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Freshwater & Oceans

Refinement of identified priorities

Wetland Prioritization Study Main Page


Field methods

  • Caltrans Regional Advance Mitigation Planning
  • Colorado Natural Heritage Program
  • Maryland Watershed Resources Registry
  • Strager et al. (2011)
  • TNC Aquatic Ecoregional Assessment
  • UMass Amherst Conservation Assessment and Prioritization System
  • Washington State Department of Ecology


Expert/stakeholder input

  • LACPRA Coastal Master Plan
  • Michigan Tech Research Institute
  • North Carolina Ecosystem Enhancement Program
  • TNC Aquatic Ecoregional Assessment
  • TNC Willamette Basin Synthesis Project


Field methods


Caltrans Regional Advance Mitigation Planning:1 Mitigation areas identified using MARXAN greenprint analysis will be field verified using the California Rapid Assessment Method (CRAM) or Level 3 intensive data, as appropriate in particular areas of California, to select final mitigation sites. CRAM assessments are field-based evaluations of four attributes of wetland condition - landscape context, hydrology, physical structure, and biotic structure - that produce an overall score that can be used to prioritize mitigation sites. Although Caltrans has not yet identified specific intensive field assessment methods, it does intend to evaluate mitigation sites identified by the MARXAN tool using such techniques where appropriate. Depending on species offset assessment requirements, these might include species protocol surveys developed by the U.S. Fish and Wildlife Service (FWS) or California Department of Fish and Game (CDFG). For instance, if eradication of invasive species is a mitigation objective, then intensive vegetation assessments might be used.

Colorado Natural Heritage Program (CNHP):2 CNHP will use results from its Landscape Integrity Model (LIM) as a coarse filter for identifying high and low quality wetlands, within which it will seek funding to apply more detailed targeted assessment methods. In this way, the LIM will support CNHP's broader conservation planning program, which primarily involves field-based assessments that are used to rank wetlands in terms of a "biodiversity significance rank" (B-rank) by conducting surveys at the county level. However, the method can also be used to rank wetlands at the watershed, planning area, and ecoregional scale. CNHP stores survey data in its Biotics database and uses the data to rank wetlands and uplands in terms of their biodiversity significance.

Maryland Watershed Resources Registry (WRR):3 WRR users may use outputs from the models as a starting point for prioritization and evaluate site-specific ratings using rapid assessment/intensive methods to narrow down prospective sites before making their final site selection. In addition, WRR is developing a method by which users can provide general site-specific information on a standardized form in order to add standardized information to the registry.

Strager et al. (2011):4 Following the landscape priority analysis, Strager et al.'s method narrowed its list of potential wetland and stream mitigation sites by conducting rapid assessment reconnaissance surveys, which were carried out by an expert team composed of specialists from academia and West Virginia Department of Natural Resources (WVDNR). These field-based assessments scored wetlands for 23 criteria and streams for 15 criteria that addressed various ecological, engineering, construction, and anthropogenic factors (see Appendices A and B of Stager et al. (2011) for a complete list of these criteria). Weightings were developed for each of these criteria using the Analytical Hierarchy Process, which asked each scientist on the project team to evaluate a series of pairwise comparisons to assess the perceived importance of each criterion. By applying Strager et al.'s approach, expert-defined weights could be applied to the field-measured criteria scores. Wetland scores were then obtained by adding all weighted wetland criteria scores, while stream scores were obtained by adding all weighted stream criteria scores. Summing wetland and stream scores produced an overall score for each site, which was then converted to a rank based on its magnitude relative to all other scores in the HUC-10 watershed (e.g., the highest score was then assigned a rank of one, and so on).

Based on the results of the rapid assessment analysis, a more intensive on-site assessment was next applied to evaluate which of the three highest ranked sites within each HUC-10 watershed was most feasible for combined wetland and stream mitigation banking. The first step in this intensive assessment was to determine the total area already wetland within the site (using U.S. Army Corps of Engineers wetland delineation procedures) and subtract this area from the overall potential wetland restoration area. This allowed researchers to gain a more accurate understanding of how much area was actually restorable within each site. The researchers next assessed several hydrological, geomorphic, and ecological parameters for each potential wetland or stream site. These included measuring surface water runoff (rational runoff method), longitudinal profile and cross-section (topographic surveys), ten ecological parameters of streams and floodplains (e.g., epifaunal substrate, vegetative protection, etc.), stream dimension, pattern, and profile (used to measure classification and condition), stream bank stability (important for describing restoration potential), and several water quality parameters (e.g., temperature, pH, etc.). Numerical scores obtained from these assessments were used by researchers to determine the top site in each watershed for combined wetland and stream mitigation banking.

