A recently completed study points to agricultural lands as a key source of concerning levels of nutrients making their way into Shuswap Lake.
The three-year study, produced in partnership between the Shuswap Watershed Council and scientists at UBC — Okanagan shows that the Salmon River and Shuswap River are the primary routes bringing phosphorous into the Shuswap watershed.
Phosphorous is a necessary nutrient for all kinds of aquatic life to grow and reproduce, but excessive concentrations can lead to undesirable effects like algae blooms.
According to the study, monitoring has shown that water quality remains good in most locations in the watershed at most times of the year. The phosphorous coming down the Shuswap and Salmon Rivers remains a concern.
Researchers collected and analyzed water samples from 100 locations on the rivers over the course of the three-year study. They found agricultural land contributes the most phosphorous to the watershed, averaging 13.5 kilograms per hectare per year. In contrast, urban land puts about 3.83 kg/ha/yr and forested land only 0.035 kg/ha/yr.
Lakes in the watershed are sensitive to increased nutrient loads; the report states that small additional loads of phosphorous could double or quadruple the total amounts found in the area’s lakes.
The researchers noted the study does not identify particular parcels of land responsible for added phosphorous getting into the water, only broad areas. They are also unsure if the phosphorous is from current activities or if it has accumulated in agricultural soils over decades and seeped out into groundwater.
The research showed the Shuswap River and Salmon River should be the focus of efforts to stop phosphorous-rich water from flowing into the rest of the watershed. Mitigation methods could include the development of wetlands and new practices for managing irrigation, livestock and manure.
The watershed council is seeking community partners who are willing to apply new land-management practices to reduce, capture or divert the phosphorous bound for rivers and lakes. The council has grant funding available to help pay for the new practices.
“We have up to $100,000 available to pay for costs associated with new nutrient management activities,” said watershed council board member and Columbia Shuswap Regional District (CSRD) director Paul Demenok.
“We are now inviting applications for grant funding from agriculturalists and landowners. We look forward to creating new partnerships in the Shuswap to keep phosphorus on the landand out of the water. This will be a win-win for everybody.”
The report from the researchers states improvements to water quality from the mitigation efforts could take years or even decades to be observed, but it is never too early to begin taking steps for the preservation of clean water.