Created 1/30/2020 Created by Tony 01 sen National Wetland Condition Assessment 2021 Survey Design Description of Sample Design Target population: NWCA includes tidal and nontidal wetlands within the conterminous U.S. with rooted vegetation and, when present, shallow open water less than one meter deep, that are not currently being used in the production of crops. Wetland types included are • E2EM - estuarine intertidal emergent (estuarine herbaceous) • E2SS - estuarine intertidal scrub shrub/forested (estuarine woody) • PEM - palustrine emergent (inland herbaceous) • PSS - palustrine scrub shrub (inland woody) • PFO - palustrine forested (inland woody) • Pf - Palustrine farmed (inland herbaceous) • PUBPAB - palustrine unconsolidated bottom/aquatic bed (inland herbaceous). While these categories are used by the U.S. Fish & Wildlife Services Status and Trends programs, they are used here to identify the types of wetlands included in NWCA. Sample Frame: The sample frame source is the U.S. Fish & Wildlife Service's National Wetland Inventory (NWI). The NWI wetland polygon data was updated on October 8, 2019 and is the latest available. Rusty Griffin, USFWS National Wetlands Inventory, National Standards and Support Team, Madison, WI provided access for NWCA to download the 22 GB file. This data is the basis for the NWI "Wetlands Mapper" to view America's wetland resources. "The Wetland Mapper fulfills the U.S. Fish and Wildlife Service's strategic plan for the development, revision and dissemination of wetlands data and information to resource managers and the public. This information is intended to promote the understanding and conservation of wetland resources through discovery and education as well as to aid in resource management, research and decision making." NWCA processed the data by assigning wetland polygons to states and within each state assigning them to the NARS nine aggregated ecoregions. In addition, the detailed wetland types were categorized into seven wetland types of interest to NWCA (E2EM, E2SS, PEM, PSS, PFO, Pf and PUBPAB) and five wetlands types not included (EOTH - estuarine other wetlands, M1M2 - marine wetlands, LOTH - lacustrine other wetlands, POTH - palustrine other wetlands, and ROTH - riverine other wetlands). The former are included as they are likely to result in sites that would meet the NWCA definition of a wetland and the latter are excluded as they are unlikely to result in sites that would meet the NWCA definition of a wetland. Cowardian wetland classes were assigned to each NWCA wetland class by two wetland ecologists. Montana provided a GIS layer similar to NWI that had not yet been incorporated. Page 1 of 6 ------- Created 1/30/2020 Created by Tony 01 sen Minnesota conducts a wetland quantity survey similar to U.S. Fish & Wildlife Service's Status and Trends program. It is based on 1 sq mi plots. NWCA used the results of this survey for the Minnesota sample frame. The Minnesota survey design also differs from the NWCA survey design completed for other states. Reporting Units: NWCA 2021 is based on 17 reporting units associated with 10 geographic areas. Inland wetland regions are based on NARS nine aggregated ecoregions where the Upper Midwest and Northern Appalachians are combined to form the North Central East region and the Northern Plains and Southern Plains are combined to form the Great Plains region. Estuarine wetland coastal regions are the Pacific Coast, Gulf and Florida Coast and the Atlantic Coast. The inland reporting regions are then divided by herbaceous and woody wetland types. 2021 National Wetland Condition Assessment Design Xeric West (XER) I Western Mountains (WMT) Tidal Saline H Atlantic Coast (ATL) Gulf and Florida Coasts (GFL) ¦ Pacific Coast (PAC) Expected sample size: The expected sample size is 904 sites for conterminous 48 states with 96 of those sites to be revisited twice for a total of 1,000 site-visits. Each state will have two sites that will be visited twice in 2021 for a total of 1,000 site-visits. Sample allocation depends on the 17 reporting units with 53 in each unit except for three (3) additional sites in CPL woody for total of 904 sites. Page 2 of 6 ------- Created 1/30/2020 Table 1 Sample size by Reporting Unit Created by Tony 01 sen Report Unit Total PRLH PRLW NCE 106 53 53 SAP 106 53 53 CPL 112 56 56 TPL 106 53 53 GPL 106 53 53 WMT 106 53 53 XER 106 53 53 ATL 53 GFL 53 PAC 53 Total 904 The number of sites for each state is proportional to the wetland area within each reporting unit with a restriction that each state must have a minimum of eight (8) unique sites and with the two revisits a minimum of 10 site visits. Survey Design: The survey design consists of two main components: sites from prior NWCA 2016 survey and new sites for 2021. Re-sampled Site Design: Approximately 30 percent of the 904 sites, 269 sites, were selected to be re-sampled from NWCA 2016. The actual number of sites was determined for each state after the number of sites in each state was determined based on wetland area. Sites were restricted to NWCA 2016 evaluated sites and then ordered by state and 2016 sitelD within state. The first "n" sites within a state were designated Base21_16RVT2 (first 2 sites), Base21_16 and the remaining sites as Over21_16. This means that some of the Base21_16 sites will likely not have been target and sampled in 2016. Hence over sample sites will likely be required. Note that all sites should be evaluated again in 2021 to determine if they are target and if target whether they can be