Drought Plan 2022 UpdateCITY OF BOULDER DROUGHT PLAN (4/13/2022
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2022 Update
City of Boulder
Drought Plan
CITY OF BOULDER
DROUGHT PLAN
This Drought Plan was developed by the City of Boulder’s Utilities Department staff, on
behalf of the city manager, with support from ELEMENT Water Consulting, Inc. and
Lynker Technologies. Recognizing that a variety of perspectives is valuable in preparing
a comprehensive drought plan and informing the development of an effective drought
response program, the city formed a Drought Committee comprising stakeholders from
multiple city departments. The Drought Committee was pivotal in the development of this
plan and will be directly involved in the implementation of a drought declaration.
Committee members include city staff from the following divisions and departments: City
Attorney’s Office, City Manager’s Office, Communications and Engagement, Planning
and Development Services, Open Space and Mountain Parks, Parks and Recreation,
Public Works Business Services, Transportation and Mobility and Utilities. The city’s
Water Resources Advisory Board, which advises the Boulder City Council, Planning
Board and city staff on community utilities issues, provided critical input on key plan
components throughout the plan development.
This Drought Plan was approved by the City Manager on November 2, 2022.
By:__________________________________
Nuria Rivera-Vandermyde, City Manager
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TABLE OF CONTENTS
PREFACE ....................................................................................................................... 1
APPLICABILITY ................................................................................................................ 2
RELATED PLANNING EFFORTS .......................................................................................... 2
1. INTRODUCTION ......................................................................................................... 3
2. RELIABILITY CRITERIA AND GUIDING PRINCIPLES ............................................. 4
3. PROJECTED STORAGE INDEX AND DEMAND REDUCTION TARGETS .............. 6
4. STAGED DROUGHT RESPONSE ............................................................................. 7
4.1. DROUGHT ALERT STAGES AND RESPONSE OVERVIEW ............................................ 7
4.1.1. PRE-DECLARATION DROUGHT WATCH .................................................................... 8
4.1.2. STAGE 1 – SERIOUS .............................................................................................. 8
4.1.3. STAGE 2 – SEVERE ................................................................................................ 8
4.1.4. STAGE 3 – EXTREME ............................................................................................. 8
4.2. SUPPLY-SIDE RESPONSE ...................................................................................... 9
4.3. DEMAND-SIDE RESPONSE ..................................................................................... 9
4.3.1. PUBLIC EDUCATION AND OUTREACH ....................................................................... 9
4.3.2. WATER BUDGETS, WATER RATES AND SURCHARGES ............................................ 10
4.3.3. WATER USE LIMITATIONS ..................................................................................... 10
4.4. ENFORCEMENT OF DROUGHT RESPONSE MEASURES ............................................ 12
5. MONITORING AND IMPLEMENTATION ................................................................. 12
5.1. DROUGHT COMMITTEE ........................................................................................ 12
5.2. MONITORING OF DROUGHT INDICATORS ............................................................... 13
5.3. DROUGHT DECLARATIONS ................................................................................... 14
5.4. REVENUE IMPLICATIONS ...................................................................................... 15
5.5. REMOVAL OF DROUGHT DECLARATION ................................................................ 15
7. PLAN APPROVAL ................................................................................................... 16
7.1. PLAN APPROVAL AND ADOPTION ......................................................................... 16
7.2. PERIODIC REVIEW AND UPDATE ........................................................................... 16
8. KEY REFERENCES ................................................................................................. 16
List of Figures
Figure 1: Guiding Principles for Water Use in a Drought. ........................................................... 5
List of Tables
Table 1: Projected Storage Index, Drought Alert Stages and Demand Reduction Goals ............ 7
Table 2: Potential Water Use Limitations. ..................................................................................11
Table 3: City of Boulder Drought Committee. ............................................................................13
CITY OF BOULDER DROUGHT PLAN
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PREFACE
The purpose of the City of Boulder Drought Plan is to provide a guidance document for
recognizing and responding to droughts and other conditions that affect water supply availability
for Boulder. This document is an update to Boulder’s 2010 drought plan 1 which was originally
prepared in 2003, revised in 2004 and appended in 2010. The original plan included an
assessment of the adequacy of the city’s water supply system and a plan for recognizing and
responding to droughts in a manner that is consistent with the city’s adopted water supply
reliability criteria. The original plan also provided research information about the use of water
budget rate structures for encouraging long-term water conservation and enhancing drought
management. In 2010, the city updated the plan content and incorporated the application of water
budgets as a drought response tool.
In the process of preparing this plan update, the city re-evaluated how it monitors for and assesses
drought conditions, mitigates potential impacts from drought and responds to drought. The city
considered analyses of recent supply and demand data along with lessons learned from prior
drought periods. While the 2010 plan was structured around using water budgets as the primary
tool to influence water use reductions during drought, experience with water budgets since that
time has informed the use of additional response measures and tools in this updated plan. An
update to how the city classifies droughts and the staged drought response program reflect that
work. New features of this plan include:
• A process for engaging stakeholders in multiple city departments in monitoring conditions
and responding to droughts.
• An updated set of Guiding Principles that applies to the selection of response measures
for each unique drought.
• A change from using four Drought Alert Stages, in which the first stage was voluntary, to
using a pre-declaration Watch category and three Drought Alert Stages, in which each
stage is mandatory, to better align with the city’s water supply reliability criteria.
• Clarification of the process by which the city formally declares a drought under one of the
three Drought Alert Stages.
• A modified staged drought response program, with guidance for selecting and adapting
best-practice Drought Response Measures.
• A monitoring and implementation strategy for responding to droughts.
Demand-side strategies are the foundation of Boulder’s drought response program. During
drought conditions, water supply shortages often occur during summer months when water use,
commensurate with landscape irrigation, is highest. For that reason and because outdoor water
use tends to be more discretionary than indoor use, many of the response measures outlined in
this plan target outdoor water uses. Supply-side measures often take longer to implement and
are primarily used as a long-term drought mitigation strategy, although certain short-term supply-
side strategies are described in Section 4, below.
