Download Lower Santa Cruz River Basin Study

Lower Santa Cruz River Basin Study
Proposal Submitted by the Southern Arizona Water Users Association
Bureau of Reclamation 2015 Basin Study
April 30, 2015
Introduction
The Southern Arizona Water Users Association (SAWUA) proposes to partner with the Bureau of
Reclamation to conduct the Lower Santa Cruz River Basin Study under the Bureau’s FY2015 Basin Study
Program.
SAWUA is a non-profit organization of municipal water and wastewater providers and agricultural water
users located in Southern Arizona working cooperatively to preserve and enhance Southern Arizona’s
water resources. SAWUA’s member agencies include Avra Valley Water Co-op, BKW Farms, Community
Water Company of Green Valley, Farmers Investment Co., Flowing Wells Irrigation District, Green Valley
Water Improvement District, Kai Farms, the Town of Marana Municipal Water System, Metropolitan
Domestic Water Improvement District, Oro Valley Water Utility, Pima County Regional Wastewater
Reclamation Department, Red Rock Utilities, Sahuarita Water Company, the Town of Sahuarita Water
Reclamation Facility and the Tucson Water Department.
SAWUA member agencies have water management authority to provide municipal water and
wastewater service to over 900,000 residents in the Santa Cruz River Basin. Collectively, SAWUA delivers
almost 200,000 acre-feet per year of potable water and treats over 64,000 acre-feet of wastewater
annually.
SCR Basin Study Area
The proposed Lower Santa Cruz River Basin (SCR Basin) Study will encompass the Tucson Active
Management Area (TAMA) in Arizona which generally coincides with the lower Santa Cruz River Basin
between the Pima County/Santa Cruz County boundary south of the Tucson metropolitan area and Pima
County/Pinal County boundary to the north. The Santa Cruz River is a tributary to the Colorado River, a
major river system within the Bureau of Reclamation’s service area.
The SCR Basin is 3,869 square miles. Its prominent physical features are the Santa Cruz River, flowing
south to north, and several surrounding mountain ranges. The Pantano Wash, Rillito Creek and Sabino
Creek in the eastern central portion of the SCR Basin are tributary to the Santa Cruz River, while the
Altar and Brawley Washes in the western portion of the SCR Basin flow south to the Santa Cruz River.
The northern boundary of the SCR Basin is formed by the Picacho Mountains and Black Mountain in the
Tortilla Mountains; on the eastern boundary are the Santa Catalina and Rincon Mountains; on the
southern boundary are the Santa Rita and the Sierrita Mountains and the western boundary is formed
by the Baboquivari, Roskgruge, Waterman and Silverbell Mountains. The elevation of the lowest point of
the SCR Basin is 1,770 feet above mean sea level (amsl) at the northern edge and the highest elevation is
9,453 feet amsl in the Santa Rita Mountains. Land ownership by area consists of 37.8 percent State Trust
Land, 31.2 percent private ownership, 25.8 percent Federal ownership (Forest Service, Bureau of Land
Management, Wildlife Refuge, National Parks and Military), 4.4 percent Native American Lands and 0.8
percent other jurisdictional ownership.
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Based on the 2010 US Census, the SCR Basin has a
population of 980,263. The jurisdiction with the largest
population, City of Tucson, operates a municipal water
system. Other jurisdictions with municipal water systems
include the Town of Marana and the Town of Oro Valley.
Additional water providers and private well owners also
provide municipal water service. Pima County, the Town of
Marana and the Town of Sahuarita operate municipal
wastewater utility systems.
Jurisdiction
Population
City of Tucson
Town of Oro Valley
Town of Marana
Town of Sahuarita
City of South Tucson
Unincorporated Pima County
Total
510,116
41,011
34,961
25,259
5,652
263,264
980,263
Table 1 – SCR Basin Population
The SCR Basin watershed is comprised of two parallel sub-basins; the Upper Santa Cruz Valley sub-basin
on the east and the Avra Valley sub-basin on the west. Both sub-basins flow from south to north. Figure
1 depicts the SCR Basin Study boundaries.
Figure 1 – Lower Santa Cruz River Basin Study Area
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Study Abstract
Key areas in the lower Santa Cruz River (SCR) Basin are experiencing groundwater declines due to lack of
access to renewable supplies and combined with drought conditions. Subsidence and loss of riparian
habitat have already occurred. Degradation of groundwater quality, increased pumping costs, the need
to deepen wells and shortages of supplies to municipal and agricultural users may be exacerbated
without more timely intervention.
For over sixty years the lower SCR Basin, including the Tucson, Arizona metropolitan area, relied on
groundwater to meet water supply needs with pumping greatly exceeding replenishment. In 1993,
water from the Bureau of Reclamation’s Central Arizona Project (CAP), a 336-mile long system of
aqueducts, tunnels, pumping plants and pipelines, began delivery of Colorado River water to the Basin.
Since then, SCR Basin water users have directly used or recharged their CAP and recycled water supplies;
portions of recharged CAP and recycled water are recovered on an annual basis. Consequently,
groundwater levels have rebounded in many areas. Still, there are significant spatial imbalances
between supply and demand within the Basin. Reasons include a lack of transmission infrastructure,
insufficient recharge and recovery capacity, a lack of recharge and recovery facilities in up gradient parts
of the basin, and the cost of constructing new facilities.
The lower SCR Basin faces several challenges. Population growth and new industrial development are
projected to increase water demand, and may generate political and legal conflicts. The CAP has junior
priority rights on the Colorado River; thus, CAP subcontractors will bear the brunt of imminent
shortages. Agricultural users will be the first affected under the CAP’s priority system, but if the
shortages are severe enough, reductions to municipal users will take place. In addition, Southern
Arizona, which naturally experiences episodic droughts, has been in an extended drought for the last
fifteen years. Water providers without physical access to renewable supplies are already experiencing
falling groundwater levels. Climate change poses additional threats to the Basin, such as increased
water demand, increased temperatures, and possible decreases in precipitation—which would
exacerbate the impacts of future droughts.
The proposed study will evaluate the current and future water supply and demand imbalances in the
SCR Basin, taking climate change impacts into consideration; analyze how existing infrastructure will
perform in response to changing water realities; develop adaptation and mitigation strategies, and
analyze each strategy for its effectiveness in addressing these imbalances. Throughout the process, we
will engage regional stakeholders, including those representing municipal, agricultural, environmental,
industrial and tribal water providers and users. We will garner and incorporate their input at key
intervals in the process. Our overarching goal is to identify where physical water resources are needed in
order to mitigate climate change impacts and improve water reliability for municipal, agricultural and
environmental sectors in the SCR Basin. The study will identify institutional, legal and regulatory
constraints affecting each strategy and develop next steps toward implementation.
