Visualizing Tribal Mitigation Opportunities in the Colorado River Basin

By Ada Wright

Offsetting new impacts to ecological resources–namely, wetlands, streams and species habitat–is critical to achieving net zero ecological function and biodiversity outcomes. Part of EPIC’s work on promoting faster and more effective restoration is ensuring that tribes have the opportunity and resources to participate in mitigation projects. We were particularly interested in identifying opportunities for tribes in the Colorado River Basin to undertake mitigation banking or in-lieu fee programs. Through compiling information and data on streams, wetlands, potential development areas, and tribal boundaries we hope tribal entities can find opportunities for local participation in compensatory mitigation schemes. Over the course of December of 2021, we developed the maps “Mitigation Attributes by Watershed” and  “Potential Mitigation Locations” to identify the best opportunities for wetland mitigation and conservation banks in the Colorado River Basin by tribal nations. 

While the original plan for this project was to identify specific areas of mitigation potential, we quickly realized that there is a huge amount of potential banking areas on tribal (and historically tribal) land. Without an intimate knowledge of the specifics of each area and a lack of recent data, we were unable to make a conclusive decision on the best areas for mitigation banks. However, we hope the compiled data could assist local entities on preliminary mitigation research and be an accessible starting point for interested tribal nations.

The finalized map includes 10 searchable layers, each detailing an important characteristic of a mitigation/conservation bank. All data was collected using the most recent available version (as of December 2021) and largely compiled from federal data sources. Our finalized visualization contains a series of two maps; the first is a Tableau tool that uses a per-watershed breakdown of the various attributes needed for a wetland mitigation or conservation bank. We hope this map can be used to identify potential watersheds for tribes to target, through searching by tribal nation. 

Once potential watersheds have been identified, the ArcGIS Esri dashboard will allow interested groups to collect more information on potential areas of mitigation. The compiled data includes specific wetland types, development potential on the land, critical habitats of threatened and endangered species, and watersheds. Both maps include a search bar that will allow users to search for an area or tribal nation of interest. As previously mentioned, we hope that the visualizations can support tribal efforts for mitigation projects in the Colorado River Basin and act as a jumping-off point for interested entities.  

If interested in this project please reach out to EPIC’s tribal mitigation fellow Mariah Black Bird at mariah@policyinnovation.org. She has also written blog entries on mitigation opportunities for tribal nations found here.

Insights

In order to show how the Esri dashboard “Colorado River Basin Mitigation Options” map could be used, we have developed the following example of a potential area for wetland mitigation on the Southern Ute reservation. To begin, I have entered the name of the tribe I am interested in researching in the search bar.

This will allow us to zoom into our area of interest and identify potential mitigation areas. I am specifically interested in seeing which wetlands or critical habitats might be near the reservation.  In order to do this, I go to the layer tab in the top righthand corner and turn on the layers by clicking the eye image: 

• protected land 

• rivers 

• critical habitat 

• wetlands on tribal land

• tribal nations

I immediately see a potential area to further investigate for conservation purposes: there is an area that does not have any protected characteristics (light yellow polygons), is on tribal land, has wetlands, and is near critical habitat for endangered species.

I then zoom in further (using the plus sign in the lower right) to gather more details on the area and identify the watershed and nearby areas. I see in the dark blue there is critical habitat for the New Mexico meadow jumping mouse near a section of wetland (light green) and freshwater ponds (light blue) as well as the intersection of San Juan river with the Southern Ute reservation. This seems like a good spot for a mitigation project. 

My next step is to identify nearby areas where there might be demand for the purchase of mitigation credits. While this map does not include current development threats (besides identifying developable and non-developable land), we have made the assumption that HUC-8 watersheds are good boundaries to identify potential development options. We plan that future versions of this visualization will include a development risk index. For the purpose of this project, however, I turned off the tribal boundaries layer and turned on the watershed layer, which allowed us to identify the watershed of the potential mitigation bank as the Upper San Juan. I then compiled research of the watershed and identified the potential for mitigation credit needs. I found that the City of Farmington, the over 70,000 acres of farmland serviced by this section of the San Juan River, and the potential for recreation development all identify this as a good location for a compensatory mitigation project for the Southern Ute Tribe.

Hopefully, the above steps will help identify potential mitigation areas on tribal lands. There are also layers for historic tribal lands and for overall wetland locations in the Colorado River Basin, allowing tribes to identify areas of potential future mitigation investment on their historic land. 

Data Used

Wetland Data: US Fish and Wildlife National Wetlands Inventory from their 2016 publication. This data is intended for regional watershed display and analysis and not specific projects, so it will be essential for interested parties to identify additional local data sources for further research.

• Wetlands: All freshwater emergent wetland, ponds, lakes, and forested wetland in the Colorado River Basin  as identified by the USFW 2016 publication found here.

• Wetlands on Tribal Lands: All freshwater emergent wetland, ponds, lakes, and forested wetland on tribal lands as identified by the USFW 2016 publication found here.

Watersheds: USGS Huc-8 watershed shows all watershed hydrological units in the Colorado River Basin. As mitigation credits must be purchased from a local source, it is essential that potential mitigation projects occur in watersheds of high development likelihood (i.e., where there will be demand for offset credits). 

• Watersheds: USGS’s most recent HUC-8 designated watersheds for the Colorado River Basin found here. 

Rivers: Rivers are identified from the USGS hydrology map and from the Colorado River Basin Institutes’ database of main rivers and tributaries located in the Colorado River Basin found here. 

• Rivers: USGS hydrology map of main rivers and tributaries located in the Colorado River Basin found here as compiled by the Lincoln Institute of Land Policy. 

Colorado River Basin: The geological boundaries of the basin as determined by hydrological units of the Colorado River. All larger datasets such as critical habitat, wetlands, and tribal boundaries have been clipped to align with the geography of the CRB.

Critical Habitat: Critical habitat is defined by the US Fish and Wildlife Service (FWS) as the essential habitat needed for the conservation of species that are listed as threatened or endangered by FWS. The identified areas may require specialized management and protection; however, there is no requirement for private landholders to follow USFWS guidelines. 

• Critical Habitat Line: An aggregation of critical habitat for species that are largely found in rivers or other line-like habitats as defined by the FWS, length of line included and found here  

• Critical Habitat: An aggregation of habitat defined as essential for the conservation of endangered and threatened species in the Colorado River Basin found here from the USFWS.

Tribal Boundaries: The boundaries of all federally recognized tribes in the Colorado River Basin as identified by the Lincoln Institute of Land Policy and their Colorado River Basin GIS Portal found here. 

Undevelopable Land: Land that has permanent protection from conversion of natural land cover and a mandated management plan to ensure a primarily natural state. Defined for the purpose of this project as any land with GAP 1 or 2 status including National Parks, BLM land, USFS, state/county parks, and privately held conservation easements. Data aggregated from the Protected Areas Database of the United States and the National Conservation Easement Database. 

Historical Tribal Land: Historic tribal boundaries as identified by Native Land Digital as of December 2021, found here. 

Developable Land: Land that has no permanent protection from conversion of natural land cover and is cleared for extractive industries such as logging, mining, or development. Defined for the purpose of this project as any land with GAP 3 or 4 status. Data aggregated from the Protected Areas Database of the United States and the National Conservation Easement Database.