Protecting Water Quality Using A Natural Resource-based Priority Parcel Process

Watershed management plans commonly include land conservation as a recommended action for reducing nonpoint source pollution and protecting water quality. Typically, land protection efforts are carried out by conservancies and local governments through land acquisition, voluntary conservation easements, master planning, and zoning. Organizations involved in land conservation have ever greater access to natural resource inventories and are able to use this information to help guide decisions. Although natural resource inventories are valuable for making generalizations regarding the environmental value of a particular parcel, they do not provide the quantitative scores that are needed for a reliable ranking system. Thus, the "priority parcel process" was developed to rank individual parcels and, in so doing, provide a tool to guide land conservation efforts.

The idea for a priority -parcel process was conceived during the development of the Little Traverse Bay Watershed Protection Plan and later improved as part of the Cheboygan River Watershed Habitat Partnership Project. Watershed advisory committee members worked with Tip of the Mitt Watershed Council staff to determine the appropriate criteria for prioritization as well as scoring systems. The following criteria and scoring system were utilized in the most recent iteration of the process:

1. Total Acreage

   1) Acres >= 10 AND acres < 40      1 pts

   2) Acres >= 40 AND acres < 80      2 pts

   3) Acres >= 80 AND acres < 120      3 pts

   4) Acres >= 120      4 pts

2. Groundwater Recharge Potential

   1) Groundwater Recharge Acres >= 10 AND < 40      1 pts

   2) Groundwater Recharge Acres >= 40 AND < 80      2 pts

   3) Groundwater Recharge Acres >= 80 AND < 120      3 pts

   4) Groundwater Recharge Acres >= 120+      4 pts

3. Wetland Ecosystems

   1) Wetland Acres > 0 AND < 10      1 pts

   2) Wetland Acres >= 10 AND < 20      2 pts

   3) Wetland Acres >= 20 AND < 40      3 pts

   4) Wetland Acres >= 40+      4 pts

4. Lake Shoreline/Riparian Ecosystems

   1) Lake Shore Distance >= 100' AND < 400'      1 pts

   2) Lake Shore Distance >= 400' AND < 660'      2 pts

   3) Lake Shore Distance >= 660' AND < 1320'      3 pts

   4) Lake Shore Distance >= 1320'      4 pts

5. River and Stream Shoreline/Riparian Ecosystems

   1) Stream Distance >= 200' AND < 1320'      1 pts

   2) Stream Distance >= 1320' AND < 2640'      2 pts

   3) Stream Distance >= 2640' AND < 5280'      3 pts

   4) Stream Distance >= 5280'      4 pts

6. Adjacency to Protected Lands

   1) Adjacent to one protected parcel      1 pts

   2) Adjacent to two or more protected parcels      4 pts

7. Threatened/Endangered Species

   1) Parcel within habitat range of 1 protected species      1 pts

   2) Parcel within habitat range of 2+ protected species      4 pts

Using these criteria, a process was developed in a GIS (Geographical Information System) to score all parcels. A number of GIS data layers were required to run the process including parcel boundaries, soils, lakes, streams, wetlands, and threatened/endangered species. Parcel boundary GIS data were acquired from county governments, threatened/endangered species data were provided by the Michigan Natural Features Inventory and all other data were downloaded from the Michigan Geographic Data Library. In a multiple step process, geo-processing tools were used to determine scores for every parcel in the county for each criterion. The priority score was calculated by summing the scores from each criterion and this total score was subsequently used to rank parcels in groups from high to low priority.

In all, parcels were prioritized in five counties in the northern Lower Peninsula of Michigan. In 2004, the process was run county-wide for Charlevoix, Cheboygan and Emmet Counties and on a limited basis in Otsego and Presque Isle Counties. After correcting errors in the GIS procedure and obtaining updated parcel boundary layers, the process was rerun to produce new priority scores for all parcels in Charlevoix, Cheboygan and Emmet Counties.

By means of the priority parcel process, land parcels throughout much of the northern Lower Peninsula of Michigan were scored to prioritize land protection efforts in a way that would benefit the region's water resources as well as protect threatened/endangered species and enhance wildlife corridors. Determination of specific environmental values for particular parcels provides a tool that conservancies and local governments can use for site-by-site decisions, inter-parcel comparisons, master planning, zoning development and modifications, and discerning ecological patterns such as wildlife corridors. Permanent protection of high priority parcels will help maintain the ecological integrity of the most sensitive areas and ultimately protect and enhance water quality of the region. To date, this tool has been applied in planning by local land conservancies and been used by water resource management organizations and advocacy groups to evaluate parcel water features.

For more information about the priority parcel process, contact Kevin Cronk, Monitoring and Research Coordinator.

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