On August 29, 2005, Hurricane Katrina slammed ashore on the southeast coast of Louisiana devastating Orleans, Plaquemines, and St. Bernard Parishes, as well as major portions of St. Tammany Parish on the north shore of Lake Pontchartrain. Less than one month later on September 24, 2005, Hurricane Rita devastated portions of southwest Louisiana, including Cameron Parish and portions of Vermilion Parish and Calcasieu Parishes.
In keeping with the objectives of the Drinking Water Protection and Baseline Monitoring Programs the Aquifer Evaluation and Protection Section staff conducted a reconnaissance of the impacted areas to: 1) survey damage to water wells and significant potential sources of contamination (SPSOCs) identified in source water assessments, and 2) determine the effect, if any, on inundation of water wells along the north shore of Lake Pontchartrain.
Assessment of Water Wells and Significant Potential Sources of Contamination
Public water supply wells in the impacted area were found to be intact. However, a number of domestic wells were damaged or destroyed. The staff made note of the location and condition of these wells when they were found. It is estimated that at most only a third of the domestic wells in these areas were located. The debris and sand covered many of them and some had already been bulldozed. All of the damaged well information was provided to the Louisiana Department of Transportation and Development (LDOTD) so that they may contact the owners to either repair these wells or plug them. The information also provided LDOTD with locations they should concentrate their efforts toward in getting wells repaired or plugged. In the Katrina-impacted area 25 damaged wells were located. In the Rita-impacted area 43 damaged wells were located.
The staff also assessed significant potential sources of contamination (SPSOCs) identified in source water assessments in the impacted areas to determine if there had been any releases or spills from these facilities. They also made note of any facilities outside of source water protection areas that were damaged and in need of further investigation. Many above ground storage tanks had either spilled or were overturned. All of the assessment information was provided to the DEQ Surveillance staff for further investigation. In the Katrina-impacted area 31 facilities were assessed. Twenty-nine of these were SPSOCs and two were overturned above ground storage tanks located outside of source water protection areas. Two of these facilities required further investigation. In the Rita-impacted area 207 facilities were assessed. One hundred ninety eight were SPSOCs and nine were above ground storage tanks and oil and gas tank batteries located outside of source water protection areas. Fourteen facilities required further investigation.
Geologist Jesse Means locates an overturned above ground storage tank by global positioning system (GPS) and makes note of spilled contents in Cameron Parish
Post-Katrina Ground Water Sampling Activities
The Aquifer Evaluation and Protection Section staff participated in a cooperative sampling program with the Louisiana Geological Survey and the U.S. Geological Survey following Hurricane Katrina. The objective of this sampling program was to determine the effect, if any, of inundation of water wells along the north shore of Lake Pontchartrain. Wells that were overtopped by storm surge were sampled for the following parameters:
- Water Quality
- Dissolved Metals
- Volatile Organic Compounds (VOCs)
Selection of the wells was based on access and availability (those that could be physically reached and could be operated by the owner). Fourteen wells were sampled in September and October of 2005. There were no VOCs detected in any of the wells that were sampled. Unpurged results from one well showed elevated aluminum, calcium, potassium, magnesium, and selenium, but the purged resample showed normal levels or were non-detect. Preliminary data show the majority of wells with a detection of one or more of the following bacteria: fecal coliform, total coliform, Escherichia coli, or enterococcus.
The after action follow up plan is to mail the sample results to the well owners, where practicable. There is a need to resample the wells to determine the status of the bacteria levels. There is also a need to expand the bacteria sampling of wells to the Rita-impacted area.
Geologist John Jennings samples a well in St. Tammany Parish