Central Lake Ontario Conservation Authority Stream-Integrated Watershed Monitoring Program

This dataset records ongoing water quality results collected by CLOCA’s staff as part of the Integrated Watershed Monitoring Program (IWMP). This long-term monitoring program aims to evaluate overall watershed health through multiple ecosystems including streams, where health indicators include fish community, invertebrate community, and water quality. 36 stream sites were chosen across CLOCA’s jurisdiction through a random stratified method. In accordance with CCME WQI guidelines, the timing of sampling was chosen to be once a month during the third week of May, June, July, and August. The dataset includes measurements of chloride, fluoride, nitrate, nitrite, phosphorus, sulphate, aluminum, copper, iron, zinc, total phosphorus, total suspended solids, and E. coli. Data collection is carried out seasonally at all 36 monitoring sites using 2 × 500 mL PET bottles, 1 × 250 mL red-cap HDPE container for metals, 1 × 250 mL blue-cap HDPE container for total phosphorus, and 1 × 250 mL bacteria bottle pre-charged with sodium thiosulphate. Water quality samples are delivered on ice to YDREL for processing and they provide the results within 10 days. CLOCA staff run these results through the CCME WQI to achieve a score that is used as health indicator.
This score is reported on CLOCA’s website as part of the IWMP which is used to inform our watershed plans and action plans. The data also supports analysis of how land use, particularly urban development and agriculture, influences water quality. Ultimately, this data informs management decisions by identifying trends and opportunities for improved source control and watershed protection.