The Sustainability of Engineered Rivers in Arid Lands (SERIDAS) project examines the future of ten engineered rivers in arid lands. It identifies challenges the rivers face and offers recommendations on how to respond. The project team asks: How sustainable are engineered rivers in arid lands?
Written by Jim Lester, President and Chief Executive Officer, and Lisa Gonzalez, Vice President and Chief Operating Officer. The following testimony was submitted to the Committee on Natural Resources of the Texas House of Representatives on June 25, 2014.
HARC is a nonprofit research hub working on water, energy and air issues. HARC is part of George Mitchell’s legacy on sustainability science. We work to find solutions that balance the environment, the economy and social well being to make things better for future generations. Today we want to describe some issues with urban and suburban land development that impact water resources in Texas and discuss potential actions that could improve water supply and protect environmental flows.
According to the State Water Plan, Texas will have a population of more than 46 million people by the year 2060. That growth in population will lead to an increase in urban and suburban development. While development of private lands represents a plus for communities in terms of property tax revenues used to pay for local infrastructure and services, there are unintended costs in loss of ecosystem services. Ecosystem services are benefits that people receive from natural ecosystems; examples include provision of food and timber, flood reduction, storage of freshwater, recreational resources, and community aesthetics (which affect property values).
Development of private lands in urban and suburban settings converts grasslands, forests, and freshwater wetlands into impervious surfaces such as buildings, roads, and parking lots. When development planning fails to consider the loss of “natural capital”, land owners and local governments must implement costly technologies and expensive efforts to manufacture and attempt to re-create those ecosystem benefits lost through development. For example, when wetlands are covered with pavement, developers must build costly detention ponds to simulate the wetland function of slowing runoff to mitigate flooding. When forests next to water supply reservoirs are cleared, land owners then replace the forests with artificial landscaping and communities must construct multi-million dollar water treatment facilities to remove pollutants introduced by the development of this land. There is a better way forward.
HARC’s founder created one of our best examples of maintaining ecosystem services subsequent to development. The Woodlands is a community developed by George Mitchell in 1974. The development is based on the concept of “Design with Nature”. Today, The Woodlands is a thriving business and residential center of approximately 100,000 people. Some components of The Woodlands’ community design concept pertaining to the protection of water-related ecosystem services are:
- Conservation of large tracts of forest resulting in higher property values, more cost-effective landscape management options, increased groundwater recharge, reduced air pollution, reduced heat island effects and lower residential and commercial cooling costs.
- Exclusion of building in the floodplain resulting in no flood damages, more riparian forest for aesthetics, and higher property values
Other examples of increasing water-related ecosystem service benefits in an urban setting are those collaborative land conservation efforts along waterways in the Houston area known as the Houston Bayou Greenway initiative. The Initiative seeks to create an interconnected system of parks and trails along the region’s 10 major bayous, extending from Clear Creek in Southeast Harris County north and west to Spring Creek in Waller and Montgomery counties. These bayou projects preserve forest and prairie habitats adjacent to waterways protecting a variety of ecosystem services, including recreational opportunities and reduction of flood damage. In addition, these land conservation projects ensure that fewer acres of trees and prairie grasses will be replaced with water-thirsty turf grass, increasing groundwater recharge and as a result more water will be stored as shallow groundwater for maintaining flow in streams and rivers.
There are multiple examples of water supply and treatment entities using wetlands for natural tertiary treatment to improve water quality. These wetlands also enhance groundwater recharge and increase habitat space. Examples include the City of Beaumont’s 600 acre marsh treating 32 million gallons per day (mgd)1; the North Texas Municipal Water District’s East Fork Raw Water Supply Wetland with 2,000 acres of wetlands treating 92 mgd; and the Tarrant Regional Water District’s George W. Shannon Water Recycling Wetland of 2,600 acres treating 91 mgd2 . All of these projects have economic justifications and are classified as green infrastructure.
The only protected recharge zone in Texas is that which is protected for the Edwards Aquifer. Suburban development in the Houston region in encroaching on the recharge zone for the Chicot aquifer and will soon be affecting the recharge zone for the Evangeline Aquifer. We need to think about protecting recharge zones of other aquifers, and that process starts with information. There are a variety of modifications that can be made to our standard development process to protect underground water resources. The first need is to understand the spatial distribution of our recharge zones. The management of such information would help to prioritize conservation lands with a high propensity for facilitating aquifer recharge.
Local governments and nonprofits are engaging in educational campaigns to discourage artificial landscapes, which have fewer benefits and higher water use. State agencies could provide more assistance in this effort. Better understanding of what is lost in terms of human benefits when natural landscapes are converted to impervious surfaces or turf grass is essential for modifying accepted practices. Land development practices are starting to change and there is increasing application of Low Impact Development using rainwater capture features and green infrastructure approaches that employ natural systems rather than concrete and steel. The increasing popularity of these approaches is similar to the popularity of LEED certified green buildings.
Finally, ecosystem services can be valued in markets and development practices can be changed by economic motivation. For example, wastewater treatment operators in the Chesapeake Bay watershed are paying farmers to maintain forest habitat along waterways to control nutrients in runoff so they do not have to build expensive water treatment facilities. New York City pays land owners situated along shorelines of their water supply lakes to manage land to minimize pollutants and avoid costs of water treatment facilities. It may be possible to develop a market in Texas for water suppliers to pay land owners for management practices that increase storage and supply of clean water. These changes in land management would raise the water table and increase surface flows for water supply and environmental flow.
We have been managing our water resources in silos for too long. It is time for Texas to connect the dots between water management and land stewardship. Using examples of success as our guide, we can do much more statewide through collaborative processes and funding programs between federal and state agencies, local government entities and nonprofits to develop information, communicate with the public, and manage our state water and land resources intelligently.