Summarizing Hurricane Harvey's Environmental Impacts
Image Courtesy of NOAA
This application was created in 2017 in response to Hurricane Harvey and the impact it had on Houston. The data, maps, and links have not been updated since 2017 and are not planning to be updated at this time. Please note that some links may now reside behind media paywalls or no longer be active. If you have any questions, please click here to contact HARC .
Intro
The Houston-Galveston Region receives on average 45 inches of rainfall each year.
During Harvey, some areas received more than 50 inches of rain in less than one week.
Disclaimer: This application is for informational purposes only and may not be suitable for legal, engineering, or surveying purposes. Mapping may not necessarily reflect on-the-ground conditions. HARC makes no claims as to the accuracy or reliability of the data, and neither assumes nor accepts liability for use. Use or reproduction of these data without acknowledging HARC as the source is prohibited.
Water
What the Water Carried
Harvey’s flood waters carried enormous amounts of debris, sediments, and hazardous pollutants. Satellite imagery (left image) clearly shows the murky waters from Harvey flowing into the Gulf of Mexico. Toxins and pathogens such as viruses and bacteria were intermixed and transported along with contaminated sediments and floating debris. Hurricane Harvey has created a legacy of health concerns for residents, rescue workers, and the environment that will linger for years to come and have to be addressed.
Photo by Revolution Messaging
Sediment
Hurricane Harvey stripped sediments from bayous, displacing tons of sediment to banks of bayous, such as Buffalo Bayou, in the Houston Ship Channel, and Galveston Bay. Sediment accumulations in some portions of the Houston Ship Channel reduced water depth by three feet , requiring dredging to restore safe conditions for vessel traffic. Sediments were deposited on city streets, residential neighborhoods, and parks, causing potential health concerns from lead, arsenic, and other pollutants.
Photo by U.S. Department of Agriculture
Toxic Pollutants
Hurricane Harvey caused hazardous spills and toxic releases (see Health and Safety, Hazardous Releases tab). Water from flooded refineries and superfund sites, commercial and industrial facilities, and common household chemicals from under the kitchen sink were swept up and spread with the flood waters. The USCG received reports of unknown materials and hazardous substances, some in drums, washed up in driveways and lawns of private residences.
Photo by Coast Guard News
Pathogens and Viruses
Flooding can often cause sewer systems to fail. Millions of gallons of untreated sewage overflows occurred as a result of Hurricane Harvey. Medical personnel reported an increase of gastrointestinal issues and skin infections as a result of contact with flood waters. A team from Baylor Medical College and Rice University , with support from the New York Times, collected samples from residential dwellings and discovered Vibrio and E. coli at levels 135 times higher than safe contact thresholds. Other flood water-borne pathogens caused even more severe forms of illnesses, such as necrotizing fasciitis and sepsis .
Source of the right picture: NASA
Salinity and Temperature
The region received trillions of gallons of rain, which resulted in vast amounts of freshwater inflows to Galveston Bay. The preliminary estimate of inflows, according to the Texas Water Development Board, is 12.2 million acre-feet to Galveston Bay - more water than Galveston Bay typically receives in a year. TWBD preliminary estimates show that inflow during August of 2017 is the highest August inflow on record (1977-present). Decreasing salinity and temperatures followed, with disastrous impacts on oysters. TPWD estimates that it could take more than two years for oysters to repopulate Galveston Bay. Some industry experts believe that as much as 90% of all Galveston Bay oysters may have been lost.
Bacteria
Elevated levels of bacteria are used to indicate risk from fecal contamination and associated pathogens in waterbodies. Bacteria are found in fecal wastes of all warm-blooded animals, including humans, livestock, and wildlife. Waterways are considered impaired for contact recreation if bacteria levels exceed health standards set by federal and state agencies. When bacteria levels are too high, infections and gastrointestinal distress can occur. Extreme events such as Harvey can cause sewer systems to fail, which means untreated wastewater is mixed with flood waters. As a result, bacteria in flood waters are often well above safe levels for human contact.
Bacteria data courtesy of Galveston Bay Foundation, Texas GLO Beach Watch Program, Texas A&M Galveston, Texas A&M and University of Houston Clear Lake, and Houston Health Department.
Flow
The map to the right shows USGS stream gauges; the size of the circle corresponds to days the gauge reported waters over flood stage (triangles did not have records available to indicate number of days above flood stage). Blue indicates flow at that gauge exceeded Historical Flood peaks (ft 3 /s) during Harvey. Green indicates flow at that gauge did not exceed peaks. Click on the circles to view a hydrograph for flow at that gauge during Harvey.
Harvey resulted in catastrophic flooding. Stream flow gauges at various locations around the region measured flooding that exceeded historically recorded flood values. The amount of flood waters associated with Hurricane Harvey can be better understood by examining these stream flow gauges. This map shows USGS and some shared NWS stream gauges only. There may be other complete flow data sets for this time period.
Air
Ozone
The slider at the bottom right will advance the time series by day. Click the arrows right or left to see differences between days.
