This presentation is intended to provide some basic information about 3 subjects: First, Why might a flood protection system be needed for the urbanized, eastern part of Galveston Island? Second, What might a flood protection system be? Third, Why not just tag along with other big projects and just let someone from somewhere else tell Galveston Island what Galveston needs to do and what they are going to allow Galveston to do?
The Galveston Ring Levee A Critical Investment in Galveston s Future Goals of the Galveston Ring Levee Provide bay-side flood protection for the City of Galveston. Essential to protect Galveston from flooding, even if Ike Dike is built. Enhance Galveston s relationship to Galveston Bay. Encourage investment in Galveston by decreasing the risk of flooding
Major storms impact Galveston on a regular basis This is the aftermath of the 1900 Storm 12 10 8 Column 1 Column 2 Column 3 6 4 2 0 Row 1 Row 2 Row 3 Row 4
The response of the citizens of Galveston to protect the city from battering storm waves was the first of multiple phases of the Seawall. This was Hurricane Ike. 12 10 8 Column 1 Column 2 Column 3 6 4 2 0 Row 1 Row 2 Row 3 Row 4
Flood waters occur on a regular basis from the north side, bay side of the island. This picture is from Hurricane Carla in 1961 which went inland on Matagorda Island by Port O'Connor, some hundred miles away.
Hurricane Ike Flood waters in 2008.
Computer simulation in 2005 about different flood levels by Johnson Space Center Office of Emergency Management
Hurricane Carly is a made up name
Just slightly less than Hurricane Ike flood level of approximately 13.5 feet on the east end of the island. Note how dry Texas City is.
Just 2 feet more surge than Hurricane Ike. Note Galveston is almost completely underwater. Note that Texas City is dry.
Texas City Levee Orange line is the Flood protection system
The Texas City Flood Protection System includes earthen embankments (levees). They have put roads on top of some.
There are Gates where the levees cross roads and train tracks, that are closed during major storm events.
Moses Lake is used as a retention lake. Note the closed gray gate which can be opened.
This diagram is from the Washington Post, done after Hurricane Rita. Noting the differences between Galveston and New Orleans, Galveston is normally above sea level, while New Orleans is below sea level. New Orleans is always in a bathtub. Galveston is not in a bathtub since water will normally flow down hill, north to the bay along streets and storm sewers.
In Galveston, gates (red) would be closed only during major flooding events to keep out flood water from the bay. Water from rain or overtopping the Seawall would be ejected from the city into the bay by big pumps.
An overview of Galveston Bay to show how big the bay is with 600 sq. miles
Following is the US Army Corp of Engineers published a Texas Coast Hurricane Study feasibility report in 1979 which listed a Galveston Ring Levee as one of the best cost/benefit ratios and most feasible engineering tasks with fewer negatives.
Shows a Ring Levee location
Following is the city of Galveston Long Term Community Recovery Plan of 2009 devoted 3 pages to a Galveston Ring Levee.
Galveston Levee Recovery Value: Moderate Project Champion (when identified sponsor is a local public body 30% cost must be borne by sponsor) Background The City of Galveston is a barrier island community subject to hurricanes from the Gulf of Mexico. The most widespread and costly damage inflicted by these storms is flood damage generally caused by the wind-driven storm surge and the wave action associated with storms. While Galveston has a seaward-facing seawall that has proven its value in protecting the city from storm waves, it is unprotected from hurricane flood damage from Galveston Bay, as evidenced by Hurricane Ike (Sep 2008). Storm surge during this storm was driven into Galveston Bay causing it to inundate the island from its bay side. Statistically, Galveston is affected by hurricanes approximately once every 2.5 years. The island is hit directly approximately once every 10 years. Extremely severe storms hit Galveston roughly once every 25 to 50 years. Historical recorded storm surges associated with hurricanes have reached 14.2 ft in the storm of 1900 (killing an at least 6,000 people, making it the deadliest natural disaster in U.S. history), 12 feet in the storm of 1915, and 15 feet for Hurricane Carla in 1961. In Hurricane Ike, the storm surge elevations were approximately 10 feet on the western end of the island and approximately 13 feet on the eastern end. Construction of the 17-foot Seawall on the southern facing shore of the City began soon after the 1900 hurricane hit Galveston. During Hurricane Ike, the Seawall functioned as designed and protected the southern part of the City from the wind driven waves as it did during previous storms since 1900. Unfortunately, Ike caused a huge mass of water to come from the bay and flood the island from the north, where there is no flood protection system in place. This flooding caused much of the island to be inundated, causing the majority of the damage to the island. The estimated cost of the damages caused by Hurricane Ike are in