1 The 2010 drought plan comprises Volume 1, titled “Drought Planning and Response Plan,” dated March 15, 2010,
and Volume 2, titled “Drought Plan Technical Information and Analysis,” dated February 20, 2003, and revised
November 2004.
CITY OF BOULDER DROUGHT PLAN
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APPLICABILITY
This plan specifically focuses on the municipal water supply system, which is managed by the
Utilities Department. Customers who have private water rights for non-municipal uses, e.g., use
of a well or irrigation ditch rights for lawn or landscape watering, are encouraged to follow the
city’s drought declarations but are not restricted under this plan for such non-municipal uses
because that water is not provided by the city. Other unique situations are described below.
O PEN SPACE AND M OUNTAIN P ARKS
Open Space and Mountain Parks (OSMP) has a separate portfolio of water rights, conveyed
primarily via irrigation ditches, which it uses for irrigation of agricultural properties. OSMP’s 2017
Agricultural Resources Management Plan calls out specific management strategies for preparing
for climate change–related impacts to water supplies, such as increased drought frequency.
OSMP staff participated in this Drought Plan update process for information-sharing and
collaboration purposes.
O THER C ITY D EPARTMENTS
Certain city departments that use significant amounts of water from the municipal water supply
system for outdoor irrigation have separate plans which address specific measures that, during a
drought declaration, will be implemented to meet water savings goals described in this plan.
Boulder Parks and Recreation (BPR) developed a drought response plan in 2003 in conjunction
with the city’s first drought plan. BPR expects to update its drought response plan in 2022–2023.
That update may inform specific water use limitations that, together with any required Drought
Response Measures, BPR can use to meet the demand reduction goals set during a drought
declaration. BPR manages many commonly used community spaces and public trees.
Maintaining those resources as feasible through irrigation is one of the Guiding Principles for
water use in a drought, as described in Section 2 below. In 2020, the Transportation and Mobility
Department developed a Plan for Transportation Landscapes which specifically outlines ways to
more efficiently irrigate medians and other vegetated areas it maintains. Staff from both
departments participated in this Drought Plan update process.
RELATED PLANNING EFFORTS
Other city planning efforts influence drought planning, including but not limited to the following:
• The city’s water conservation program was established in 1992 to address the need to
use water efficiently. Conservation and efficient water use programs help mitigate the
impacts of drought, delaying the need for a drought declaration in some instances. The
conservation program includes ongoing efforts related to customer education and
outreach and technical assistance. Boulder continues to evaluate opportunities to
implement technology to help manage water loss and to support the city and its customers
in monitoring water use and using data to make educated decisions about water use.
Water use reduction measures that take longer than a drought period to implement or
have a delayed response to implementation are presented in the City of Boulder 2016
Water Efficiency Plan, which is anticipated to be updated in 2023.
• The city is actively engaged in efforts to mitigate climate change and build a more resilient
community. While led by the Climate Initiatives Department, much of this work overlaps
with the Drought Plan. For example, the city prioritizes preserving large landscape trees,
in part because research indicates that, in addition to mitigating climate change and urban
heat island effects, such trees have been associated with reduced water use on properties
CITY OF BOULDER DROUGHT PLAN
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along the Front Range. The city models the performance of its water supply system under
future climate scenarios in long-term water supply planning efforts. That work informed
several aspects of this plan.
• The city conducts long-term planning to improve the reliability of its water supplies, as
informed by its Source Water Master Plan. Actions implemented from the long-term
planning may mitigate impacts of droughts in the future. Boulder evaluates and, as
appropriate, pursues opportunities to apply for new water rights, acquire existing water
rights and change them for municipal use through the water court process; expand storage
capacity; and work with other water rights owners and neighbouring water suppliers to
develop emergency or interruptible water supply agreements. The city will continue to
explore opportunities for additional use of raw water from ditches on city facilities, to reuse
its rights as feasible and legally allowed and to pursue other avenues identified in the long-
term planning process.
1. INTRODUCTION
Boulder’s municipal water supply originates in watersheds on both sides of the Continental Divide.
Approximately two-thirds of Boulder’s supply comes from the Boulder Creek basin and the
balance comes from water diverted and stored by the Northern Colorado Water Conservancy
District in the Colorado–Big Thompson (C-BT) and Windy Gap projects at the headwaters of the
Colorado River basin. The Colorado River supplies water to much of the southwestern U.S. and
is subject to a complex set of agreements, compacts and operating constraints. Colorado River
management is an ongoing process which Boulder continues to monitor and consider in its water
supply planning efforts.
Boulder’s raw water system includes the diversion structures, reservoirs, pipelines and canals
that convey and store water prior to its treatment, as well as a diversified water rights portfolio.
Boulder uses that raw water system to supply the city’s two water treatment plants in a manner
that meets seasonal and daily demand patterns and treatment needs. The treated water system
delivers high-quality water at appropriate flow rates and pressures to the city’s customers for
residential; commercial, industrial and institutional; firefighting and other purposes. The system
must operate in a manner consistent with Colorado’s prior appropriation doctrine water laws and
the city’s water rights decrees, with policies and rules that govern the operation of the C-BT and
Windy Gap projects and with the city’s internal system operating policies, including the water
supply reliability criteria.
Based on modeling and infrequency of historical drought declaration, the city’s municipal water
system is not currently expected to experience conditions requiring drought declaration very often.
However, Boulder is located in a semi-arid climate, and droughts are an expected part of the
natural hydrologic cycle in this region, particularly under climate change. Although meteorological
and hydrological droughts 2 will occur regularly, the city may not experience significant shortfall in
water availability because Boulder’s water rights and municipal water system are highly reliable.
Sections 2 and 3 describe how the city assesses drought conditions to determine when they
warrant a drought declaration and response in order to protect the municipal water supply and
appropriately meet demand.
2 Meteorological drought occurs when dry weather patterns dominate, including below-normal precipitation, and
hydrological drought occurs when streams, reservoirs, lakes and aquifers have below-normal levels of water supply.
