Carol Franze and Brian D. LeBlanc

A lush rural setting, the Northshore of Lake Pontchartrain with its dominant pine forests, abundant rivers and streams, and proximity to metropolitan New Orleans is an attractive place for people wanting to build new homes. Since 2005, an exponential growth rate caused by loss of coastal land and people seeking protection from tropical storms increased the population of the Northshore beyond local 25-year projections. With this unprecedented growth comes a burden on local infrastructure and increased water pollution to rivers and streams. Water pollution is regulated by the U.S. Environmental Protection Agency through the Clean Water Act. In an effort to stop or reduce the pollution to local waterways, a joint task force was formed by local parish governments and the Lake Pontchartrain Basin Foundation, with technical assistance from the Louisiana Department of Environmental Quality, the EPA, the St. Tammany Parish Department of Health and Human Services, and LSU AgCenter specialists.

The task force meets bimonthly to identify issues and devise strategies to reduce and prevent water pollution. Pollution is described as point source (identified) and nonpoint source (cannot definitively identify one specific source). Point-source pollution scenarios include things like broken sewer lines, illegal dumping and inadequate or overloaded sewerage systems. Nonpoint sources are typically from stormwater runoff or improperly working septic systems. Depending upon the pollutant, fish and other wildlife can be killed outright from pollution or indirectly by low dissolved oxygen that can slowly stress the animals, causing sickness and decreased reproduction.

Louisiana is required to conduct water quality surveys of stream segments to determine pollution loading. These surveys have identified pollution-loading hot spots, which are areas in waterways that fail the EPA dissolved oxygen standard. The hot spots result from too great a load of oxygen-demanding constituents that overburden a stream’s ability to cleanse itself or maintain the water quality standard. Many hot spots result from home sewer system failures. Visual inspections of ditches in areas dominated by home systems show low-oxygen septic conditions dominated by solids. During rainfall events, these solids wash from the ditches into receiving streams, resulting in dissolved oxygen collapse.

The task force recognized that homeowners do not always know the correct procedure for maintaining their septic systems. In response, St. Tammany Parish applied for and received EPA funding to conduct door-to-door inspections of septic systems, assess functionality, identify needed repairs for homeowners to complete and train homeowners to properly operate and maintain their systems. The parish monitored water quality in the affected watershed before the program began and continues throughout the inspection process to track improvements to waterways. In older subdivisions, low-income homeowners who qualify can have their units repaired or replaced through a separate HUD grant administered through the St. Tammany Parish Department of Health and Human Services. These efforts have been successful in reducing pollution in local watersheds. Preliminary results indicate a significant reduction in oxygen-demanding substances because of the home sewer system inspection and repair program.

Additionally, the parish has completed a three-year study to reduce stormwater pollution by converting detention or retention ponds to water quality ponds to test effectiveness of three management practices. The tested practices were aeration, a floating wetland and vegetative planting of a dry detention basin. Water quality was measured entering and exiting the ponds; removal efficiencies were calculated and compared with standards from the International Stormwater Quality Database. Plants in the floating wetland used excess nutrients in the water as fertilizer to stimulate growth. By the third year, the pond became a habitat for fish and wildlife and an amenity for homeowners in the subdivision. Data from the St. Tammany Parish study indicate the retrofitted water quality ponds are reducing pollution in several local watersheds.

One of the fundamentals of behavior change is through youth education. To encourage good stewards of the environment, AgCenter personnel developed an education program for youth in the region. Area students participate in hands-on, wetland education events where they learn about wetland plant functions and the role plants play in water pollution reduction and habitat restoration. These wetland programs are taught throughout the region at local state parks and parish facilities as well as at the Shell Robert Training and Conference Center in Tangipahoa Parish.

Carol Franze is an associate area extension agent, and Brian D. LeBlanc has the Roy and Karen Pickren Professorship in the School of Plant, Environmental and Soil Sciences. Both are specialists with Louisiana Sea Grant at LSU.

(This article is in the fall 2017 issue of Louisiana Agriculture.)

Brian LeBlanc, professor in the School of Plant, Environmental and Soil Sciences, shows students from Hammond Eastside and Champ Cooper Elementary schools how to determine dissolved oxygen concentration in a water sample at the Louisiana Wetlands Exploration Day at the Shell Robert Training Facility in Robert, Louisiana, on the Northshore. At left is Carol Franze, who is an AgCenter extension agent and specialist with Louisiana Sea Grant at LSU. Photo by Johnny Morgan