Friday, September 02, 2011

Dredging FAQs

Begins on page 33 of the Belle Isle Dredging info.

Copied text from a memo from BT Squared to the City:

August 30, 2011
File No. 25211430.00
City of Monona
F ROM: SCS BT Squared Project Team
S U B J E C T : Dredging Project – FAQ’s

Hydraulic Dredging vs Mechanical Dredging
The dredging process specified in the plans and specifications will be hydraulic dredging, and
not mechanical dredging. Hydraulic dredging will be something like taking a large “shop vac” in
the lagoon on a barge and pumping the muck along with some water from the bottom of the
channel to a dewatering location at Fireman’s Park.

Park Fill Material
Oneida Park is taking the roadway subgrade cut material (~11,000 cubic yards of material). The
plans for Oneida Park provided by the City of Monona Park and Recreation department with the
feedback from the residents does not allow for placement of the lagoon dredge material.
Park Restoration in Fireman’s Park
Park grading and restoration for Oneida park will not be part of the assessments provided to the
residents for the road project. The dredged material will be pumped to location in Fireman’s
Park that would need minimal site preparation to store the dredged material. No matter where
the dredge material ends up, the site would need to be prepared to accept the material and then
shaped and restored after dewatering. The Fireman’s Park was close to the channels for easy
return of the pumped water, and the site naturally was low and could accept fill without trucking
costs or additional grading that other sites might require.
What grants might be available?
The City applied for a Recreational Boating Fund (RBF) grant through the Wisconsin
Department of Natural Resources. The project scored low and did not receive a grant. To score
high for an RBF grant, dredging projects have to be for navigational channels that benefit the
public (e.g., provide access to a boat launch or connect two waterways). This is up to 50% cost
share, but more often in the 40 – 45% range. Grant applications must be submitted by June 1,
with awards likely sometime in August.
The Sport Fishing Grant uses the same application form as the RBF grant. This is a 50% cost
share. Applications are due February 15, but grants are not awarded/funded until August
because it is a federally funded grant.

There may be other local public or private funding sources, including Madison Fishing Expo
Group Funds and various Dane County funds. Many grants have similar requirements in terms
of demonstrating a public benefit from the project.
If we wait to dredge until 2012, will we need to reapply for permits?
The following permits have been obtained and are valid through the date listed.
• Chapter 30 permit – December 31, 2013
• Construction Site Erosion Control Permit – July 11, 2014
• WPDES Carriage Water Return Permit – July 2012, but can be extended as long as
project scope does not change
We are still awaiting approval/renewal of the Army Corps of Engineers permit; however, the
previous permit was valid for 4 years.
Pier/Lift Removal
The plans noted that piers would be removed prior to dredging. This note was based on
discussions with dredging contractors who confirmed that the best bid prices and removal of
material would come if the piers were removed. Pier removal letters were sent out as an early
notification to residents. After the bids were received and based on the feedback from the
residents, both contractors were asked if they could remove sediment with piers left in. Both
said “yes” but that they would not be responsible for any damage to any piers due to their
operations and removal of the project sediment. Landowners leaving piers in will need to sign
an indemnification form issued by the City allowing the contractor to perform dredging
operations around their pier and/or lifts and will not hold the contractor, City of Monona, SCS
BT Square, or any other entity working on the project responsible for any damage.
Plan Cross Section
The plans show cross section of the channel. The cross sections were based from a topographic
survey completed in June 2011. The cross sections show the amount of material that is proposed
to be removed at each location. The top of silt was the top of the muck as it existing in June.
The bottom of silt was the depth to which we could push the survey level rod down into the
muck in order to get to what we are calling the “hard bottom.”

Berms or Ground Giving Away
The purpose of the project is to remove the silt/muck from the lagoons. We are not proposing to
remove the actual hard bottom which forms the shape of the lagoon. The existing sideslopes are
3:1 sideslopes (3 foot horizontal to 1 foot down vertically) which are gradual enough to maintain
the banks.

Contractor Bidding
Bids were taken for the dredging project on August 3, 2011. The plan holders list was comprised
of 14 dredging companies and subcontractor / suppliers. There were 2 bids submitted: Gro America and PCI (Petersen Companies). The bids comprised of a base bid (dredge depth is ~ 5
feet, water surface at 845 and muck removal to 840), and an alternate bid to remove of all the
muck down to the harder lagoon depth.

Company Base Bid Alternate Bid Total Bid
GroAmerica $389,000 $67,151 $465,151
PCI $413,375 $61,325 $474,700

2012 Rebid
The option to rebid the project in 2012 has risk in that no one knows how many bids Monona
may get and prices could increase. Generally bidding in the early part of the year generates more
interest from contractors as they are trying to solidify project work for the year, but this does not
guarantee a project cost.


  1. Will there be any odors or other nuisance issues for residents immediately adjacent to Fireman's Park? Where will the sediment go once it is dewatered?

  2. When the city dredged the Cove Circle lagoon in the early 1990's, the sediment was placed in Maywood Park. I don't recall it being terribly stinky, but it may have been for a while.

    The sediment will be placed near the Blue Playground (across the lagoon from what I would call Firemen's Park; see page 20 of the Report) It will be left there and then graded and landscaped. That area is quite low.

  3. Will it be tested for toxic materials, such as heavy metals that are often found in sediments resulting from urban runoff?

  4. "Will it be tested for toxic materials, such as heavy metals that are often found in sediments resulting from urban runoff?"

    I believe the answer is 'yes', but I am checking with staff. I also think the sediment has to be tested as part of the permitting process, but am checking that with staff too.

  5. "Will it be tested for toxic materials, such as heavy metals that are often found in sediments resulting from urban runoff?"

    The answer from BT Squared:

    The sediment in all the lagoons proposed for dredging were sampled and tested in 2006 for the original dredging permitting. All lagoons were again re-sampled, tested and re-evaluated by the WDNR for all the 2011 dredging permits. In both 2006 and 2011 the sediment samples were found to be within WDNR standards for non-toxic material. Once dredging commences the WDNR only requires the return or carriage water to be sampled for Total Suspended Solids (TSS), so toxic material testing is not and will not be completed during the dredging processing.

  6. Thanks for checking Doug. Glad to see these regulations are in place. For now anyway.