The Nature Conservancy Aquatic Ecoregional Assessment:5,6 TNC refined the Conservation Priority Areas (CPA) identified in its Aquatic Ecoregional Assessment by developing a Conservation Action Plan (CAP). A CAP is essentially a series of strategies - including those pursued by Virginia Aquatic Resource Trust Fund (VARTF) like restoration and habitat preservation - that guide TNC's specific conservation actions in or in support of a particular geography.1 For each CPA, TNC defined primary attributes that determine the biological health for each target within each ecological drainage unit (EDU). If the primary attributes are missing, the target is thought to degrade or be lost over time. For example, an attribute for a stream target may be some measure of water quality - if water quality becomes sufficiently degraded the stream may no longer be viable. For each target, TNC defined the acceptable range of variation of target attributes by establishing a viability rating scale that rates the status of each attribute as "very good," "good," "fair," or "poor." TNC then set goals for each target attribute in terms of these ratings.

TNC also ranked threats (defined as proximate stresses) to targets in terms of their contribution to target impairment and irreversibility. In addition, TNC ranked stresses (defined as impaired aspects of targets resulting from human activities) in terms of their scope and severity of impact to targets. For each of these threat/stress categories (impairment, irreversibility, scope, and severity), TNC collaborated with a team of experts to assign a rating of "very high," "high," "medium," or "low." This process allowed TNC to identify the most critical threats to targets within each EDU.

TNC applied this viability and threat information to data it collected on-the-ground within Priority Conservation Areas to identify specific locations and strategies for implementing aquatic resource restoration and conservation projects. TNC does not use standard rapid assessment/intensive methods for its field-based assessments, instead relying on a variety of techniques including simple walkthroughs, sophisticated site feasibility analyses, and detailed parcel analyses that identify priority tracts of land. Furthermore, TNC also projected the demand for credits within each service area (service areas are similar to EDUs for the In Lieu Fee program) to understand where credits could be pooled to enable larger and more effective projects. Using this information, TNC developed strategies for implementing on-the-ground restoration and conservation activities that would meet the goals it had set for each target.

UMass Amherst Conservation Assessment and Prioritization System (CAPS):7 The CAPS model provides information about the ecological benefit that can be expected to be produced if a site is restored but provides no information about the feasibility of restoration at the site. After identifying a site using CAPS, users must complete field-based assessments to determine whether restoration is feasible there.

Washington State Department of Ecology (WSDOE):8 In addition to the Watershed Characterization Tool, WSDOE has also developed rapid assessment methods for completing on-the-ground site-specific prioritization. Prioritization using rapid assessment methods is a separate step that follows application of the landscape analysis tools.


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Expert/stakeholder input


Louisiana Coastal Protection and Restoration Authority ( LACPRA) Coastal Master Plan:9 In order to facilitate analysis of the outputs of its landscape analysis tools, CPRA developed a computer-based Planning Tool. This tool allowed the state to systematically consider many variables for individual projects or groupings of projects, such as project costs, funding, landscape conditions, and stakeholder preferences. The Planning Tool allowed the team to analyze the effectiveness of hundreds of different groupings of projects and identify which groupings worked together best to achieve the state's goals.1

  1. The team assembled projects into two groups, those that maximized risk reduction and those that maximized land building. All subsequent decision criteria were considered alongside to these two primary decision drivers.
  2. The team then used the Planning Tool to assess how different allocations of funding between risk reduction (e.g., elevating housing) and restoration projects affected results. Based on these results it identified a 50/50 funding split as best balancing risk reduction and restoration benefits.
  3. Next, the team assessed how funding should be allocated between restoration projects that deliver near-term versus long-term results in terms of land building. Using the Planning Tool, they selected a 50/50 split between projects that provided immediate land-building results (important given the severity of Louisiana's land loss crisis) and those that reversed land loss and provided longer-term benefits.
  4. In addition, the team used the Planning Tool to assess how different projects would perform under different projected future conditions. For example, the team evaluated how projects that performed well under moderate future conditions performed under poor future conditions. They found that projects built closer to existing land were more resilient to worsening future conditions that those built closer to the gulf.
  5. The team also used the Planning Tool to identify other decision criteria that would not substantially affect the plan's ability to achieve its primary decision drivers of risk reduction and land building. These included: distribution of risk across socioeconomic groups, flood protection of historic properties, flood protection of strategic assets, operation and maintenance costs, use of natural processes, support of navigation, sustainability, support for cultural heritage, and support for oil and gas.
  6. The team assessed ecosystem services (e.g., habitat suitability indices and other variables) to ensure that groups of projects considered did not have significant impacts on coastal ecosystem services.
  7. The team evaluated the ability of sediment diversion projects to both maximize land building and reduce impacts to saltwater-dependent resources. Using the Planning Tool, the team found that sediment diversion projects were necessary for sustainable restoration of the coast.
  8. The team used the Planning Tool to identify channel realignment strategies that were most effective for achieving land building goals, however further study was needed before this large-scale project could be implemented.