excess of $22 billion, making it the third most costly hurricane in U.S. history. Included in this estimate are the costs of the devastating damage to essential infrastructure such as the wastewater treatment plants and the potable water distribution system caused by Ike. The threat of disease and disruption of service resulted in the island residents not being allowed back to their homes for over 12 days, which caused additional damages from extensive mold growth and spoiled food. A substantial proportion of the island s residences are undergoing or awaiting repair at the time of preparing this plan, six months following the storm. Goals To protect the health, welfare and property of the residents and businesses of the densely populated area of Galveston Island from storm related floodwaters. To encourage investment (commercial, residential, medical, educational, infrastructure, governmental, and utilities) in Galveston by decreasing the risk of flooding with a structural flood control system. Additional Benefits: Enhancing land values (and subsequently increasing the tax base) Reducing losses of income by residents and businesses Reducing emergency response and recovery costs during and following storm events Complementing other recovery and development projects for Galveston Project Description This project calls for the construction of a levee around the more densely populated eastern portion of the island. It is an effort to minimize the exposure to flood damages during large-scale storm events and protect the lives and property of the residents of Galveston. The proposed levee system would protect the City on its bay side and connect with the eastern and western ends of the existing seawall. The project proposes to enhance the existing storm protection provided by the seawall by constructing a levee/floodwall system encircling the City (Figure 1). Depending on its final
engineering and alignment after thorough study, the system might include both earthen levees and concrete floodwalls, pump stations, gates, interior storm water outlets and other features to control floodwater intrusion and removal from the city. Galveston Long-Term Community Recovery Plan 112 Figure 1. Proposed Galveston Levee system and existing Texas City levee shown with 15.8foot storm surge and the resulting flood protection. Potential additional benefits of the plan to other developments for Galveston Island are also indicated. The exact course and components of the system would be determined by a detailed feasibility and engineering study. The community recommends that this study be initiated immediately. The issue of storm related flood protection is not a new one and is one that the community and federal agencies have considered in the past. In 1979, the USACE released a report entitled Feasibility Study Texas Coast Hurricane Study. This report preliminarily studied the effects of hurricanes on five Gulf coastal areas in Texas including the Houston-Galveston Area. The report contains a Galveston levee plan that closely resembles the measures conceived in the project described here (Figure 2). The 1979 plan contains a brief economic analysis of the project including the potential benefits associated with it. All of the analysis provided is based on 1970s data and would need to be updated to current figures for any new levee plan. The updated plan should include the knowledge learned over time including the success of the Texas City levee system during Hurricane Ike. The 1979 plan proposed a levee/seawall based protection system that encompasses the eastern end of the island and includes approximately 7.8 miles of earthen levee and approximately 4.7 miles of concrete floodwall (predominately through the port area). In addition, the report recognized that the system would need to accommodate the roads, railroads and other infrastructure that would be impacted. This plan was identified at the time to be the most feasible when
compared to several other plans for protecting larger areas of the island and Galveston Bay (up to 127 miles of coastline) because it provided the highest benefit-cost ratio (2.4 compared to 1.1) and had the fewest environmental, engineering and management challenges. Further study and discussion should take place with the USACE to determine current feasibility. Figure 2. Recommended Galveston Levee plan resulting from the 1979 USACE study. In addition to the primary function of protecting the majority of the City s residents and businesses from flood damage during storm events, the proposed levee project could benefit a number of other projects to help Galveston s recovery and development (Figure 1). For example, the levee could be incorporated into a plan to raise Harborside Drive and/or provide an easement for the Galveston end of a commuter rail line to Houston. It could provide an elevated highway connecting FM 3005 and West End traffic directly to the I-45 causeway via a bridge and floodgate at the entrance to Offatts Bayou. If the plan is designed and constructed in an appropriate and aesthetic manner, the levee and its adjacent areas could be an eco-tourist draw, providing a hiking/bike path with wetland, city and bay
