Galveston Bay is one of the most important ecological areas in Texas. This 31 by 17 mile estuary is highly productive for shellfish (oysters and shrimp) and finfish (Spotted Sea Trout and Red Drum); has many recreational and tourist attractions (Clear Lake Area and Galveston Island); and is economic home to many oil, natural gas, pipeline, and petrochemical companies and facilities.
Living near Galveston Bay and the Gulf of Mexico (GOM) shorelines is exciting but has pitfalls. Too many people live in floodplains and storm surge zones. This results in property damage, injury, and death. There are ways to live in harmony with Galveston Bay, the GOM, and avoid many of the impacts of hurricanes and storms. We have the information and technology to make sensible decisions about development on our hurricane-prone coast. The question is, do we have the political courage, foresight, and will.
Nature provides us with challenges. Our first response to challenges, like hurricanes, is to fight and conquer Nature. If we take a step back we learn from and begin to understand that hurricanes have their place in coastal human and natural ecosystems. The first principle for “Living By the Rules of the Sea” is, “Work with, not against, Nature”.
Hurricanes are Nature's way of providing needed ecological change in our coastal and near-coastal ecosystems. Hurricanes drive natural ecological processes like erosion, deposition, vegetative succession, nutrient distribution, increased biological diversity and production, and drought breaking so we have changed, but healthy, ecosystems.
Heavy hurricane rainfall, as it travels inland, increases water in streams, rivers, and floodplains. As these waters flow to bays, estuaries, and the GOM they bring a mixture of freshwater, organic matter, nutrients, and sediments. Flushed out floodplains provide new places where plants and animals live. The “flush” of freshwater, organic matter, nutrients, and sediments fertilizes bays, estuaries, and GOM so that, over time, biological productivity increases. The benefits of hurricanes are not just local or regional, but global. With a bit more knowledge we can avoid harm, assist ourselves, and protect Nature where hurricanes occur.
Today, natural ecosystems that are damaged by hurricanes, do not bounce back as quickly as they used to. Human development and other impacts have degraded the health of natural ecosystems so they are no longer as resilient to hurricanes as they once were.
Some Alternatives for Galveston Bay's Hurricane-Prone Shorelines
We have a personal choice whether to stay or leave from “harm's way.” We must exercise that responsibility appropriately and reasonably. We want every person to be kept out of “harm's way,” but not every structure can be protected.
Communities can approve tight development, building, and planning standards. This makes sense for West Galveston Island and Bolivar Peninsula where large numbers of second, vacation, and rental homes exist. In these areas, the focus should include keeping people out of “harm's way,” recreational activities, ecosystem restoration, and environmental protection. The focus should not be on the protection of every structure or on the encouragement of denser development and greater population growth.
For parts of Galveston Bay and the GOM where infrastructure, population, and development are already dense (like East Galveston Island), a ring levee can be constructed. For those who live in the Texas City area, the existing levee can be strengthened and improved and around the NASA/Clear Lake Area a levee and or gate can be constructed.
For the cities of Shoreacres and La Porte, the choices are more difficult due to low land elevations and Galveston Bay front vulnerability. Buyouts (planned withdrawal) may make the most sense, although the construction of a levee around La Porte's industrial zone may be justified.
Sensitive ecological areas should be mapped and avoided, worked around so that environmental damage is minimized, and the damage should always be mitigated. The acquisition of land buffers for national wildlife refuges, state parks, natural shoreline, beaches, sand dunes, coastal prairie, and salt marshes is critical. This allows these landscapes to migrate toward the mainland as sea level rises.
We must not interfere with the coastal sediment budget/movement system which includes wind-blown and wave-moved sand and sediments on barrier islands. We must not fragment landscapes if we expect to retain healthy coastal ecosystems with natural populations of animals and plants.
Planning efforts should include the retention and protection of existing Galveston Bay and GOM views and vistas. These are important recreational, spiritual, and economic resources that must be preserved. Large storm surge suppression projects negatively impact or eliminate these inherited and treasured shoreline views and vistas which are part of our natural coastal heritage.
A levee district can be created to plan and implement protection for the Houston Ship Channel, fence-line communities, and the oil, natural gas, refinery, petrochemical, and other facilities that exist in this area. A risk assessment of all existing industrial levees and other storm surge and flood protection structures should be prepared to determine where weaknesses are and how they can be reduced or eliminated.
Important alternatives to the status quo should include construction of individual levees, removal of vulnerable storage tanks, use of construction materials that are more protective or stronger, replacement of more toxic chemicals with less harmful ones, etc. These options reduce the risk of spills and reduce damage if spills occur from facilities and individual units.