CITY OF BOULDER DROUGHT PLAN
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A comparison of relatively recent droughts in 2002, when the city last implemented drought
restrictions, and in 2012 demonstrates differences between droughts. Both years had a
combination of below-average snow accumulation, below-average summer precipitation and
above-average temperatures, all of which collectively led to low streamflow. The 2002 drought
was exceptional in that severe to extreme drought conditions were present for 11 consecutive
months. That drought is the worst on record in terms of single-year streamflow deficit and average
streamflow deficit over the multiyear drought period. Comparatively, in 2012, drought conditions
spanned a shorter period and were less extreme, and July 2012 turned out to be Boulder’s third
wettest July on record. Those differences help illustrate why Boulder imposed drought restrictions
in 2002 but only increased water efficiency messaging in 2012 without imposing restrictions.
The city’s long-term water supply and demand modeling shows that, with planned investments in
water conservation and water system infrastructure, Boulder’s water supply system can meet
projected build-out demands in a manner that is consistent with the city’s water supply reliability
criteria (listed in Section 2) under current climate conditions. Climate change is projected to
increase the severity of drought. Under certain future climate scenarios modeled for the years
2050 and 2070, results suggest that drought declarations may become more frequent. This plan
is intended to support the city’s response to drought conditions that may occur in the relatively
near term. It does not address potential impacts to the city’s supplies or demands in response to
future climate conditions; however, the city is actively planning for potential longer-term impacts
and will update this plan in the future as new information becomes available.
While this plan specifically references drought conditions as the cause for water shortage
response, other conditions such as wildfires, infrastructure outages, operational issues, supply
shortages, floods and water quality impacts may also create water shortages.3 The city may use
this plan to guide mitigation and response to drought conditions and, as appropriate, to other
conditions that may create a water shortage.
2. RELIABILITY CRITERIA AND GUIDING PRINCIPLES
During the development of Boulder’s 1988 Raw Water Master Plan, the city established water
supply reliability criteria intended to strike a balance between the costs and environmental impacts
of increased reliability and the consequences of temporary supply restrictions. These reliability
criteria provide standards for the number of occurrences of water demand reductions in response
to drought within a given number of years and were described in that plan as follows:
1. For that increment of water needed to fully satisfy all municipal water needs, Boulder
shall make every effort to ensure reliability of supply against droughts with recurrence
intervals of up to 20 years.
2. For that increment of water use needed to provide continued viability of outdoor lawns
and gardens, Boulder shall make every effort to ensure reliability of supply against
droughts with recurrence intervals of up to 100 years.
3. For those uses of water deemed essential to the maintenance of basic public health,
safety, and welfare such as indoor domestic, commercial and industrial uses, and
firefighting uses, Boulder shall make every effort to ensure reliability of supply against
droughts with recurrence intervals of up to 1,000 years.
3 A projected or actual water shortage occurs when the projected or actual water supply is less than the projected or
actual water demand, due to drought and/or other conditions.
CITY OF BOULDER DROUGHT PLAN
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Expected impacts to vegetation, including dormancy of certain plant types, are considered in the
reliability criteria, though not explicitly specified. For example, the phrase “continued viability of
outdoor lawns and gardens” has been interpreted as a provision, at a minimum, of the amount of
water necessary to meet the basic survival needs of outdoor landscaping in general, including
trees and shrubs. As a result, during droughts with recurrence intervals between 1-in-20 years
and 1-in-100 years, landscape watering may be restricted to the extent that irrigated turfgrass
(e.g., bluegrass) goes dormant and other vegetation becomes stressed. In more severe droughts,
watering may be restricted to the point of threatening the continued viability of portions of the
landscape.
This Drought Plan is structured to support the city in meeting the water supply reliability criteria
through a staged response program based on drought severity, which is segmented into Drought
Alert Stages4 as described in Section 3. Because each drought event is unique, it is more effective
to have approaches that apply to specific drought declarations. The staged drought response
program involves a menu of potential response options for each Drought Alert Stage, as described
in Section 4. A set of Guiding Principles, listed in Figure 1, provides the framework to inform
highest-priority water uses in a drought. The Guiding Principles are intended to inform selection
and implementation of Drought Response Measures5, to empower the community to actively
participate in reducing water use when needed due to drought and to provide flexibility and
reasonableness in responding to drought.
Figure 1: Guiding Principles for Water Use in a Drought.
Utilities staff worked with the Drought Committee and the Water Resources Advisory Board
(WRAB) to develop these Guiding Principles, using the Racial Equity Instrument to inform the
process. All agreed that the highest priority in a drought is the provision of water for essential uses
4 Drought Alert Stages are water supply alert levels that represent the severity of drought and potential water supply
shortages. The city manager is authorized to declare a Drought Alert Stage and impose Drought Response Measures.
5 Drought Response Measures are requirements, limitations, tools and programs that may be implemented in
response to projected or actual drought-related water shortages. Drought Response Measures include but are not
limited to price-related actions through adjustments to water budgets and water rates; water use limitations and
temporarily limiting new water-related activities.
EQUITY
•Ensure availability of water for uses deemed essential to the maintenance of basic public health, safety and welfare.
•Support water use for commonly used community spaces.
•Minimize impacts to businesses.
ECOSYSTEM AND CLIMATE
•Support Boulder’s urban forest by minimizing impacts to tree canopy throughout the city.
•Protect instream flows in Boulder Creek.
LOCAL FOOD PRODUCTION
•Minimize impacts to food production, including local farms, community gardens and private edible gardens.
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such as those necessary to maintain basic public health, safety and welfare. The city solicited
feedback from the community through a questionnaire on the remaining five Guiding Principles.
The respondents ranked the Guiding Principles almost equally, resulting in a staff
recommendation that all principles be included to support the Drought Plan. Typically, water uses
that are named in the Guiding Principles will be prioritized and subject to restrictions only after
other lower-priority uses have been restricted.
