Printer-friendly version Reader Comments

Leach fields have become saturated or don't meet the two-foot dry zone required by code.

STEPHEN M. KASPRZAK November 7, 2009

The recent front page story in the Press Herald about trace amounts of three product chemicals being found by Portland Water District at its intakes ignored the much bigger story of Sebago's declining water quality.

The district issued a 2008 report that concluded that Sebago Lake has had an increasing trophic state (i.e. declining water quality) over the period of 1990-2008. During this time period, the concentration of phosphorous and chlorophyll-a, the pigment in algae cells, has increased.

Ron Miller, general manager of the district, said "the presence of ibuprofen and Triclosan makes sense," and "with 2,500 septic tanks around Sebago Lake, within 200 feet of Lake ... it's not surprising."

What Mr. Miller does not discuss is that these septic tanks were designed to have a two-foot unsaturated zone between the bottom of the leach field and ground water.

Since the implementation of the Department of Environmental Protection's Lake Level Management Plan in 1997, which was done with the knowledge and consent of the Portland Water District, these leach fields have become either saturated or have less than the two-foot dry separation zone as required by the State Plumbing Code for more than five months of the year.

The elimination of this dry zone is a likely contributor of these chemicals and phosphorus.

The district fails to acknowledge that the measurement of these chemicals at the intakes has been greatly diluted because the intakes are located in 80 feet of water in the center of Lower Bay. Without dilution, you would expect much higher concentrations in shoreline waters near the leach fields or in Sebago's wetlands.

Suspecting higher concentrations, Friends of Sebago Lake recently had a water sample from Stickey River wetland analyzed for total phosphorous. Total phosphorous concentration was 4,000 percent higher in this wetland than measurements by the district in Sebago Lake's deep basins.

According to a 1991 District Study "... many of the septic systems located in older lakefront communities, such as Harmon's Beach and Long Beach, are either saturated or have less than a two-foot separation from groundwater for much of the summer season," and "At Harmon Beach, the maximum lake elevation that maintains a two-foot separation is 262.9 feet and at Long Beach it would be no higher than 263.7 feet."

The May 1 target of the Lake Plan is 266.65 feet and Aug. 1 is 265.17 feet.

In a March 13, 2008, Maine Voices Column, the district wrote: "The message is clear, what we flush down the toilet DOES end up in our waters." This is especially true if the mandated two-foot unsaturated zone for hundreds of leach fields is flooded for over five months of the year.

In a July 24, 2009, Maine Voices editorial, the district wrote: "The most significant risk to long-term water quality, we believe, is human activity Human activity adds an element of risk – both of slow deterioration and of sudden contamination from boat accidents and spills."

These chemicals have not been introduced by boats or ice fisherman. The district has spent years trying to close the Standish Boat Ramp because its 1991 Waiver for a Filtration System from U. S. Environmental Protection Agency was subject to the removal of this boat launching facility.

Friends of Sebago Lake asked Sebago Technics Inc. to evaluate the impacts of the Lake Level Plan as it relates to phosphorous export to the lake and declining water quality. It reported:

"Additional advanced statistical analysis on Sebago Lake Water quality beyond that which has been done to date confirms that water quality has declined in the period 1990 to 2008 and the decline appears to have accelerated starting mid-2006."

"Several possible sources of incremental phosphorus export into the lake have been identified, but none...