Ditch maintenance must be done within specific limitations to comply with the Wetland Conservation Act (WCA). The applicability of exemptions can be confusing so it is advisable to contact Dennis Rodacker at the Anoka Conservation District (ACD) or your Local Governmental Unit (LGU) for more information prior to conducting any work within a private or public ditch. Also, other jurisdictions including the US Corps of Engineers may have regulatory authority on the wetlands affected.
Exemption Standards Subpart 2 states "a replacement plan is not required for draining type 1 wetlands, or up to five acres of type 2 or 6 wetlands, in an unincorporated area on land that has been assessed drainage benefits for public drainage system" provided that:
Also, a replacement plan is not required for draining or filling of wetlands resulting from the maintenance or repair of existing public drainage systems, except for draining types 3, 4 or 5 wetlands that have been in existence for more than 25 years.
A replacement plan is not required for draining or filling of wetlands resulting from the maintenance or repair or existing private drainage systems, except for draining wetlands that have been in existence for more than 25 years.
The landowner must provide evidence to the LGU that any wetland that will be partially or completely drained by ditch maintenance has not existed for more than 25 years. Typical documentation includes aerial photographs, climatological records, soil borings, vegetative analysis, elevation surveys, sworn affidavits, cross section profiles, historical construction information, etc.
Wetland replacement is not required for impacts resulting from public drainage system improvement activities that receive final approval from the drainage authority between July 1, 1986 and July 1, 1991 provided the approval remains valid, the project remains active and the impacts are limited to the extent originally approved.
To prevent wetland drainage, the public drainage authority may install control structures and dikes, realign the ditch, or make other modifications.
Wetlands of all types that would be drained as part of the public drainage repair project are eligible for the Permanent Wetlands Preserve Program under Minnesota Statues, section 103F.516.
Peat mining, defined under MN Statues, section 93.461, is subject to mine permit and reclamation requirements under MN Statues, section 93.44 to 93.51 and the rules of the commissioner of the DNR adopted under those sections.
Contact your LGU for additional permit information. Also, contact Julie Jordan, Mining Hydrologist, Department of Natural Resources, Division of Land and Minerals, 1525 3rd Ave E, Hibbing, MN 55746.
Anoka County residents frequently inquire how to improve their land for waterfowl or other wildlife. A common practice in Anoka County are pond excavations in seasonally saturated areas, or cattail-choked wetlands to provide an open water habitat.
The WCA regulates excavations in the permanently and semipermanently flooded areas of type 3, 4 or 5 wetlands and also regulates the placement of spoil and the depth of the excavation in all types of wetlands. Also, other jurisdictions including the US Corps of Engineers may have regulatory authority on wetland excavation projects.
Draining: There is potential for pond excavations to drain adjacent wetland areas. Typically, in Anoka County, if the hydrology is predominantly groundwater driven, a pond excavation can be designed that will not drain adjacent wetlands. However, some Anoka County wetlands are surface water driven, which increases the likelihood that a pond excavation could drain adjacent wetlands. This is an issue that is best addressed by your LGU during a specific project.
Filling: Filling of wetlands must be avoided during pond excavations. The spoil from the excavation must be placed in an upland area. A qualified wetland professional may be needed to ensure that the destination of the spoil is upland. Rarely, some soil deposition in wetlands during excavation is allowable if certified by the wetland specialist at the ACD.
Proper erosion control practices must be incorporated. You may contact the ACD for assistance with an erosion control plan.
| Water Depth | % of Pond at this depth | Likely Result |
| 0 - 1 foot | 5 to 15% | Cattails and emergent vegetation, usually dry by July |
| 1 - 3 feet | 40 to 70% | Mixed emergent vegetation and open water, dry in drought |
| 3 - 5 feet | 25 to 50% | Mostly open water, dry in severe drought |
Native grasses and forbs should be seeded in areas after final grading. Please contact Dennis Rodacker at the ACD for more information.