Dredging Rule

Adopted April 24, 2014
Effective June 6, 2014

1. POLICY

It is the policy of the Board of Managers to:

(a) Preserve the natural appearance of shoreline areas; recreational, wildlife and fisheries resources of surface waters; surface water quality and the ecological integrity of the riparian environment;

(b) Protect backwater areas and wetlands adjacent to or hydrologically connected to area lakes, with particular protection of backwater areas and wetlands that have been identified by the District as particularly sensitive to stormwater impacts or as providing valuable vegetative diversity or integrity; wildlife or fish habitat; shoreline protection; or exceptional aesthetic, educational, recreational or cultural features;

(c) Minimize impacts from dredging to the biologically productive and ecologically sensitive littoral zone of water bodies to prevent the deterioration of water quality, the proliferation of invasive species and increased seepage;

(d) Balance the riparian rights of property owners with the public interest in protecting water resources.

2. REGULATIONS

No person shall dredge in the beds, banks or shores of any public water or public waters wetland in the District without first securing a permit from the District, and posting a bond or letter of credit pursuant to the Financial Assurance Rule.

3. GENERAL STANDARDS

All permitted dredging shall comply with the following standards:

(a) A spoil disposal site must be identified and found not to be below the OHW of a public water or public water wetland, wetland subject to the Wetland Conservation Act of 1991, or floodplain and not prone to erosion.

(b) Where there is an identifiable source of sediment under the control of the applicant, the plan shall include remedial action to minimize deposition of sediment into a waterbody or off-site.

(c) Before District review, all dredging proposals that involve navigational access to docking structures shall be submitted to and approved by, in the case of public waters, the Minnesota Department of Natural Resources and, in the case of Lake Minnetonka, the Lake Minnetonka Conservation District. Proposed dredging in Lake Minnetonka is subject to the dredging standards of the DNR, MCWD and LMCD Dredging Joint Policy Statement (April 1993).

(d) The proposed project shall represent the “minimal impact” solution to a specific need with respect to all other reasonable alternatives such as dock extensions, aquatic nuisance plant removal without dredging, beach sand blankets, excavation above the bed of public water, less extensive dredging in another area of the public water, or management of an alternative water body for the intended purpose. For a project determined by the District to present potential impacts to Preserve wetlands and other ecologically sensitive areas, the applicant must demonstrate that the proposed project is likely to cause minimal ecological impact and that it presents the least ecological impact of all reasonable alternatives.

(e) The dredging shall be limited to the minimum dimensions necessary for achieving the stated purpose.

(f) If the dredging will be accomplished by means of hydraulic dredging the following additional standards will apply:

The spoil disposal site shall have a minimum storage capacity equal to four times the calculated volume of solid material to be removed, and a minimum free board between the top of the projected water surface elevation and the top of the dike of one foot, if no outlet from the spoil disposal site is proposed.
The construction of the spoil containment site shall be with earthen dikes. No such dike shall exceed 5.5 feet in height at any point. Dikes shall have a minimum 4 foot wide top and side slopes of 2:1 (H:V) or flatter. The dikes shall be adequately compacted by traversing with appropriate equipment during construction.
Proposed embankments which differ from the standard in 3(f)(2) shall comply with generally accepted engineering principles and be designed and certified by a professional engineer registered in the State of Minnesota.
Spoil containment sites of limited storage volume which propose a discharge back into a receiving water body through a control structure shall meet applicable State water quality guidelines for the receiving water body. Weekly monitoring of the instantaneous discharge shall be performed and paid for by the applicant. The results shall be promptly forwarded to the District Engineer for comparison to state water quality standards for turbidity and total suspended solids.
A restoration plan prepared by a qualified individual shall show proposed methods of retaining waterborne sediments on site during the period of operation. The plan shall show final grades and how the site will be restored, covered and/or vegetated after construction. Sites with high erosion potential characterized by steep slopes or erodible soils may require a cash deposit or surety to ensure performance and any necessary remedial actions.

4. CRITERIA

(a) Dredging shall be permitted only:

To maintain, or remove sediment from, an existing public or private channel, not exceeding the original or originally permitted extent of dredging, whichever is less, and subject to such further limitations on method or extent of dredging as this rule may provide;
To implement or maintain an existing legal right of navigational access;
To remove sediment to eliminate a source of nutrients, pollutants, or contaminants;
To improve the public recreational, wildlife, or fisheries resources of surface waters; or
For actions by public entities for public purposes.

