Carp management expands to Lake Owasso Chain

by Chris O'Brien

Following recent success managing common carp in the Phalen Chain of Lakes, the Ramsey-Washington Metro Watershed District is now setting its sights on the Lake Owasso system. With four interconnected lakes (Owasso, Wabasso, Bennett and Grass) and twelve shallow ponds, the system offers prime habitat for carp to potentially out-compete native gamefish, uproot aquatic vegetation and harm water quality.

Carp management in Lake Owasso and connected lakes is part of the District’s goal to control phosphorous-loading in these waters. As carp root for food along the lake bottom, they stir up phosphorous-laden sediment, which in turn contributes to turbid water and algal blooms.

The key to keeping carp in check is figuring out how many there are, where they go, and how they spawn and recruit (survive to adulthood). Using this information, the District hopes to efficiently remove large numbers of adult carp while also limiting their ability to repopulate the system.


Counting carp

The District enlisted Jordan Wein of Carp Solutions to conduct a general population assessment through electrofishing this summer. After calculating a biomass estimate, they found that each lake in the chain contained more than 100 pounds of carp per acre, the threshold generally considered to inhibit water quality. Most concerning were Lake Owasso and Lake Wabasso, which each turned up more than 400 pounds of carp per acre.

The team also marked over 200 carp with a fin clip as part of a mark-and-recapture study to verify these estimated population numbers. “We’re being strategic by marking the carp now so that when we eventually harvest them, we’ll be able to get a good estimate of how many were in the lake,” explained Bill Bartodziej, RWMWD Natural Resources Specialist.

The video below shows the Carp Solutions team using box nets baited with corn to capture large numbers of carp on Lake Owasso.

Location, location

In addition to the population assessment, Carp Solutions surgically implanted radio transmitters in 20 adult carp to figure out where they congregate in the winter and where they spawn in the spring. Since carp tend to travel in dense schools, the radio-tagged fish will likely betray their rubber-lipped brethren and help the research team track seasonal movements of the larger population. 

One of 20 adult carp implanted with radio tags, which will
help the District track seasonal movements and develop a
comprehensive carp control strategy for the Owasso system.


At 37 feet deep, Lake Wabasso is likely an overwintering hotspot for carp. Using radio telemetry to pinpoint locations where thousands of carp school up under the ice, the District plans to enlist a commercial fishing operation to harvest these fish with large sein nets.
 

Carp nurseries

While netting adult fish should put a dent in the carp population, confirming spring spawning locations could be key to a long-term management strategy. “It’s very unikely that carp are successfully reproducing and recruiting in Wabasso, so they are probably spawning elsewhere in the system,” said Wein.

Bluegills are voracious predators of carp eggs and tend to control numbers of young carp in large lakes. However, shallow ponds and wetlands often serve as carp nurseries where they can hatch by the millions and grow in relative safety from predators. Future management strategies may include setting up barriers to keep carp out of these nursery areas, netting them there and/or stocking bluegills to eat the carp eggs.

Over the last five years, District carp management in the Phalen Chain has reduced carp density by over 60 percent. Among those efforts was eliminating carp in Lake Casey (a former carp nursery in North St. Paul) by drawing down the water level, allowing carp to winterkill, and then stocking bluegills and largemouth bass. Tracking the movements of Owasso carp could help identify similar carp nursery locations and allow the District to rein in these prolific fish.

Flood study underway for Grass Lake and Snail Lake area

In response to high-water conditions around Grass Lake, Snail Lake and nearby wetlands, the Ramsey-Washington Metro Watershed District is coordinating a large-scale flood study, currently underway. The goal is to identify strategies that will stabilize the system to withstand increasingly heavy precipitation and rebounding groundwater levels, ultimately protecting homes and property.

The District contracted with Barr Engineering this summer to begin evaluating various flood control options. Meanwhile, District staff continues to closely monitor surface water and groundwater levels to gather additional data. Below is a summary of the work completed to date.

Snail Lake

Challenge: Snail Lake is currently landlocked without a managed outlet. High water has forced closure of the swimming beach, and while homes on the lake have not been impacted to date, an extreme rain event could potentially put low-lying properties at risk for flooding.

