July | 2014 | Decision Center for a Desert City

Satellite Study Reveals Parched U.S. West Using Up Underground Water

Posted on July 28, 2014 by Liz Marquez

July 24, 2014 via NASA

A new study by NASA and University of California, Irvine, scientists finds more than 75 percent of the water loss in the drought-stricken Colorado River Basin since late 2004 came from underground resources. The extent of groundwater loss may pose a greater threat to the water supply of the western United States than previously thought.

This study is the first to quantify the amount that groundwater contributes to the water needs of western states. According to the U.S. Bureau of Reclamation, the federal water management agency, the basin has been suffering from prolonged, severe drought since 2000 and has experienced the driest 14-year period in the last hundred years.

The Colorado River Basin lost nearly 53 million acre feet of freshwater over the past nine years, according to a new study based on data from NASA’s GRACE mission. This is almost double the volume of the nation's largest reservoir, Nevada's Lake Mead. Image Credit: U.S. Bureau of Reclamation — The Colorado River Basin lost nearly 53 million acre feet of freshwater over the past nine years, according to a new study based on data from NASA’s GRACE mission. This is almost double the volume of the nation’s largest reservoir, Nevada’s Lake Mead.
Image Credit: U.S. Bureau of Reclamation

The research team used data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite mission to track changes in the mass of the Colorado River Basin, which are related to changes in water amount on and below the surface. Monthly measurements of the change in water mass from December 2004 to November 2013 revealed the basin lost nearly 53 million acre feet (65 cubic kilometers) of freshwater, almost double the volume of the nation’s largest reservoir, Nevada’s Lake Mead. More than three-quarters of the total — about 41 million acre feet (50 cubic kilometers) — was from groundwater.

“We don’t know exactly how much groundwater we have left, so we don’t know when we’re going to run out,” said Stephanie Castle, a water resources specialist at the University of California, Irvine, and the study’s lead author. “This is a lot of water to lose. We thought that the picture could be pretty bad, but this was shocking.”

Water above ground in the basin’s rivers and lakes is managed by the U.S. Bureau of Reclamation, and its losses are documented. Pumping from underground aquifers is regulated by individual states and is often not well documented.

“There’s only one way to put together a very large-area study like this, and that is with satellites,” said senior author Jay Famiglietti, senior water cycle scientist at JPL on leave from UC Irvine, where he is an Earth system science professor. “There’s just not enough information available from well data to put together a consistent, basin-wide picture.”

Famiglietti said GRACE is like having a giant scale in the sky. Within a given region, the change in mass due to rising or falling water reserves influences the strength of the local gravitational attraction. By periodically measuring gravity regionally, GRACE reveals how much a region’s water storage changes over time.

The Colorado River is the only major river in the southwestern United States. Its basin supplies water to about 40 million people in seven states, as well as irrigating roughly four million acres of farmland.

“The Colorado River Basin is the water lifeline of the western United States,” said Famiglietti. “With Lake Mead at its lowest level ever, we wanted to explore whether the basin, like most other regions around the world, was relying on groundwater to make up for the limited surface-water supply. We found a surprisingly high and long-term reliance on groundwater to bridge the gap between supply and demand.”

Famiglietti noted that the rapid depletion rate will compound the problem of short supply by leading to further declines in streamflow in the Colorado River.

“Combined with declining snowpack and population growth, this will likely threaten the long-term ability of the basin to meet its water allocation commitments to the seven basin states and to Mexico,” Famiglietti said.

The study has been accepted for publication in the journal Geophysical Research Letters, which posted the manuscript online Thursday. Coauthors included other scientists from NASA’s Goddard Space Flight Center, Greenbelt, Maryland, and the National Center for Atmospheric Research, Boulder, Colorado. The research was funded by NASA and the University of California.

Read the original article at NASA.

For more information on NASA’s GRACE satellite mission, see:

http://www.nasa.gov/grace

and

http://www.csr.utexas.edu/grace

GRACE is a joint mission with the German Aerospace Center and the German Research Center for Geosciences, in partnership with the University of Texas at Austin. JPL developed the GRACE spacecraft and manages the mission for NASA’s Science Mission Directorate, Washington.