sampled. Conditions could have changed since 2016. New Site Design: The remaining approximately 70%, 635, are new sites. The new site survey design is initially stratified by state and reporting unit to ensure sample size requirements are met. An over sample 20 times the number of sites required for the reporting unit was included. Sites were selected using a Generalized Random Tessellation Stratified (GRTS) survey design for an area resource. After the sites were selected, a second survey design was completed on the selected sites for the purpose of removing the reporting unit stratification so that sites could be replaced within a state by inland wetland and, if present, estuarine wetland. Panels: The survey design includes three panels. Base21_16RVT2: identifies sites that are to be visited twice from NWCA 2016, Base21_16 identifies sites that will be visited once from NWCA 2016, Base21_21 identifies new sites selected for 2021, Over21_16 Page 3 of 6 ------- Created 1/30/2020 Created by Tony 01 sen identifies sites to be used if any Base21_16 site cannot be sampled in 2021, and Over21_21 identifies new sites to be used if any Base21_21 sites cannot be sampled. Site Use: All "base" sites are expected to be evaluated and sampled if possible. If one or more "base" sites cannot be sampled, then the site replacement process is completed within a state. Sites are listed in sitelD order within a state. The replacement process is completed by PANELUSE within each STRATUM. The STRATUM possible values are ReSamp_2016, Estuarine and Inland. • STRATUM equal to ReSamp_2016. Replace sites as follows: o Base21_16RVT2 sites will be sampled twice in 2021. If one of them cannot be sampled, then the first Base21_16 site is evaluated and if it can be sampled it is sampled twice. If no Base21_16 site is available, then the next available Over21_16 site is evaluated and if it can be sampled it is sampled twice. o Base21_16 sites will be sampled once in 2021. If one of them cannot be sampled, then the next available Over21_16 site is evaluated and sampled. o If no Over21_16 site is available, then no site is used to replace it. In this case, an additional site must be sampled in the Inland stratum. • STRATUM equal to Estuarine. If a state has estuarine stratum, then replace sites as follows within the Estuarine stratum: o Base21_21 sites will be sampled once in 2021. If one of them cannot be sampled, then the next available Over21_21 site in the Estuarine stratum is evaluated and sampled. • STRATUM equal to Inland. Replace sites as follows within the Inland stratum: o Base21_21 sites will be sampled once in 2021. If one of them cannot be sampled, then the next available Over21_21 site in the Inland stratum is evaluated and sampled. Sample Frame Summary See accompanying excel worksheet. Sample frame area in acres by reporting unit and wetland type. EOTH EST LOTH M1M2 POTH PRLH PRLW ROTH Sum ATL 1084891 1592982 0 68681 0 0 0 0 2746554 CPL 0 0 3311394 0 35946 9214653 34136743 1784049 48482785 GFL 2482748 2690574 0 61025 0 0 0 0 5234348 GPL 0 0 2028600 0 3970 8753988 1073167 457102 12316826 NCE 0 0 6092439 0 23789 6444900 20269081 1060699 33890907 PAC 125718 80424 0 27087 0 0 0 0 233230 SAP 2 0 2452141 0 6519 2480256 2788725 1746543 9474186 TPL 0 0 1615596 0 28906 7367449 3802818 971326 13786093 WMT 0 0 1902575 0 18521 5469099 1355735 487878 9233808 XER 0 0 5114093 0 28770 11077044 1211176 317677 17748759 Sum 3693360 4363980 22516838 156793 146421 50807387 64637444 6825273 153147497 Page 4 of 6 ------- Created 1/30/2020 Created by Tony 01 sen Note that the summary accounts for assignment of small assignments of ecoregions in some states to other ecoregions for the purpose of eliminating rare categories within a state. Site Selection Summary See accompanying excel worksheet for details. Summary by Aggregated Ecoregions Base Over Total CPL 225 3639 3864 NAP 58 926 984 NPL 27 509 536 SAP 94 1437 1531 SPL 57 1008 1065 TPL 107 1761 1868 UMW 59 864 923 WMT 133 1974 2107 XER 144 2571 2715 Total 904 14689 15593 Summary by Reporting Unit. Includes three Minnesota ecoregions (MWP, MWS, NPL) Base Over Total ATL 48 830 878 CPL 128 2004 2132 GFL 57 882 939 GPL 76 1468 1544 MWP 10 140 150 MWS 10 140 150 NCE 82 1283 1365 NPL 8 53 61 PAC 48 860 908 SAP 101 1628 1729 TPL 107 1720 1827 WMT 113 1730 1843 XER 116 1951 2067 Total 904 14689 15593 Description of Sample Design Output: PSTL CODE sitelD Site ID for 2021 LON DD83 Longitude in decimal degrees NAD83 LAT DD83 Latitude in decimal degrees NAD83 STRATUM Stratum 2021: ReSamp_2016, Inland, Estuarine PANEL USE Panel used for site replacement Page 5 of 6 ------- Created 1/30/2020 Created by Tony 01 sen sitelD 16 Site ID from NWCA 2016 EVAL 2016 Site evaluation from NWCA 2016 PROB CAT Unequal probability selection category for NWCA 2021 AG EC09 Aggregated ecoregion (see above) RPT UNIT NWCA reporting unit (see above) WETCLSDSN NWCA wetland class based on NWI for survey design WETGRPDSN NWCA wetland group (EST, PRLH, PRLW) WETCLS NWI NWI wetland class from sample frame WGT Initial design weight (acres) Projection Information PROJCS["Albers", GEOGCS["GCS_GRS 1980(IUGG, 1980)", DATUM["D_unknown", SPHEROID["GRS80",6378137,298.257222101]], PRIMEM["Greenwich",0], UNIT["Degree",0.017453292519943295]], PROJECTION["Albers"], PARAMETER[" standard_parallel _1",29.5], PARAMETER[" standard_parallel_2" ,45.5], PARAMETER["latitude_of_origin",23], PARAMETER["central_meridian",-96],PARAMETER["false_easting",0], P ARAMETER[" fal senorthing", 0], UNIT["Meter",l]] Page 6 of 6 ------- |