2019 Excellence in Environmental Engineering and Science® Awards Competition Winner

Grand Prize - Planning

The Water Forward Integrated Water Resource Plan - Austin Water

Entrant: CDM Smith
Engineer in Charge: Christina Petersen, Ph.D., P.E.
Location: Austin, Texas
Media Contact: Julia Forgas

Entrant Profile

CDM Smith is a full-service engineering and construction firm headquartered in Boston, Massachusetts. For more than 100 years, Austin Water has been committed to providing safe, reliable, high quality, and affordable water services. Austin Water partnered with CDM Smith to develop an Integrated Water Resource Plan (IWRP) for the City of Austin, Texas. This groundbreaking plan identifies strategies to diversify Austin's water supplies by expanding conservation and water reuse, developing alternative water supplies, protecting the environment, and increasing resiliency during droughts and climate change. The IWRP was developed with significant input and support from a Mayor and City Council-appointed citizen task force.

CDM Smith and Austin Water performed the following:

IWRP Methodology. Team developed a powerful methodology to develop, compare and rank portfolios of demand-side and supply-side options.
Extensive Public Engagement. Team engaged in a wide-reaching public outreach effort, including 5 public workshops, 4 targeted stakeholder meetings, and over 80 other outreach events located throughout City.
Disaggregated Water Demand Forecast. Team developed a disaggregated and spatial demand model by sector and end-uses for 100 years, as well as conducted a statistical analysis to determine impacts of climate.
Lot-Scale Solutions. Using the disaggregated demand forecast, team evaluated decen- tralized greywater, blackwater and rainwater harvesting options to reduce potable water demands.
Alternative Water Supplies. Team conceptualized supply yields, locations and costs for aquifer storage and recovery, indirect potable reuse, and desalination.
Resiliency. Team used advanced supply modeling tools to estimate impacts of climate change and test resiliency of IWRP portfolios.

Project Description

Overview

Central to Austin's economic vitality and high quality of life is a reliable, safe water supply. Currently, all the city's drinking water comes from the Lower Colorado River system. Looking forward, future climate change is estimated to exacerbate droughts—both in severity and duration. Coupled with rapid growth and economic development, these factors make future water planning more challeng- ing than in the past.

Following an 8-year span of historic drought in which lakes that supply Austin's drinking water fell to historically low levels, the city chose to proac- tively plan to increase the sustainability, reliability, and diversity of the city of Austin's water supply. To achieve its goals, Austin Water partnered with CDM Smith to complete an Integrated Water Resource Plan (IWRP) for the city. This plan helps support Austin Water's enduring commitment to providing water services to its customers for the next 100 years and beyond.

The IWRP recommendations were developed using a holistic planning approach that balances multiple objectives such as water reliability, social, environmental, and economic benefits, and ease of implementation.

Key aspects included:

Water supply alternative evaluations using decision-support tools to make use of all water, including rainwater harvesting, stormwater capture, graywater and blackwater, air conditioning condensate, and highly treated wastewater for non-potable and indirect potable reuse.
The exploration of innovative, sustainable and resilient water conservation strategies to make homes, landscapes and buildings more water-efficient.
A robust public stakeholder outreach program that included a Citizen Task Force to provide support and input on demand-side and supply-side options and to develop the overall strategy for meeting future water demand.
Near- and long-term recommendations using adaptive management to implement strategies in logical order and to reflect uncertainties.

In a changing climate and growing community, there will always be uncertainty and risks to manage. The IWRP will support Austin Water's commitment to provide environmentally-responsible, resilient and cost-effective water supply to its customers for decades to come.

Integrated Approach

A true "one water" perspective provided integrated solutions – The IWRP examined innovative solutions such as blackwater, graywater, and indoor non-potable water use. A series of models and decision tools were used to compare the trade-offs between alternatives and search for the best combination of strategies to meet the IWRP's multiple objectives.
Diversified strategy creates increased water supply resiliency – Additional strategies (water conservation, reuse and alternative local water supplies) are complementary to the city's core Colorado River supplies and result in an increased ability to meet the city's current and future needs during droughts and long-term climate change.
Triple bottom-line approach safeguards sustainability – The plan's recommendations resulted in economic, environmental and social benefits to the Austin community. Conservation, wastewater reuse and stormwater capture provide environmental and social benefits. Alternative water supplies (aquifer storage and recovery, indirect potable reuse and brackish groundwater desalination) were evaluated to maintain an affordable water supply for the future. By examining growth, climate change, and future water supplies for the next 100 years, the IWRP lays out a roadmap for proactive measures to protect Austin's quality of life for current and future generations.

Quality

Collaborative process built public support – A public engagement process that included regular monthly meetings with a City Council and mayor-appointed task force and public workshops were essential to the IWRP's success. The process included close coordination with regional partners and key stakeholders.
Use of multi-criteria decision analysis identified trade-offs – To arrive at a preferred long- term strategy, the use of decision tools to compare alternatives was used. This clearly showed differences and trade-offs between reliability, cost, environmental and social objectives.