Study Proposal
The SCR Basin Study will address six key elements:
1. Extent and Consequences of Existing and Anticipated Imbalances in Water Supply and Demand
Magnitude and frequency. The Lower Santa Cruz River Basin is critical to the viability of the nearly
one million residents living in Southern Arizona. For over sixty years water demand has exceeded
replenishment in the aquifer beneath the SCR Basin. In 1980 Arizona recognized the need to manage
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its finite groundwater resources and identified five areas with heavy reliance on mined groundwater
designating them as Active Management Areas. The goal in TAMA is to achieve and maintain safe
yield by 2025 and to prevent the local groundwater aquifer from experiencing long-term declines.
Safe yield is achieved when no more groundwater is being withdrawn than is being annually
replaced. A water supply and demand assessment prepared by ADWR projected total water demand
could be 525,807 acre-feet in 20251. To meet this demand, water supplies would have to be
supplemented with 259,254 acre-feet of groundwater, resulting in an increase in groundwater
overdraft.
Southern Arizona has been in extended drought for the last 15 years. The SCR Basin is in the arid
Southwest, receiving an average of 11.6 inches of precipitation annually. Therefore drought
conditions impact an area already sensitive to low precipitation. The National Weather Service cites
four historic periods of extended drought2. The 1810’s experienced six years of drought, followed by
seven years in the 1860’s, eight years in the 1930’s and five years in the 1950’s. The most recent
drought, now in its fifteenth year, was declared in 1999 and shows no signs of abating. Climate
change is expected to increase temperatures, further reducing local water availability and possibly
increasing municipal and agricultural water demand.
The detrimental impacts of persistent drought, such as reduced stream flow, declining groundwater
levels and stressed vegetation in local riparian areas are being observed in the Lower Santa Cruz
River Basin. Continued drought conditions and climate change impacts will result in loss of valuable
riparian areas locally. Water providers that have no access to renewable supplies or lack of water
infrastructure may experience declining groundwater levels or water service interruptions as
drought conditions persist. Residents in rural areas that rely on private groundwater wells may
experience water shortages resulting from ongoing drought conditions.
Global climate models indicate that with continued high rates of heat-trapping greenhouse gas
emissions, annual average temperatures will increase 4-5:Centigrade across the Southwest,
including the Lower Santa Cruz River Basin by the 2071-2100 time period3. While there is some
uncertainty about projected precipitation, increased temperatures are expected to result in drier
conditions and less groundwater recharge to the regional aquifer; in fact, recent studies show a
statistically significant trend toward decreases in the observed soil moisture in the region.4
Known and anticipated demands. The SCR Basin relies on water from the Colorado River delivered
through the Central Arizona Project (CAP) to meet water supply and demand for municipal,
industrial and agricultural sectors. Municipal and industrial sectors used 169,369 acre-feet of CAP
water in 2014, while the agricultural sector took delivery of 2,635 acre-feet of CAP water. Federal
delivery of CAP water to Indian tribes was 30,173 acre-feet and the Arizona Water Banking Authority
1
Tucson Active Management Area Water Demand and Supply Assessment: 1985-2025, Arizona Department of
Water Resources, January 2012.
2
Hazardous Weather Climatology for Arizona, NOAA Technical Memorandum NWS WR-282, C. Shoemaker and J
Davis, National Weather Service, Tucson, Arizona, February, 2008.
3
Garfin, G. G. F., H. Blanco, A. Comrie, P. Gonzalez, T. Piechota, R. Smyth, and R. Waskom. 2014. Chapter 20:
Southwest. Pages 462-486 in T. C. R. J.M. Melillo, and G.W. Yohe, editor. Climate Change Impacts in the United
States: The Third National Climate Assessment. U.S. Global Change Research Program, Washington, DC.
4
Seager, R. and M. Hoerling. 2014. Atmosphere and Ocean Origins of North American Droughts. Journal of Climate
27:4581-4606.
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took 29,759 acre-feet for long-term underground storage. In 2012 the Bureau of Reclamation
published a study, Colorado River Basin Water Supply and Demand Study, which projects future
imbalances between supply and demand on the Colorado River. Reclamation’s study determined
demand on the Colorado River is beginning to outpace supply. Because Arizona has junior priority
rights on the Colorado River and Reclamation’s study indicates shortages are likely, Arizona is
expected to bear the brunt of these shortages. Initially, shortages on the Colorado River will first
impact agriculture, but continued shortages could result in reductions to municipal and Indian water
supplies. Since there are few perennial streams in the SCR Basin, renewable water resources are
extremely important to the long-term viability of these streams. Ongoing drought in the Southwest,
changes to snowpack, timing of snowpack melting, decreased runoff and declining water levels in
Lake Mead could reduce water supplies to the SCR Basin in the future.
The SCR Basin area is within the Southwest’ Sun Corridor. According to the Pima Association of
Governments, the study area population is expected to reach 1.45 million by 2041. Pima County’s
draft Comprehensive Plan, Pima Prospers, recognizes that efficient use of existing and planned
infrastructure is important to support the current and future populations and that proposed new
development may impact overall water supply. The City of Tucson’s General Plan, Plan Tucson, also
recognizes the importance of water resources for a healthy environment and economy for Tucson
current population and projected growth.
A water supply and demand assessment conducted by ADWR in 2010 described water supply and
demand characteristics for 1985 through 2006 as well as projections to 2025 for the SCR Basin. The
assessment included municipal, industrial, agricultural and Indian water demand and evaluated
scenarios to address groundwater overdraft. A subsequent ADWR effort in 2013, Regional
Groundwater Flow Model of the Tucson Active Management Area, Model Update and Calibration,
projected water level changes in the SCR Basin through 2025. The model identifies areas where
groundwater levels are expected to recover, stabilize, or decline. Adaptive strategies need to be
developed in areas where groundwater is expected to decline.
The City of Tucson recently completed its Recycled Water Master Plan for the planned use of the
City’s recycled water. This effort complements their 2012 Water Plan Update that provides for long
term water reliability for the Tucson Water service area through 2050. Metropolitan Domestic
Water Improvement District completed its 50-year Long Range Water Resources Plan in 2015. Other
regional water providers are collaborating on groundwater replenishment programs, including
underground storage and recovery of Central Arizona Project (CAP) water and reclaimed water. A
SAWUA-sponsored study completed in 2015, Municipal Water Demand Trends Project, evaluated
anticipated trends in water use in the SCR Basin.
