ArcGIS Story Map Outline 2021 taught by USC Geoscience

The East Galveston Bay Watershed (HUC 8) and Surrounding Influences

Welcome to the East Galveston Bay Watershed, home to Texas' rich biodiversity, Houston's nearest shipping channel, and one of the state's leading sources of seafood (e.g. the oyster reefs), and oil production.

 

Geological and Hydrological Features of East Galveston Bay

The East Galveston Bay houses some of Texas' most precarious ecosystems, bordered with Wetlands and in such proximity to massive anthropogenic influences. The Bay descends from the Upper Fort Worth Metroplex and Trinity River into the Gulf of Mexico, passing through Houston and Dallas, two of the main oil supplying cities in Texas, the largest oil-producing state in the nation (U.S. Energy Information, 2019). As one would expect, the fight for the wildlife began recently with military coastal teams and researchers alike scrambling to find solutions as even apex predators now face numerous threats (see Watershed Management). As a Texan, I can say it's common knowledge that Galveston Bay's resident dolphin colonial waterbird and wild fish populations share the body of water with some of Texas' rarest visitors such as Leatherback Sea Turtles, Whooping Cranes, West Indian Manatees (Galveston Bay Fact Sheet Series, 2012). We'll delve into more of the interactions with marine life as we near the Human Modifications section.

Geology

As for East Galveston Bay's geology, environments range from Estuarine wetlands to upland prairies. An overview of the key habitats are:

  • Seagrass Meadows are shallow waters that are the most protective habitats for the commercialized species in the ecosystem and line the shoreline of the bay but are highly dependent on the salinity, rainfall, and turbidity of their inflow.

    • These habitats house more saline-adapted plants and protect finfish, shellfish, waterfowls.

  • Coastal Prairies are the most endangered habitat in the E. Galveston Bay area, once existing in millions of acres, now more closely to 65,000.

    • These were also the most biodiverse of the area: supporting food webs of buffalos, red wolf, black bears, and so on. However, they've been gravely threatened by Chinese tallow trees and other invasive plants.

  • Riparian Forest is yet another habitat of conservation concern due to its dependency on its neighboring bodies of water. Urban development also threatens these areas shaving off almost 9,000 acres in only five years.

    • This habitat is dominated by smaller mammals like bobcats, raccoons, snakes, and more. Again, equally threatened by Chinese tallow trees, elephant ear, and more invasive species. 

  • Oyster Reef are some of the E. Galveston Bay's most harvested habitats, housing the popular Eastern Oysters and cousins.

  • Estuarine Wetlands are known as the fringing marshes as they border the shore of the bay and consist of a salinity gradient (e.g. salt marshes and brackish marshes).

    • Within these pools reside brown and white shrimp and the wading birds that prey upon them. 

  • Freshwater Wetlands tend to develop from rainfall-runoff or severed watersheds. These areas are found to slope elevation wise and transition the freshwater to salt marshes and so on.

    • In these areas, live the spiny aster, and other plants like the invasive water hyacinth. When hurricanes push into the bay, these areas suffer most as seawater kills the biomass.

  • Forested Wetlands are located further up into the Trinity Valley River around the floodplains of its watersheds, i.e. aren't in the E. Galveston Bay, but if disrupted are bound to influence sediment transport.

  • Prime Farmland Soil are agricultural areas around E. Galveston Bay. These areas tend to be faulted for nutrient-rich run-off that disrupts the biota and sediment of more fragile ecosystems downstream.

  • Urbanized Area is the most ominous and encroaching habitat, pushing habitats onto each other and terrestrial species to the shorelines and shoreline inhabitants into the water.

Hydrology

East Galveston Bay like other watersheds is a body of water that serves as a transition zone for freshwater from the rivers to mix with saltwater from the sea. This process works in tandem with the prior habitats mentioned that function on a salinity gradient.However, as you can see on this figure of the Texas coast: the watershed contains small openings to allow for natural inflow and outflow for salinities to mix. So, water management becomes extremely important since we know this area is not only ecologically fragile but also at risk for flooding if water velocity and tide are disturbed by natural disasters. On top of the risk of natural disasters, urbanization around the bay has forced mass channelization which in turn can concentrate contaminants in run-off and affect the surrounding groundwater systems e.g. the three aquifers further upstream.

Human Modification affecting the East Galveston Bay

As aforementioned, East Galveston Bay supports the fishing, maritime, and oil industry immensely. With triple the industrial strain than most watersheds, it's no surprise that the entire watershed up from Dallas to the Gulf is developed, frequented by seaports, oil refineries, and fields too. The E. Galveston Bay with its famous population of Eastern Oysters manages to move 3 million pounds of oyster product for a $10 million profit, roughly 80% of Texas' oyster product. This commerce without a doubt invites interdependence between the Galveston city community and the E. Galveston Bay, as a source of income to profit from and protect.

 

On the contrary, exists the oil industries grasp on E. Galveston Bay. Texas produces about 41.4% of the nation's oil and the U.S. produces at a close second to the world's oil (U.S. Energy Information, 2019). Furthermore, the Bay is highly representative of the Water-Energy Nexus issue, in that each gallon of petroleum produced necessitates 1-1.9 gallons of water, reaching almost double the product output (Sun, 2018). Sun continues to note that both industries that exist in the E. Galveston Bay have severe trade-offs: transportation producing almost 24% of the Greenhouse Gases and crude oil refineries consuming almost 10% of what they produce (Sun, 2018).

