At the September 23 Livable Houston meeting, Scott Jones of the Galveston Bay Foundation discussed freshwater inflows to Galveston Bay, which, along with habitat loss and water pollution, is one of the main problems facing the Bay. Freshwater inflows refers to the constant level of freshwater from streams and rivers that is needed to maintain a healthy ecosystem.
The Bay, he said, covers 600 square miles (384,000 acres), roughly the size of the City of Houston. The entire Galveston Bay watershed, he said, encompasses 24,000 square miles and stretches north along the Trinity River past Dallas-Fort Worth and almost to the Oklahoma state line. Half of the Texas population - roughly 12 million people - lives within the watershed. That population is supposed to grow to 19.5 million by 2050. “Environmental flows is key because of the growth that’s coming,” said Jones. If too much freshwater is consumed upstream, he said that the Bay could hit a tipping point and become too salty, severely damaging the ecosystem and the coastal fishing economy.
It is the seventh-largest bay in the US, but it is the second-most productive bay behind only Chesapeake Bay. Per square mile, he said, Galveston Bay may be even more productive than Chesapeake Bay. It produces more oysters - about 6 million pounds per year before Hurricane Ike - than any other body of water in the country. The entire Louisiana coast, by comparison, produces about 11 million pounds per year. The Bay’s productivity, however, depends largely on freshwater inflows.
Freshwater inflows bring crucial nutrients and sediments to the Bay, and they also help maintain the proper salinity for plants and animals. Salinity varies depending on tides, rainfall, and other factors, but a constant inflow keeps the Bay within a health range.
Jones said that oysters, in addition to being a crucial part of the Bay economy, are also a “keystone species,” requiring a suitable level of salinity as well as moving current. Oysters also clean the water through filter feeding, and oyster reefs provide habitat for other species. In the West Bay, oyster populations have been significantly reduced by the construction of a dike, which diverted freshwater away from the area and raised the salinity level.
Freshwater inflows face several problems, Jones said. First, most of the water in the watershed has already been allocated. Second, Texas Senate Bill 1 (1997) addressed human water needs in Texas but did not examine environmental needs. Finally, previous environmental studies have been done on a limited number of Bay species, rather than the entire ecosystem.
Texas Senate Bill 3 (2007) finally addressed environmental needs, creating an environmental flows allocation process for the Texas Commission on Environmental Quality (TCEQ) to set aside some unallocated water. While not a guarantee, it enables TCEQ to work with a Bay and Basin stakeholder group, which speaks for human water needs, as well as a Bay and Basin expert science team, which speaks for environmental needs, and a statewide environmental flows science advisory committee.
However, freshwater inflows will face even more challenges in coming decades due to the massive growth expected within the Galveston Bay watershed. A report by the National Wildlife Federation, Jones said, projects that Galveston Bay will be in “critical condition” by 2050 because of all the residential, commercial, industrial, and agricultural water demands in the area.
For more information, please visit the Galveston Bay Foundation’s environmental flows webpage.