By Therese Oldenburg, Wisconsin Master Naturalist

Friends of Turtle Creek 7-30-2015 (4) (Custom)This is my own personal, non-scientific observation about weed growth in Turtle Creek in the past three years 2013-2015. It appears as though weeds are starting to get a strong foothold in the creek and I have concerns about this. I have noticed more growth in the last two years than previous years of 2011 –  2012. Previous to that time I did not have much opportunity to paddle the creek.

Below are photos I took about 1 mile upstream from Tiffany Bridge on July 30, 2015. The thick mat of weeds almost covered the creek in areas, which would make it impossible to float in a tube or raft, and a bit challenging to paddle in.

In 2014, the weed growth was heaviest between Highway 140 bridge and Tiffany Bridge. I have not paddled through Beloit since early July, so I’m not sure if this weed growth continues further down, although patches of weeds are visible from bridges.

Filamentous Algae?

Friends of Turtle Creek 7-30-2015 (13) (Custom)Research on the hair-like plant on the WI DNR website reveals that it is probably “filamentous algae, sometimes called “moss” or “pond scum.” This is a common and troublesome aquatic plant that forms dense, hair-like mats in shallow water where sunlight reaches the bottom of the pond or lake. As the algae grows, it produces oxygen that gets trapped in the entangled strands of algae. This entrapped oxygen makes the algae buoyant and causes it to rise to the surface of the pond or lake. Some of the more common forms of filamentous algae can be identified by their texture, although microscopic examination is usually required for exact recognition.” More information at this DNR link.

Possible Causes?

According to an article by Gina D. LaLiberte,  a research scientist with the Wisconsin Department of Natural Resource’s Bureau of Science Services – “As Wisconsin’s population and development have increased, the amount of nutrients pouring into our rivers and lakes from point sources and non-point sources has grown as well. A point source is wastewater from a single source, such as a wastewater treatment facility or a factory, discharged to a waterway. Non-point sources, in contrast, come from many sources and consist of runoff flowing over urban, agricultural, or forested lands, bringing sediments and nutrients into streams and rivers.”   Read entire article at this link.

Water Level

The water level at Carvers Rock gauge was 3.75′ on July 30 (data provided by USGS). It’s pretty low right now. Compare that to 2 years ago when the creek flooded and crested at 11.76 ft on 06/26/2013!

Water Clarity

The water in the creek is very clear (as of August 5, 2015), as we have not had significant rainfall to stir up sediment.

Water Lily Plants

Other observations are that the waterlily plants are continuing to spread in some areas along the edges of the creek.

Invasive Reed Canary Grass

I recently paddled to O’Reily Road (July 5), paddling through the Turtle Creek Natural Area. The water levels are higher than the Shopiere and Beloit sections. A large amount of what appears to be invasive reed canary grass in the water are quite prevalent in this section, sometimes growing across almost the whole creek channel, leaving just a narrow passage for kayaks and canoes to get through.

Comments, Concerns?

If you’d like to comment on the weed growth or share your observations, please fill out the contact form below the photos.

Thank you! – Therese Oldenburg, Beloit, WI – Friends of Turtle Creek

Friends of Turtle Creek 7-30-2015 (4) (Custom)

This was one section between Tiffany Bridge and Highway 140 – July 30, 2015

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A closeup of the weeds – July 30, 2015

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The water was shallow, so the weeds brushed my kayak. – July 30, 2015

Friends of Turtle Creek 7-30-2015 (13) (Custom)

My kayak in the mat of what is likely filamentous algae- July 30, 2015

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