How healthy is your lake? July is Lakes Appreciation Month and we’re celebrating with a contest! To raise awareness about water quality, we’re encouraging people who enjoy lakes to participate in a “Secchi Dip-In” for a chance to win a $100 Amazon gift card and a one-year membership to the North American Lake Management Association (NALMS).
What is the “Secchi Dip-In”?
The “Secchi Dip-In” is an annual citizen science event created by NALMS in 1994. It was developed in order to involve lake-goers and associations across North America in using a simple Secchi disk to monitor the transparency or turbidity of their local waterway.
This data collected is evaluated on a regional scale by NALMS and helps lake managers further understand the water quality of lakes in their region. Since 1994, more than 10,000 trained volunteers have generated 42,000 transparency records, giving a glimpse of lake water transparency at sites across North America and the world, according to NALMS.
How do I collect a Secchi sample?
- What is a Secchi disk and what data is collected with it?
The typical Secchi disk used in lakes is an 8-inch disk with alternating black and white quadrants. It’s lowered into the water until the observer can no longer see it. The depth of disappearance, called the Secchi depth, is a measure of the transparency of the water. The disk is named in honor of Father Pietro Angelo Secchi, astronomer and scientific advisor to the Pope, who tested this new instrument in the Mediterranean Sea on April 20, 1865.
- Where can I get a Secchi disk?
Secchi disks are a low-cost investment and a great tool to have for measuring water quality. You can purchase a Secchi disk on Amazon or other online marketplaces for $20-$30. Alternatively, you can always ask a friend or your local lake manager to borrow one. Some people even make their own!
- How do I take a measurement? How many times do I do it?
A measurement is taken by lowering the disk on the sunny side of the boat. To eliminate sun glare, an underwater viewer (viewscope) can also be used if so desired. Allow sufficient time (preferably 2 minutes) when looking at the disk near its vanishing point for the eyes to adapt completely to the prevailing luminance level. Record the depth at which the disk disappears. Slowly raise the disk and record the depth of reappearance. The “Secchi depth” is the average depth of disappearance and reappearance. For further accuracy, several people can each record several Secchi depths. Then, all of the depths can be averaged into one single reading. Please note: the water depth should be at least 50% greater than the Secchi depth so that the disk is viewed against the water background, not bottom-reflected light.
- What’s the best time of day to collect a sample?
The best time of day to collect a sample is when the sun is at its highest point in the sky, generally around midday. Most volunteers generally collect data between the hours of 10:00 AM and 2:00 PM.
- What do the results mean?
The Secchi disk measures transparency, which serves as an indicator of changing water quality. Transparency decreases as the amount of particles in the water— such as algae and sediment—increases.
How to Enter the Contest:
- During the month of July, get out on your local lake and take a few Secchi measurements.
- Snap a photo of yourself in action and post it to Facebook or Twitter using #LakesAppreciation and tag Princeton Hydro (@PrincetonHydro on Twitter!). (Note: Your account or post must be public for us to view your entry.)
- Submit your data to NALMS here: Secchidipin.org/data.
One lucky winner will be randomly selected on August 1, 2018. The selected winner will receive a $100 gift card to Amazon and a one-year membership to NALMS. We’ll reach out to you via social media to collect your email and address for prize distribution. If the winner does not respond within 5 working days with the appropriate information, we will select another winner at random. Good luck, everyone!
By submitting an entry (Photograph) via Facebook or Twitter to Princeton Hydro’s 2018 #LakesAppreciation Month Contest, you agree to the following: You represent and warrant that:
- You are the sole and exclusive author and owner of the Photograph submitted and all rights therein; and
- You have the full and exclusive right, power, and authority to submit the Photograph; and
- You irrevocably grant Princeton Hydro a non-exclusive, worldwide, royalty-free, perpetual license to use the Photograph in any manner related to the Contest, including all associated use, reproduction, distribution, sublicense, derivative works, and commercial and non-commercial exploitation rights in any and all media now known or hereafter invented, including, but not limited to public relations purposes, posting on social media accounts, and/or for company marketing materials; and
- No rights in the Photograph have been previously granted to any person, firm, corporation or other entity, or otherwise encumbered such that the prior grant would limit or interfere with the rights granted to Princeton Hydro herein; and
- No part of your Photograph defames or invades the privacy or publicity rights of any person, living or decreased, or otherwise infringes upon any third party’s copyright, trademark or other personal or property rights.