Based on the results of these analyses, which incorporated the results of the landscape analysis tools, the team selected 109 restoration and structural protection projects and a coastwide nonstructural program for the Coastal Master Plan. Of these, certain project types, such as levees and large-scale diversions, were found to be essential to the future of the coast. The team also found, however, that a variety of project types was necessary in certain targeted locations.

Michigan Tech Research Institute:10 Based on the priority sites that it identifies using the Wetland Mitigation Site Suitability Tool (WMSST) site suitability analysis, Michigan Department of Transportation (MDOT) may contact local real estate offices to obtain additional information (e.g., land ownership) on potential wetland mitigation sites.

North Carolina Ecosystem Enhancement Program (NCEEP):11 Candidate watersheds that are identified through the NCEEP HUC-14 screening method are evaluated more thoroughly using windshield surveys and input from local resource professionals. After gauging local interest and verifying that appropriate restoration opportunities are likely to exist, NCEEP produces a refined short list of candidate watersheds. NCEEP then obtains further feedback from local interests, before making a final selection of HUC-14 watersheds in which to target conservation actions in order to produce the largest functional benefit.

In addition, based on the priority subwatershed "focus areas" identified using its landscape prioritization methods, NCEEP draws upon the following sources of information it has collected throughout the Local Watershed Planning (LWP) process to identify specific project sites for mitigation activities:

  • GIS assessments: Desktop GIS analyses, such as the LWP subwatershed prioritization method, help NCEEP identify subwatershed-scale focus areas in which it can target wetland/stream restoration and conservation to improve watershed functions.
  • Field assessments: In Phases 1 and 2 of the LWP, NCEEP evaluates the target HUC-14(s) for assets (e.g. taxonomically-rich benthic communities), problems (e.g., 303(d) listed impaired streams), and stressors (e.g., unbuffered streams). NCEEP uses this information to identify potential project sites.
  • Stakeholder input: Local stakeholders may contribute projects that they believe to be important to the final set of potential project sites.

With a set of potential project sites identified, NCEEP proceeds to develop a final Project Atlas that ranks projects based on the criteria listed below:

  • Ecological criteria: NCEEP uses ecological criteria to rank projects or project combinations based on the amount of functional uplift that they could potentially generate within subwatersheds. The highest-ranked projects generally have the highest potential to produce functional uplift and are located within focus areas in optimal landscape positions (e.g., headwaters areas) in the subwatershed.

NCEEP often evaluates ecological criteria by using watershed modeling to determine the functional benefits (e.g., pollutant load reductions) that might result from specific projects. These models rank projects according to how much each will improve watershed functions, with the most functionally impaired areas receiving the highest ranks for restoration and enhancement projects and the most asset-rich or functionally unimpacted areas ranking highest for preservation projects. NCEEP recognizes, however, that implementing a set of top-ranked projects does not always maximize function uplift and that sometimes implementing a strategic combination of projects produces the best results. For this reason, it sometimes uses simulation modeling to determine which combinations of projects are together capable of maximizing functional uplift.

  • Feasibility criteria: Feasibility criteria considered in project ranking include number of landowners (obtained from County parcel data layers), site constraints (e.g., utility lines, road/bridge crossings), and landowner willingness.
  • Stakeholder criteria: Local stakeholders may develop criteria for ranking sites that are unrelated to ecological and feasibility criteria (e.g., proximity of project to schools/parks for educational purposes).

Final site-specific projects generally include traditional mitigation projects (stream and water restoration, enhancement, or preservation) and best management practices (BMPs) in agricultural and urban areas.

The Nature Conservancy (TNC) Aquatic Ecoregional Assessment:5 After applying its landscape screening analyses , TNC solicited aquatic resource experts from land or resource management agencies, academic institutions, private consulting firms, and local non-profits in a series of workshops to obtain expert feedback on priorities identified. In addition, the experts delineated areas of aquatic biological significance on maps, including written descriptions of the identified areas, based on their professional knowledge of the area. Next, TNC requested that experts identify river systems within each ecological drainage unit (EDU) that ranked the highest, in their judgment, for a number of ecological criteria. These included identifying those river systems that were most intact, in best condition, most free from exotic species, contained the highest presence of rare species, contained the most native fish communities, and contained the most stream invertebrates.

