Amy Hardberger

San Antonio is a rapidly growing city with exciting future prospects for becoming an even better place to live.  Growing cities provide many opportunities, but they also create challenges for citizens and leaders alike.

San Antonio is no exception.

Perhaps one of the greatest challenges is ensuring adequate future energy and water resources for the community. Water has been a major driver in shaping San Antonio’s past and will determine its future.

Ever since the Edwards Aquifer litigation in the 1980’s, the City of San Antonio and San Antonio Water System (SAWS) have been national leaders in water conservation and efficiency. CPS Energy has also actively encouraged efficiency programs and diversified its generation capacity to include more gas, coal, nuclear and eventually wind and solar.

From CPS Energy's presentation to City Council on Oct. 3, 2013.
CPS Energy’s Vision 2020 goals, adapted from goals put forth by SA2020. Graphic from CPS Energy’s presentation to City Council on Oct. 3, 2013.

While both SAWS and CPS are recognized leaders in their respective sectors and both have adapted well to changing community needs, the city’s future requires a systems approach to decision-making that recognizes the interdependence of energy and water on San Antonio’s future and how they directly tie to land use and growth decisions. Decisions must incorporate viable strategies for land use and resource planning that are aligned with these interdependencies and demands.

Growth is the driver that defines projected resource needs and growth is the key to the city’s sustained success; but, only when properly planned and managed.  Future water and energy supply needs will depend on our vision for the future and our decisions made along the way. These decisions cannot be tasked to any one entity, but require input from multiple sectors of leadership including the Mayor’s Office and City Council, business leaders, citizens, real estate developers, and municipal suppliers such as SAWS and CPS.  Certainly, diversity of water and energy supply is important for resilience, but the quantity of supply needed to sustain growth will vary based on the vision for that growth.

A Place to Grow

The Texas Water Development Board predicts that South Central Texas will grow by 75% between 2010 and 2060.  Municipal water use is one of fastest growing water categories. The SAWS Land Use Assumptions Plan predicts that the population of their service area will increase by approximately 230,000 people in the next 10 years.   This translates to almost 100,000 household units, each of which will need approximately 300 gallons of water per day excluding the water required to provide energy to these same homes.

In just two years, SAWS added 146,549 acres of serviced land.
In just two years, SAWS added 146,549 acres of serviced land.

Growth is the key to the city’s continued success, but only when the vision is clearly defined, the requirements clearly understood and the plan effectively implemented. How much water and energy the city needs in the future depends on what we want the city to look like and the land use decisions made along the way. Water demand is dictated by both the residential and commercial needs of a city. Water demands are calculated based on the approved land uses within the potential service areas, coupled with the average annual day water demand factors and peaking factors associated with the various land uses.

Because demand projections are based on usage assumptions, they can be altered by behavior modifications.

Most water and electric supply plans are primarily concerned with ensuring service for limited peak demand times of the year when usage spikes and maximum supply is needed.   In Texas, this occurs in the summer when air conditioners are cranking and lawn watering increases substantially.  Some new supply measures can be avoided by simply reducing demand on those peak usage days.  A change in land use requirements can also result in an increase or decrease in anticipated demand.

Much of the anticipated new water demand is driven by developments in undeveloped areas and in the extra territorial jurisdiction (ETJ).  Studies show that new homes require considerably more water than older homes as a result of the systematic installation of irrigation systems in many new housing developments. It is also a product of large lot sizes and houses with larger footprints.  New businesses can also add to water demand so appropriate planning in all growth sectors is important.

What’s the Plan?

Where and how a city grows defines demand and water resource protection. Two primary strategies can be employed by water utility managers to balance increasing water demand and supply in the urban sector: (1) increase the stock of water resources available for public supply, and (2) water demand management.

Natural vegetation and still waters on the San Antonio River. Photo by Garrett Heath.
Natural vegetation and still waters on the San Antonio River. Photo by Garrett Heath.

In addition to growth, water supply challenges are complicated by demand for in-stream water uses, environmental costs of groundwater withdrawals and concerns about the potential impact of climate change.

San Antonio is already a national leader in water demand management through implementation of conservation and efficiency measures. In addition to the suite of incentive and rebate programs offered by both the water and electric utilities, demand also can be managed through city ordinances such as efficiency oriented building codes. Land use limits  also are tools that can be used to minimize demand while still allowing for growth.

Examples of effective land use initiatives include encouraging high-density growth near the urban core and dictating water efficient landscaping and energy efficient construction for new buildings.

Landscaping is particularly important because outdoor watering can account for 30-50% of the city’s total withdrawals, particularly in the summer months when water is scarcer. Houses with irrigation systems can more than double a household’s water use as compared to houses to those who do not have one. Therefore, requiring installation of irrigation systems often provides a disincentive to plant drought resistant plants in new communities and increases demand more than if the same communities were planned differently.  This means that it is not necessarily the growth itself that causes the challenge; it is growth without the appropriate guidelines.

Comming soon? Stage III water restrictions will allow this kind of watering only once every two weeks. Photo courtesy SAWS.
Photo courtesy SAWS.