Nature of imbalances. Climate change can be expected to impact water supply availability of CAP
water to Arizona and the SCR Basin. Decreased Colorado River Basin snowpack and stream flow may
result in curtailments of water deliveries to some users. The probability of a Tier One shortage
declaration on the Colorado River is estimated to be 20 percent in 2016 and over 50 percent in
2017. This shortage will impact deliveries to agriculture in the SCR Basin. Additional future shortages
could ultimately impact municipal and Indian water deliveries. Climate change and persistent
drought conditions may also impact local water supplies. Natural recharge and mountain front
recharge may be reduced from increased evaporation resulting from projected increasing
temperatures and decreased precipitation from ongoing drought and future droughts generated by
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variations in ocean-atmosphere interactions. Curtailments in CAP water delivery will result in
increased groundwater use for municipal, industrial and agricultural sectors resulting in local
groundwater declines. The projected increased temperatures and CAP water reductions will result in
increased water demand for agriculture. There is uncertainty about municipal water demand
impacts due to climate change and water conservation. Spatial geographic imbalances in water
supply and demand within the SCR Basin need to be better understood.
Severity of potential consequences for not addressing imbalances and impacts. The consequences
for failing to address projected imbalances in water supply and demand will impact municipal,
industrial and agricultural sectors as well as the environment. Curtailments of CAP water to
agriculture will result in increased groundwater pumping and declining groundwater levels.
Subsidence has been strongly linked to increased groundwater pumping.5 Increased temperatures
from climate change will result in higher agricultural water demand and groundwater pumping
rates, and greater energy usage.
While municipal water conservation programs have been effective, Southern Arizona has been in
extended drought for the last 15 years. Water providers that have no access to renewable supplies
or lack water infrastructure may experience declining groundwater levels or water service
interruptions as drought conditions persist and climate change occurs.. Uncertainty about water
availability and water scarcity will have adverse economic impacts to the tourism, agricultural and
business sectors in the SCR Basin.
Different sectors have varying ability to adapt to the impacts of water supply and demand
imbalances. The large municipal water utilities have been banking renewable supplies water for
years to mitigate drought and shortage. Other utilities that rely on groundwater may experience
service interruptions due to declining groundwater levels and lack the infrastructure to access
renewable water resources. Rural residential areas that rely on private groundwater wells for water
supply may experience water shortages due to decreased mountain front recharge resulting from
changes in precipitation. These residents are particularly vulnerable to the impacts of drought,
climate change, and increased groundwater pumping. These vulnerable populations should be
identified and mitigation strategies identified.
The risks from climate change impacts to water providers could be numerous. Water providers
relying on groundwater could see higher power use and increased operational costs. Higher
intensity storms could cause widespread flooding and damage CAP delivery infrastructure and water
utilities’ transmission infrastructure. Shortages of CAP water delivery will also diminish the
availability of CAP water available for long term storage, also known as water banking. Shortages of
CAP water are expected to result in higher rates resulting in financial impacts to the municipal,
industrial and agricultural sectors that take delivery of CAP water. At this time it is unknown how
higher temperatures will affect residential water demand. Wildfires have been observed to increase
sediment in local streams and could impact natural infiltration rates as well as in channel reclaimed
water recharge projects.
Large water utilities are required by ADWR to have drought response plans in place. When a
Colorado River shortage declaration is declared by the Bureau of Reclamation, some water providers
5
Anderson, M. T. and L. H. Woolsey. 2005. Water availability for the western United States--Key scientific
challenges. U.S.G.S. Circular, 1261. Washington DC, USGS, 94 pp.
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that rely on CAP water will implement drought restrictions, while other water providers that rely on
groundwater will not. In order to be effective, coordination of drought response actions is
necessary. CAP water is now the primary water supply for the major water providers in the SCR
Basin. Stored or banked water will augment water supplies should CAP water delivery to municipal
water provider be necessary. However, under chronic, long-term shortages, once banked water
reserves are depleted, water resource managers will return to unsustainable groundwater pumping
to meet water demand.
Drought impacts to the environment are already being observed. Stream length in Cienega Creek,
one of the few perennial streams in the SCR Basin, has declined each year since the current drought
began. Stream flow is vital to the riparian habitat along these stream reaches. Agua Caliente springs
flow has declined and is attributed to both drought conditions and increased regional groundwater
pumping. The springs are currently being supplemented with groundwater which is not considered
a sustainable mitigation strategy. Adaptation and mitigation strategies could provide protection for
some of these vulnerable areas. Many riparian areas in the SCR Basin are hydrologically connected
to groundwater sources. These will be adversely impacted by declining groundwater levels. Drier
conditions from climate change could result in a higher possibility for wildfires as well as increased
flooding because of reduced plant cover. Climate change and drought are expected to impact
wildlife habitat and migration.
Climate change will have numerous impacts to agriculture in the SCR Basin. Warmer winter
temperatures are resulting in lower yields for crops such as wheat, as the plants mature earlier. At
the most restrictive Tier Three Colorado River shortage level, agricultural pool water deliveries to
farms will be curtailed resulting in either fallowing or use of groundwater for irrigation. If Colorado
River curtailments affect municipal and industrial users, water deliveries to groundwater savings
facilities will be curtailed as well. The cost of agricultural pool water will also increase under CAP
water curtailments and adversely impact agriculture financially. Extreme flood events could also
damage agricultural water delivery infrastructure.
2. Extent to which Proposal Describes and Provide Support for SAWUA’s Ability to Address Basin Study
Elements with the Timeframe Required
Projections of water supply and demand. Abundant data on existing and projected water supply and
demand are available from ADWR’s Tucson Active Management Area Water Use and Demand
Assessment. Projections are made through the year 2025. However, water supply and demand
projections for the proposed basin planning horizon of 2060 will be needed. Projections will include
a near-term, mid-term and long-term (2060) horizon. Water supply and demand projections
developed by ADWR were updated in a subsequent report: Tucson Active Management Area
Groundwater Flow Model. This model uses MODFLOW-NWT.
Numerous climate change models are available for the Southwest. SAWUA partners at the
University of Arizona will provide input on appropriate climate models that integrate climate change
to the water supply and demand model, with input from Reclamation. SAWUA’s partners at ADWR
will work with SAWUA to integrate climate change and water demand into the water supply and
demand model.