3. PROJECTED STORAGE INDEX AND DEMAND REDUCTION GOALS
The drought response program is designed to progress through Drought Alert Stages as the
severity of a unique drought event increases, described below in Table 1. Water supply availability
is the primary driver that influences the city to declare a drought. Boulder’s water supply is a
function of available streamflow and reservoir storage levels. Reservoir inflows in the alpine and
sub-alpine environment are driven by processes including snow accumulation,
evapotranspiration, runoff generation and soil moisture. Drivers such as customer water
demands, water rights administration, operations and maintenance, regional circumstances
affecting the C-BT system and emergencies can also affect water supply availability.
To help predict storage contents and supply availability under varying hydrologic conditions,
Boulder uses detailed modeling of the operation of the water supply system, C-BT allocations and
recent water use data. Each year, as spring approaches, the city evaluates hydrologic and climatic
data along with information from its modeling to project storage levels following mountain
snowmelt and corresponding runoff.
The city uses a Projected Storage Index (PSI) calculation to help indicate the potential need for a
drought declaration. The PSI is the ratio of the city’s projected useable storage 6 to unrestrained
system demand, as represented below:
𝑃𝑃𝑃𝑃𝑃𝑃=𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚𝑑𝑑
𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚=𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚+ 0.4𝑃𝑃𝐶𝐶−𝐵𝐵𝐵𝐵
Where:
• Smountain is the city’s projected useable mountain storage in the Boulder Creek system.
• SC-BT is the city’s portion of projected C-BT Project storage.
• d is the city’s typical unrestrained (no drought restrictions) municipal water demand.
Based on historical conditions and the state’s water rights administration, the city’s mountain
reservoirs typically fill by early July. However, Boulder makes drought declarations by the
beginning of May, when sufficient key water supply data are available and there is considerable
potential to influence water use behavior before the upcoming irrigation season. Staff forecast
expected reservoir contents by the end of the runoff period using observed May 1 reservoir
contents and projected reservoir inflow during the ensuing runoff period of May and June. While
that forecast currently relies primarily on the use of snow-water equivalent data in the reservoir
watersheds, Utilities staff will continue to investigate ways to improve the accuracy of the forecast,
6 Useable storage is storage that is available to the city for consumptive use. That does not include dead-pool or
storage contents earmarked for delivery obligations.
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including adjusting the timing of the forecast, as relevant technology and environmental
information become available.
Table 1 summarizes the city’s drought classification approach, with water reduction goals and a
brief overview of demand response measures at each stage. Based on the calculated PSI, staff
may identify drought conditions, classify drought severity and inform the designation of a Drought
Alert Stage. As discussed further in Section 5, staff also use other relevant drought indicators and
operating experience when recommending a Drought Alert Stage declaration and in determining
an appropriate drought response. Drought Alert Stages 1 through 3 roughly align with the city’s
reliability criteria, and as such, a Stage 1 declaration is expected to be most common and a Stage
3 declaration expected to be rare. Section 4 of this plan provides details about the drought
response program in alignment with the response overview in Table 1.
Table 1: Projected Storage Index, Drought Alert Stages and Demand Reduction Goals
Projected
Storage
Index (PSI)
Drought
Alert
Stage 7
Annual Citywide
Water Demand
Reduction Goals Response Overview
As
Conditions
Warrant
Watch -
Water conservation is encouraged. This is a
pre-declaration communication tool to raise
public awareness of conditions.
0.85 to 0.56 1 Up to 20% Limitations are placed on lower-priority
outdoor uses.
0.55 to 0.41 2 Up to 30%
Additional limitations are placed on lower-
priority outdoor uses to allow higher-priority
uses.
0.4 or Less 3 Up to 50%
Additional limitations are placed on outdoor
water uses; some indoor use limits may be
required to prioritize health and safety.
4. STAGED DROUGHT RESPONSE
Every drought is unique, and the necessary drought response will depend upon the severity of
the conditions. The staged drought response program outlined below is designed to provide
flexibility in responding to droughts in alignment with the city’s water supply reliability criteria and
this plan’s Guiding Principles. Drought response programs in Colorado and throughout the
western United States typically target outdoor water use to achieve demand reduction goals. In
Boulder, as in other communities, outdoor uses tend to be considered of lower priority than indoor
uses. Accordingly, the staged response program focuses most heavily on outdoor uses.
4.1. DROUGHT ALERT STAGES AND RESPONSE OVERVIEW
During less severe drought conditions, the city may initially focus on expanded water
conservation–related public education and outreach and the implementation of Drought
Response Measures such as the use of water budgets as a drought messaging and management
tool. That approach allows flexibility for customers to choose how they use water while
contributing to the necessary drought response. Under prolonged and more severe drought
7 The paired PSI thresholds and Drought Alert Stages were developed through water supply system modeling and
operational experience.
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conditions, water budget reductions and water use limitations 8 may be implemented, together with
other Drought Response Measures, as part of a specific drought declaration. The most extreme
conditions may require some indoor water use limitations as part of the drought declaration.
Annual water demand reduction goals are specified for each Drought Alert Stage and are
anticipated to be met primarily by outdoor water use reductions. To support achievement of
annual reduction goals, outdoor water use reduction goals are specified (Table 2). The
progression is described below. Further details of measures that can be used in each stage are
found in Sections 4.2 and 4.3. As detailed further in Appendix A, the city’s Racial Equity Instrument
will be used to evaluate drought response measures in each stage in an effort to reduce
disproportionate impacts to communities of color and other underserved communities.
4.1.1. PRE-D ECLARATION D ROUGHT W ATCH
The Drought Watch is a pre-declaration communication tool to raise public awareness about
conditions that do not trigger the first PSI threshold (e.g., lower than normal water supplies,
drought conditions in the region or the Colorado River basin), and to help prepare the community
if a formal drought declaration is anticipated. The city will increase the communication and
customer education it typically conducts, promoting water conservation activities as informed by
the water conservation program and in coordination with neighboring water providers. Customer
water budgets will continue to be used to communicate about efficient water use. The
determination of a Drought Watch stage may be made by Utilities staff at any time of the year and
does not require a formal city manager declaration, because it does not trigger mandatory actions
or changes to water budgets.
