Lake Pontchartrain Northshore

Lacombe Sub-Area Land Use Superfund Sites There are two Superfund sites that were located in the Lacombe sub-area, both in the Slidell area. The first site is called Bayou Bonfouca and was a wood treatment facility using primarily creosote. The site is 55 acres and is located 7 miles north of Lake Pontchartrain, southwest of where West Hall Avenue and Bayou Lane intersect, within the 100-year flood plain of Bayou Bonfouca (USEPA 1996). There is a cement plant to the east of the site, residential and commercial areas to the north and a residential subdivision to the west. This site began operation around 1882 treating pilings for bridge and railway construction. It operated under the ownership of Southern Creosote Company, Hattiesburg Creosoting Company, Gulf States Creosoting Company and American Creosote Works. In 1970 there was a large fire that ruptured creosote storage tanks causing creosote to run across the site into Bayou Bonfouca. The site was listed to the NPL in 1982 and remedial action began in 1987. Creosote contamination in Bayou Bonfouca was so severe that 1.5 miles of the bayou was biologically sterile and caused second- degree burns to divers (USEPA 2009). The remediation activities included on-site incineration of contaminated soils and bayou sediments and groundwater extraction and treatment. The goals of remediation were to reduce or eliminate the potential for ingestion of carcinogens in groundwater, surface soils and in the food chain, control the migration of polynuclear aromatic hydrocarbons (PAH's) into aquifers and eliminate threat of direct contact with contaminated sediments and on-site wastes (USEPA 1996). Treatment of contaminated soils included incineration of 132,000 tons of hazardous sediments from the bayou and 25,000 tons of on-site soils (Acharya and Ives 1994). After trial operations, commercial incineration of large quantities began in 1993. In 1996, significant quantities of creosote were still being removed from groundwater at 300 to 800 gallons per month (USEPA 1996). At the second 5-year review in 2001 and at the third in 2006 water treatment operations continued and swimming bans in the Bayou remained. The second Superfund site is located at 999 Canulette Road in Slidell and is 54 acres. The site in known as Southern Shipbuilding Corporation and operated as a manufacturing and repairing facility for shipping vessels. The company began operations in 1919 as Canulette Shipbuilding, was purchased in 1954 by J & S Shipbuilding and then purchased by Southern Shipbuilding in 1957. The company filed bankruptcy and ceased operations in 1993 (USEPA 2000). There were two sludge pits in operation until 1972 that were used to dispose of waste from ships. Contamination resulted from these pits as well as bad waste management practices where waste was dumped onto the ground. The site is surrounded by residential areas on the west and south and by a wooded area to the east. The Bayou Bonfouca site mentioned above is located 1.5 miles upstream. The Louisiana Department of Environmental Quality (LDEQ) issued compliance orders to Southern Shipbuilding in 1984 when unauthorized discharge from the sludge pits was observed. In 1992, the LDEQ received complaints of contamination and it was discovered that the levees around the sludge pits had failed and 325,000 gallons of waste were released into Bayou Bonfouca. In both 1993 and 1994 EPA initiated an Emergency Removal Action to pump down the liquid levels in the sludge pits and in 1995 installed sheet piling around the levees to stop leakage into Bayou Bonfouca. The site was listed to the NPL in May of 1995. The sludge pits and surrounding soils were contaminated with PAH's and the soils on the site were contaminated with tributyltin. The soils around the site were contaminated with PAH's, PCB's, lead, arsenic and asbestos. The soils were excavated to a depth of 2 feet, and incinerated and approximately 2,000 cans, containers and drums were removed. The first and second five-year reviews in 2000 and 2005, respectively, found no problems with the site and as of 2008 the site was under discussion for potential re-use. Current Land use The Lacombe sub-area is the largest of the three areas in the report at 207.4 square miles. It contains many natural areas with 15% of the land in upland forest (31.8 sq miles) and 19% (39.5 sq miles) in wetland habitat. Within the wetland habitat categories almost 7% is swamp and almost 10% is marsh (Table 13; Figure 83). The marsh in this area is mostly brackish and intermediate as it is closer to the Rigolets and Chef Menteur passes which provide means for saltwater to enter the