Actions: 

• Engineers surveyed the six lowest homes on Snail Lake to help determine a feasible 100-year flood level elevation for the lake.
• The team is now evaluating options for constructing a managed outlet system that could allow water out of Snail Lake if it were to reach this maximum level.

Grass Lake

Challenge: While Grass Lake’s water level fluctuates seasonally, its annual low point has been steadily rising since 2009. During periods of heavy rain in 2016 and 2017, the lake topped its banks on the north end, flooding trails and raising the water levels of nearby ponds and wetlands.

Actions:

• Two temporary sandbag berms have been installed along the north and northeast sides of Grass Lake.
• The engineering team took soil core samples at both sites and is now working to determine the proper design and elevation for permanent earthen berms, which could be completed by March 2018.
• In late March of 2017, the outlet channel from West Vadnais Lake (downstream of Grass Lake) was cleaned to promote drainage of the system. A similar project is planned for the Grass Lake outlet channel this winter.

Vadnais-Snail Lakes Regional Park

Challenge: Flooding from Grass Lake into adjacent ponds and wetlands, accompanied by seepage from high groundwater levels, has forced closure of several county park trail sections. Wetland A (pictured above), bordering the nearby Crestview Addition neighborhood, has been especially impacted as it is the lowest elevation point of the area and has no natural outlet.

Actions:

• The District installed two new groundwater monitoring wells, which record automatic readings every 15 minutes, along with seven surface water level gauges at key points around Grass, Snail and West Vadnais lakes. Staff has taken manual on-site readings up to 3 times per week while also checking inlet/outlet pipes to ensure they are functioning as designed.
• In April, water was pumped out of Wetland A back into Grass Lake to see if this would alleviate high groundwater levels in the Crestview Addition neighborhood. Lowering the surface level of Wetland A had little effect on neighborhood groundwater. However, pumping other smaller ponds near Gramsie Road did have the desired effect of lowering groundwater and will be an important maintenance strategy in the future.
• Once a peak flood level is established for Grass Lake and Wetland A, the District will advise Ramsey County on options for restoring trail access in low-lying areas of the regional park.

The District is committed to finding long-term solutions to the flood risk in this area, including replacing/adding outlet pipes to increase drainage. However, this is a complex system with flood considerations downstream through the Phalen Chain of Lakes, so any projects designed to move water from one area to another will require further thoughtful consideration.

  

How Can Minnesota Reach its 25 by 25 Water Goal?

By Sage Passi


Join us in a conversation this September about what can be done at the local level to help Minnesota reach its 25 by 25 water quality goal.

Early this year Governor Dayton announced a new “25 by 25” Water Quality Goal, which would spur collaboration and action to improve Minnesota’s water quality 25 percent by 2025. Without additional action, the quality of Minnesota’s waters is expected to improve only 6 to 8 percent by 2034. Governor Dayton’s proposal would not add new regulations, but would instead drive public engagement and partnerships to address Minnesota’s water quality challenges.

Ramsey Washington Metro Watershed District, along with Conservation Minnesota, Capitol Region Watershed District, Ramsey Conservation District and Rice Creek Watershed District, is hosting a community water meeting on September 12 to discuss local water health and hear your ideas for improving and protecting our water resources in Ramsey County. We invite you to join this discussion! Water meetings like this are part of Conservation Minnesota’s effort to include local communities in responding to the Governor’s proposed water pollution reduction initiative.

This summer and early fall, the Governor’s office is holding ten regional town hall meetings across the state to gather input on what it could take to realize this goal. Townhall meetings in the metro area are scheduled for late September and early October in Minneapolis, Burnsville and Stillwater. Dates and locations for these town halls are listed HERE.



“All Minnesotans have a stake in water that’s safe for drinking, swimming and fishing,” says Governor Dayton. “These town hall meetings will further the important conversations already happening across Minnesota around water quality. Together we can develop strategies and solutions that work for all of our communities.”

We are hosting a local meeting to ensure that those who cannot attend the Governor’s meetings or who want extra time to talk through their ideas have the chance to do so.

 

Join us and
share your ideas!