NASA monitors Earth’s vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

To learn more about NASA’s Earth science activities in 2014, visit:

http://www.nasa.gov/earthrightnow

Steve Cole
Headquarters, Washington
202-358-0918
stephen.e.cole@nasa.gov

Alan Buis
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0474
Alan.Buis@jpl.nasa.gov

Janet Wilson
University of California, Irvine
949-824-3969
janet.wilson@uci.edu

City of Phoenix Cool Urban Spaces Project

Posted on July 21, 2014 by Liz Marquez

City of Phoenix Cool Urban Spaces Project

Urban forestry and cool roofs: Assessment of heat mitigation strategies in Phoenix

Prepared by the Center for Integrated Solutions to Climate Challenges at Arizona State University in collaboration with the Climate Assessment for the Southwest (CLIMAS) at the University of Arizona and Decision Center for a Desert City (DCDC).

Executive Summary

The City of Phoenix’s Cool Urban Spaces Report (2014) investigated the impact of the Phoenix Cool Roofs and Tree and Shade Master Plan initiatives on the city. The study evaluated how these heat mitigation efforts affect microclimates and human thermal comfort in the Phoenix metropolitan area. These findings are especially relevant as rapid and extensive urbanization has led to an urban heat island (UHI) effect that has increased steadily at approximately 0.9°F per decade.

The city’s questions guiding this research were:

What are the cooling benefits achieved by increasing tree canopy from 10% (current) to 25% (2030 goal) and/or implementing cool roofs under existing conditions and projected warming?
What is the diurnal thermal benefit of tree canopy shade for a typical heat wave day during premonsoon summer?

The impacts of cool roofs and trees on near-ground air temperatures were modeled through 54 scenarios for a typical residential neighborhood in Phoenix. We ran the model for a combination of three treeplanting scenarios (no trees, current canopy cover and 2030 canopy goal) and three landscaping scenarios (mesic, oasis and xeric) with regular roofs and cool roofs under current climate conditions and two climate change projections.

Two significant results of the tree and shade initiative are: (1)increasing tree canopy cover to 25% leads to an additional temperature reduction of 4.3°F, which is a total cooling benefit of 7.9°F as compared to a bare neighborhood, and 2) switching landscaping from xeric to oasis, i.e., adding grass patches to residential backyards, reduces average neighborhood temperatures by 0.4°F to 0.5°F.

The scenario with the lowest air temperatures is the residential neighborhood with mesic landscaping, 25% tree canopy cover and cool roofs under current climate conditions with an average neighborhood temperature of 99.5°F. In contrast, the xeric neighborhood with no tree cover and regular roofs under the high-emissions climate change scenario is the hottest. This indicates that the combination of increased tree canopy cover and cool roofs does lower temperatures as well as reduce the demand for air conditioning, thereby reducing anthropogenic heat. However, trees and cool roofs are only part of the solution and need to be included in a broader, more comprehensive mitigation and adaptation plan.

Across all climate and tree scenarios, the effect of cool roofs alone on local daytime temperatures is relatively low. Air temperature reduction only amounts to 0.5°F in the neighborhood. Regarding the city’s cool roofs initiative, results show little benefit for extending this project to commercial and residential properties based on its cooling impacts alone.

Our research thus far indicates that there is no simple solution to mitigating the UHI, but a complex balance of strategies will be necessary so that efforts to lower the daytime temperatures do not increase nighttime temperatures or shift UHI impacts to more vulnerable populations.

Introduction

The Center for Integrated Solutions to Climate Challenges and Decision Center for a Desert City (DCDC) at ASU, along with Climate Assessment for the Southwest (CLIMAS) at the University of Arizona, through a NOAA-funded grant, convened a workshop with urban managers and practitioners in October 2012. One goal of the workshop was to provide useful, state-of-the-art climate knowledge to encourage the use of climate science in longrange decision processes. Another was to provide opportunities for working with urban managers and planners to develop tangible products and/or processes that will enable the incorporation of this information into their unique planning documents and policies. Attendees were asked to develop project proposals for tractable, city-specific adaptation projects on behalf of their municipality. Three proposals were chosen for funding: Tucson, Flagstaff and Phoenix. The City of Phoenix asked for support in assessing the impact of their urban forestry and cool roofs initiatives on projected heat increases and the urban heat island (UHI).

