A tip-of-the-blogger-hat to Street & Park Supervisor TJ Heinricy and his staff for doing this.

Mr. Wigley,

We plan to dredge the pond just east of Heywood Rd (between Creek Ln & Sunset Dr ), that we refer to informally as Rosewood Pond. The pond near Hidden Valley Rd. is in reasonably good shape compared to the ponds at Rosewood, John North Park and Grant Park. Those three ponds will be addressed first, and then Hidden Valley and the two ponds near the High School (east of Division on either side of Washington St S) at a later date.

Given the cost of restoration for each pond we expect that it will take at least 5-7 years to complete the first three ponds (the are included in the CIP to be presented to the Council tomorrow night). Hidden Valley Pond would likely come after that, closer to 2018-2020. The current rate of sediment infill is low so we do not anticipate significant changes to the pond’s functionality in that time frame.

We have a meeting scheduled this week with the regulatory agencies (DNR, Corps of Engineers, BWSR, etc.) to discuss their jurisdictional claims on the first three ponds. The construction time frame will be governed by any regulatory permitting process we are required to complete. Once we have a handle on the permitting process we will hold a neighborhood meeting for the Rosewood Pond area. The John North Park Pond work will be discussed in conjunction with the road work planned in 2012 for that neighborhood.

TJ will likely be involved in the initial draining of the Rosewood Pond, but the dredging project itself will be run through the Engineering Dept. Please contact me if you have any questions.

Regards,

Brian

——-
Brian Welch, Engineering Resources Manager/Transit Manager
City of Northfield
801 Washington St S.
Northfield, MN 55057
507-645-3027

See: Stormwater Pond Evaluation and Prioritization: Assessment of Six Basins (PDF). It was prepared for City of Northfield on June 13, 2011 by Barr Engineering.

http://northfieldnews.com/content/pond-cleanup-project-begin-fall

According to Brian Welch, engineering resources manager for the city of Northfield, the Cannon River and the ponds that flow into it have seen a significant increase in sedimentation and runoff since then.

“We knew we needed to reduce the runoff levels to 1984, so we had to go back and look [at the Cannon River],” he said. “Now we know we need to cut the levels in half. We knew that a number of ponds needed work.”

With that in mind, Welch and his team have proposed a pond maintenance and rehabilitation program designed to return Northfield ponds to their original states.
In a plan to dredge the ponds and restore them to their original dimensions, six have gotten priority: Rosewood, Grant Park, John North Park, Hidden Valley and Sibley View (East and West). Rosewood, located at the corner of Heywood Road and Creek Lane, is about 10 years old and has about 29 percent sedimentation. It will cost around $58,600 to maintain.

Storm Water Ponds! Could this be us?
A blog post speaking of the anatomy of a storm pond.

City to conduct assessment of Hidden Valley Pond this week
Brian Welch, GIS Technician for the City of Northfield, has this update in Northfield City Administrator Joel Walinski’s June 25 Friday Memo:

Photos: Barr Engineering surveyor

The City has contracted with Barr Engineering to help the city develop a prioritization of stormwater ponds in need to dredging and other rehabilitation work to improve management of surface runoff.

A guy from Barr Engineering did his thing today.

Stormwater Pond Rehabilitation Assessment

The City has contracted with Barr Engineering to help the city develop a prioritization of stormwater ponds in need to dredging and other rehabilitation work to improve management of surface runoff.

Six ponds have been designated as the initial priority based on the presence of significant sediment plumes, vegetation growth, or deteriorating storm pipes: John North Park, Grant Park, Hidden Valley Park, Sibley View ponds (north of Jefferson Pkwy to the east and west of Washington St S), and the small pond to the west of Heywood Rd. between Sunset and Creek Lane.

The week of June 28 survey crews from Barr will be mapping the bathymetry of the ponds and determining the elevation of inlets and outlets to the ponds. State regulations require testing of sediment samples from the pond in order to determine whether special treatment is required of dredged materials. Barr Engineering will conduct the core sampling and testing in coming weeks. Once the pond assessments are complete a rehabilitation plan and schedule will be developed for each pond.

Funding for the pond assessments and rehabilitation comes from the city’s stormwater utility fund. The city will continually work through the inventory of stormwater ponds to ensure proper functionality of the ponds as part of the citywide stormwater infrastructure.

It should be noted that treatment of stormwater is the priority function of these ponds.

They were killing Bird’s foot trefoil, described on their website as an exotic species of wildflower. 

In some cases exotic species find just the right niche and become highly competitive with native species already in place, reducing diversity and upsetting stable communities of both plants and animals.

See the Wikipedia for more about Bird’s-foot Trefoil. And see the Prairie Restorations blog for lots more about their recent activities in restoring prairies around Minnesota.

The rains have been plentiful this spring and thus making the frogs around the pond in the middle of Hidden Valley Park very happy.   I captured their music while sitting in front of our backyard fireplace last week and again tonight while walking around the park watching the moon rise. Watch/listen to this 38-second video.