Ramsey County Community
Water Meeting

Tuesday, September 12
6:30 - 8:30 PM
Autumn Grove Park
395 Lydia Ave W, Roseville

To ensure we have enough space and refreshments, please RSVP by emailing Julie Drennen or call 612-767-1569. This is an open meeting, so you’re welcome to invite all who you think would be interested. 

This event is sponsored by:

Beneath the Surface: Many Hands = Clean Water

By Sage Passi

Photo Credit: Clean Water Minnesota

 
You have to admit, it was a hard winter. Not for the usual reasons. Not in these parts perhaps. The storms around us didn’t overwhelm us. The snow didn’t pile up interminably. In the midst of it there were some temptingly warm and sunny, April-esque days. Were these the antidote for our winter blues? There were days when we were sure spring had arrived for good. Then a cold snap would besiege us and it was back to hunkering down, turning on the space heater, pulling out books like Year Round Indoor Salad Gardening and burrowing under the covers.

As we inch our way into spring with its zigzags between cold and warm spells, the antidote for me has been thinking about the cool people who emerge and I get to know in the midst of my work. It’s like snorkeling and stirring up the layers of a lake and finding all these colorful stones and fish and a myriad of mysteries beneath the surface. They are so many individuals going about their missions, making change while many others are waiting to be discovered. Here are a few of their stories that rose to the top of the surface recently! 

A Gardener Extraordinaire

Photo Credit: Clean Water Minnesota

May Lee is a Ramsey County Master Gardener who calls me in the early part of each year. I know I will hear from her then, because she is very busy the rest of the year. Getting a call from her at 7:00 in the morning is not surprising. Her voice is familiar. We are both up early and she is anxious to sign up for seed planting and transplanting shifts at schools.

 

May signs up for practically every seed-planting and transplanting shift. It’s just what we need. Her approach with kids, like many Master Gardeners, is helpful, gentle and encouraging. 



May Lee helps Farnsworth third graders transplant seedlings in late March.

Photo Credit: Sage Passi

I met May Lee for the first time many years ago on a rain garden project in the Battle Creek neighborhood. When we planted seeds together in late February this year, we had some time to chat. She told me about the documentary that TPT (Twin Cities PBS) had just produced about her life.

Photo Credit: Clean Water Minnesota

May Lee, as a young woman, left Laos in the early 1980’s in the wake of the U.S. withdrawal from Viet Nam. She told me she did not know how to read at the time she came to this country. Eventually she went to school. Now May Lee and her daughter, Mhonpaa run the first organically-certified Hmong garden near Stillwater. May Lee also mentors others who are interested in learning about organic approaches to farming. Here’s a video created by SPNN (St. Paul Neighborhood Network) with May Lee at the farm where she and her daughter raise organic vegetables for sale at farmer’s markets and for their own family’s use. 

I recently arranged an interview with May Lee with writer Maddy Wegner at one of our last planting sessions for the season at Farnsworth. This story is featured on the Clean Water Minnesota website created by Watershed Partners. You can read the story here.

Someday I’d like to go visit her farm and have May Lee mentor me! Thank you for volunteering with us each year, May Lee!

To read more about May’s life story and work as a mentor click here. 

----------------------------------------------------------------------
 

 

Helping Hands Assist with the Birth of Spring

A team of volunteers and students assemble at Menomini Park to study Battle Creek Lake’s water quality.

Photo credit: Nicky Thompson

 

On the cusp between February and March, I lose my voice. It’s my second cold within two months, but I have two back-to-back field days at two different lakes so there’s no hiding under the covers for me. The balmy weather of the last day of February has shifted and on March first I wake up to a crusty layer lingering on the ground from a surprise overnight snowfall. What a change from the day before when we were out on the dock at Beaver Lake with four classes in the balmy pre-spring air.

The purpose for this second trip is to help fourth grade students from another school, Woodbury Elementary, understand the relationship between their upcoming rain garden project on their schoolground and its positive impact downstream at Battle Creek Lake where the storm run-off from their school parking lot, road and rooftop drains. They alternate their time on the boardwalk at Menomini Park, a short distance from their school, by listening to Watershed staff Dave Vlasin and Eric Korte talk about their water quality monitoring equipment, then try their own hand testing the water back on shore with simpler measurement tools.

