DOI: 10.5061/dryad.b5mkkwhrr
title: Data and code from: Spatial selection undermines flood protection in U.S. wetland markets

description: Wetland mitigation markets aim to offset environmental damage by allowing
 developers to purchase credits from previously restored wetlands. We test
 whether wetland credits traded in these markets offer equivalent flood
 protection benefits. Using newly developed, high-resolution estimates of
 wetland flood protection for 915 wetland markets within the continental
 U.S., we document a likely decline in flood-protective value due to
 wetland loss over the 1985 to 2021 period. Consistent with standard models
 of urban economic geography, wetlands lost to development exist near prior
 developed areas and therefore provide relatively high levels of downstream
 flood protection compared to wetlands created in compensation--on average
 4.1 times as much, though in some cases up to 78 times. We document a high
 concentration of lost flood protection in Florida. While wetland markets
 may succeed in preserving total wetland acreage, they may systematically
 fail to preserve downstream flood protection services. More generally,
 this suggests that designing environmental markets to preserve complex
 bundles of spatially heterogeneous ecosystem services while still allowing
 meaningful compliance flexibility may be challenging.
description: # Data and code from: Spatial selection undermines flood protection in
 U.S. wetland markets Dataset DOI:
 [10.5061/dryad.b5mkkwhrr](10.5061/dryad.b5mkkwhrr) ## Description of the
 data and file structure We created a nationwide 30 m raster dataset to
 analyze flood protection value in wetland mitigation banks across the
 continental United States. ### Files and variables ## Data *
 **footprints_and_buffers.shp (or footprints_and_buffers.rds**): Shapefile
 of mitigation bank footprint polygons. * **ServiceAreas_agg.shp (or
 ServiceAreas_agg.rds)**: Shapefile of mitigation bank service area
 polygons. * **service_area_huc12_to_downstream_tracts.csv:** raw output of
 "Upstream_iteration.ipynb", one column is HUC12 watersheds and
 the other column is a list of downstream census tracts. *
 **Htdt_conus.rds**: Dataframe relating HUC12 watershed boundaries to all
 respective downstream census tracts. * **huc12_boundaries.gpkg**:
 Shapefile of HUC12 watershed polygons for the entire U.S. *
 **LCMAP_CU_1985_V13_LCPRI.tif**: Raster of land cover data from the USGS
 LCMAP product for 1985. * **LCMAP_CU_2021_V13_LCPRI.tif**: Raster of land
 cover data from the USGS LCMAP product for 2021. ## Code/software We use
 RStudio version 4.5.1 to run all code, with the exception of one script
 run in Python version 3.13.0. ## Script Files * **create_variables.R**
 Creates and cleans necessary variables for analysis, including wetland
 raster generation, census data retrieval, and watershed-to-tract mapping.
 * **Upstream_iteration.ipynb** Maps HUC12 watersheds to their downstream
 census tracts. * **run_conus.R** Defines and applies a distance-decay
 function to wetland pixels across all mitigation banks, saving output as
 classified HUC12 watershed rasters. * **missing_huc12s_analysis.R**
 Applies the distance-decay function to missing HUC12s where downstream
 tract centroids were out of range, assuming uniform population
 distribution. * **run_wetlandloss.R** Identical to `Run_conus.R` but
 applied to raster of wetland loss (wetland-to-development conversion
 between 1985 and 2021). * **mosaic.R** Stitches together individual HUC12
 classified rasters into larger mitigation bank service area rasters. *
 **extract_cell_values.R** Extracts classified cell values into dataframes
 for each bank footprint and service area. Also applies to the classified
 wetland loss raster. * **summarize_ecdf_fn.R** Computes empirical
 cumulative distribution functions (ECDFs) for extracted cell values in
 each service area, for both existing and lost wetlands. * **pooling.R**
 Creates pooling and pool mapping for mitigation banks with identical
 service areas geometries. * **generate_main_figures.R** Generates the
 primary figures used in the manuscript. * **generate_supp_figures.R**
 Produces supplemental figures for the manuscript.