Introduction

A water quality monitoring program involving the collection of ambient water and suspended solids samples at the head (Fort Erie) and mouth (Niagara-on-the-Lake) of the Niagara River has been undertaken by Canada, the United States, New York State and the Province of Ontario in accordance with the Niagara River Toxics Management Plan and the Declaration of Intent (1987). The program is operated by Environment Canada and uses sampling and analytical methods agreed upon by all four parties.
 

Monitoring data were interpreted jointly by a group of scientists representing Environment Canada, the United States Environmental Protection Agency, Ontario Ministry of the Environment and New York State Department of Environmental Conservation, known as the Data Interpretation Group. Their annual reports have the consensus of all members. The information given here has been excerpted from the report for 1988-89 [1].
 

Station Location and Sampling Protocol

The Data Interpretation Group assumes that the locations of the Fort Erie and Niagara-on-the-Lake stations are adequate to monitor, respectively, chemical inputs to the Niagara River from the Eastern basin of Lake Erie and chemical outputs from the river into Lake Ontario.
 

Site selection was also dictated by operational considerations such as acquisition and availability of property, accessibility, availability of electrical power, and site security. Since there was no single best site, sites were chosen to serve as the best possible compromise between acceptable representativeness and operational constraints.
 

The sample collection system at both locations consists of an intake structure, intake line, pump, continuous-flow centrifuge, and Goulden Large Sample Extractor (GLSE). The intake structure, intake line and pump are permanently submerged in the river while the pump controllers, centrifuge and GLSE are housed on the river bank. Intakes were positioned in the water column such that they were sufficiently far from the bottom to avoid sampling bedload yet far enough below the surface so as not to constitute a hazard to navigation.
 

Generally, sample collection at Fort Erie commenced on Tuesday afternoon of each week while sample collection at Niagara-on-the Lake was started on Wednesdays. The delay of 15 to 18 hours between sample collection at Fort Erie and Niagara-on-the Lake was introduced to account for the time required for water to travel the length of the river from Fort Erie to Niagara-on-the-Lake. Staggered sampling times could not account for storage and release of water from the Robert Moses and Sir Adam Beck power plant reservoirs. However, the introduction of time-delayed sampling provides a closer approximation of the river's hydrologic regime.
 

The 1988-89 report of the Data Interpretation Group [1] gives a map, diagrams illustrating the configuration of the sampling stations, and flow charts for the sampling procedures and chemical analyses and preprocessing of the data.