Saltwater intrusion on coastal farmlands can render productive land unsuitable for agricultural activities. While the visible extent of salt-impacted land provides a useful saltwater intrusion proxy, it is challenging to identify in early stages. Moreover, associated ecological and economic impacts are often underestimated as reduced crop yields in farmlands surrounding salt patches are difficult to quantify. Here we develop a high-resolution (1 m) dataset showing salt patches on farm fringes and quantify the extent of salt-impacted lands across the Delmarva Peninsula, United States. Our method is transferable to other regions across and beyond the mid-Atlantic with similar saltwater intrusion issues, such as Georgia and the Carolinas. Our results show that between 2011 and 2017, visible salt patches almost doubled and 8,096 ha of farmlands converted to marsh—another saltwater intrusion consequence. Field-based electrical conductivity measurements show elevated salinity values hundreds of metres from visible salt patches, indicating the broader extent of at-risk farmlands. More farmland areas were within 200 m of a visible salt patch in 2017 compared to 2011, a rise ranging between 68% in Delaware and 93% in Maryland. On the basis of assumed 100% profit loss in at-risk farmlands within a 200 m buffer around salt patches in 2016–2017, the range of economic losses was estimated between US$39.4 million and US$107.5 million annually, under 100% soy or corn counterfactuals, respectively.
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The high-resolution dataset for salt patches and other land covers for 2011–2013 and 2016–2017 are available at https://zenodo.org/record/6685695#.Y9AiVXbMIdU.
Sample GEE code is available along with the high-resolution dataset57.
White, E. & Kaplan, D. Restore or retreat? Saltwater intrusion and water management in coastal wetlands. Ecosyst. Health Sustain. 3, e01258 (2017).
Kirwan, M. L. & Gedan, K. B. Sea-level driven land conversion and the formation of ghost forests. Nat. Clim. Change 9, 450–457 (2019).
McKenzie, T., Habel, S. & Dulai, H. Sea-level rise drives wastewater leakage to coastal waters and storm drains. Limnol. Oceanogr. Lett. 6, 154–163 (2021).
Tully, K. et al. The invisible flood: the chemistry, ecology, and social implications of coastal saltwater intrusion. BioScience 69, 368–378 (2019).
Tully, K. L., Weissman, D., Wyner, W. J., Miller, J. & Jordan, T. Soils in transition: saltwater intrusion alters soil chemistry in agricultural fields. Biogeochemistry 142, 339–356 (2019).
White, E. E., Ury, E. A., Bernhardt, E. S. & Yang, X. Climate change driving widespread loss of coastal forested wetlands throughout the North American coastal plain. Ecosystems 25, 812–827 (2022).
C-CAP Regional Land Cover and Change (NOAA Office for Coastal Management, accessed August 2022); www.coast.noaa.gov/htdata/raster1/landcover/bulkdownload/30m_lc/
DeSantis, L. R. G., Bhotika, S., Williams, K. & Putz, F. E. Sea-level rise and drought interactions accelerate forest decline on the Gulf Coast of Florida, USA. Glob. Change Biol. 13, 2349–2360 (2007).
Sallenger, A. H., Doran, K. S. & Howd, P. A. Hotspot of accelerated sea-level rise on the Atlantic coast of North America. Nat. Clim. Change 2, 884–888 (2012).
Fagherazzi, S. et al. Sea level rise and the dynamics of the marsh–upland boundary. Front. Environ. Sci. 7, 25 (2019).
Sweet, W. V. et al. Global and Regional Sea Level Rise Scenarios for the United States: Updated Mean Projections and Extreme Water Level Probabilities Along U.S. Coastlines (NOAA, 2022); https://oceanservice.noaa.gov/hazards/sealevelrise/noaa-nos-techrpt01-global-regional-SLR-scenarios-US.pdf
Ury, E. A., Wright, J. P., Ardón, M. & Bernhardt, E. S. Saltwater intrusion in context: soil factors regulate impacts of salinity on soil carbon cycling. Biogeochemistry 157, 215–226 (2022).
Maas, E. V. & Grattan, S. R. in Crop Yields as Affected by Salinity (eds Skaggs, R. W. & van Schilfgaarde, J.) 55–108 (ASA, 1999).
Tanji, K. K. & Kielen, N. C. Agricultural Drainage Water Management in Arid and Semi-arid Areas. Annex 1. Crop Salt Tolerance Data (FAO, 2002).
Zörb, C., Geilfus, C.-M. & Dietz, K.-J. Salinity and crop yield. Plant Biol. J. 21, 31–38 (2019).
de la Reguera, E., Veatch, J., Gedan, K. & Tully, K. L. The effects of saltwater intrusion on germination success of standard and alternative crops. Environ. Exp. Bot. 180, 104254 (2020).
