Part One in a Three-Part Series on HARC’s program of work and research utilizing LiDAR in the Houston-Galveston region.
From Data to Images
The “no net loss” concept – essentially the idea that the nation should work to create enough new wetlands to offset the loss of wetlands where dredging, filling and other impacts are allowed under federal permits – dates back 25 years to 1989.
That was the year that former President George H.W. Bush committed the U.S. to the “no net loss” goal.
As the Houston Chronicle reported in 1993, reviewing four years of the “no net loss” policy’s successes and failures until that time, the goal had been developed by Bush’s Environmental Protection Agency chief in consultation with business leaders, elected officials and environmentalists prior to Bush’s election.
The newspaper reported that at that point, 21 years ago, there was “a broad consensus among wetlands experts in Texas that, despite the absence of any comprehensive survey or data, ‘no net loss’ is not being realized” in the state.
“We’re not achieving ‘no net loss,’ and we’re not even anywhere close,” a top Texas Parks and Wildlife Department official told the Chronicle at the time.
A new report on trends related to the status of the nation’s coastal wetlands, issued by federal officials late last year, concluded that the nation has been falling further behind in recent years in efforts to live up to the “no net loss” aspiration in these areas – especially along the Gulf Coast:
“The average annual rate of wetland loss in the coastal watersheds was 80,000 acres between 2004 and 2009. This rate of loss increased by 20,000 acres from the previous reporting period (1998 – 2004),” the report by the U.S. Fish and Wildlife Service and National Oceanic and Atmospheric Administration concluded. “Principal causes for wetland losses included coastal storms, urbanization and silvicultural [forest-related] operations.”
While the report did not break out statistics on a state-by-state basis, it said that by far the biggest losses have been occurring along the Gulf coastline:
The Atlantic, Gulf of Mexico and Pacific coastal regions experienced net wetland losses of 111,960 acres, 257,150 acres and 5,220 acres, respectively. The watersheds of the Great Lakes region experienced a net gain in wetland area of an estimated 13,610 acres. Seventy-one percent of the estimated wetland losses between 2004 and 2009 were in the coastal watersheds of the Gulf of Mexico.
Regarding the Gulf region, the report said:
In general, wetland reestablishment in coastal watersheds has lagged behind reestablishment rates observed nationally for a variety of reasons. A strategy of achieving ‘no net loss’ by offsetting wetland acreage losses with wetland creation or reestablishment [mitigation] does not appear to be effective in the coastal watersheds as wetland losses have increased in some coastal regions. Continuing losses of wetlands in coastal watersheds have direct costs for people and longer-term resource implications for fish, wildlife and other natural resources.
The report listed benefits that coastal wetlands provide:
Wetlands in coastal watersheds provide crucial habitat for wildlife by providing spawning grounds, nurseries, shelter, and food for finfish, shellfish, birds and other wildlife. These wetlands also help improve water quality by filtering and detoxifying runoff from residential, agricultural, and urban areas. Furthermore, there is an increasing awareness of the important role these coastal wetlands play in buffering coastlines against storm and wave damage and in stabilizing shorelines in the face of climate change impacts.
The 2011 State of the Bay report on environmental trends in Galveston Bay, which was co-edited by HARC Vice-President Lisa Gonzalez and HARC President Jim Lester, had this to say about impacts sustained by bay-region wetlands over the years:
Wetlands serve important hydrological and ecological functions in the bay system, but have experienced significant rates of loss over the past century. Most of the loss of salt and brackish marsh has been caused by a rise in relative sea level, due in large part to land subsidence from groundwater withdrawals and subsequent conversion to open bay and barren flats. Creation of subsidence districts and protections under the Clean Water Act have slowed the loss of these estuarine wetlands over the last 10 years. The continuing loss of freshwater wetlands, however, remains significant. The loss is primarily associated with conversion to agriculture and, more recently, suburban and urban purposes.