Coastal erosion processes and measurements
Program or Topic Area Leader
The shorelands of the Great Lakes are a dynamic and quickly changing environment. Lake levels may fluctuate dramatically in response to weather and climate. Wave action, storms, wind, ground water seepage, surface water runoff, and frost are contributing factors to changing and reshaping the shoreline. During periods of low water property owners are often lulled into believing homes may be safely built closer to the water's edge. Yet longtime residents have many stories about high water levels, the subsequent erosion of the Great Lakes shoreline and the homes that have fallen into the lake as their foundations have been compromised. This destruction has resulted in severe financial loss to property owners. Public losses to recreation facilities, roads and other public works have also occurred. Structures threatened by erosion may be moved landward, protected by costly shore protection or lost.
The purpose of the High Risk Erosion Area program is to prevent structural property loss in an area of the shoreland that is determined by the department, on the basis of studies and surveys, to be subject to erosion as required by Part 323 of the Natural Resources and Environmental Protection Act, 1994 PA 451 as amended (NREPA) and the corresponding Administrative Rules. High risk erosion areas are those shorelands of the Great Lakes where recession of the landward edge of active erosion has been occurring at a long-term average rate of one foot or more per year, over a minimum period of 15 years. DEQ staff conducted the initial recession rate research of coastal counties between 1980 and 1986; during that time they identified high risk erosion areas in 36 of 41 coastal counties. Recession rates change over time as water levels fluctuate and coastal conditions change. The recession rate research is ongoing and often results in changes to the locations of high risk erosion areas along the shoreline.
The high risk erosion area program increases consumer awareness of the danger of shore erosion and allows staff to provide advice and technical assistance to many citizens living with the dynamic Great Lakes shorelines. Presently about 7,500 individual property owners are affected by setback requirements. All citizens benefit from the program's efforts to reduce the need for public disaster assistance, promote consumer protection, and reduce the loss of natural resources.
Studying the Shoreline
The rates of recession are determined by comparing the location of the erosion hazard line of the shoreline on historical and modern aerial photographs. Depending on the availability of historical aerial photos the studies typically cover the longest possible time period to capture the widest range of water levels and shoreline fluctuations. Additional information from fieldwork, shoreline photos, and online resources, such as the 2012 USACE Great Lakes Oblique Imagery, is used to aid in the determination of the erosion hazard line. The recession rate data are used to calculate the appropriate setback distances for construction. Setbacks are determined for the projected recession of the shoreline 30 years and 60 years into the future. The 30 year setback distance (feet) is for those structures considered readily moveable as defined in Rule R 281.21 (k). If the structure was threatened by erosion it could be moved landward before loss of the structure occurred. The 60 year distance is for non-readily moveable structures such as a septic system. These structures are too large, or not possible, to move. Once a recession rate study is complete the property owners, and their local officials, in the proposed high risk erosion areas are notified and given the opportunity to comment on the proposed designations before they become effective.
A DEQ permit is required prior to construction on a parcel in a high risk erosion area regardless of where the structure is proposed on the parcel. Any person or local governmental agency proposing to erect, install, move, or enlarge a permanent structure on a parcel must obtain a permit prior to the commencement of construction. The projects requiring a permit include the construction of a house, garage or addition, substantial reconstruction or restoration of an existing home, the installation or upgrade of a septic system or a commercial building. During the permit application review the proposed location of the structure will be compared to the required setback distance for the site. Depending on the site the setback may be measured from the top of the bluff or the erosion hazard line. The permit application and associated fees are found online as is the ability to track applications. Beginning August 17, 2015, application processing moved into MiWaters.
Local units of government may adopt a zoning ordinance for high risk erosion areas to assume regulatory authority under Part 323 of NREPA which, if approved by the Department, replaces the need for a state high risk erosion area permit. Other state permits such as those required for critical dune areas, wetlands or shore protection may still be necessary from the Department. The Department then monitors the performance of the community and provides technical assistance. Some local units of government adopt zoning ordinances which regulate setbacks but do not assume the authority of Part 323 of NREPA. In those communities a permit is required from the Department and from the local community for construction in a high risk erosion area.
Primary Stakeholder Audience
- Non-formal education audience
The lawful administration, coordination and oversight of the high risk erosion area program under Part 323, Shorelands Protection and Management, of the Natural Resources and Environmental Protection Act, 1996 PA 451 as amended (NREPA) and promulgated rules. The recession rates of the coastlines are studied and the results presented to the public and local officials.