Analysis of How Existing Water and Power Infrastructure and Operations will Perform in the Face of
Changing Water Realities. Regional water planning for the SCR Basin is based on regionally accepted
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water supply and demand projections and water delivery infrastructure has been developed
consistent with these projections. Imbalances between water supply and demand and its impact to
water infrastructure will need to be analyzed to take into consideration future curtailments in
Colorado River water deliveries, reductions in water supply availability and changes to water
demand.
Although the SCR Basin has no hydroelectric power production facilities within its boundaries, water
and power are interrelated. Colorado River water delivered through the Central Arizona Project is
pumped 336 linear miles at an elevation increase of 2,400 feet to its terminus in Tucson, Arizona.
Power to deliver Colorado River water to Central Arizona is generated at the Navajo Power
Generation Station. This generating station provides more than 90% of the power to deliver CAP
Water. Environmental regulations could increase the power costs to deliver CAP water resulting in
financial impacts to CAP water users.
Reductions in CAP water deliveries may require recovery of CAP water stored in underground
aquifers. Power costs may be incurred to recovery this stored water. Imbalances between water
supply and demand may require return to groundwater pumping for agriculture and municipal
sectors. Power costs for water and wastewater utilities are also one of the largest budget expenses.
Water use is also imbedded in power production. The SCR Basin is served by two electrical utilities;
Tucson Electric Power and Trico Electric Cooperative. Much of the electricity produced for use in the
SCR Basin is generated at coal-fired power plants located in Northeastern Arizona.6 Coal fired power
plants use an average of 510 gallons per MW-hour.7 Projected temperature increases from climate
change are expected to increase power consumption throughout all sectors, which will result in
increased water consumption for power generation.
Development of Appropriate Adaptation and Mitigation Strategies to Meet Future Water Demands.
The proposed study will develop strategies to address water supply and demand imbalances. The
Arizona Water Banking Authority, Central Arizona Water Conservation District and local water
providers are storing CAP water and/or effluent in underground storage facilities throughout the
SCR Basin area. Analysis of where this stored water will be needed within the basin for future
demand and evaluation of the infrastructure needed to delivery it is one of the mitigation strategies
that will be evaluated. The impacts of climate change on natural recharge and its impact to stream
flows and groundwater levels could also influence mitigation strategies such as groundwater
pumping and its impacts to rural well owners and groundwater dependent ecosystems.
The Arizona Water Banking Authority has prepared a recovery plan for 600,000 acre-feet of CAP
water stored in the SCR Basin Study. There are an additional 800,000 acre-feet of CAP and effluent
stored underground within the basin by various entities. The timing, location and access to recover
this water to meet future water demand, particularly if persistent drought and long term CAP
shortages become a reality, will be key mitigation strategies in the SCR Basin’s viability. Areas in the
SCR Basin that have no access to infrastructure for renewable water supply will be especially
vulnerable. EPA’s climate change risk assessment tool could be used for a pilot evaluation on one of
6
Ties That Bind: Plans for New Energy Infrastructure in Pima County, Arizona, Fonseca, pg 4, J, and Connolly, N.,
Pima County Office of Sustainability and Conservation, January 2012.
7
The Water Costs of Electricity in Arizona, Pasqualetti, M. and Kelley, S, ASU School of Geographical Sciences,
December 22, 2008.
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the smaller water providers. Colorado River Shortage adaptation and mitigation plans should also be
reviewed, as the SCR basin receives CAP water and some sectors will be impacted by shortages.
Trade-off Analysis of the Strategies Identified and Findings. It is recommended that a scenario
planning approach, coupled with modeling, be used to develop strategies for addressing water
supply and demand imbalances. Tucson Water and the Bureau of Reclamation’s Colorado River
Basin Study both used scenario planning and quantitative analyses and/or modeling. This study
proposes to use scenario planning to evaluate water supply and demand imbalances and their
impacts.
3. Need for Federal Involvement
Reclamation Technical Abilities. Reclamation’s technical expertise is needed because of the nature
and complexity of the issues in the SCR Basin. Reclamation’s West-Wide Climate Risk Assessment
will be used to assess climate change impacts on water supply and demand and will be integrated
with the groundwater predictive model for this study. Additionally, Reclamation’s experience in
previous basin studies can provide guidance in the development of adaptation and mitigation
strategies and analysis of these strategies. Reclamation’s involvement in implementation of Indian
water rights settlements will enhance the planning process for water infrastructure and operations
that benefits stakeholders in the SCR Basin, Arizona and the U.S.
Multijurisdictional Issues and Issues of National Significance. Reclamation’s role in managing the
Lower Colorado River and water resource projects and programs in the Southwest makes it a key
partner for this study. Reclamation’s responsibility in declaring shortage on the Lower Colorado
River is of regional and national significance. Because Arizona has junior priority rights on the
Colorado River, Arizona is expected to bear the brunt of any shortage declared by Reclamation.
Although initial shortages on the Colorado River will impact water deliveries to agriculture in the SCR
Basin, all CAP customers will be impacted financially. Continued shortages could result in
curtailments to municipal and Indian water supplies.
Reclamation Activity in the SCR Basin. Reclamation has a strong presence in the SCR Basin. The SCR
Basin is within the Santa Cruz River, a tributary to the Colorado River, one of the major river systems
within the Reclamation’s service area. Colorado River water is delivered through the Central Arizona
Project, a water delivery system that provides renewable water to many municipal and agricultural
sectors in the SCR Basin.
Reclamation provides Colorado River water to meet Indian water rights settlement obligations in the
SCR Basin. This study could complement Reclamation’s efforts to support implementation of the
Southern Arizona Water Rights Settlement Act and the Arizona Water Settlements Act with the San
Xavier and Schuk Toak Districts of the Tohono O’odham Nation through cooperative planning for
local renewable water resources and infrastructure.
Reclamation Projects Affected by the SCR Basin. CAP, authorized by Congress in 1968, delivers
Colorado Water to the SCR Basin. The Tucson Aqueduct, completed in 1993 under Reclamation’s
oversight, is the last segment of a 336-mile water delivery system that delivers over 180,000 acrefeet of Colorado River water to the SCR Basin. The Central Arizona Project delivers Colorado River
water to seven municipal water utilities, three Indian entities and two agricultural farms. Colorado
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River water shortages will impact each of these sectors significantly. SCR Basin study partners and
other entities recharging CAP water in underground storage facilities will also be impacted.