Originality and Innovation

Teamwork helped identify potential reuse and rainwater harvesting opportunities – Working closely with CDM Smith's partner sub-consultant GHD, the team examined Austin Water's innovative and highly disaggregated water demand forecast to identify where distributed (lot-scale) graywater, blackwater and rainwater harvesting could be developed, and estimated quantities of water saved and costs for such measures.
Incorporating climate change set new standard for water planning – Explicit consideration of climate change was taken in the water demand forecasting and water supply modeling, including climate change scenarios ranging from period of record to an extended period simulation of 10,000 years.
Advanced computer systems modeling evaluated future scenarios – This project included sophisticated geospatial modeling of decentralized water supply opportunities (such as blackwa- ter, graywater, and rainwater harvesting) and evaluated the impact of these strategies across the city. These models were essential to evaluating complex alternatives and were used to rank the alternatives against objectives that aligned with the city's sustainability goals.

Complexity

Analyzing a highly complex system resulted in a highly resilient plan – There was a high degree of complexity given the factors involved. Various tools were developed to analyze these factors and were integrated to evaluate demand management and water supply strategies for this plan.

Tools created to analyze these factors included:
- A highly disaggregated water demand model that broke demands into single-family, multi- family, commercial, industrial; and major indoor and outdoor end-uses
- Geospatial decentralized modeling effort (230 individual planning areas across the city)
- Water Availability Modeling of Austin's Colorado River supply, including impacts of climate change
- Decision support tools to compare and rank alternatives
Adaptive management provided flexibility for implementing plan recommendations – The plan identified important triggers – such as evaluation of Alkali-Silica Reactivity pilot testing – to determine pathways forward.

Social and Economic Advancement

Ensuring a reliable water supply promotes future economic vitality – In the future, the Colorado River system will likely experience climate change impacts, additional droughts, and future uncertainties. Coupled with rapid growth and economic development, these factors make future water planning more challenging than ever before. The IWRP provides the city with cost-effective strategies to ensure a reliable and sustainable water supply.

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The city of Austin, Texas is a bustling center of economic development and explosive population growth. With climate change, Austin faces water planning issues that are more challenging than ever before.	Drought and climate change post challenges for surface water resources such as the Colorado River

During Austin's historic drought from 2008 to 2016, water storage dropped to near-record lows and inflows were lower than ever before. The city evaluated a number of emergency strategies on an accelerated schedule. With Water Forward, Austin has taken the opportunity to proactively develop future demand management and supply strategies to avoid potential water shortages.	One of the ways the Water Forward plan gauged the effectiveness of water conservation and reuse for Austin's growing population was to calculate how much water was used per person per day across the city — a measure known as gallons per capital per day (GPCD). This graph shows the projected Austin Water served population, customer demand, and calculated long-term average GPCDs assuming implementation of the recommended Water Forward strategies. Though the Water Forward plan was not developed to meet specific long-term average GPCD targets, the GPCD was able to be used to track the progress of several implementation plan strategies.
	<
Climate scientists project that in the future, the Austin region will see longer and deeper periods of drought punctuated by heavy rain events. This photo illustrates the projected increase in temperature and changing precipitation in the Austin region, which will likely have profound impacts on flood and drought patterns. Water Forward evaluated multiple future scenarios which considered climate change effects and droughts worse than those experienced in the past to ensure reliability of the plan recommendations through a range of possible futures.	p>A true "one water" approach is utilized to make use of all water—including greywater, stormwater, rainwater and wastewater—in order to meet non-drinking water demands. This approach is expected to dramatically increase the amount of non-drinking water supply that will meet non-drinking water demand by 2115.
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p>Austin Water's IWRP planning process began with defining the city's objectives, sub- objectives and performance measures in alignment with community values. Identification and characterization of various water supply and demand-side options also took place, using high-level unit-cost comparison and high-level implementation risk comparison to screen options. Groupings of those options were then combined to develop portfolios around themes such as "Maximize Reliability" or "Maximize Cost-Effectiveness" or "Maximize Conservation."This allowed the team to evaluate how different combinations of multiple options scored against all of the IWRP objectives and sub-objectives. Each portfolio was then evaluated for how well it achieved the sub-objectives under various hydrologic conditions (like historical and climate change scenarios). Ultimately, the portfolios were ranked and a preferred IWRP strategy to implement various options within the portfolios based on various triggers was recommended. For full report information, go to austintexas.gov/page/water-forward-resources.	Customized decision-support software called Criterium Decision Plus (CDP) was used to rank portfolios against multiple criteria to predict performance. This multi-attribute ranking technique allowed the project team to convert raw performance into standardized scores so each could be summarized into an overall value and add hybrid portfolios without impacting the scores of those portfolios previously evaluated.

In this example of portfolio ranking, the larger the color bar segments, the better the portfolio performs for a given objective. For example, Portfolio 5 has the best supply reliability and hence the longer bar segment for the supply objective. Portfolio 6 also has the best supply reliability score, but it is not as cost-effective (meaning it is higher in cost) than Portfolio 5 and hence it has a relatively small bar segment for the cost objective.	Austin's IWRP was developed by a team of public utilities staff, consultants and public stakeholders from various industries. Austin Water held three Targeted Stakeholder Meetings aimed at gathering input on specifically identified options from the project team's draft list of 25 demand management options. These meetings helped to formulate key objectives, identify innovative ideas and solicit critical feedback, which ultimately led to an effective plan supported by the public.

On August 3, 2016, Austin Water director Greg Meszaros and IWRP Community Task Force chair Sharlene Leurig shared insights on the process and importance of creating a long-term plan that would help secure Austin's water supply for future generations. The series, titled "Water Forward—Planning for the Next 100 Years," was attended by 62 members of the community.