St. Lawrence Monitoring Network – Lake Ontario Lake Management Plan Massena, NY Area of Concern (AOC)

The St. Lawrence River at Massena Remedial Action Plan (RAP) Area of Concern (AOC) begins above the power dam facilities and seaway locks at the Massena Village drinking water intake and follows the river downstream for about fifteen miles to the international border. For New York State, the AOC includes portions of the Grasse, Raquette and St. Regis Rivers. There are three governmental agency groupings that share jurisdictional responsibilities for the AOC. These are the United States, Canada, and the St. Regis Mohawk Tribe at Akwesasne. The Cornwall portion of the AOC includes lands in Ontario, Quebec, and the Mohawks extending downstream of the power dam to the eastern outlet of Lake St. Francis. 

Since 2010, connecting channels have been included in each of the Great Lakes’ Lake Management Plans (LAMPs). Lake Ontario now includes both the Niagara River and the St. Lawrence River. While the Niagara River is well characterized by a number of long-term programs, such as the Upstream/Downstream Monitoring program, which have offered a wealth of data and information and continue to do so, the St. Lawrence River and the adjacent Massena Area of Concern (MAOC) constitute a data gap in the information needed for the LAMP and the AOC. 

EPA Region 2 has identified a need for additional information on water quality for rivers in and adjacent to the MAOC. Critical information needs include basic water quality parameters, total suspended solids and nutrients and flow data. These data are needed to aid in the identification of sources of water quality impairment in the MAOC. These data should provide a basis for future monitoring and the long-term development of load estimates in the MAOC and the LaMP. 

The primary purposes of this project are: 1) to include the St. Lawrence River as a connecting channel to Lake Ontario by formally establishing a monitoring network on the St.Lawrence River and in its Basin to collect baseline data and to develop the permanent network design; and 2) EPA Region 2 has identified a need for additional information on water quality for rivers in and adjacent to the Massena Area of Concern (MAOC). Critical information needs include basic water quality parameters, total suspended solids and nutrients and flow data. These data are needed to aid in the identification of sources of water quality impairment in the MAOC. 

The monitoring network consists of seven sites on four rivers. Sample design includes monitoring two locations on three rivers (Grasse River, Raquette River, and St Regis River; see Table 1). Monitoring sites will be located on each of these rivers upstream of the MAOC (denoted as Upstream Sites in Table 1) and at a location within or just downstream of the MAOC (referred to as Downstream Sites in Table 1). These locations were selected to provide an assessment of water quality conditions inside and outside the MAOC. In addition, the St. Lawrence River, which is located near the MAOC, will also be sampled to document water quality conditions in the mainstem St Lawrence River. The sites are described in Table 1. 

Table 1.  Sites included in sampling. 

Project Location by County

St. Lawrence County, NY