Reclamation is collaborating with a local water provider on a groundwater savings project that will
deliver treated wastewater to agricultural lands to accrue long term storage credits. The project
participants include Metropolitan Domestic Water Improvement District, Cortaro-Marana Irrigation
District, Pima County and Reclamation. Metro Water effluent and effluent allocated under the
Southern Arizona Water Rights Settlement Act will be delivered to Cortaro-Marana from the County
wastewater reclamation facility
4. Availability and quality of existing data and models applicable to the proposed study
List of Data and Models to be Included. The number and quality of existing data and models on
water supply and demand for the municipal water sector in the SCR Basin is robust. ADWR prepares
management plans every ten years. As part of the next upcoming plan, ADWR prepared a water
supply and demand assessment in 2012. The assessment also included a regional groundwater flow
model for the SCR Basin Study Area. The groundwater model predicts areas of decreasing
groundwater levels and areas where groundwater is expected to rise. The model code simulates
groundwater flow in the SCR Basin area using MODFLOW-NWT, developed by the U.S. Geological
Survey. A residential water demand study8 completed in 2015 evaluates trends in municipal water
demand. Results of this study will provide input on anticipated municipal changes to water demand.
A number of climate change model projections exist, at varying spatial and temporal scales, to
provide estimated changes to temperature and precipitation. The Bureau of Reclamation’s WestWide Climate Risk Assessment, and updates to these projections9 will be employed to assess
projected impacts to stream flows, water supplies and demands, and other relevant factors. This
assessment will form the foundation for detailed analysis and development of adaptation options
for the SCR Basin area. The study will collaborate with the University of Arizona to identify
additional appropriate climate and paleoclimate data and climate model projection data10 11, using
publicly-available resources, in order to consider additional uncertainties, including those embodied
in multiple projections of summer precipitation12.
Data or models to be developed. The water supply and demand projections for water planning are
made through 2025. However, projections for a longer period, at least through 2060 or beyond
should be considered or developed. Water supply and demand projections for the SCR Basin study
area will need to be modified to take climate change into consideration.
8
Final Technical Memorandum, Pima County Residential Water Demand Study, G Woodard, Montgomery &
Associates, March 2015.
9
http://gdo-dcp.ucllnl.org/downscaled_cmip_projections/dcpInterface.html
10
Meko, D., C. A. Woodhouse, C. A. Baisan, T. Knight, J. J. Lukas, M. K. Hughes, and M. W. Salzer. 2007. Medieval
drought in the Upper Colorado River Basin. Geophysical Research Letters 34.
11
Griffin, D., C. A. Woodhouse, D. M. Meko, D. W. Stahle, H. L. Faulstich, C. Carrillo, R. Touchan, C. L. Castro, and S.
W. Leavitt. 2013. North American monsoon precipitation reconstructed from tree-ring latewood. Geophysical
Research Letters 40:954-958.
12
Castro, C.L., H-I. Chang, F. Dominguez, C. Carrillo, J. Kyung-Schemm, H. H-M. Juang, 2012. Can a regional climate
model improve warm season forecasts in North America? J. Climate, 25, 8212-8237.
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An analysis of climate change projections and determination of the appropriate set of climate
change projections for the SCR basin study area needs to be determined to recalibrate projected
water supply and demand deficiencies.
Impacts to mountain front recharge from increased temperature and changes to precipitation will
impact water supply and especially impact rural residents who rely on private groundwater wells for
their water supply. The climate change impacts13 need to be translated to groundwater flow models
to determine the availability of water supply and impacts to groundwater levels.
The impacts of anticipated CAP shortages to water supply sectors need to be better understood. If
CAP shortages result in increased groundwater pumping, the magnitude and impacts need to be
better identified and understood. Expertise in model operations will be needed to run additional
scenarios incorporating climate change data and projected changes to water supply and demand.
Available data and models to be used in this study are listed in Table 2 below:
Data or Model
Regional Groundwater
Flow Model for the Tucson
Active, Arizona. Model
Update and Calibration,
Modeling Report No. 24.
April 2013
Draft Fourth Management
Plan for Tucson Active
Management Area 20102020 (anticipated)
Tucson Active Management
Area Water Demand and
Supply Assessment: 19852025
Arizona’s Next Century: A
Strategic Vision for Water
Supply Sustainability,
January 2014
Colorado River Basin
Supply and Demand Study,
U.S Bureau of Reclamation,
November 2013
A Forecast Model of Single
Family Residential Water
Demand for Pima County,
November 2014
Recycled Water Master
Plan, Tucson Water,
December 2013
Description
Source
Upgrades previous numerical groundwater flow model and
provides a more current tool to assist in management of Tucson
Active Management Area water resources
ADWR
Water management programs for the Tucson Active Management
Area over the next ten years. Projections about future conditions,
assessment of progress toward achieving safe yield goal for
groundwater and recommendations regarding future water
management strategies
Historical water demand and supply characteristics for 1985
through 2006 and projections to 2025. Evaluates possible
scenarios for future groundwater overdraft using low, medium and
high reasonable water demand
ADWR
ADWR
Assesses current and projected water demands and supplies and
provides potential strategies to help Arizona meet its future water
supply and demand needs over the next 100 years
ADWR
Defines future imbalances in water supply and demand through
2060 for the seven Colorado River Basin States. Develops and
analyses options and strategies to resolve imbalances
Reclamation
Forecasts significant changes in single family residential demand
using a dynamic simulation model
Montgomery
& Associates
Provides integrated recycled water program that maximizes the
benefits of the City of Tucson’s recycled water resource and
provides framework for activities to ensure implementation of
recycled water projects and programs
City of Tucson
13
Ajami, H., T. Meixner, F. Dominguez, J. Hogan, and T. Maddock. 2012. Seasonalizing Mountain System Recharge
in Semi-Arid Basins-Climate Change Impacts. Groundwater 50:585-597.
Lower Santa Cruz River Basin Study
SAWUA Proposal
Page 11
Data or Model
2012 Update: Water Plan
2000 - 2050
2013 Effluent Generation
and Utilization Report
Metropolitan Domestic
Water Improvement
District Long Range Water
Resources Plan, Feb 2015
Recovery of Water Stored
by the Arizona Water
Banking Authority, April
2014
Draft 2015 Central Arizona
Groundwater
Replenishment District
Plan of Operation,
December 2014
Additional Water Demand
Data
Additional Water Supply
Data
Additional Water Supply
Data
Remediated Water Use
Water Accounting Areas
West-Wide Climate Risk
Assessments: BiasCorrected and Spatially
Downscaled Surface Water
Projections, March 2011
and updates
Description
Scenario planning based long-term water resource plan for the
Tucson Water Service Area.