Other concerns are noted in this compilation of layers for the E. Galveston Bay's oil production scene (left; simplified, note that if depicting oil wells and rigs, one wouldn't be able to see any labels on the map). Sadly, the orange boundaries denote polluted waters and streams, the yellow, orange, and pink nodes sitting upstream to the bay denoting fracking sites, and at the small openings that I mentioned in the hydrology section, sit oil spill residue, ready to be circulated through the bay with any flooding from the frequent hurricanes. With some navigation up and down the Texas coast, the pollution ebbs and flows, but never as dramatically at E. Galveston Bay,

Impact on the East Galveston Bay

The Anthropogenic Impact left on E. Galveston Bay has been extensive over time, the oil discovery occurring in Spindletop 1901, and the urban areas exploding around the hope of striking gold for oil, exploiting native tribes and resources well into today. So, we'll look at the two of the largest threats to the E. Galveston Bay and its surrounding communities: Oil spills and Hurricane Patterns.

Oil Spills

A pervasive threat in the East Galveston Bay will always be oil spills. In April 2010, Texans across the state braced themselves as news of the flaming combusted BP Deepwater Horizon Oil Well spread as fast as its pollutants did as the largest oil spill in history. More often than not, smaller oil spills result from the transportation of oil in channels, a practice E. Galveston Bay practices in masses (note the seven seaports in the Bay alone represented by blue dots) but lately larger oil spills seem to be becoming more frequent (Galveston Bay Status and Trends, 2010). Although Texas A&M Researchers applaud the coastline's resilience, other scientists and NASA Imagery unveil an even more extensive oil spill than the originally anticipated Oklahoma-sized patch, the effects still underresearched (Randall, 2020). Factors however did help the coastline retain its integrity like oceanic currents, microbial life, and more, but not fast enough and researchers now worry that the cleanup in store after the ten-year mark may be more harmful to the ecosystem than the initial spill that already cost $50 billion in fines. Medical studies that feared for oil spill cleanup workers showed little effect on the lungs after exposure to the dispersant in this spill but found minor cardiac effects just one day after exposure (Roberts et al. 2015). Researchers warn that the probability of a spill of this magnitude occurring again is high, that the 2,000 deap-sea wells drilled in the last two decades are ticking time bombs with the addition of the next section, Hurricane Patterns

Hurricane Patterns

Another immediate and growing threat to the East Galveston Bay are hurricanes and their newfound prevalence and intensity. As we know, climate change can drastically alter the hurricane trajectories by heating up the cold water that would normally break a hurricane from touching down on land, as well as increased precipitation that ups moisture and thus fuel for the hurricane. Within my the last three years in Texas, I've sat through four tornadoes that reached as inland as San Antonio, the record number of tornadoes for a city well outside of "tornado alley". Although tornadoes are formed over land, they're derived from the same wind patterns of warm and cold clashing.

On this leftmost map (Live Atlas Hurricane Trajectories), you can see the trajectories and intensities of historical hurricanes dating back to the 1800's (in blue) as well as the most recent hurricanes (multicolored). Clicking through historical data, it's obvious that Category 4 and 5 hurricanes spread themselves out by decades. This year, 2020 has seen up to three upper-level hurricanes in a day, rivaling the Gulf's frequency in 2005 with hurricanes like Katrina-- La Nina supposedly to blame. Sources praise some of the factors that kept the hurricanes from reaching Katrina's levels of destruction such as monsoon activity blocking the trajectory of the hurricanes across the Atlantic (Henson, 2020)

As for the effects of the hurricanes on the East Galveston Bay specifically, the saline pushes can be catastrophic to biodiversity. As stated in the geology and hydrology section, the salinity gradient of wetlands are fragile and even a sudden push in velocity can disrupt the health of these habitats (shown below by a precipitation trajectory). Another effect is sheer damage to wildlife. Hurricane Harvey decimated the dolphin population in the E. Galveston Bay, leaving 96% of dolphins with skin lesions, 65% of those being severe and reducing encounters by almost 70% as they healed (Devadanum, 2020). Note that dolphins are apex predators in this ecosystem and if endangered would allow for a population explosion of prey animals, ultimately disrupting biota balance.

Watershed Management of the East Galveston Bay

For Watershed Management in the East Galveston Bay, involvement occurs on almost every level given the immense commerce, transit, and ecological significance of the Bay. Initiatives Include, but aren't limited to:

  • Creating Vegetative Buffers along waterways, stormwater detention basins and more in an effort to improve water quality.

  • Cumulative Analysis of Seafood Export helps determine not only the health of the ecosystem,

  • Limiting aviary hunting by educating local and visiting rotary clubs on the environmental impacts of their hypothetical disappearances.

  • Expanding the Texas City Levee is another speculated act to protect Houston from routine, but now worsening flooding.

  • Lastly, but not least: the Coastal Spine, a barrier project being drafted and now re-drafted by the U.S. Corps to provide the E. Galveston Bay with a refuge from the powerful effects of hurricanes.