 

Woodbury students in Nicky Thompson’s fourth grade class on the boardwalk at Battle Creek Lake.

Photo credit: Nicky Thompson

 

The storm has delayed the bus’s arrival, but after several cell phone calls from teachers, the first two classes arrive. I need to provide instructions, but for the whole morning I must resort to other people talking for me. I’m glad I’ve recruited a team of veteran ace leaders. There’s a lot of explaining to do! One of the new people who steps up to the plate is an energetic Washington County Master Gardener, named Bobbie Sweeney, who Master Water Steward and Master Gardener Anna Barker recruited to support our rain garden project. This is my first opportunity to see her in action.

 

Washington County Master Gardener Bobbie Sweeney
assists another school with winter seed sowing.

Photo Credit: Anna Barker

 

 


From the moment I meet Bobbie, I can tell she is going to be great! She jumps into the pool, so to speak, like she’s been swimming there for years. I appreciate her exuberance and positive energy on this brisk and challenging morning.

She, along with the rest of our hearty local team of water educators, Angie Hong, Jenn Radtke, Stephanie Wang, Tracy Leavenworth and Anna Barker, divide up the morning classes to help students perform the tests, as I point, nod and whisper instructions. I just know they will all be a godsend when we are planting our large-scale rain garden project in the fall!









Students perform a dissolved oxygen test.

Photo credit: Nicky Thompson

After scooping and hauling buckets of icy water from the lake, Bobbie gathers the five students on her team, and they plunge their pH/temperature meter into a bucket, record their results, then snap dissolved oxygen ampules to mingle lake water with the reagent, compare them with a color chart and record those readings as well. There’s a chilly crisp wind coming off the lake that wasn’t there yesterday at Beaver Lake when we did our water quality monitoring with fourth graders during those balmy, mischievous spring-like conditions. Nevertheless, the students are real troopers and conduct all the tests! 

 

A team of Woodbury fourth graders collect data about Battle Creek Lake.

Photo credit: Nicky Thompson

 

The last test is the hardest. Several of our tubes on our new secchi tubes freeze where the water is supposed to be released and we can’t get a true reading. Nevertheless, the kids are empowered, having both braved the conditions and gathered revealing details about their neighborhood lake. 

When the buses leave, Stephanie Wang, one of our Master Water Stewards who is helping for the day, invites me to her house during the lunch break before the third class arrives at the lake. I gladly take her up on this offer. I definitely need to get inside somewhere and warm up!

I drive over to her house near Tamarack Nature Preserve, and the first thing I do after I remove a few layers of outerwear is ask her if I can lay out the contents of my wallet. When I was carrying water from the lake and setting the pail down, my wallet had slipped into the icy water. I retrieved it quickly and it didn’t seem too wet, but I was worried because my flash drives were inside it!

Stephanie does me one better and offers to spread the contents (not the credit cards or the flash drives!) on a baking pan and slides them into the oven. A short while later my dollar bills come out looking crisp and new. I can’t say the same for my Office Max receipt for clipboards for the trip, but at least I can still see the dollar amount and the date!

Stephanie proceeds to serve me tea and then makes me a hot bowl of oatmeal, which is just the ticket for a chilled lake monitor! We spend the next hour chatting about her ideas for engaging her neighborhood in protecting the Watershed District’s crown jewel wetland, Tamarack Swamp, that is located practically out her back door, and other ideas she has to help her community. Stephanie is a Master Water Steward who completed her capstone rain garden project this past summer with her partner, Anna Barker. They helped a homeowner, Mitzi Knutzen, build a rain garden above Battle Creek just up the street from Menomini Park in her back yard to help prevent erosion that otherwise could impact Battle Creek Lake downstream.

I feel nurtured, supported and rejuvenated with all of Stephanie’s hospitality and the help of our morning team.


Anna Barker explains the problem with salt in lakes.

Photo credit: Nicky Thompson


We return to the lake for round two. By afternoon most of the snow has melted and the sun is shining. Anna Barker primes the class about the impacts of chlorides on this water body. She explain that it just takes one teaspoon of salt to pollute five gallons of water.