Quantity of effluent produced at Pima County regional wastewater
reclamation facilities and utilization of effluent in the SCR Basin
Study Area
Strategy for managing water resources for the next 50 years.
Water demand and supply scenarios through 2065
Provides strategy for recovering water stored underground by the
Arizona Water Banking Authority using the Colorado River
Simulation System model and a custom recovery model that
calculates the probability of specific recovery volumes occurring
through time based on a range of supply and demand conditions.
A joint plan by Arizona Water Banking Authority, Arizona
Department of Water Resources, Central Arizona Water
Conservation District
Provides an estimate of projected groundwater replenishment
obligations for 100 years, a description of the water resources that
the Groundwater Replenishment District plans to use to meet
obligations and description of infrastructure and projects to be
used for replenishment
Water Providers Assured Water Supply Submittals
Annual Groundwater Withdrawal Reports-last 5 years
Water Service Area Maps
Subsidence Maps
Underground Storage Facility Permits in the study area
Groundwater Savings Facility Permits in the study area
Water Storage Permits in the study area
CAP Water Deliveries to SCR Basin Study Area-last 5 years
CAP Entitlements in the SCR Basin Study Area
Projected CAP Shortages to SCR Basin Study Area
Data associated with groundwater pump and treat systems
removing contaminants from the aquifer. This volume of water
pumped each year will be constant or increased through the study
period. It will not be associated with pumping to meet water
demands, except where occurring currently
Source
Tucson Water
Pima County
Metropolitan
Domestic
Water
Improvement
District
CAWCD
CAWCD
ADWR
ADWR
CAWCD
ADWR
WAAs refine the study area into regions that are experiencing
different aquifer responses to groundwater use. Scenarios will be
evaluated to seek potential solutions and their impact on
individual WAAs that are experiencing continued aquifer level
declines
Safe Yield
Task Force
Analysis of changes in hydroclimate variables and documentation
for new hydrologic projections datasets. Will be used to assess
changes in natural mountain front recharge potential
Reclamation
Lower Santa Cruz River Basin Study
SAWUA Proposal
Page 12
Data or Model
Assessment of Climate
Change in the Southwest
U.S.
Description
Evaluates and synthesizes information from a wide range of
sources and assesses climate change effects on sectors including
water. Various climate change models will be reviewed to
determine the optimum model to be used to assess water supply
and demand in the SCR Basin area
Source
Climas/UA
Table 2 – Data and Models Proposed
Data and Model Coordination. Existing data, studies and modeling tools will be used for the Basin
Study striving for a full integration of information and predictive models. A large part of the efforts
will focus on the ADWR TAMA groundwater flow model which will provide the means to evaluate
different water management strategies and infrastructure projects on each of the Water Accounting
Areas where the regional aquifer is experiencing continued water level declines.
Various module input files of the TAMA model will be manipulated based on recent water demand
trends, new recent infrastructure projects affecting groundwater pumping and climate change
modeling affecting stream flows and evapotranspiration, as well as, mountain front recharge.
Utilizing scenario planning will provide a family of future scenarios that may address aquifer
management in different water accounting areas. The TAMA model will be used to run different
strategies necessary to evaluate the potential successes and feasibility of each scenario.
5. Level of Support for the Basin Study The local cost share study partner for the SCR Basin Study is the
Southern Arizona Water Users Association (SAWUA). SAWUA members represent diverse regional
interests including municipal water providers, wastewater providers and agricultural interests.
SAWUA members have water delivery authority to over 80 percent the study area population.
Water providers in the SCR Basin Study area have a total entitlement of 196,798 acre-feet of
Colorado River water and took delivery of 86 percent of their entitlement in 2014. The SAWUA
members will be directly impacted by water supply and demand imbalances resulting from climate
change. SAWUA members will be providing water supply and demand data, infrastructure data and
long term planning information for the study. SAWUA’s in-kind contribution is $245,000 and
additional partners will contribute $148,000 to the study. SAWUA support includes:
Tucson Water
Pima County
Metro Water
Oro Valley
Remaining SAWUA agencies
$75,000
$45,000
$40,000
$10,000
$75,000
ADWR prepares water management plans for the basin area to address groundwater overdraft.
ADWR has a regulatory authority in implementation of Arizona’s Groundwater Management Act and
provides regulatory permitting of underground water storage facilities and groundwater pumping.
ADWR represents the State of Arizona in policy negotiations of Colorado River operations and
administration of Colorado River entitlements. ADWR will provide access to the Regional
Groundwater Flow Model and will provide staff to coordinate the model with water supply and
demand projections. ADWR estimated in-kind contribution is $5,000 and can also provide $50,000
cash from the Water Management Assistance Program. This program, funded from revenue from
the groundwater withdrawal fees can be used for water conservation, augmentation, monitoring
and studies. ADWR total cost share is $55,000.
Lower Santa Cruz River Basin Study
SAWUA Proposal
Page 13
Pima Association of Governments (PAG) is the study area’s regional metropolitan planning
organization for transportation planning, environmental planning and technical services. It is the
Designated Planning Agency (DPA) under Section 208 of the Clean Water Act, which addresses
wastewater and non-point source pollution in stormwater. Both reclaimed water and stormwater
have growing potential for utilization as a water resource in the Basin Study area. PAG’s governing
body, Regional Council, consists of eight elected officials from each of the local and tribal
governments, plus a representative of the Arizona State Transportation Board. In its regional
planning role, PAG can provide an integrated approach to watershed planning and management,
involving multiple stakeholders that cross jurisdiction and disciplines. For example, PAG’s expertise
in shallow groundwater investigations and habitat issues along edges of the basin will be an asset to
the Management Committee for the study. PAG will lead the stakeholder engagement process by
convening outreach meetings and communications support. PAG expertise will be used to inform
and engage decision makers through its Watershed Subcommittee, Environmental Planning
Advisory Committee, Management Committee and Regional Council. PAG will provide its technical
expertise by providing input to the study and document review. PAG’s estimated in-kind
contribution to the SCR Basin Study is $73,000.
The Central Arizona Water Conservation District (CAWCD) operates and manages the Central
Arizona Project which is designed to bring about 1.5 million acre-feet of Colorado River Water to
central Arizona through a 336-mile system of aqueducts, tunnels, pumping stations and pipelines.
