South Nation/Nation sudPhosphorus Levels

Point sources of phosphorus in the South Nation River and tributaries include municipal and industrial wastewater treatment discharges. Non-point sources may include runoff from fertilizer application, urban stormwater runoff, and leaching due to poor management of septic systems or storage of manure and stream bank erosion.

Compared to other rivers located on the Canadian Shield and St. Lawrence Great Lakes lowlands the South Nation has one of the highest concentrations of total phosphorus. Additions of phosphorus from point and non-point sources have been associated with algal blooms. Increased algal biomass contributes to reduced light penetration crowding out other submerged vegetation and reducing the available habitat for aquatic animals. In order to prevent algal blooms and increased plant densities the Ontario PWQO recommends a maximum phosphorus concentration of 0.03 mg/L.

Population Density

The average population density within the South Nation watershed is 40 persons per km2, except within the municipalities of Gloucester and Cumberland where it is considerably higher. The highest population growth rates within the South Nation region were just south of the Rideau River within Oxford and South Gower growing nearly one quarter in 5 years (5% per year). The municipalities of Cumberland and Clarence also showed high growth rates. High population growth rates southeast of city of Ottawa may signify potential urban sprawl from the Ottawa region. A study of the Rideau River watershed showed that urban density (persons per ha) within the city of Ottawa is actually decreasing. High population growth rates around significant wetlands (Groveton and Mer Bleue bogs) may put increasing pressure on these wetlands from a potential increase in recreational and public use.
 

Sourced from the South Nation Conservation: State of the Nation Report