Then we walk the students over to the channel that leaves the lake. This is the birthplace of Battle Creek. The students cross the road to see how it snakes through a valley and heads downstream.





Battle Creek leaves the lake, travels under a culvert and heads west toward the Mississippi River.

Photo credit: Nicky Thompson

In the afternoon our secchi tubes work and we are cheered and warmed up by the sun. We feel less rushed and are able to conduct all of our tests.



Anna Barker helps an afternoon team conduct their water quality tests.

Photo credit: Nicky Thompson

With more time for our second round, we are able to do Part 2 of our watershed journey. After monitoring at the lake, the class follows the creek in their bus and travels to McKnight Basins to see how the creek enters Battle Creek Park. The excitement builds as we head on the path to watch the fast moving water hit the walls of the weirs as it slow down and gets directed into several stormwater basins to settle out its sediment and pollutant loads before heading downstream to the Mississippi River. 




Nicky Thompson’s class assembles to learn about the weir system in Battle Creek Park.

Photo credit: Nicky Thompson

One of the other champions of the day, Nicky Thompson, the fourth grade teacher whose class is on this round of our field trip, comes through with flying colors. Her enthusiasm is palatable and it spreads to her students. I met her this fall for the first time at the Children’s Water Festival at the State Fairgrounds. She’s been taking her classes there for five or six years. Each year I receive a packet full of thank you letters from her students thanking the Watershed for funding their buses.



The students are watching the water flow over the first weir in the system.

Photo credit: Nicky Thompson

After seeing one of the weirs, Nicky sends the kids who are cold back to the bus to warm up and the rest of us run with enthusiasm to get a view of the turbulent water of the creek as it plummets into the second weir.

Thanks to Nicky, I received some great photos of this event from her a few days later. 



Woodbury students marvel at the quantity of water moving through the second weir.

Photo credit: Nicky Thompson





As the day comes to an end, and the bus returns to school, I feel appreciative of everyone’s contributions. It definitely takes a village to understand and protect our water and to birth spring! 

Finding Value in Our Healthy Shallow Lakes

By Bill Bartodziej, Natural Resources Specialist

Going up to "the lake" is a Minnesota tradition.

Lakes up north

It’s a flawless summer morning – light breeze, sun is rising, and the temperature is a perfect 70 degrees. We pack the SUV full of floaties, sun screen, fishing rods and swim suits. We program our favorite music playlist for the road trip and then set course for “up north”. Getting away from the city bustle and spending a few weekends on north-country lakes is a tradition that’s in our blood; it’s just the Minnesota way.



Lake Superior

Photo credit: Rosanna Imholte

So what do you think makes the ideal lake? Some descriptors that are often associated with high quality lakes are: clean, clear, weed-free, deep, good fishing, sandy beaches, blue water, panoramic views and secluded. Not that we ever brag, but Minnesota does have the most lakes (11,842, actually) in the contiguous United States. Lakes vary quite a bit, depending on where they are located in the state and how deep they get.

Generally, the lakes that we have up north are quite different from the lakes that we find in the Twin Cities area. This mainly has to do with geology and watershed type. Northern lakes are often formed by depressions in granite bedrock, with their watersheds being dominated by forest cover. This combination usually harbors lakes that are low in nutrients, clear and deep, with minimal aquatic plant growth.

Casey Lake in a clear-water state

Urban lakes

In our urban watershed, we have a mix of relatively deep and shallow lakes. Rich soils and storm water runoff contribute to our local lakes being higher in nutrients compared to the lakes that we visit up north. Our local lakes are generally more “productive”, meaning that they support more plant growth. Free floating algae, cattail, lily and submersed rooted species take advantage of the nutrients in our urban lakes and become well established. 




Casey Lake in murky-water, algae-dominated state

Usually, shallow lakes (less than twelve feet) are found in one of two completely different states: a murky-water, algae dominated state (poor quality) and a clear-water, plant dominated state (healthy or high quality). It is uncommon to find shallow lakes that are in the middle, with moderate algae and rooted aquatic plant growth, for a long period of time – say several years. Watershed management works to reduce nutrient inputs to our lakes and to improve water quality.

 

 

 

Native aquatic plants growing in a clear lake.

