Volunteers monitor water quality of Rockport ponds

Rockport’s Rocky Pond high phosphorous counts attributed to Route 17 runoff

Thu, 10/18/2018 - 8:15pm

    The Rockport Conservation Committee has partnered with the Volunteer Lake Monitoring Program to collect information and learn more about the ecology, health, and function of the ponds in Rockport.

    The Volunteer Lake Monitoring Program relies on volunteers to collect information as to expand the database on what is know about the health of Maine waters.

    On June 16, Rockport volunteers for Chickawaukie Pond, Rocky Pond, Lily Pond, Tolman Pond, and Maces Pond traveled to Auburn to be trained and certified in how perform and interpret Secchi disk transparency tests, as well as how to properly take phosphorous samples. Volunteers have been doing Secchi disk transparency tests approximately twice a month, and just completed a second phosphorus test for the summer.

    Rockport volunteers working for the VLMP did a first round of total phosphorus surface grab samples between July 17-20.

    The samples were transported to the Maine Health and Environmental Testing Laboratory (HETL) in Augusta where they were analyzed on July 25.

    Tolman Pond, Maces Pond, and Rocky Pond all had total phosphorus levels of 14 micrograms/liter (ug/L), Lily Pond had a TP level of 13 ug/L, and Chickawaukie Pond was 12 ug/L. The Maine state average for total phosphorus is 12 ug/L, and it is recommended that TP levels remain below 20 ug/L.

    The second round of Phosphorus tests for these ponds were performed between August 13-17, and were analyzed at HETL in Augusta on August 25.

    Tolman Pond had phosphorus levels at 14 ug/L, Maces Pond was, 15 ug/L, Rocky Pond had a TP level of 26 ug/L, Lily was 10 ug/L, and Chickawaukie Pond was 11 ug/L.

    These results were generally consistent. Maces Pond only increased TP levels by 1 ug/L, Chickawaukie decreased by 1 ug/L, Lily Pond decreased by 3 ug/L, and Tolman Pond increased by 3 ug/L.

    The average total phosphorus level for these four ponds was 10.75 ug/L, which is 1.25 ug/L below the Maine state average of 12 micrograms/liter, and well below the recommended limit of 20 ug/L.

    The acceptable increase in Tolman and Mace’s phosphorus concentration is only 1 ug/L, so both ponds were 2 ug/L over their individual limit. Tolman Pond was also 4 ug/L over the state average, and Maces Pond was above by 3 micrograms/liter.

    Lily Pond is only allotted a 0.50 ug/L phosphorous concentration increase, and decreased by 3 ug/L. Chickawaukie has a 0.75 ug/L acceptable increase, and decreased by 1 ug/L.

    Rocky Pond, however, had increased total phosphorus levels by 12 ug/L, from 14 ug/L to 26 ug/L.

    The acceptable increase in the Pond’s phosphorus concentration is 1 ug/L. 26 micrograms/liter is more than double the state average and 6 ug/L over the recommended limit.

    This sudden increase in phosphorus was likely caused by stormwater runoff from Rockland Street along Route 17 in the preceding weeks, flushing decaying organic matter, septic system and animal waste, and residential fertilizers. Increased phosphorus generally results in algae blooms and reduced dissolved oxygen levels in the water due to the increase in algae.

    This phosphorus was the second and final test for this year, and volunteers have concluded their bi-weekly Secchi disk transparency tests.

    The Rockport Conservation Committee intends to continue this partnership with the Volunteer Lake Monitoring Program in the coming years, as well as expand which tests are performed on the ponds in order to increase knowledge about the health and ecology of each. The data from this summer will be analyzed in order to best determine which tests should be introduced in the future, what solutions should be implemented for any potential issues, and to make some conclusions about the baseline information Rockport now has.

    The RCC is excited to move forward with this project, and would also like to thank all of the volunteers who collected quality data to help set the baseline for Rockport ponds! All RCC meetings are open to the public and are held on the first Thursday of the month in the Richardson Room at the Rockport Town Office at noon.

    Sadie Mills is a senior at Camden Hills Regional High School