Although San Antonio has made some strides in this direction of land use regulations, such as the tree ordinance, there are still many untapped opportunities remaining.  Although the city continues to be successful with conservation, all of the city’s growth needs cannot be met with these measures alone. The continuance of these programs is critical to minimizing the need for new supply; however, additional supply must also be procured. The question is how much?

San Antonio relies on the Edwards Aquifer for the majority of its water so, in addition to managing demand, the city must also increase available water from other sources.  The need to diversify water resources first became evident in the 1980s as a result of a lawsuit.

An environmental nonprofit brought a lawsuit because excessive pumping of the Edwards Aquifer threatened several endangered species that were dependent on spring flow from the aquifer.  Spring flow diminishes when aquifer levels drop below a certain level. Data presented at trial demonstrated that, but for human withdrawals, the springs’ natural discharge would be stable and species would be protected, but continued pumping would result in extended no-flow periods for the springs in drought conditions. These dry periods would threaten the survival of the species that live there.

The judge in the Edwards case ordered the Texas Legislature to provide the appropriate management of the aquifer so that spring flow would be maintained to protect the species. This mandate paved the way for the Edwards Aquifer Authority, a legislatively created special district.   The Authority’s permitting decisions are guided by a firm pumping cap, which limits the amount of water that can be removed from the aquifer.  The limit on pumping means that access to Edwards’ water is not unlimited and no new permits can be issued.

Image courtesy of Gregg Eckhardt.
Image courtesy of Gregg Eckhardt.

In light of this reality, SAWS is currently pursuing several new and expanded supply projects in addition to the acquisition of new Edwards supplies and increased conservation.  By 2020, SAWS projects the completion of a brackish water desalination plant that will produce 13,000 acre-feet of water per year by 2016 and almost 34,000 acre-feet per year by 2026.

San Antonio also has the Aquifer Storage and Recovery (ASR) project, which stores surplus Edwards Aquifer water in the Carrizo Aquifer until it is needed. The 2009 SAWS Water Management Plan (WMP) estimated maximum ASR storage capacity of 50,000 acre-feet; however, the latest WMP increased this to 120,000 acre-feet.

In addition, SAWS is completing the Regional Carrizo Water Supply Program in late 2013, which will pump 16,000 acre-feet of Carrizo Aquifer water to San Antonio from Gonzales County. The latest WMP also proposes to increase the existing Local Carrizo Project to 21,000 acre-feet of water per year by 2026.  This project pumps Carrizo water in southern Bexar County into San Antonio.

A pipeline map presented to City Council by SAWS.
Pipeline map presented to City Council by SAWS.

Finally, SAWS is pursuing the purchase of groundwater from another part of the state and delivered to San Antonio through a long-haul pipeline.  The original RFP requested bids for 20,000 acre-feet of water, but it was recently increased to 50,000 acre-feet. The goal of this project is to provide 50,000 acre-feet of water a year to the city by 2018; however, there are still many legal hurdles.  While new projects are important for the city, they will not work alone and it is impossible to know how much we will need without making land use decisions first.

The success of the city depends on a plan that includes all aspects of planning including water and energy needs within a land use context.  A city cannot predict demand of resources before first determining who it will service, which is dependent on land use decisions.

Costly water purchases should not be made before demand is fully understood; however, this analysis must be balanced with other realities. New infrastructure projects require several years to complete and limited water resources may not be available in the future.  The need for a big picture plan and supply decisions are not in conflict with one another, but they do necessitate initiative and vision to move forward in an effective and timely manner.

Water Forum IV: San Antonio’s Future

While past water forums have focused on defining and understanding the resource needs of San Antonio, this water forum will focus on the path to get there.  By involving leadership representatives from all sectors, the forum hopes to go beyond education and awareness to propose solutions or at least viable alternatives leading to solutions.  Instead of the traditional conversation format utilized in previous water forums, this forum panel will be aided by an expert panel that will pose questions about how the represented groups should interrelate, who should be charged with the vision of our future and how all the entities can work together to get there.  The goal is to join together these intertwined aspects of planning to ensure successful and sustainable growth for San Antonio.

san antonio water energy forum clean tech

Full disclosure: The Arsenal Group conducted a four-month review of CPS Energy communications for the utility starting in June 2012. Monika Maeckle, a former member of the The Arsenal Group and wife of Robert Rivard, now works at CPS as its Director of Integrated Communications. 

 Amy Hardberger is an Assistant Professor at St. Mary’s School of Law. Her areas of research are Texas Water Law, Water Conservation, and the Energy/Water Nexus. Ms. Hardberger holds a bachelor’s degree in Geology from Earlham College, a Masters of Science in Geology with a focus in Hydrogeology from the University of Texas at San Antonio, and a doctor of jurisprudence from Texas Tech University School of Law. Before joining St. Mary’s, Ms. Hardberger was with the Texas Office of Environmental Defense Fund where she worked on Texas Water Policy issues.  She also worked as an environmental consultant involved in the remediation of closed Air Force bases around the United States.

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Amy Hardberger is an Assistant Professor at St. Mary’s School of Law. Her areas of research are Texas Water Law, Water Conservation, and the Energy/Water Nexus. Hardberger holds a bachelor’s degree...