4.1.2. STAGE 1 – SERIOUS
Under a Stage 1 declaration, the city will target an annual total (indoor and outdoor) water use
reduction of up to 20% and an annual outdoor water use reduction of up to 50%. The city will
advance its drought education materials and increase its water conservation communication to
customers and stakeholders. Adjustments to customer water budgets will target a reduction in
outdoor use and be supported through selected Drought Response Measures. Mandatory water
use limitations may be placed on lower-priority outdoor water uses, requiring specific customer
action. As such, this and subsequent stages require a city manager declaration, described further
in Section 5.
4.1.3. STAGE 2 – SEVERE
Under a Stage 2 declaration, the city will target an annual total water use reduction of up to 30%
and an annual outdoor water use reduction of up to 70%. Additional mandatory limitations will be
placed on outdoor water uses, with the intent of maintaining higher-priority outdoor uses and
supporting community vitality. Education and outreach will continue to play an important role in
achieving the necessary demand reductions. Additional adjustments to customer water budgets
may be implemented to further reduce outdoor water use.
4.1.4. STAGE 3 – EXTREME
Under a Stage 3 declaration, the city will target an annual total water use reduction of up to 50%
and an annual outdoor water use reduction of up to 100%. Additional mandatory limitations will
8 Water use limitations are specific Drought Response Measures identified in the Drought Plan and the rules and
regulations that the city manager may impose to address the occurrence of water supply shortages. Potential water
use limitations are described in Table 2.
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be placed on outdoor water uses, with the potential of maintaining only the most mature and
established trees and shrubs. Restrictions may be placed on new water connections, i.e., new
water taps. The city will be in continuous communication with customers and stakeholders to
implement water use limitations that produce significant reductions in water use. Customer water
budgets will be adjusted to reflect significant reductions in outdoor allocations, may remove
outdoor allocations entirely and may require some indoor water use reductions in the most
extreme droughts. Those messaging and pricing signal actions will increase customer awareness
of the drought severity. Under extreme conditions, rationing may be required to prioritize health
and safety.
4.2. SUPPLY-SIDE RESPONSE
During a drought, Boulder has the opportunity to increase water supply through provisions in
several of its agreements. Those include reducing deliveries to Silver Lake Ditch and using water
rights that are often used to support instream flows in Boulder Creek for municipal purposes
instead. Boulder may evaluate municipal needs and projected supply and determine that its ability
to lease surplus water to farmers is limited compared to normal years. It may thus reduce or curtail
its leasing program to make the most of its supplies during a drought period.
4.3. DEMAND-SIDE RESPONSE
This section provides further detail about public education and outreach and the demand-side
Drought Response Measures summarized for each stage in Section 4.1, including water budgets
and water use limitations. Table 2 provides a concise summary of potential water use limitations
for each Drought Alert Stage.
4.3.1. PUBLIC EDUCATION AND O UTREACH
Boulder’s water customers generally tend to be engaged and informed in local water resource
conditions and how to efficiently use water. The city and its customers will need to respond to
droughts in a variety of ways. To effectively implement a successful drought response program
and achieve the necessary water savings, it is important that customers understand how the city’s
water supplies are affected during a drought, how water budgets work and why customers are
being asked to use less water under a drought declaration. Consistent messaging before, during
and after a drought helps provide the city’s customers with a better perspective under all
conditions.
Beginning with the pre-declaration Drought Watch stage, and to the extent possible with all
drought stages, drought response will be achieved by educating and influencing customers to
change their water use behavior without being penalized. If a drought declaration is anticipated,
customers will be informed as timing allows of current conditions and what to expect with the
declaration of a Drought Alert Stage. Customer communication and outreach will increase with
each drought declaration, and information will be clear, credible and concise. Drought Response
Measures, demand reduction goals and enforcement protocol will be communicated and
reinforced through various mediums, in accordance with municipal code and rule requirements
and as guided by the city’s Drought Committee. The city will develop a drought information
campaign in close coordination with its existing water conservation education and outreach
program to maintain consistency and reinforce the importance of efficient water use under all
conditions. In an effort to effectively target all municipal water users, the city will build on
partnerships with local organizations which specialize in bringing conservation messages to
specific audiences, including Resource Central and Partners for a Clean Environment (PACE),
and will continue to work with Community Connectors and Neighborhood Liaisons to collaborate
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on approaches to education and outreach with communities of color and other underserved
communities.
4.3.2. W ATER BUDGETS, W ATER R ATES AND S URCHARGES
Municipal water customers are billed according to a water budget structure intended to promote
efficient water use through price signals. The water budgets include an indoor allocation and an
individualized outdoor water budget that is based on each customer’s estimated irrigable area
and generalized landscaping water needs.
Beginning with the Drought Watch stage, the city will increase communications with customers
about how water budgets work and how they may be modified under a drought declaration. During
a drought declaration, water budget blocks can be lowered to encourage customers to reduce
water usage while still allowing flexibility in how they use water. Staff will consider racial equity
implications of using pricing to influence water use behavior, as described in Appendix A, and
integrate it with other approaches, including mandatory water use limitations and public outreach
and communication, to achieve demand reduction goals. Water rates may also need to be
adjusted to maintain revenue stability, as further described in Section 5.4. Overall, the
effectiveness of the water budgets as a Drought Response Measure may be improved by
additional outreach about water budgets under non-drought conditions and by refinement of the
water budget structure.
Drought surcharges, in the form of a penalty rate or additional fee applied to the volume of water
used in a given water budget rate block, may be implemented as a penalty to customers who do
not conserve water in the amounts specified under the drought declaration. Drought surcharges
are intended to provide an emergency response to a temporary and severe limitation and are
removed after the recovery. The city will carefully consider potential financial impacts and racial
equity implications when preparing drought surcharges under a specific drought declaration.
4.3.3. W ATER U SE LIMITATIONS
Specified water use limitations, initially targeting lower-priority water uses as informed by the
Guiding Principles, may be needed at times to achieve the necessary drought response and to
support customers in managing use within their water budgets. Mandatory indoor water use
reductions are anticipated under only the most extreme drought conditions. Some water use
limitations, including day-of-the-week watering schedules, will require ongoing water use
monitoring to determine the most appropriate frequency to achieve water savings.
