Tuesday, October 14, 2014

Natural Resources Update - October 2014

By Bill Bartodziej and Simba Blood

Nets staked in front of the outlet on the west side of Markham Pond.

Carp Management - Markham Pond

Markham Pond, a small water body off of County Rd C and Hazlewood St in Maplewood, has been identified as a significant carp nursery in the Phalen Chain of Lakes. Our short-term goal is to eliminate carp in this pond.

Over the last couple of weeks, we have been in contact with DNR, U of MN, and Maplewood discussing the fall drawdown for Markham (17 acres). On September 18th, we opened the valve and started a slow drawdown of the pond. We placed two fine-mesh nets in front of the outlet so that carp are trapped in Markham and do not travel downstream. As we write this, hundreds of adult carp were cautiously swimming around in front of the outlet.

Hundreds of adult carp are attracted to water flowing out of the pond (red arrows).

The north end of Markham with exposed pond bottom.

Although large areas of the Markham Pond bottom are already exposed, we estimate that 13 acres (surface area) of water will remain, with a 1.0’ maximum water depth. Staff will work with Greg Nelson at Barr to look into a pump (1,000 GPM) to further reduce the volume and coverage of water in Markham. As you recall, a pump was tried last winter during the drawdown, but severe cold and ice hampered that operation. Staff remains optimistic that we will be able to substantially reduce the volume through pumping, hopefully, reducing the water level by at least another 0.5’. We believe that getting an early start on this effort will dramatically improve our ability to achieve a more substantial drawdown.

U of MN trap-nets, partially exposed, set into place to capture carp on the west side of Markham Pond.

The U of MN carp research team set fish trap-nets to conduct a carp survey. The objective was to collect carp population data prior to any sort of control effort. After 24-hrs, the nets were pulled. Each net trapped over 250 young-of-the-year carp, ranging in size from 4-6 inches. These were the highest carp densities (in the nets) that the U of MN team has seen in our watershed. This finding very much reinforces the fact that Markham is a real threat to the Phalen Chain, in terms of water quality and ecology.

We are in contact with Dr. Jim Cotner at the U of MN to partner on a federal permit to use carbon dioxide to control carp in the remaining pockets of water after pumping. Our target is to have less than 3 acres of water remaining when the treatment takes place. Permit approval, in part, determines the timing of the treatment, whether it will happen in the fall or early winter. DNR fisheries will also be involved with this effort.

 We will be closely monitoring Markham during the drawdown operation and continue to report all significant findings.

Keller Golf Course

A newly-hatched turtle heads for fresh water.

Last week at the golf course, Paul and his crew had a very interesting observation. A group of juvenile snapping turtles were making their way from a prairie area (that we began to restore last year) to the Hole #15 pond. They traveled over #14 green into the fairway, and down into the pond buffer (several hundred feet). The female snapper apparently made a nest somewhere in the young prairie. This is a great example of how these natural areas are connected, and the upland prairie areas do have an influence on the pond and wetland ecosystems in the Phalen Corridor. It is very possible that one or more of these turtles will find their way into the Phalen Chain of Lakes.

Hole #15 pond.

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