observation points. The plan would also incorporate an improved storm water drainage system for the city. Similar ideas have been implemented in other areas including the nearby community of Texas City. The levee system protecting Texas City is 17 miles long and 23 feet in elevation at its highest point. The Texas City levee was built in response to Hurricane Carla and has functioned well in all subsequent hurricanes protecting that city from flood damage during hurricanes, tropical storms and torrential rains (see Figure 1). In addition to creating a barrier to storm surge, the Texas City levee system was designed to handle 9 inches of rainwater runoff in a 24-hour period and a 14-inch rainfall during non-hurricane tide conditions. There are considerable hurdles to cross in conjunction with this project including (but not limited to): funding, environmental impacts, state and federal regulations, land acquisition, timing, construction management and inspection, and public sentiment. However, though the obstacles and costs may be high the community believes the considerable benefits of this project outweigh those costs and that further study to update the previous USACE study is warranted. The community recommends that the city and county move rapidly to revisit and update the previous studies for protecting Galveston, and seek funding to implement a modern levee protection system for the city. Otherwise, it is only a matter of time before Galveston will once again experience devastating flooding from a hurricane. Sustainable Opportunities: The construction of a Galveston levee system would help the City rebound from this disaster by helping to ensure the future growth and vitality of Galveston. It would protect the City from damages from future storms and may help in the implementation of other reconstruction projects (such as storm sewer system upgrades and evacuation route and transportation enhancements). Financial Considerations
determined with engineering study Funding Funding Gap: $ 400 to 800 million Potential Funding Sources Federal Grants (see http://www.fema.gov/government/grant/government.shtm#2) Emergency Management Performance Grant (CDFA Number 97.042) Flood Mitigation Assistance Program (CDFA Number 97.029) Repetitive Flood Claims Programs (CDFA Number 97.092) Community Disaster Loan Program (CDFA Number 97.03) Hazard Mitigation Grant Program (CDFA Number 97.039) Pre-Disaster Mitigation Program (CDFA Number 97.017) Superfund Amendments and Reauthorization Act USACE State of Texas Grants (see http://www.txdps.state.tx.us/dem/pages/grants.htm) State of Texas Governor s Division of Emergency Management (GDEM) ORCA Funds Local Businesses Local Residents Tax Revenue
Following is the US Army Corp of Engineers' Coastal Texas Protection and Restoration Study Report from May 2015 which included a Galveston Ring Levee.
The Gulf Coast Community Protection and Recovery District's (GCCPRD) Storm Surge Suppression Study Phase 3 Report of June 2016 included a Galveston Ring Levee.
Storm Surge Suppression Study Central Region Alternatives Galveston, Chambers, and Harris Counties Central Region Alternative #1 (CR#1) - High Island to San Luis Pass Coastal Spine Central Region Alternative #2 (CR#2) - Texas City Levee Modifications and Extensions North (SH-146) and West--Galveston Ring Levee A map from the report showing a Galveston Ring Levee Figure 2: Central Region Alternatives Selected for Development
GCCPRD Phase 3 Report Recommendations A High Island to San Luis Pass Coastal Spine A navigation gate at Clear Lake and a Galveston ring levee Provides a region-wide reduction in storm surge that enhances protection for communities located along the shoreline of Galveston Bay and industry located along the Houston Ship Channel. While the Coastal Spine alone provides a dramatic reduction in overall surge, there are still heavily populated areas within the region that can expect to experience four to 12 feet of surge-related flooding. The addition of the Galveston ring levee and a navigation gate at Clear Lake will enhance protection for the City of Galveston, Seabrook, Taylor Lake Village, El Lago, Clear Lake Shores and Kemah. With the coastal spine in place, the structure design elevation for the modified Galveston ring levee is expected to be in the 12 to 15 feet range.
Some possible alignment options in yellow lines. White is existing storm barriers.
An actual levee in New Orleans
An actual levee in New Orleans
An actual levee in New Orleans
New Orleans Flood wall and Gate Alley north of Galveston Strand
2 to 3 meter storm surge on north side of Galveston Island 10pm Friday night Hurricane Ike Water Levels 9/13/09 04:00 UTC
2 to 3 meter storm surge at 6am. The eye passed over at 2.10am Saturday. Hurricane Ike Water Levels 9/13/09 12;00 UTC
Following is a map from Wikipedia that shows the Seiche flooding on Lake Okeechobee caused by the 1928 Hurricane. The lake does not connect to the Atlantic, so what happened was caused by moving around the water already in the lake. The lake is 12 to 20 feet deep and is roughly the size of Galveston Bay. There was a surge to 20 feet and 2,500 people died.