(b) In evaluating an application to dredge to maintain or remove sediment from an existing public or private channel, the significance of historic dredging will depend on how recently the original dredging or subsequent maintenance to sustain use took place, the extent of recent use, and the amount and significance of evidence supporting use for the proposed purpose.

(c) In evaluating an application to dredge to create or maintain navigational access, the District will determine whether the navigation sought is reasonable under the circumstances, considering:

The ecological sensitivity or preserve status of any potentially affected water body or wetland;
The size, draft, speed, motorized status and other characteristics of watercraft historically used or proposed to be used in the area proposed to be dredged;
The size, draft, speed, motorized status and other characteristics of watercraft typically moored and used within 200 yards of the area proposed to be dredged;
The size and restrictiveness of existing channels and bridge openings that may affect navigation; and
The availability of alternative means of gaining access, such as extending docks; purchasing, renting or leasing shore moorings; or anchoring watercraft away from shore moorings.

(d) No dredging shall be permitted:

Above the ordinary high water level or into the upland adjacent to the lake or watercourse;
That would enlarge a natural watercourse landward or that would create a channel to connect adjacent backwater areas for navigational purposes;
Where the dredging will alter the natural shoreline of a lake;
Where the dredging might cause increased seepage or result in subsurface drainage;
Where any portion of the dredged area contains any slope steeper than 3:1 (H:V) in a marina or channel, or steeper than 10:1 (H:V) for an area adjoining residential lakeshore; or
Where adverse ecological impact to a preserve wetland or other ecologically sensitive area cannot be minimized.
No dredging in a public water shall occur between April 1^st and June 30^th. No dredging in any other waterbody shall occur between April 1^st and June 30^th unless the applicant demonstrates that fish spawning does not occur in the waterbody.

(e) Dredging presenting the conditions identified in 4(d)(1-3) above may be permitted where the project complies with applicable DNR rules.

5. REQUIRED EXHIBITS

The following exhibits shall accompany the permit application. One set – full size; one set – reduced to maximum size of 11″x17″.

(a) Site plan showing property lines, delineation of the work area, existing elevation contours of the adjacent upland area, ordinary high water elevation, and 100-year high water elevation (if available). All elevations must be reduced to NGVD (1929 datum).

(b) Profile, cross sections and/or topographic contours showing existing and proposed elevations and proposed side slopes in the work area. (Topographic contours should be at intervals not greater than 1.0 foot.)

(c) In the case of projects using hydraulic means of sediment removal and on-site spoil containment the applicant shall supply:

Cross section of the proposed dike.
Stage/storage volume relationship for the proposed spoil containment area.
Detail of any proposed outlet structure, showing size, description and invert elevation.
Stage/discharge relationship for any proposed outlet structure from the spoil containment area.
Site plan showing the locations of any proposed outlet structure and emergency overflow from the spoil containment area.

(d) Site plan showing the proposed location of floating silt curtains.

(e) Support data:

Description and volume computation of material to be removed.
Description of equipment to be used.
Construction schedule.
Location map of spoil containment area.
Erosion control plan for containment area.
Restoration plan for any proposed permanent on-site spoil containment site showing final grades, removal of control structure, and a description of how and when the site will be restored, covered or revegetated after construction.
Detail of any proposed floating silt curtain including specifications for the silt curtain.

(f) In the case of projects where dredging:

Might cause increased seepage or result in subsurface drainage, or
Will remove sediment to eliminate a source of nutrients, pollutants, or contaminants, a minimum of two soil bearing logs extending at least two feet below the proposed work elevation shall be required.

6. FAST-TRACK PERMIT

A Fast Track permit may be issued by District staff for the removal of accumulated sediment caused by a stormwater outlet. The application otherwise must comply with all provisions of this rule. In addition to the requirements of sections 3, General Standards and 5, Required Exhibits of this rule, the following criteria shall be met:

(a) Authorization shall apply only to removal of sediment identified as non-native material accumulated due to stormwater runoff or erosion.

(b) Dredging shall not materially change the elevation or contour of the bed of the affected basin.

REVISIONS PURSUANT TO MINNESOTA STATUTES § 103D.341