Developing a Methodology to Prioritize Texas Watersheds for Environmental Restoration Efforts

摘要

During the past 150 years, several Texas watersheds have undergone significant changes that affect land use, the amount of water flowing through these systems, water quality, and the numbers and types of fish and aquatic species that live in rivers and lakes (McKinney, 2002). For the most part, these changes can be attributed to human activities such as dam building and reservoir management, population growth and resulting increased water use, increased runoff from paved surfaces, the introduction of non-native plant species, and others (Jensen, 2003a). As a consequence, competition for waters between human uses and environmental purposes has now increased to such an extent that some habitats and ecosystems that rely on water may be in peril, especially in semiarid and arid regions of Texas (TWDB, 2002).Recently, there has been increased public interest in investigating whether policies and management strategies could be implemented to restore watersheds, riparian zones, and other natural areas critically important to support wildlife, fisheries, and forests (Brown, 2000 and Alnwick, 2003). Often, the goal is to restore these sites to conditions that approximate conditions that existed prior to intensive human settlement in the 1800s. Interest in restoring watersheds and ecosystems has been expressed by several agencies including the U.S. EPA (2000 and 2001) and the U.S. Fish and Wildlife Service (2000).At a local or regional level, efforts have been undertaken to identify restoration opportunities along the Texas Gulf Coast by General Land Office Natural Resources Inventory program (1998). In addition, organizations including the Nature Conservancy (2000), the National Wildlife Federation (1998), and the Galveston Bay Foundation (19980 have also examined the need to set priorities for environmental restoration. For example, the Nature Conservancy published a report, Designing a Geography of Hope (Groves et al, 2000), that describes one method of assessing restoration opportunities across ecosystems and watersheds.A special challenge facing restoration efforts is in developing management strategies that will benefit ecological conditions in watersheds while, at the same time, preserving existing land uses (including homes and businesses) as well as dams and other infrastructure. Activities to identify estuaries and other watersheds that may be in need of restoration efforts have been initiated by the U.S. Army Corps of Engineers (2000) and the National Oceanic and Atmospheric Administration (2002).To deal with these public concerns, the U.S. Army Corps of Engineers Fort Worth District Office has expressed interest in determining how watershed restoration programs could be designed and implemented. One of the primary needs in this regard is to develop a science-based process that could objectively evaluate, prioritize, and identify watersheds that most need restoration efforts as well as regions where these measures are most likely to succeed. If such a methodology were developed, the Corps could use these recommendations, in conjunction with non-Federal sponsors, to develop full-fledged feasibility studies within targeted watersheds. Obviously, such a method could potentially be used by other natural resources agencies and organizations in Texas and elsewhere. It should be noted that the Corps is already engaged in ecosystem restoration studies and projects in some parts of Texas, though these efforts are developed as a part of comprehensive Corps projects. Some of these Texas projects include efforts in San Antonio (Salado Creek), Dallas, Houston, the North Bosque River watershed, and other regions. This project seeks to create a methodology that can be used to prioritize watersheds throughout Texas for possible restoration projects, the feasibility of which would be determined in subsequent detailed studies.Environmental operating principles that should guide the Corps in its public works and water resources projects were identified in a March 2002 speech in Louisiana by Lt. General Robert Flowers (Corps of Engineers, 2002). Some of the main points he addressed include the following:* The Corps should strive to achieve environmental sustainability,* Balance should be sought between human activities and natural systems* Potential problems should be resolved by designing environmental and economic solutions that complement one another.* The Corps should seek ways to assess and mitigate potential adverse affects caused by Corps of Engineers projects on the environment.