Shallow lakes with good water quality support lush rooted aquatic plant growth. This is natural, healthy and a normal condition for shallow lakes. But, this concept is not all that intuitive. Shallow lakes are often misunderstood. Abundant plant growth tends to work against the thought of what an “ideal” or high quality lake is all about. 

Our vision of clear, deep northern Minnesota lakes can distort our expectations for our urban lakes. This is especially true with shallow lakes and ponds in our urban watershed. Some use northern Minnesota lakes as a gauge to define how a healthy shallow lake should behave. But not all lakes are created equal, and making direct comparisons between deep and shallow lakes is not advised. This would be analogous to a doctor using a health chart of a six foot male to assess the condition of a five foot female. This examination would obviously be flawed and lead to misdiagnosis.


What we value

In many cultures and places around the world, the clear-water, plant dominated state of shallow lakes is widely accepted and highly desirable. For instance, in Europe and Japan, turbid lakes are turned to clear-water, plant dominated lakes, and this is considered very successful lake management. From a conservation standpoint, their citizens would be upset by the thought of doing anything to impede aquatic plant growth in these lake systems.* But for some reason, our Minnesota cultural heritage seemed to generally miss the important lesson that “healthy shallow lakes grow a lot of plants”. Good water quality promotes a robust aquatic plant community.

So what makes aquatic plants so important in shallow lake systems? A majority of the healthy shallow lakes in our watershed support over ten native submersed plant species. This plant community can be thought of as the underwater forests of our lake systems. Aquatic plants provide food and shelter for wide variety of aquatic insects. This underwater cover creates excellent game fish habitat for species such as largemouth bass, bluegill and northern pike. Rooted plants hold lake-bottom soils in place which limits “turbidity” or particles being suspended in the water column. Aquatic plants also provide a surface or substrate for algae to grow. These algae take nutrients from the water and can lower the nutrients that are available to free-floating algae. This competition for nutrients lowers the risk of substantial algal blooms, especially in the hot summer months. This relationship helps to perpetuate the clear-water state in shallow lakes.

 

 

 

Watershed management and shallow lakes

Our Watershed District implements intensive lake and watershed management projects to reduce nutrient inputs to our lakes. Our activities are directed by federal and state water quality laws. Over the last few years, through this work, two shallow lakes in our watershed, Kohlman and Casey Lakes, have seen dramatic improvements in water quality. These lakes are now in a clear-water state. The changes that have occurred have brought about many discussions with citizens concerning lake use, aesthetics and the value of aquatic plants. The conflict really boils down to how shoreland owners use and view the lake. From water quality and biological diversity standpoints, watershed management is a huge success, but from a recreational use standpoint, management has failed. 

Casey Lake before the shoreline restoration and
carp removal was complete.

Most often, people that move around on the water with speed would like healthy shallow lakes to act like deep lakes. This means clear water and very limited plant growth in the center of the lakes. However, a shallow lake with clear water will support lush rooted plant growth throughout the entire lake. The extent of the plant growth is really the crux of the problem. Surfaced plants do not mix well with water skiing and pleasure boating. Deep water lakes have large expanses of open-water throughout summer, but healthy urban shallow lakes often do not. In addition, many shoreland owners view surfaced aquatic plants as “weedy” and “unsightly”.


Sharing information

Maybe in a perfect world, with knowledge and exposure to a different point of view, affected lake users would quickly embrace the idea that abundant plant growth is an essential component in healthy shallow lakes. They would realize that this response is the direct result of improved lake water quality, which substantially benefits our watershed community as a whole. However, in reality, it will take time to share knowledge and educate residents on healthy shallow lakes and how they differ from our deep lakes. Maybe, over a period of years, we will see the intrinsic value of healthy shallow lakes go up.

This summer, to begin to address this important educational need, watershed staff and our Citizen Advisory Commission will be working on the production of a shallow lakes educational video. We are happy to have videographer Ben Hansen lead our team on this effort. You may remember the video Ben helped us produce about six years ago about the common carp in the Phalen Chain. It was a great educational tool that highlighted cutting-edge research and management. It can be found at this this LINK.