Large Storm Surge Suppression Alternatives
One hurricane-related concern is storm surge. Storm surge is the rise of shoreline water in the GOM during a hurricane. This occurs when wind presses down on water as it approaches the shoreline. Some people support a huge levee system, the Ike Dike, which they say will address the storm surge problem. One current description of the Ike Dike Alternative is:
(1) an 18 to 21 foot tall levee, which measures 221,105 linear feet (or 41.85 miles) of new levee, that extends all the way down Bolivar Peninsula, starting at High Island, and ends on Galveston Island at San Luis Pass, and ties into the Galveston Seawall, for a total length of 55.6 miles; (2) a ring levee 12 to 15 feet tall built around East Galveston Island; (3) a navigation gate at Clear Lake; (4) the levee on the east end of Bolivar Peninsula will tie into the mainland at High Island in a north/south direction; (5) the levee on the west end of Galveston Island will be armored with rock and end just east of San Luis Pass; (6) the levee would be built on Bolivar Peninsula near State Highway (SH) 87 and FM 3005 on Galveston Island; (7) installations to facilitate shipping at Bolivar Roads include: a. a large horizontal rotating flood barrier and floating navigation gate (two sections 18-21 feet tall with a gate opening 840 feet, and having a 60 foot deep sill); b. twenty-five vertical lift gates (with 100 foot wide openings); c. two artificial islands to support the gates; d. 100 feet of Combi-wall, with a single 100 foot wide vertical lift gate; (8) the right-of-way for the levee would consist of 1,220 acres; (9) construction of 18,926 linear feet (3.58 miles) of new T-wall (large, concrete, wall); (10) construction of 41,651 linear feet (7.88 miles) of seawall enhancements; (11) construction of 78 drainage structures; (12) construction of 35 highway gates; (13) construction of 12 miles of two-lane highway; (14) and the levee, using a 20H (horizontal width):1V (vertical height) ratio, would be 360 feet wide at 18 feet vertical height to 420 feet wide at 21 feet vertical height.
A preliminary and incomplete cost estimate for an Ike Dike Alternative is over six billion dollars.
Potential Environmental Impacts of Large Storm Surge Suppression Projects
Because large storm surge suppression projects, like the Ike Dike Alternative, attempt to stop or control natural ecological processes they have the potential for significant environmental impacts. Some of the potential environmental impacts of an Ike Dike Alternative include:
(1) the loss of the beach in front of an Ike Dike Alternative; (2) the loss of the beach will require perpetual beach sand re-nourishment; (3) the loss of sand dunes, prairies, and wetlands in front of an Ike Dike Alternative; (4) the loss of residences in front of an Ike Dike Alternative; (5) the loss or degradation of salt marshes on the back side of Galveston Island and Bolivar Peninsula; (6) the loss or reduction of wind generated sediments in front of the Ike Dike Alternative; (7) the loss or reduction of animal and plant species due to fragmentation caused by an Ike Dike Alternative; (8) the loss of nesting beach for the federally endangered Kemp's Ridley Sea Turtle; (9) the loss of wintering and foraging habitat for the federally threatened Piping Plovers; (10) degradation and interruption of ecological functions/processes in San Luis Pass; (11) the loss or degradation of movement of Galveston Island and Bolivar Peninsula; (12) the loss or degradation of views or vistas of the GOM; (13) a degradation or loss of existing recreational and inspirational activities at San Luis Pass; (14) ebb-flows (from storm surge) from Galveston Bay will create erosion, sedimentation, and flooding for ecosystems and properties behind an Ike Dike Alternative; (15) alteration of salinity may affect dolphins that live in Galveston Bay; and (16) alteration of salinity may affect oysters, oyster reefs, and oyster hash areas in Galveston Bay.
We Need to Proceed Carefully and Engage in Detailed Community Discussions
What has been proposed is that nature should be protected from nature. The so-called natural disaster of a hurricane is exactly that for people who have built in places that are vulnerable to storms. People have been warned about this “natural disaster” for decades and want the government to subsidize their decisions to put themselves, with the approval and help of local government and developers, in “harm's way.”
Coastal ecosystems have evolved to adapt to and change with storm surge. When we talk about damage to these ecosystems from hurricanes we forget that they are already resilient and that changes to these ecosystems due to hurricanes are not bad – they reflect the natural processes of adaptation and change which have always occurred in the coastal zone. We forget the benefits that hurricanes provide for these coastal ecosystems. New habitats for fish and wildlife are created, new sand/sediment is provided for marshes, and new inlets that provide connections to bays, estuaries, and the GOM are created.
Instead of keeping out of “harm's way” and allowing natural processes to work, people want to interfere, manipulate, and stabilize an inherently dynamic and ever-changing set of natural processes. Over the long-term this will not work for humans or coastal ecosystems.
How do we approach whether a storm surge suppression project or a development in a coastal area where hurricanes occur makes sense? To begin, we must determine whether development contradicts “The Rules of the Sea” which include (1) the coastal zone is unique and requires unique management strategies; (2) coastal physical processes must be identified and understood from a whole-island perspective; (3) property damage potential is site-specific and each site is different; (4) property damage mitigation must be from a whole-island perspective; (5) relative risk areas can be recognized on the basis of well-defined criteria; (6) all coastal hazard evaluation and mitigation must consider a rising sea level; (7) repair alterations due to development; (8) conserve sand; (9) conserve vegetation cover; and (10) conserve land-forms.
We can use lessons from coastal management to score a development proposal. These lessons include (1) wide beaches protect property; (2) dunes protect property; (3) vegetation protects property; (4) shore-perpendicular roads act as overwash and storm-surge ebb conduits; (5) notches in dunes create overwash passes; (6) overwash and storm-surge ebb are intensified when funneled by structures; (7) seawalls can protect buildings, but they also can cause beaches to narrow, which reduces both recreation and storm protection value; (8) setbacks protect; (9) elevation protects; and (10) proper community governance offers a degree of self-protection.
If development makes sense after considering all of these criteria, only then can we use a four-step process to determine if mitigation of the proposal makes sense. This process entails (1) understand the physical processes (the hazards); (2) map zones of relative risk of property damage caused by these processes; (3) develop site-specific (non-structural) property damage mitigation techniques; and (4) implement mitigation techniques.
“Living with the rules of the sea”, reflects the same philosophy as “Work with, and not against, Nature”. Our purpose should be to “Keep our natural coast, ecosystems, and people out of “harm's way.” If we practice this philosophy then we can weather hurricanes and enjoy our coastal heritage.
Brandt Mannchen
October 9, 2016