In Phoenix, rapid and extensive urbanization has led to an UHI in the metropolitan area that has increased steadily at approximately 0.9°F (0.5°C) per decade. A time-trend analysis of Phoenix Sky Harbor air temperatures showed nighttime temperature differences between rural and urban areas of up to 11°F (6°C) in the summer (Brazel et al., 2000). Winter mobile transect observations in Phoenix found a UHI intensity of 14°F (8°C) (Sun et al., 2009), and a study in the spring observed an average UHI intensity of 17°F to 23°F (9.4°C to 12.9°C) (Hawkins et al., 2004). Discussions with Philip McNeely, the city’s Environmental Program Manager; Richard Adkins, Phoenix Parks and Recreation Department’s Forestry Supervisor; and a number of ASU researchers provided insight into the current activities being undertaken by the city to mitigate heat. Among these were their green building and urban forestry initiatives.

The stakeholder questions coming from the activities guiding this research were:

What are the cooling benefits achieved by increasing tree canopy from 10% (current) to 25% (2030 goal) and/or implementing cool roofs, under existing conditions and projected warming?
What is the diurnal thermal benefit of tree canopy shade for a typical heat wave day during premonsoon summer?

This study used micro-scale modeling, hourly meteorological observations and a research synthesis workshop with UHI experts from ASU to help inform the City of Phoenix’s green building and urban forestry initiatives. Initial results were presented to the City of Phoenix in late 2013.

Download the report.

New DCDC Publication

Posted on July 17, 2014 by Liz Marquez

Assessing the sustainability of water governance systems: the sustainability wheel

Published online in the Journal of Environmental Planning and Management on July 11, 2014.

Authors

Flurina Schneider (a,b,e), Mariano Bonriposi (d), Olivier Graefe (c), Karl Herwega (a), Christine Homewood (c), Matthias Huss (c), Martina Kauzlaric (b), Hanspeter Liniger (a), Emmanuel Rey (b), Emmanuel Reynard (d), Stephan Rist (a), Bruno Schädler (b) & Rolf Weingartner (b)

Affiliations
a Centre for Development and Environment, University of Bern, Bern, Switzerland
b Department of Geography and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland
c Geography Unit, Department of Geosciences, University of Fribourg, Fribourg, Switzerland
d Institute of Geography and Sustainability, University of Lausanne, Géopolis, Lausanne, Switzerland
e Decision Center for a Desert City, Julie Ann Wrigley Global Institute of Sustainability, Arizona State University, Tempe, AZ, USA

Flurina Schneider is a visiting scholar at Arizona State University, where she is affiliated with the School of Sustainability and Decision Center for a Desert City of the Julie Ann Wrigley Global Institute of Sustainability. She holds a PhD in human geography from the University of Bern, Switzerland. Schneider has conducted research on sustainable governance of water and land in Switzerland, Germany and Chile, focusing on multiple stakeholders’ perspectives and values, processes of transdisciplinary knowledge, co-creation through social learning and network building, as well as on issues of power and social justice.

Dr. Schneider is currently the scientific coordinator of the MontanAqua project, which develops strategies for moving towards more sustainable management of water resources in the Alps (Swiss National Science Foundation, Sustainable water management (NRP61)). Within this program, she also has the lead role in two synthesis projects concerning the development of principles of sustainable water use in Switzerland as well as the analysis of potentials and limitations of transdisciplinary knowledge production in research projects of the NFP61.

Abstract

We present and test a conceptual and methodological approach for interdisciplinary sustainability assessments of water governance systems based on what we call the sustainability wheel. The approach combines transparent identification of sustainability principles, their regional contextualization through sub-principles (indicators), and the scoring of these indicators through deliberative dialogue within an interdisciplinary team of researchers, taking into account their various qualitative and quantitative research results. The approach was applied to a sustainability assessment of a complex water governance system in the Swiss Alps. We conclude that the applied approach is advantageous for structuring complex and heterogeneous knowledge, gaining a holistic and comprehensive perspective on water sustainability, and communicating this perspective to stakeholders.

Introduction

In Switzerland, as in many other parts of the world, there is increasing concern that water shortage problems might become more frequent. Consequently, many research and policy efforts focus on issues of more sustainable water governance. However, there are few holistic approaches, which evaluate the sustainability of water governance systems based on comprehensive, interdisciplinary assessments (Reed and Kasprzyk 2009; Wiek and Larson 2012). Most frameworks emphasize singular aspects such as quality and supply of freshwater resources (Kondratyev et al. 2002), infrastructure, adaptive capacity (Hill 2013), or social learning (Pahl-Wostl 2006; Pahl-Wostl et al. 2007). Moreover, studies that investigate the sustainability of water governance systems from holistic perspectives (Larson, Wiek, and Withycombe Keeler 2013) primarily focus on the present situation without in-depth assessments of possible future developments.