Titus, J. G. et al. State and local governments plan for development of most land vulnerable to rising sea level along the US Atlantic coast. Environ. Res. Lett. 4, 044008 (2009).
Cropscape—Cropland Data Layer (USDA-NASS, accessed 24 August 2022); https://nassgeodata.gmu.edu/CropScape/
Ullah, A., Bano, A. & Khan, N. Climate change and salinity effects on crops and chemical communication between plants and plant growth-promoting microorganisms under stress. Front. Sustain. Food Syst. 5, 618092 (2021).
Devkota, K. P., Devkota, M., Rezaei, M. & Oosterbaan, R. Managing salinity for sustainable agricultural production in salt-affected soils of irrigated drylands. Agric. Syst. 198, 103390 (2022).
National Agricultural Statistics Service Surveys (NASS, accessed 24 August 2022); https://www.nass.usda.gov/Surveys/Guide_to_NASS_Surveys/index.php
Schieder, N. W., Walters, D. C. & Kirwan, M. L. Massive upland to wetland conversion compensated for historical marsh loss in chesapeake Bay, USA. Estuaries Coasts 41, 940–951 (2018).
Schroeder, C. S., Kulick, N. K. & Farrer, E. C. Saltwater intrusion indirectly intensifies Phragmites australis invasion via alteration of soil microbes. Sci. Rep. 12, 16582 (2022).
Epanchin-Niell, R., Kousky, C., Thompson, A. & Walls, M. Threatened protection: sea level rise and coastal protected lands of the eastern United States. Ocean Coast. Manag. 137, 118–130 (2017).
Gedan, K. B., Epanchin-Niell, R. & Qi, M. Rapid land cover change in a submerging coastal county. Wetlands 40, 1717–1728 (2020).
Gardner, L. R. et al. Disturbance effects of Hurricane Hugo on a pristine coastal landscape: North Inlet, South Carolina, USA. Netherl. J. Sea Res. 30, 249–263 (1992).
Allen, J. A., Conner, W. H., Goyer, R. A., Chambers, J. L., & Krauss, K. W. Freshwater forested wetlands and global climate change. In Vulnerability of Coastal Wetlands in the Southeastern United States: Climate Change Research Results 1992–1997 (eds Guntenspergen, G. R. & Vairin, B. A.) 33–44 (U.S. Geological Survey, 1998).
Domagalski, J. L. et al. Comparative Water-Quality Assessment of the Hai He River Basin in the People’s Republic of China and Three Similar Basins in the United States (USGS, 2001).
Karegar, M. A., Dixon, T. H., Malservisi, R., Kusche, J. & Engelhart, S. E. Nuisance flooding and relative sea-level rise: the importance of present-day land motion. Sci. Rep. 7, 11197 (2017).
Steppuhn, H., van Genuchten, M. T. & Grieve, C. M. Root-zone salinity. Crop Sci. 45, 221–232 (2005).
Bhattachan, A. et al. Evaluating the effects of land-use change and future climate change on vulnerability of coastal landscapes to saltwater intrusion. Elementa 6, 62 (2018).
Goebel, M., Pidlisecky, A. & Knight, R. Resistivity imaging reveals complex pattern of saltwater intrusion along Monterey coast. J. Hydrol. 551, 746–755 (2017).
Da Lio, C., Carol, E., Kruse, E., Teatini, P. & Tosi, L. Saltwater contamination in the managed low-lying farmland of the Venice coast, Italy: an assessment of vulnerability. Sci. Total Environ. 533, 356–369 (2015).
Genua-Olmedo, A., Alcaraz, C., Caiola, N. & Ibáñez, C. Sea level rise impacts on rice production: the Ebro Delta as an example. Sci. Total Environ. 571, 1200–1210 (2016).
Michael, H. A., Russoniello, C. J. & Byron, L. A. Global assessment of vulnerability to sea-level rise in topography-limited and recharge-limited coastal groundwater systems. Water Resour. Res. 49, 2228–2240 (2013).
Nordio, G. & Fagherazzi, S. Groundwater, soil moisture, light and weather data collected in a coastal forest bordering a salt marsh in the Delmarva Peninsula (VA). Data Brief. 45, 108584 (2022).
Nordio, G. et al. Frequent storm surges affect the groundwater of coastal ecosystems. Geophys. Res. Lett. 50, e2022GL100191 (2023).
Global Map of Salt-affected Soils (GSASmap) (FAO, accessed 24 August 2022); https://www.fao.org/soils-portal/data-hub/soil-maps-and-databases/global-map-of-salt-affected-soils/en/
Guimond, J. A. & Michael, H. A. Effects of marsh migration on flooding, saltwater intrusion, and crop yield in coastal agricultural land subject to storm surge inundation. Water Res. 57, e2020WR028326 (2021).
