concentrations below 1 part per billion. His research team also calculated the acceptable daily intake, and found that individuals would have to intake hundreds to thousands of liters of water per day for any harmful impact. His presentation concluded by re-iterating that all water has been, or can be re-used, and that global sustainability will depend on recycling water.

The next panel member to speak was Mike Fulton, the Director of the Water Quality Division at the Arizona Department of Environmental Quality (AZDEQ). Fulton’s presentation primarily focused on examining the past and present trends in wastewater treatment and reclaimed water in Arizona. He gave a detailed description of the treatment which includes: 1) primary treatment (physical processes), 2) secondary treatment (biological processes), and 3) tertiary treatments (chemical processes). The management options for reclaimed water following this treatment regime include discharge to surface water courses, infiltration, recharge, and re-use.

Chuck Graf, Senior Hydrologist at AZDEQ followed Fulton and gave a presentation that detailed the regulatory framework around reclaimed water in Arizona. There are five different classifications for reclaimed water in Arizona: A+, A, B+, B, C. The lowest classification, class C, is designated for extremely minimal public contact and is to be used for irrigation and forage production. Class B is for restricted public use and is designated for uses such as golf courses, livestock watering, orchards, and landscape. Class A reclaimed water, the highest classification, is for open public access and can be used for irrigation, recreation, snowmaking, etc.  In Arizona, wastewater treatment plants own their treated wastewater and have control over the distribution and re-use of it. There are two types of permits for end uses: single end users and reclaimed water agent permit. Because of this strong regulatory framework, 65% of Arizona’s water treatment plants distributed treated wastewater for reuse. The last portion of his presentation addressed CEC’s in Arizona’s treated wastewater and announced that the Governor’s Blue Ribbon Panel on water sustainability recommends accelerating research on CEC’s in reclaimed water.

Guy Carpenter, the Vice President of Carollo Engineers and Board Member on the National WateReuse Association, presented information regarding the wastewater treatment process, applications for re-use, and the costs associated with different levels of treatment. There are five general steps to wastewater treatment: bar screening, settling, activated sludge, filtration and disinfections through chlorine or UV radiation. Although this conventional method does an excellent job of treating sewage, they can only go so far to remove trace organic chemical. Advanced treatment options, such as microfiltration, reverse osmosis and advanced oxidation processes can reduce the content of CEC’s, but these facility upgrades have significant cost implications. To improve CEC removal in the City of Flagstaff’s wastewater treatment facilities to a 95% removal rate, each person in Flagstaff would have to contribute $700. To increase CEC removal to 90%, each person in Flagstaff would have to contribute $140. Ultimately, the treatment comes down to a tradeoff of cost and quality. As ratepayers who have a vote in their public utilities, it is our decision. 

Questions and answers

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Questions were written on cards by the audience and submitted during the presentation. Questions were not addressed individually, but were grouped into general themes.

How can we mitigate the lag time between scientific knowledge and its incorporation into policy?

Chuck Graf noted that sometimes it can take years to test a new idea, get data and then translate that into policy. Brad Hill asserted that because of this time lag, the utilities industry has taken upon itself to decide to treat water for a number of compounds on a cautionary basis, even though not required by the government.

What are the health risks associated with prolonged exposure to CEC’s through reclaimed water?

Carpenter cited an example of reclaimed water use in Namibia, where water users have been consuming reclaimed water as potable water for over 35 years. He also noted that endocrine disruptors likely have a generational impact. At the levels that we are being exposed to, the extrapolations are showing no risk to human health. Dr. Snyder then explained that although fish and amphibians have shown deformities from exposure, extrapolating those effects to humans is an enormous leap.

What is the difference between A+ reclaimed water and drinking water?

Graf stated that drinking water and A+ reclaimed water are just two different things that are treated to two different standards. Drinking water has to meet standards for a number of different standards, and these standards are based on exposure. For reclaimed water, the concern is on pathogenic contaminants.

Is eating snow safe?

All panelists agree that “safe” is subjective. A+ water is not advisable for drinking but it is safe for very casual exposure. Reclaimed water standards stipulated that there can’t be any E. coli, whereas surface water standards include higher tolerances for E. coli.  One panelist said “I think the standards are protective of human health”. Carpenter mentioned that the process of making snow may increase pathogen die-off, but other than that, snow making likely does not change the composition or compound content of reclaimed water.