A holistic framework for the analysis of sustainable water governance systems is proposed by Wiek and Larson (2012). Their framework combines a systemic understanding of the water governance system and its evaluation through a set of sustainability principles. They stress the importance of justifying the normative claims in the system analysis with a transparent set of value laden sustainability principles.

Another approach that is commonly chosen to evaluate water governance sustainability from an interdisciplinary perspective is the application of indicators (Sullivan and Meigh 2007; Valenzuela Montes and Matarán Ruiz 2008; Ioris, Hunter, and Walker 2008; Babel et al. 2011; Lachavanne and Juge 2009 ). The great advantage of indicators is that they provide a reasonably simple tool to combine biophysical and socioeconomic information (Sullivan and Meigh 2007), and allow the reflection and communication of complex ideas by condensing their multifaceted nature into a manageable amount of meaningful information (Babel et al. 2011), yielding good learning opportunities (Ioris, Hunter, and Walker 2008). However, they also have limitations; quantitative indicators often require (over)simplifying complex and dynamic water governance systems (Ioris, Hunter, and Walker 2008). Consequently, aspects that are hard to measure, or hard to quantify, such as informal governance practices, are neglected (e.g. Lachavanne and Juge 2009 ). Furthermore, gaps in data often limit the applicability and information value for different case study areas.

Against this background, our goal is to present a conceptual and methodological approach for an interdisciplinary sustainability assessment for water governance systems – based on what we call the sustainability wheel – and its application in the Crans-Montana-Sierre region of Switzerland, the case study area of the MontanAqua project (Weingartner et al. 2010). For this purpose, we took the basic ideas of the two approaches described above and combined them in a way that would allow the evaluation of the water governance system through a comprehensive, interdisciplinary assessment.

In this article, we use the term water governance system in a broad sense. Water governance systems are understood to include social practices and institutions, as well as biophysical aspects and processes. When using the term water resource systems, we only refer to the biophysical aspects and processes.

Download the entire article.

Lake Mead Levels to Drop to Historic Lows

Posted on July 9, 2014 by Liz Marquez

July 9, 2014

Listen to DCDC director, Dave White, discuss the regional impact of the drop in Lake Mead’s water level in his interview with KJZZ’s Here and Now.

July 8, 2014

via Bureau of Reclamation by Rose Davis, 702-293-8421

BOULDER CITY, Nev. – Lake Mead, the reservoir created by Hoover Dam, is anticipated this week to reach its lowest water level since the lake’s initial filling in the 1930s. The Bureau of Reclamation’s Boulder Canyon Operations Office is projecting the elevation to drop to 1,081.75 feet above sea level during the week of July 7 and to continue to drop, reaching approximately 1,080 feet in November of this year.

Reclamation’s Lower Colorado Region annually delivers about 9 million acre-feet (MAF) to homes, businesses, farms, Native American tribes and communities, and Mexico.

“We will meet our water orders this year and we are not projecting a shortage condition in 2015,” said Lower Colorado Regional Director Terry Fulp. “We continue to closely monitor the projections of declining lake levels and are working with stakeholders throughout the Lower Basin to keep as much water in Lake Mead as we can through various storage and conservation efforts.”

Annual releases from Lake Powell and Lake Mead are determined in accordance with the 2007 Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead (Guidelines). Only if Lake Mead is projected to reach elevation 1,075 feet on January 1 of each year would the Secretary of the Interior determine a shortage condition and reduce water deliveries in the Lower Basin.

Lake Mead’s elevation is currently projected to be at approximately 1,083 feet on January 1, 2015.

In Water Year 2014 (ending on September 30, 2014), Lake Powell will have released a record low amount of water, 7.48 MAF into Lake Mead in accordance with the Guidelines. As of July 1, 2014, the forecasted inflow into Lake Powell is 95 percent of average for the water year. In Water Year 2015, Lake Powell’s release to Lake Mead is currently projected to be between 8.23 MAF and 9.0 MAF.