Table 2 provides a summary of potential water use limitations that may be required for each
Drought Alert Stage. The city will use this table as a guide when imposing specific limitations as
necessary, based on drought severity and water use reduction needs, to address the unique
drought conditions of each drought declaration. City staff will identify appropriate limitations based
on specific drought characteristics. This is not an exhaustive list of water use limitations and may
be revised as needed as water supply or water use conditions change.
The city may, at its discretion, grant exemptions from the drought response for individual
customers. For example, the city manager may approve exemptions in instances of extreme
economic impacts, health and safety issues and religious objections.
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Table 2: Potential Water Use Limitations.
CATEGORY STAGE 1 – SERIOUS STAGE 2 – SEVERE STAGE 3 – EXTREME
Potential Water Use
Impacts
Limitations are placed on lower-
priority outdoor uses.
Additional limitations are placed
on lower-priority outdoor uses to
keep higher-priority uses (as
listed in Guiding Principles).
Additional limitations are placed on
outdoor water uses; some indoor
use limits may also be required to
prioritize health and safety.
Citywide Water Demand Reduction Goals
(Specific systemwide target percentages will depend upon drought severity.)
Annual Total Up to 20% reduction Up to 30% reduction Up to 50% reduction
Annual Outdoor Up to 50% reduction Up to 70% reduction Up to 100% reduction
Outdoor*
(Unless otherwise noted, restrictions will allow watering on designated days and times)
Existing Irrigated
Turfgrass and Annual
Flowers
Allowed 2-3 days/week,
depending on severity
Allowed 1-2 days/week,
depending on severity Not allowed
New and Existing
Vegetable Gardens
Hand, drip or subsurface
irrigation any day; overhead
irrigation allowed 2-3 days/week,
depending on severity
Hand, drip or subsurface
irrigation any day; overhead
irrigation allowed 1-2 days/week,
depending on severity
Not allowed
Existing Shrubs and
Perennials
Hand, drip or subsurface
irrigation any day; overhead
irrigation allowed 2-3 days/week,
depending on severity
Hand, drip or subsurface
irrigation any day; overhead
irrigation allowed 1-2 days/week,
depending on severity
Established shrubs only, watered
by hand, drip system or deep root
fork or needle 1 day/week
Existing Trees
Recommended 3 or fewer
days/week
(customers choose days)
When water use limitations in other categories impact the watering of
trees, follow Save Our Shade or more recent guidance for watering
established trees
Existing Community
Parks,
Athletic/Playing Fields
Irrigation reduced to achieve
annual outdoor demand reduction
goal of up to 50%
Irrigation reduced to achieve
annual outdoor demand reduction
goal of up to 70%
Not allowed
New Landscape
Installation (Other
Than Vegetable
Gardens)
Allowed from September to April No new installation allowed; stormwater control measures must be
maintained
Sprinkler System
Maintenance Minimize test run times per zone Not allowed
Swimming Pools,
Splash Parks, Misting
Devices, Water
Features*
Follow best practices to limit spillage, reduce evaporation (e.g., use pool covers), use backwash systems
and maximize water reuse while maintaining water quality; pool filling/refilling and use of splash parks
and/or water features may be prohibited under certain conditions
Vehicle Washing Limitations may be placed on car washing, particularly where water recycling technologies or other water
efficient technologies and practices are not in place; at a minimum, best practices will be encouraged
Additional Outdoor Uses for Public/Commercial/Industrial
Public
Street/Sidewalk
Cleaning
Essential cleaning for the protection of public health, safety and the
environment only;
dry methods must be deployed first whenever possible
Extreme health and safety issues
only;
high-efficiency equipment only
Irrigated Stormwater
Control Measures
Overhead irrigation allowed 2-3
days/week, depending on
severity
hand, drip or subsurface irrigation
any day
No overhead irrigation;
hand, drip or subsurface irrigation
allowed 1-2 days/week,
depending on severity
Established shrubs only, watered
by hand, drip system or deep root
fork or needle 1 day/week
Construction Dust
Control and
Construction Water
Encourage alternative (non-
water) dust control measures;
implement current industry best
management practices
Whenever possible, industry best
management practices must be
deployed first
Allowed only when no alternative
(non-water) dust control measures
exist that meet environmental
standards
Hydrant Flushing and
Testing Limit to an as-needed basis to meet operational requirements or to address water quality concerns
Indoor
Indoor Uses Encourage efficient water use
Measures will be implemented to
reduce non-sanitary indoor uses
with exceptions for certain
business functions
Indoor measures will be
recommended and/or may be
required
* BPR will follow internal guidance per the BPR Drought Plan, which may differ from the limitations listed above, to conserve and
restrict water use on city-owned facilities to meet the required demand reduction goals specified in a drought declaration.
CITY OF BOULDER DROUGHT PLAN
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4.4. ENFORCEMENT OF DROUGHT RESPONSE MEASURES
The city’s municipal code authorizes enforcement of Drought Response Measures through
administrative charges or fees, suspension of water service and criminal prosecution. The city will
customize enforcement strategies to identify violations and the enforcement process based on
the Drought Alert Stage and customer engagement levels. Racial equity considerations will be
included in the enforcement strategy, as described in Appendix A. The enforcement protocol also
will be influenced by the availability of staff, additional staff needs and additional resources or
equipment needed for enforcement. Based on those conditions, the city will provide customers
with consistent communication and the information necessary to comply with restrictions. Certain
water use limitations, such as day-of-the-week landscape irrigation schedules, will facilitate
identification of compliance and thus help with enforcement.
The city may also provide guidance and resources to help customers meet water use limitations
in the future and avoid repeated violations. The city may work with third-party consultants to
support enforcement of Drought Response Measures. For example, the city currently partners
with Resource Central for several water conservation support programs. It is possible that,
through that partnership, Resource Central could act as an extension of city staff through a
program like Slow the Flow.