Pontchartrain estuary system. The swamps lie in between the marsh and upland habitats. Development represents 16% of the land area (34.5 sq miles), mostly under low intensity development. The development is due to presence of the eastern half of Mandeville, Slidell and the small community of Lacombe in the sub-area (Figure 84). There is a large amount of undeveloped land, especially uplands that these communities can expand into if the pressure for development caused by an increasing population continues. The sub-area currently has 18,000 acres in conservation in the Big Branch Marsh National Wildlife Refuge (BBMNRW; Figure 85). The National Wildlife Refuge System has refocused its commitment to maintaining the integrity of biological systems with its Improvement Act of 1997 where the system posits that it will focus on preserving natural systems first and human uses will come second only if there is minimal effect on the natural ecosystems (Meretsky et al.2006). The Act also instructs the USFWS to expand conservation, assessment and management activities to the surrounding landscapes. In the BBMNRW Comprehensive Conservation Plan written in 2007, the refuge makes a commitment to "the management of natural resources to maintain and improve wetland habitat, monitor targeted flora and fauna representative of the Pontchartrain Basin" and improve public use opportunities while monitoring this use to evaluate if there are any adverse impacts to the natural landscape (BBMNWR CCP 2007). Table 13: Land use in Lacombe sub-area 2005. Class Acres Square Miles Percent High Intensity Development 1,572.60 2.50 1.19 Medium Intensity Development 4,472.70 7.00 3.37 Low Intensity Development 16,006.50 25.00 12.06 Total Development 22,051.80 34.50 16.62 Ag/Grass/Barren 3,892.50 6.10 2.93 Upland Forest 20,348.80 31.80 15.33 Upland Scrub/Shrub 8,271.70 12.90 6.23 Wetland Forest 9,200.90 14.40 6.93 Wetland Scrub/Shrub 3,053.00 4.80 2.30 Marsh 13,023.30 20.30 9.81 Total Wetland Habitat 25,277.20 39.50 19.05 Water 5,532.30 8.60 4.17 132,703.30 207.40 100.00 Figure 83: Habitat map for Lacombe sub-area . Figure 84: Development and infrastructure map for the Lacombe sub-area. Figure 85: Conservation areas in Lacombe sub-area. Land Loss/Land Use Change Land Loss 1932-2005 Land loss during this time period occurred mostly during the 1932-1958 and 1958-1974 time periods (Table 14; Figure 86). The land loss during the first period can mostly be attributed to the impoundment and subsequent flooding of Eden Isles and the section between Eden Isles and Fritchie Marsh. This land loss occurred at a rate of 152.27 acre per year during this time. Some land loss occurred in the marshes in Big Branch Marsh NWR as well as in the form of shoreline erosion during this time period. During the 1958-1974 time period most of the land loss was in the coastal marshes in the sub-area when large pond areas formed, and land was lost at a rate of 120.32 acres per year. In the 25 years between 1974 to 2001, 688.52 acres of land were lost total. Recently, the marshes in BBMNWR have continued to degrade contributing to land loss in the sub-area. There was significant land loss attributed to Hurricane Katrina storm surge which expanded existing ponds and created new ones through the rafting of marsh vegetation. Table 14: Land loss in the Lacombe sub-area from 1932 to 2005 and acres per year lost within each time period. Time Period Acres Acres/Year 1932-1958 3966.91 152.57 1958-1974 1925.1 120.32 1974-1983 356.57 39.62 1983-1990 29.68 4.24 1990-2001 302.27 27.48 2000-2004 3699.2 924.80 2004-2005 2674.35 2674.35 Figure 86: Land loss in Lacombe sub-area, 1932-2005. Land Use Change 2005-2008 In the Lacombe sub-area, the largest sub-area in the report, there were significant land use changes from 2005-2008 (Table 15). The greatest land use type gain was ag/grass/barren (1630.89 acres or 33.5% of the total land use gain), mostly from open water and upland forests; development (1222.66 acres or 25% of the total), mostly from upland forest; and open water (950.61 acres or 19.5% of the total), mostly from marsh. There was also a significant gain in area of marsh (448 acres or 10% of the total), mostly from wetland forest. Significant land use losses occurred in marsh (1189.86 acres or 24% of the total land use lost), mostly to open water; wetland forest (1104.86 acres or 23 % of the total), mostly to marsh; open water (901.74 acres or 18.5% of the total), mostly to ag/grass/barren; ag/grass/barren (788.5 acres or 16% of the total) mostly to development; and upland forests (725.9 acres or 15% of the total), mostly to ag/grass/barren.

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