How storm surge is created by storm winds acting on an enclosed water body Seiche, or sloshing, is a well studied phenomena with courses on the subject at universities around the Great Lakes and other places.
Published LSU research study showing sloshing effect in Galveston Bay caused by Hurricane Ike
Modeling study by UT showing how flooding can still occur in Houston Ship Channel and Galveston behind a closed Ike Dike The storm track is the dotted line on the left. The flooding is around 16 feet
Modeling study by UT showing how flooding can still occur in Galveston behind a closed Ike Dike The storm track is to the right and the flooding is still in the range of 10 feet
Flooding of Galveston with only a 6 ft rise of water in Galveston Bay. This could be the general area protected by a Ring Levee
Post Hurricane Ike at Market and 25th
Summarizing the 3 subjects of the presentation: Why might a flood protection system be needed for the eastern part of Galveston Island? Historically and scientifically, it is well demonstrated that substantial flooding can occur from storm winds pushing water around the bay. What might a flood protection system be? It would likely be a combination of earthen embankments (levees), walls and gates. Different examples are Texas City, Freeport, Jefferson/Orange, New Orleans, the Netherlands. Books such as the Atlas of Sustainable Strategies for Galveston Island, Section III, Design Proposals is full of possibilities. Why not just tag along with other big projects and just let someone from somewhere else tell Galveston Island what Galveston needs to do and what they are going to allow Galveston to do? A Ring Levee is much smaller and therefore more feasible and can be done in a much shorter time. Big projects are more complex and are delayed by a myriad of issues. Tying a Ring Levee to a big project will conceivably stall the Ring Levee for years, decades or never happen. A Ring Levee is listed as a desirable project in all of the studies. The GCCPRD Study Recommendations list it as a desirable project. The GCCPRD Study Recommendations are most likely what is going to happen because the GCCPRD was authorized by the Texas legislature. The US Army Corp of Engineers have listed it in 2 different studies. Moving ahead with one aspect of a series of recommendations does not cancel the other recommendations. Texas City moved ahead with their levee system 50 years ago and they saved billions of dollars by staying dry during Hurricane Ike flooding. Freeport is in the process of getting a levee system. Jefferson/Orange are moving ahead with an enhanced levee system after experiencing the disastrous flooding from Hurricanes Rita and Ike. Why on earth would Galveston wait around to be told what to do when? Galveston led with the Seawall construction and with the grade raising of the city. Galveston has led with many things so shouldn t it continue to do so?
2.5 mile flood wall with gates 4.5 mile levee 0.4 mile Floodgate 2.1 mile levee
Delft Univ research program that has not been presented, but Dr. Merrell was an advisor The effects of the Ike Dike barriers on Galveston Bay A 2D numerical modeling study on hydrodynamics and the implications for the water quality and morphology of Galveston Bay Delft, June 2011 M.Sc. Thesis of M. Ruijs Committee: prof. dr. ir. M.J.F. Stive dr. ir. Z.B. Wang dr. ir. G.J. de Boer dr. ir. M. van Ledden ir. A.J. Lansen dr. W.J. Merrell
Blue colors show decrease in flow through channel due to structures that allow 40% and 20% of original flow
Conclusions of the Study of Ike Dike Effects on Galveston Bay The placement of barriers in Bolivar Roads results in a decrease of the tidal prism (the volume of water in the bay at any time during the tidal cycle) and a decrease in the current velocities, that would change the morphology of tidal channels Due to the placement of the barriers it is likely that the sediment exchange from the Gulf of Mexico into Galveston Bay through Bolivar Roads is blocked. The extra sediment that is needed to maintain tidal channels would then only come from inside the bay. This could lead to shoreline erosion, erosion of tidal flats and erosion of the marshes. The health of the tidal flats and marshes is also strongly influenced by the amount of time that the flat or marsh is under or above water. The reduced tidal range together with sea level rise, subsidence and sediment deficit, the shorelines, flats and marshes might retreat. Decreased flow through Bolivar Roads will increase water residence time within the bay and substantially decrease salinity within the bay.
Galveston Bay is essential to the ecological life-cycle of shrimp and other marine life. No structure would be allowed to be built without these significant environmental and ecological impacts being addressed. Diagram by Texas Parks and Wildlife