5. MONITORING AND IMPLEMENTATION
Implementation of this plan includes monitoring of drought indicators, progressing through drought
declaration protocols, implementing and enforcing the staged Drought Response Measures
described in Section 4, evaluating revenue impact and intermittently reviewing the effectiveness
of the drought response efforts to support modifications as needed. The following sections provide
an overview of implementation details.
5.1. DROUGHT COMMITTEE
Table 3 provides a list of the departments and workgroups with Drought Plan implementation
responsibilities. To effectively implement and manage the drought response program, additional
roles and responsibilities will be developed for and by Drought Committee members during a
drought declaration.
CITY OF BOULDER DROUGHT PLAN
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Table 3: City of Boulder Drought Committee.
Division/Department/
Work Group Responsibilities
City Manager Take ultimate responsibility for drought declarations and rulemaking in
consultation with the Utilities director.
Utilities Director Provide overall direction, coordinate with staff and liaise with city manager.
Utilities – Water Resources
Lead implementation of Drought Plan with internal and external partners;
monitor drought indicators; provide guidance on water supply conditions, water
rights yields and Instream Flow Program; and evaluate demand response
measures, including costs and effectiveness.
Utilities – Billing Provide water bill format changes as needed, conduct customer database
queries and assist with customer education and outreach.
Utilities – Community
Engagement Manager Coordinate and lead public education and outreach efforts.
Utilities – Engineering Manage infrastructure improvements and coordinate capital projects regarding
water supply limitations.
Utilities – Finance Provide lost revenue estimates and input on water budget and rate adjustments
and, as necessary, use of reserves or other funds.
Utilities – Maintenance Coordinate on distribution issues and assist with customer interactions via the
meter program.
Utilities – Water Treatment Track daily demand and coordinate on needed treatment adjustments to meet
supply constraints.
Utilities – Water Quality Monitor water quality in source watersheds and urban creeks. Assess impacts
of drought restrictions on ability to meet stormwater permit requirements.
Public Works Business Services Assist with public education and outreach.
Parks and Recreation Implement water use reductions while maintaining assets to the extent feasible,
including trees, community parks and recreation facilities.
City Attorney’s Office
Advise on legal issues involved in a drought declaration, including
implementation of Drought Response Measures, code interpretation and rule or
code changes needed during a drought.
Communications and
Engagement
Provide input on public education and outreach; lead media relations and press
releases.
Planning and Development
Services
Coordinate on restrictions related to development, such as landscaping
restrictions or stormwater treatment modifications.
Facilities and Fleet Implement water use reductions at city facilities.
Open Space and Mountain Parks Coordinate on agricultural demands.
Transportation and Mobility Implement water use reductions while maintaining assets to the extent feasible,
including medians, trees and other irrigated transportation facilities.
Climate Initiatives Coordinate on messaging related to climate change and water supply impacts.
5.2. MONITORING OF DROUGHT INDICATORS
Utilities staff regularly monitor water supply conditions and the potential for drought. By early May
each year, staff calculate the PSI discussed in Section 3, which entails evaluation of current
reservoir levels, snow-water equivalent
, C-BT quota, runoff generation and customer demands. Staff also evaluate other supporting
indicators, including:
• Local water supply conditions and projections, including anticipated streamflow
conditions.
• Rate of snowpack dissipation and streamflow response, based on watershed operator
observations and historical trends.
• Customer demands, including changes in demand in specific sectors or uses, both internal
(e.g., the BPR and Transportation and Mobility departments) and external (e.g., new
businesses).
• Weather data and long-range forecasts, which may identify temperature or precipitation
trends.
CITY OF BOULDER DROUGHT PLAN
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• Regional soil moisture levels and discussions with other water users, which inform
projections of downstream water use and expected water rights administrative call
patterns.
• The U.S. Drought Monitor, which is used to understand general regional conditions and
provides a reference for the city to support its review of other more localized indicators.
This list represents the primary indicators relied upon for preparing the city’s drought response
recommendations but is not a comprehensive list of all the indicators that the city monitors. Other
factors considered as needed include state water rights administration issues, city water system
operational constraints, the degree to which current demands approach projected build-out water
demand levels and any other factor that may be affecting either water supply or water demand
during the drought period. Staff will also monitor information provided by the State of Colorado
through its Water Availability Task Force, which notifies the Governor when drought conditions
reach significant levels and recommends activation of the Colorado Drought Mitigation and
Response Plan. In addition, staff will monitor a sub-set of these indicators on a year-to-year basis
to watch for signs of climate change impacts that specifically affect Boulder’s water supply and
may indicate the need to adjust the timing of drought determination, re-evaluate the PSI
methodology, and/or update the Drought Plan.
The calculated PSI in conjunction with the drought indicators described above inform
determination by May 1 of whether a drought should be declared. However, later-season droughts
may occur. As conditions warrant, staff may recommend a drought declaration after May 1.
5.3. DROUGHT DECLARATIONS
Based on the monitoring described above, each spring Utilities staff complete a water supply
analysis. If it indicates need for a drought declaration, staff will prepare that recommendation, in
coordination with the Drought Committee, and present it to the Utilities director and city manager,
keeping WRAB and City Council informed. The recommendation will include the designated
Drought Alert Stage and Drought Response Measures, including specific water use limitations, to
address the unique drought conditions.
The city manager is ultimately responsible for making drought declarations. The Boulder Revised
Code authorizes the city manager to declare a Drought Alert Stage and implement necessary
Drought Response Measures. Utilities and City Attorney’s Office staff will support the city
manager in formally declaring a drought and imposing response measures specific to the drought,
as guided by this plan. This declaration will provide additional details and considerations as
needed to guide the implementation of specific Drought Response Measures. Staff from the
Drought Committee will use the best available means to inform the public about the declaration
and Drought Response Measures, as discussed in Section 4, including providing advance notice
before implementation of Drought Response Measures, if possible.