Ground level (tropospheric) ozone is a secondary air pollutant formed by the chemical reaction between volatile organic compounds (VOCs) and nitrogen oxides (NO x ) in the presence of sunlight. Ozone is a respiratory irritant that can lead to coughing, difficulty breathing and shortness of breath, exacerbate the frequency and intensity of asthma attacks, throat irritation, and even lung infections and damage. Children and the elderly are especially sensitive to these health effects. Ozone can also affect the growth of vegetation and trees and reduce crop yields. High levels of ozone can be caused by elevated emissions of VOCs and NO x , especially when coupled with weather conditions characterized abundant of sun and heat that facilitate photochemical process associated with ozone formation. During and after Harvey, the Houston region experienced many storm-related releases and spills of VOCs. Storm-associated shutdowns and startups at refineries and petrochemical facilities have also resulted in the release of large amounts of ozone precursors such as VOCs.
Toxics
The slider at the bottom right will advance the time series by day. Click the arrows right or left to see differences between days.
“BTEX” refers to a group of volatile organic compounds (VOCs) made up of benzene, toluene, ethylbenzene, and xylenes. The primary sources of BTEX emissions are refineries, petrochemical plants, vehicle emissions, and evaporative losses from fuel storage tanks. Exposure to toxic air pollutants (air toxins) that comprise BTEX gases can lead to headaches, eye and nose irritation, and nervous system, liver, and kidney damage. Benzene is a known carcinogen (cancer causing). Elevated levels of these hazardous air pollutants (HAPs) seen after Hurricane Harvey are likely due to storm-related spills and releases at industrial facilities, shutdowns and startups at refineries and petrochemical facilities, as well as increased numbers of small, gasoline-powered engines in portable generators, chainsaws, and leaf blowers operating in the region after the storm.
Heath and Safety
Hazardous Releases
The USCG National Response Center maintains a database of reported incidents involving hazardous materials across the United States. These data facilitate public awareness about the nature, timing and location of chemical, oil, and other hazardous spills. Please note these data include only reported releases and likely represent a mere fraction of Harvey-related pollutant impacts in the regional environment.
During Hurricane Harvey, 90 incidents were reported in the greater Houston-Galveston region involving more than 700,000 gallons of pollutants released into water and on land, and more than 38,000 pounds of air pollutants. Pollutants included oil and gasoline compounds, organic toxics such as benzene, PCBs, and butadiene, nitrogen oxides, ammonia and sulfur dioxide among others. Volumes of liquids spilled ranged from less than five to more than 460,000 gallons. Air pollutant releases ranged from less than five to more than 10,000 pounds.
Superfund
Select a station to learn its floodplain, activity and phase status, as well as pollutants associated with the site.
Superfund is a US government program designed to fund the cleanup of sites contaminated with hazardous substances and pollutants. Superfund sites are typically designated because the substances pose a risk to human health and/or the environment. The EPA has determined that 13 federal Superfund sites in the Houston region experienced flooding by Harvey. As of September 14, two sites have been identified for additional assessment : U.S. Oil Recovery and The San Jacinto Waste Pits. The potentially responsible parties of the San Jacinto Waste Pits Superfund site have been directed to take immediate action to address damages. TCEQ identified 13 State Superfund sites for impact assessment post-Harvey. No major issues were noted .
Built Environment and People
FEMA Modeled Damages
The large pie chart below shows FEMA Modeled Damages for the region based on total observations. The pie charts on the map to the right show FEMA Modeled Damages by county based on total observations for that county.
FEMA Modeled Damages (Total Observations: 105,065)
Development, Rainfall, and Watersheds
Click on a watershed to display a popup with Harvey rainfall information. Hint: Use arrows (in the top right corner of the popup header) to cycle through additional information on Harvey rainfall amounts, impervious coverage (types of land cover that do not allow water to pass through, such as pavement), watershed wetlands, and land use. In the map estuarine wetlands are shown in blue, and palustrine wetlands are shown in orange, per the NOAA 2010 Coastal Change Analysis Program data.
Wetlands, forests, and prairies are natural habitats vital to mitigating impacts and damages caused by high precipitation storm events such as Harvey. These habitats trap and slowly release rain and flood waters. From 1996 to 2010, the eight-county region has lost over 12 billion gallons of wetland water storage capacity (one acre of wetland holding one foot of water can contain 325,851 gallons of water). The loss of these habitats results in greater volumes and rates of stormwater runoff. Development projects that include rain gardens, bioswales , permeable pavement, and green spaces at parks can help reduce flood waters and improve stormwater quality.
Electricity and Energy
Power Generation and Outages
UTMB Galveston Post Ike 2008
Hurricane Harvey wreaked considerable havoc on the electric power transmission and distribution system. During the span of the storm approximately 1.5 million power customers along the Gulf Coast lost power. Combined Heat and Power (CHP) installations at several critical infrastructure facilities to sustained power for continuous operation during the storm. Installed after the devastation of Hurricane Ike, the UTMB-Galveston CHP system exemplified an effective means of maintaining power for hospital operations during a natural disaster event.
Power Demand
Click on the graph below to see regional ERCOT power demand from 2002 to 2015, showing an overall increasing trend, with dips for Hurricanes Ike and Harvey. The inset graph in the top right hand corner shows Harvey power demand by weather zones.
About
We at HARC are grateful to Houston Endowment for their support in the development of this project. Hurricane Harvey brought record rainfall to Houston; the resulting flooding led to regional devastation, impacting lives, homes and livelihoods. The storm also had numerous environmental impacts.