CAWCD delivers over 230,000 acre-feet of Colorado River water to municipal, industrial, agricultural
and Indian customers in the SCR Basin area. CAWCD is evaluating how near-term shortages on the
Colorado River will impact CAP water delivery to central Arizona’s farmers and is working closely
with stakeholders in the SCR Basin area to identify and address the impacts of future potential
Colorado River shortages. CAWCD is also working collaboratively with Arizona and other Colorado
River users to address the effects the Colorado River Basin drought conditions and impending
potential Colorado River shortages. CAWCD can provide historic CAP water delivery data and water
supply projections under various shortage scenarios. CAWCD also collaborates with local water
providers to store CAP in underground storage basins. CAWCD recently completed a plan of
operation for the Central Arizona Groundwater Replenishment District (GRD). The plan included
water demand projections for water providers in its service area which includes the SCR Basin Study
area. The plan also evaluates water supply utilization to assess the replenishment obligations for
GRD member lands and member service areas. CAWCD’s study contribution is $15,000 of in-kind.
The University of Arizona, located within the SCR Basin Area, has extensive expertise in water issues
and climate change. The Climate Assessment for the Southwest (CLIMAS) housed at the University’s
Institute of the Environment, conducts research on the nature, causes and consequences of climate
change and variability in the Southwest. CLIMAS and colleagues from the University’s Hydrology and
Water Resources, and Atmospheric Sciences Departments, will partner with Reclamation to identify
appropriate climate projections that will be coordinated with ADWR Regional Groundwater Flow
Model and water supply and demand projections. The Center for Climate Adaptation and Science
and Solutions (CCASS), also housed at the Institute of the Environment, brings together the
University’s expertise in climate impacts and vulnerability assessment at regional, national and
international scales. The Water Resources Research Center, housed at the University’s College of
Agriculture and Life Sciences, promotes understanding of critical state and regional water
management and policy issues through research, community outreach and engagement and public
education. The University’s in-kind contribution will be $5,000.
Lower Santa Cruz River Basin Study
SAWUA Proposal
Page 14
Many stakeholders in the SCR Basin area have a significant interest in the impacts of climate change
on water supply and demand and are prepared to assist in this study. Letters of support from the
stakeholders are included in Appendix A. There is no known opposition to the proposed study.
Stakeholder Engagement. Throughout the Lower SCR Basin Study, stakeholders will be informed and
their input will be garnered and considered at key intervals as the project progresses. PAG will be
the lead agency for stakeholder involvement and public communications. However, SAWUA
members will be invited to participate in all events and will have input on all materials distributed.
Stakeholder Information Meetings. Annual public meetings will be held to inform and garner input
about the project. These three meetings will be held in a publicly accessible location and will be
noticed through press releases, social media, printed media and flier distribution. Particular efforts
will be made to invite key stakeholders including municipalities and tribal governments, water
providers and private well owners, agricultural and industrial users, and environmental
stakeholders.
Regional Standing Committee Meetings. Pima Association of Governments will engage technical
experts, professionals and interest groups through its Environmental Planning Advisory Committee
(EPAC) and its Watershed Planning Subcommittee. EPAC is a 35-member standing committee with
the following representation:




Member governments (City of Tucson, Pima County, Towns of Marana, Oro Valley and
Sahuarita, City of South Tucson, Tohono O’odham Nation, Pascua Yaqui Tribe)
Citizen representatives from each of the above listed member jurisdiction area
Interest groups (public interest, professional technical, environment, natural resources
conservation, energy industry, mining industry, construction industry, local business,
education/research, transportation)
Ex Officio: State and federal entities (Arizona Department of Water Resources, Arizona
Department of Environmental Quality, Arizona State Land Department, Davis Monthan Air
Force Base, U.S. Environmental Protection Agency).
In addition, all meetings are public and widely distributed through a large mailing list. PAG plans to
have presentations on the Lower SCR Basin Study at a minimum of four EPAC meetings and two
Watershed Planning Subcommittee meetings during the course of the project. If needed, EPAC can
also be utilized to receive direct feedback on project elements because it is a voting body with
standing representation.
Regional Managers and Decision Makers. This basin study will develop adaptation and mitigation
strategies to address water supply and demand imbalances in the face of climate change. In order
to move into future implementation and collaboration, it is essential that management and political
decision makers be well informed and have opportunity to provide input during the evaluation.
PAG will ensure that jurisdictional managers are informed about the Lower SCR Basin Study to
through its top policy advisory committee, the PAG Management Committee. Members of this
committee include the Pima County Administrator, the city managers from the cities of Tucson and
South Tucson, the town managers from the towns of Marana, Oro Valley, and Sahuarita, a Tribal
Lower Santa Cruz River Basin Study
SAWUA Proposal
Page 15
Council member from the Pascua Yaqui Tribe and the Roads Division Manager from the Tohono
O’odham Nation.
During the study process, key elected officials will be kept abreast of project progress and results
through information provided to the PAG governing board and the PAG Regional Council. The
Regional Council includes a Pima County Supervisor, mayors from the City of Tucson, the City of
South Tucson, the Town of Marana, the Town of Oro Valley and the Town of Sahuarita, the Vice
Chairwoman from the Pascua Yaqui Tribe, the Chairman of the Tohono O’odham Nation and a
member of the Arizona State Transportation Board.
6. Extent to which proposed study will employ integrated watershed planning and management
approach
As the local study partner, SAWUA provides an ideal framework for regional water resource
planning and management as it has a strong history in regional collaboration on water issues in the
SCR Basin. Until 1993, the region relied solely on groundwater for its water supply. Regional
collaboration to utilize renewable water resources has resulted in localized recovery of groundwater
levels in some areas. There is great interest in addressing localized areas experiencing groundwater
declines through implementation of adaptation and management strategies including water
resource management, conservation, reuse, replenishment and recovery infrastructure. Because of
the arid nature of the Sonoran Desert, the interconnectedness and need for balance of water
resources for municipal, industrial, agriculture and environment is valued.
The SCR Basin has extremely limited surface water supplies. The rare perennial creeks primarily
provide water for environmental and eco-recreational benefit, ranching and one golf course. Many
basin-edge streams feed water into shallow groundwater areas that support critical riparian habitat.
