COMPARISON OF TWO TRIBUTARIES TO OWASCO LAKE, NEW YORK, FROM 2011 TO 2012

Owasco Lake is critical to the agricultural and tourism-based economy in the surrounding area, and it supplies drinking water to ~44,000 people; however its water quality was consistently ranked among the worst Finger Lakes over the past decade. Its residence time of 1-3 years indicates that it is quick to pollute but also quick to cleanup if proper remediation efforts were employed. Two streams, Dutch Hollow Brook and Owasco Inlet, which collectively drain 70% of the watershed, were sampled to determine point and nonpoint sources of nutrients and changes over time. Identification of the sources could dictate mitigation and remediation efforts to improve water quality in the lake.

In 2012, we sampled seven sites along Dutch Hollow Brook (DHB) and eleven sites along Owasco Inlet (OI) every month starting in March. Stream water was analyzed on-site for temperature, pH, conductivity, alkalinity, dissolved oxygen and stream discharge. Additional water was collected and analyzed in the lab for total phosphates, total suspended solids, silica, nitrates, and soluble reactive phosphate following standard limnological techniques. A companion study presents results from an autonomous sampler and stage recorder at Dutch Hollow Brook and water quality at two sites within the lake.

The 2012 data revealed smaller discharges, concentrations, and fluxes than 2011. The trend parallels a decrease in precipitation during 2012. Two wastewater treatment plants were point sources of nutrients to OI. However their impact decreased from 2011 to 2012, and partially reflected a greater compliance to discharge limits. Agricultural nonpoint sources were also observed, especially in DHB. The Benson tributary and Firelane 20 sites drain large CAFO operations. Firelane 20 site revealed mixed results, whereas, the Benson tributary site revealed a significant source of nutrients. We recommend that buffer strips and improved barnyard practices be established to reduce nutrient runoff.

Murray Rd site, monitored for the first time in 2012, revealed a smaller discharge, concentrations and fluxes than the other sites, and partially reflects the forested land cover upstream of the site.

We suggest that Owasco Lake residents support mitigation and remediation within this tributary’s watershed to see if nutrient loading is reduced in the future.