Based on this expert input, the results of the GIS screening analysis, and TNC's goals for target representativeness and connectivity within each EDU, TNC was able to prioritize aquatic systems to include in its final portfolio. Guided by TNC, experts selected medium and large river systems and river networks connecting headwaters to coast (in accordance with its goals) to incorporate into TNC's portfolio, expressing their confidence in each selection using a Confidence Code (see below).


High Confidence. We have high confidence that these expert recommended systems are both important and viable as aquatic conservation targets. Confidence 1 AESs often fall within the optimal condition analysis (%natural cover, road density, dams) as well.


Lower Confidence. These occurrences are only conditionally in the portfolio. Confidence 2 occurrences require more evaluation before we would take conservation action at these sites. They appear to be good aquatic conservation areas and appear to be necessary additions to the portfolio but we need more information on these sites.


TNC's expert group also assigned a Portfolio Type Code to each portfolio selection that ranked each selection area in terms of its overall quality as an aquatic system and its connectivity to other aquatic resources (see below).


Best available example of a stream/river system type and part of a regional or intermediate scale connected stream network


Best available example of a stream/river system type but disjunct/not part of a focus connected stream network


Additional good example of a stream/river system type and part of a regional or intermediate scale focus connected stream network, but not the best example of its system type


Additional good example of a stream/river system (often included in the headwaters in all matrix sites) but disjunct from larger focus connected network


Connector. Not an excellent or additional good best example of a stream/river system. It is considered as part of the portfolio as a connector segment in a focus connected stream network. These connectors usually are the lower mainstem reaches in a focus network that are highly altered but needed for connectivity. This connector occurrence is necessary to meet regional connectivity needs.

The Nature Conservancy (TNC) Willamette Basin Synthesis Project:12
TNC used a "nomination" process to incorporate recommendations from the public regarding the modification, addition, or removal of conservation opportunity areas (COAs) into the Synthesis Map using a nomination form and online mapping site. Using this mapping website, members of the public could draw features over the Union Portfolio to indicate which areas should be added or changed and print the resulting modifications as a PDF. Contributors were instructed to make changes that furthered the recovery of listed species or protected habitat for Oregon Conservation Strategy, addressed multiple conservation values, or improved ecosystem functions that benefit people.


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Wetland Prioritization Study Main Page


1Interview on 8/4/2011 with Jim Thorne, Andrea Williams, and Rebecca Loefller.
2 Colorado Natural Heritage Program. 2010. Colorado Natural Heritage Program Wetland Program Plan: A Vision for Building Comprehensive Wetland Information for the State of Colorado. Planning Years 2011-2015.
3 Interviews on 8/3/2011 with Ellen Bryson, USACE Baltimore District, and on 8/11/2011 with Ralph Spagnolo, USEPA Region III.
4 Strager MP, Anderson JT, Osbourne JD, and Fortney R. 2011. A three-tiered framework to selection, prioritize, and evaluate potential wetland and stream mitigation banking sites. Wetlands Ecology and Management 19:1-18.
5 The Nature Conservancy. 2009. The Nature Conservancy's watershed approach to compensation planning for the Virginia Aquatic Resource Trust Fund.
6 Interview on 8/12/2011 with David Phemister, Director of Federal Government Relations for TNC in Virginia.
7 Interview on 7/29/2011 with Scott Jackson, Program Director, UMass Extension's Natural Resources and Environmental Conservation Program, Department of Environmental Conservation, University of Massachusetts, Amherst.
8 Interview on 8/3/2011 with Tom Hruby, Senior Ecologist, Washington State Department of Ecology.
9 Coastal Protection and Restoration Authority of Louisiana. 2012. Louisiana's Comprehensive Master Plan for a Sustainable Coast. Coastal Protection and Restoration Authority of Louisiana. Baton Rouge, LA.
10 Interview on 1/17/2012 with Colin Brooks, Manager of the Environmental Science Laboratory at Michigan Tech Research Institute.
11 North Carolina Ecosystem Enhancement Program. 2011. NC Ecosystem Enhancement Program Local Watershed Planning Manual (draft).
12 Interview on 5/22/2012 with Dan Bell, Willamette Basin Conservation Director, The Nature Conservancy.