Throughout the drought, staff will continue to monitor water supply, water quality and water
reduction achievements. Certain members of the Drought Committee will assist in key areas of
monitoring. For example, Utility Billing, Finance and Water Treatment staff will assist with
comparing actual water use to demand reduction targets to evaluate the effectiveness of the
drought response. The Drought Committee will meet monthly or as needed to review water supply
conditions and customer water use data. Utilities staff will summarize Drought Committee
observations and provide frequent status updates about conditions, as well as any
recommendations to adjust stages or response measures, to the Utilities director and the city
CITY OF BOULDER DROUGHT PLAN
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manager. The city manager and staff will inform City Council as the drought response program is
implemented and drought conditions progress.
5.4. REVENUE IMPLICATIONS
Water utilities often experience two competing goals during drought: to reduce the amount of
water use and to maintain adequate revenues to meet system requirements. In the event of a
drought declaration, staff will take the following five steps to understand and respond to potential
financial impacts to the water enterprise fund:
1. Estimate decreased revenue based on anticipated/declared water use reduction goals
associated with the Drought Alert Stage.
2. Consider use of resiliency reserve funds to offset revenue lost due to water use limitations.
3. Evaluate immediate cost savings potential in delaying capital improvement plan (CIP) and/or
operating expenses, such as forgoing annual programs or specific CIP projects.
4. Evaluate temporary rate increases and surcharges that may help encourage water use
reduction goals while also reducing the revenue impact to the utility (rate increases and
surcharges may be implemented as Drought Response Measures as part of a drought
declaration). As described in Appendix A, staff will use the racial equity instrument to assess
such adjustments and will seek to reduce or eliminate any disparate impacts of rate increases
or surcharges on communities of color and other underserved communities.
5. Assess fund balances to determine if the potential revenue shortfall should also be addressed
in the next budget cycle through rate adjustments.
As drought progresses, particularly if it extends into multiple years, staff will monitor water use
and billing revenue data to determine if any additional approaches are necessary to offset revenue
depletions, accommodate fund deficiencies and meet water reduction goals.
5.5. REMOVAL OF DROUGHT DECLARATION
Both during and after a drought declaration, and as long-term water supply and demand
conditions change, members of the Drought Committee will evaluate the effectiveness of the
drought response program to fine-tune and advance the response plan for future droughts.
Drought Committee members will record observations and experiences during the declaration.
Once the declaration is removed, the committee will convene and review committee member
experiences, observations and recommendations. Water use data, storage level and supply
condition data, financial impacts and customer violation data collected during the drought
declaration will help the committee evaluate the effectiveness of the drought response and inform
the development of future responses and policies.
Utilities staff will monitor changing water supply conditions and the results of Drought Response
Measures throughout the year to evaluate the degree to which water use reduction goals have
been achieved, with a focus on reductions achieved during the typical landscape irrigation
season. Because the city’s annual water supply is directly dependent on spring snowmelt, the
decision to officially remove a drought declaration will typically not be made until the following
spring. However, larger than expected water use reductions or significant improvements in water
supply may be cause for an easing of the severity of Drought Response Measures prior to the
next spring snowmelt period. Once drought conditions have ended, as determined based on
assessment of the indicators discussed in Section 5.2, the city manager will remove the drought
declaration. As applicable, the city will fully restore monthly water budgets, remove surcharges
and remove administrative charges for certain types of water use.
CITY OF BOULDER DROUGHT PLAN
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6. PLAN APPROVAL
This section describes the processes used to adopt this Drought Plan and future updates.
6.1. PLAN APPROVAL AND ADOPTION
This plan was prepared by Utilities staff and consultants, with input and support from the Drought
Committee. Staff presented a draft of this plan to WRAB on April 25, 2022. Following WRAB’s
review, WRAB made a formal recommendation on May 23, 2022 for the city manager to adopt
the Plan. The city manager adopted this Drought Plan on Nov. 2, 2022 and an
updated Rule that reflects the plan and covers making and removing drought
declarations and addressing responses to a drought or potential drought (Drought
Declaration Rule) became effective on Nov. 21, 2022. City Council approved changes to
relevant municipal code sections on October 20, 2022. The city manager will use this
plan as a resource when preparing rules and regulations to address necessary
responses to drought conditions, when declaring a specific drought
declaration and when implementing Drought Response Measures.
6.2. PERIODIC REVIEW AND UPDATE
This plan is intended to be a living document that will be reviewed and periodically updated. A
variety of factors may inform those updates, such as experience implementing the plan; changes
in water use trends, water supply or climate conditions; and major changes in policy. Boulder will
continue to evaluate its drought response program and the associated impacts of climate change
through ongoing monitoring of key indicators and related planning efforts. Interim updates to the
response program and measures may occur before the next plan update, based on Drought
Committee observations and recommendations.
7. KEY REFERENCES
Water Budget Rules. Rule 11-1-3.A(21). Establishing the Methodology to Determine the Monthly
Water Budget for the Component of the Monthly Water User Charges Known as the Treated Water
Quantity Charge, and to Determine the Monthly Wastewater User Charges. January 5, 2021.
2016 Water Efficiency Plan. Prepared for the City of Boulder by Rozaklis & Associates, LLC., October
2016.
Drought Declaration Rules. Rule Related to Declaring and Removing a Drought Alert and Addressing
Responses to a Drought or Potential Drought, the City Manager May Declare. Final Copy as Approved
June 29, 2011, with Changes.
Drought Plan Vol. 1. City of Boulder, Colorado Drought Plan Volume 1 Drought Planning and
Response Plan. Prepared for the City of Boulder. Prepared by Hydrosphere Resource Consultants
and Aquacraft Inc., March 15, 2010.
Drought Plan Vol. 2. City of Boulder, Colorado Drought Plan Volume 2 Drought Plan Technical
Information and Analysis. Prepared for the City of Boulder. Prepared by Hydrosphere Resource
Consultants and Aquacraft Inc., February 20, 2003, revised November 2004.
Raw Water Master Plan. Prepared for the City of Boulder by WBLA, Inc., September 15, 1988.
Municipal Code. City of Boulder Charter and Revised Code. Title 11 – Utilities and Airport.
Save Our Shade, A Guide to Tree Care in Dry Climates. https://sam.extension.colostate.edu/wp-
content/uploads/sites/19/2017/02/save_our_shade_Spring.pdf