There really isn’t a video about shallow lakes like this available locally or nationally, so we see this benefiting our watershed, and potentially having impact on a regional and maybe even a national level. We will be shooting video on Kohlman, Casey, Bennett and possibly other shallow lakes in our watershed. We hope to incorporate some aerial and underwater footage in order to make this video product unique and inspiring.

You can help!

If you run across something interesting on a local shallow lake this summer, please let us know! We may be able to get a camera out quickly to film some footage. The plan is to have the shallow lakes video available on You Tube and shorter clips showing up on Instagram and Facebook. Please stay tuned and be on the lookout for a cool video highlighting your healthy shallow lakes this fall.

*Citation: Cooke, D.G., P. Lombardo, and C. Brant. 2001. Shallow and Deep Lakes: Determining Successful Management Options. Lakeline (North American Lake Management Society) 21: 42–46.

 

 

 Boundary Waters Canoe Area sunset.
Photo credit: Rosanna Imholte

 

Big Yellow Excavators Improve Local Fishery

By Bill Bartodziej

 

How can big yellow excavators improve a local fishery and create a safeguard against carp in the Phalen Chain of Lakes?

Let’s back up before we answer this question.

Markham Pond is at the headwaters of the Phalen Chain of Lakes and drains into Kohlman Creek, which feeds Lake Kohlman. About six years ago, Markham Pond was identified as a carp nursery area. Thousands of carp, young and old, had the ability to migrate down into and infest the main lakes in the Phalen Chain. Carp are bottom feeders that stir up sediments, release nutrients and can negatively impact water quality. 

 

Markham Pond is a shallow system, with a maximum depth of four feet. During harsh winters, it’s likely that game fish species, like bluegill sunfish and largemouth bass, froze out and died. However, carp are a very resilient species and can handle winter conditions in shallow lakes and ponds.

Over the last couple of winters, Markham Pond was drawn down (or drained) in order to manage the carp population. This year, summer sampling in the pond revealed a few native fish species, like minnows, green sunfish, and bullhead, but no common carp. We took that as a sign that we were successful in significantly reducing carp and eliminating this threat to the Phalen Chain of Lakes.

University of Minnesota Carp Research Team
netting carp on Markham Pond

So the bad guys that threaten water quality are gone, end of story, right?

Wrong. Carp are stealthy and reproduce like crazy, and have to potential to explode in Markham again. What can we do to naturally control carp in Markham? The surprising solution was actually discovered in our watershed by the University of Minnesota’s Carp Research Team; bluegill sunfish zealously consume carp eggs, acting as a biological control mechanism. Carp have a very difficult time successfully reproducing in lake and pond systems with high bluegill populations. Thus, reintroducing a healthy bluegill population in Markham Pond will create a safeguard against the re-establishment of a substantial carp population.  

 

Bluegill's appetite for carp eggs should keep the carp population in check.

So how do we improve habitat for bluegill sunfish and other game fish in Markham Pond and help them survive the winter? A reasonable approach is to create a deep water refuge by excavating a wide and deep hole for game fish to hunker down in during the cold months. This fall the watershed is in the process of drawing down the pond by opening up a water control structure. A dry pond bottom will make it easier for excavators and earth moving equipment to do their work this winter.

 

The Plan
 

Pond levels are down as we intentionally lower
the lake level in anticipation of construction.

During January and February, we plan to remove accumulated sediment that has washed into the pond and create a fourteen foot deep refuge almost an acre in size. A grant from the Minnesota Pollution Control Agency will help support this work. The paved parking lot at the north end of Hazelwood Park will be used as the construction site entrance and equipment staging area.



Next spring, the pond will be filled back up again and the watershed will work with the DNR to stock game fish species. This deeper refuge area will not freeze to the bottom, even during harsh winters, and will have suitable dissolved oxygen levels for game fish.

Additional benefits of the project will include increased recreational fishing opportunities, robust aquatic plant growth, enhancement of wildlife habitat, reduced pond bottom re-suspension from carp activities and, hence, improved water quality in Markham Pond and downstream waters in the Phalen Chain of Lakes.

So when you drive by Markham Pond this winter and see big yellow backhoes digging away, be assured that this work will help to improve our fisheries and preserve the water quality in the Phalen Chain of Lakes.