Sternberg, L. S. L., Teh, S. Y., Ewe, S. M., Miralles-Wilhelm, F. & DeAngelis, D. L. Competition between hardwood hammocks and mangroves. Ecosystems 10, 648–660 (2007).
Wendelberger, K. S. & Richards, J. H. Halophytes can salinize soil when competing with glycophytes, intensifying effects of sea level rise in coastal communities. Oecologia 184, 729–737 (2017).
Poulter, B., Christensen, N. L. & Song, Q. S. Tolerance of Pinus taeda and Pinus serotina to low salinity and flooding: implications for equilibrium vegetation dynamics. J. Veg. Sci. 19, 15–122 (2008).
Google Earth Engine Guides. Eigen Analysis (Google, 2021); https://developers.google.com/earth-engine/guides/arrays_eigen_analysis
McFeeters, S. K. The use of the normalized difference water index (NDWI) in the delineation of open water features. Int. J. Remote Sens. 17, 1425–1432 (1996).
Townshend, J. R. G., Goff, T. E. & Tucker, C. J. Multitemporal dimensionality of images of normalized difference vegetation index at continental scales. IEEE Trans. Geosci. Remote Sens. 23, 888–895 (1985).
Maxwell, A. E., Warner, T. A., Vanderbilt, B. C. & Ramezan, C. A. Land cover classification and feature extraction from national agriculture imagery program (NAIP) orthoimagery: a review. Photogramm. Eng. Remote Sens. 83, 737–747 (2017).
Karl Pearson, F. R. S. L. III On lines and planes of closest fit to systems of points in space. Philos. Mag. 2, 559–572 (1901).
Dharani, M. & Sreenivasulu, G. Land use and land cover change detection by using principal component analysis and morphological operations in remote sensing applications. Int. J. Comput. Appl. 43, 462–471 (2021).
Google Earth Engine Guides. Eigen Analysis (Google, 2023); https://developers.google.com/earth-engine/guides/arrays_eigen_analysis
Xue, J. & Su, B. Significant remote sensing vegetation indices: a review of developments and applications. J. Sens. 2017, 1353691 (2017).
Google Earth Engine Guides. Convolutions (Google, 2022); https://developers.google.com/earth-engine/guides/image_convolutions
Breiman, L. Random Forests. Mach. Learn. 45, 5–32 (2001).
Congalton, R. G., Oderwald, R. G. & Mead, R. A. Assessing landsat classification accuracy using discrete multivariate analysis statistical. Tech. Photogramm Eng. Remote Sens. 49, 1671–1678 (1983).
Congalton, R. G. A review of assessing the accuracy of classifications of remotely sensed data. Remote Sens. Environ. 37, 35–46 (1991).
Landis, J. R. & Koch, G. G. The measurement of observer agreement for categorical data. Biometrics 33, 159–174 (1977).
Maxwell, A. E. & Warner, T. A. Thematic classification accuracy assessment with inherently uncertain boundaries: an argument for center-weighted accuracy assessment metrics. Remote Sens 12, 1905 (2020).
Mondal, P. et al. High-resolution remotely sensed datasets for saltwater intrusion across the Delmarva Peninsula [data set]. Zenodo https://doi.org/10.5281/zenodo.6685695 (2022).
Dill, S., Beale, B., Johnson, D., Lewis, J. & Rhodes, J. 2022 Field Crop Budgets (Univ. Maryland Extension, 2022); https://extension.umd.edu/resource/field-crop-budgets
Virginia Grain Historical Prices (Virginia Department of Agriculture and Consumer Service, 2021); https://www.vdacs.virginia.gov/markets-and-finance-market-news-grain-stats.shtml
This publication was made possible by the National Science Foundation EPSCoR grant no. 1757353 and the State of Delaware that supported P.M. and V.Y. This work was also supported by the National Aeronautics and Space Administration EPSCoR grant DE-80NSSC20M0220 awarded to P.M., the Delaware Space Grant College and Fellowship Program (NASA grant 80NSSC20M0045) that supported M.W. and the USDA-National Institute for Food and Agriculture (grant 12451226) awarded to J.M., R.E.-N., K.G. and K.T. We acknowledge the support provided to P.M., M.W., J.M., R.E.-N., K.G. and K.T. by the US Environmental Protection Agency (Assistance Agreement no. CB96358101), USDA Natural Resources Conservation Service (Assistance Agreement no. NR193A750007C005) and the National Fish and Wildlife Foundation’s Chesapeake Bay Stewardship Fund (grant 0603.20.071142), as well as the State of Maryland and Harry R. Hughes Center for Agro-Ecology. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
The authors declare no competing interests.
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Mondal, P., Walter, M., Miller, J. et al. The spread and cost of saltwater intrusion in the US Mid-Atlantic. Nat Sustain 6, 1352–1362 (2023). https://doi.org/10.1038/s41893-023-01186-6
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