Stormwater flows also provide much needed environmental water for the region and it is
increasingly being incorporated into urban and suburban areas through green infrastructure and
rainwater harvesting projects. By following Low Impact Development principles, the region realizes
further benefits as it uses stormwater for landscaping instead of irrigating with potable or reclaimed
water supplies. These coordinated management approaches can be incorporated into scenario
planning because there is growing policy support for this type of water management in the region.
Study Cost Estimate.
The proposed Basin Study is estimated to cost $785,500 with fifty percent contributed by the study
partners and the remainder by Reclamation. A summary of the study costs by task is shown in Table 3.
Tasks and Description
1.
2.
3.
4.
5.
6.
7.
8.
9.
Non-Federal
$ Share
Plan of Study and MOA
20,000
Conduct Scenario Planning
40,000
Develop Groundwater Model Inputs
45,000
Implement Groundwater Model
4,000
Conduct Infrastructure Analysis
26,000
Identify Adaptation & Mitigation Strategies
66,000
Analyze Alternatives & Trade Offs
40,000
Prepare Basin Plan
60,000
Conduct Technical Sufficiency Review
0
Lower Santa Cruz River Basin Study
SAWUA Proposal
Federal
$ Share
10,000
20,000
45,000
50,000
10,000
75,000
20,000
10,000
20,000
Total
Cost
30,000
60,000
90,000
54,000
36,000
141,000
60,000
70,000
20,000
Page 16
Tasks and Description
Non-Federal
Federal
Total
$ Share
$ Share
Cost
10. Communication & Outreach Plan
53,000
15,000
68,000
11. Prepare Final Report
39,000
50,000
89,000
12. Administer Study
0
56,250
56,250
13. Non-Federal Contracting
0
11,250
11,250
Total Costs
$393,000 $392,500 $785,500
Table 3 – Study Costs
Responsibility Assignment
SAWUA is the lead partner for this study and has support and participation of several partners. In
addition to the water and wastewater providers and agricultural interests represented by SAWUA, the
study will include participation from the Pima Association of Governments (PAG), the Arizona
Department of Water Resources (ADWR), Central Arizona Water Conservation District (CAWCD) and the
University of Arizona (UA). A study management committee will oversee coordination, stakeholder
outreach and overall management of the study. It will include representatives from water providers,
agriculture, ADWR, PAG, CAWCD and UA. A technical committee will provide input on data collection,
scenario planning, groundwater modeling and infrastructure and alternative analysis. It will include
water and wastewater providers, agricultural interests, ADWR, CAWCD and the UA.
The proposed study partners have access to and have developed robust data on water supply and
demand in the study area. Groundwater models developed in coordination with ADWR will be updated
under this study. A summary of the partners’ primary responsibility is provided in Table 4 below.
Task
1
2
3
4
5
6
7
8
9
10
11
12
13
Description
Plan of Study and MOA
Conduct Scenario Planning
Develop Groundwater Model Inputs
Implement Groundwater Model
Conduct Infrastructure Analysis
Identify Adaptation & Mitigation Strategies
Analyze Alternatives & Trade Offs
Prepare Basin Plan
Conduct Technical Sufficiency Review
Communication & Outreach Plan
Prepare Final Report
Administer Study
Non-Federal Contracting
Study Partners
X
X
X
Reclamation
X
X
X
X
X
X
X
X
X
X
X
Table 4 – Primary Responsibility Assignment
Study Milestone Schedule
SAWUA anticipates completing the proposed Basin Study within 33 months after initiation. A schedule
of milestone tasks is included in Table 5 below.
Lower Santa Cruz River Basin Study
SAWUA Proposal
Page 17
Milestone
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Year One
Qt1 Qt2
Qt3
Qt4
Year Two
Qt1 Qt2
Qt3
Qt4
Year Three
Qt1 Qt2 Qt3
Plan of Study and MOA
Conduct Scenario Planning
Develop Groundwater
Model Inputs
Implement Groundwater
Model
Conduct Infrastructure
Analysis
Identify Adaptation &
Mitigation Strategies
Analyze Alternatives &
Trade Offs
Prepare Basin Plan
Conduct Technical
Sufficiency Review
Communication &
Outreach Plan
Prepare Final Report
Administer Study
Non-Federal Contracting
Table 5 – Study Milestone Schedule
Cost-Share Partners and Study Contacts
Cost share partner and contacts for this study are indicated below.
Local Share Partner
Warren Tenney, President
Southern Arizona Water Users Association
Metropolitan Domestic Water Improvement District
6265 N La Cañada
Tucson, Arizona 85704
[email protected]
Federal Partner
Mary J. Reece, P.E.
Manager, Program Development Division
Phoenix Area Office
U.S. Bureau of Reclamation
6150 West Thunderbird Road
Glendale Arizona 85306-4001
[email protected]
Kathleen M. Chavez, P.E.
Southern Arizona Water Users Association
Regional Wastewater Reclamation Department
Pima County
201 N Stone Avenue – 8th Floor
Tucson, Arizona 85701
[email protected]
Eve Halper
Natural Resources Specialist
U.S. Bureau of Reclamation
Tucson Field Office
300 W. Congress St., FB-37
Tucson, AZ 85701
[email protected]
Lower Santa Cruz River Basin Study
SAWUA Proposal
Page 18
Lower Santa Cruz River Basin Study
Appendix A
Letters of Support
Lower Santa Cruz River Basin Study
SAWUA Proposal
Page 19
PO BOX 638 • MARANA AZ 85653-0638 • 520-682-2516 • FAX 520-682-2517 • BKWFarms.com
Bureau of Reclamation
Attn: Ms. Amanda Erath
Mail Code: 84-52000
P.O. Box 25007
Denver, CO 80225
RE:
Lower Santa Cruz River Basin Study Proposal Application
Dear Ms. Erath,
BKW Farms is pleased to support for the above-reference proposal application submitted by the
Southern Arizona Water Users Association (SAWUA) to the U.S. Bureau of Reclamation’s Basin Study
Program.
BKW Farms is a member of SAWUA and uses CAP water on its agricultural lands. Persistent drought
conditions locally and in the Southwest are expected to have significant impact on agricultural water
supply and demand. We support SAWUA’s efforts to seek a partnership with the Bureau of Reclamation
to analyze the potential impacts of climate change on the availability of water resources in the Lower
Santa Cruz River Basin.
The proposed study will be beneficial in planning for long-term water supplies to BKW Farms and to the
entire Tucson Active Management Area.
Please feel free to contact me if you have any questions or require additional information.
Sincerely,
Brian Wong
S/S