The Spatial–Racial Patterns of U.S. Dam Removals Since 2010

Abstract

Dam removal in the United States has grown exponentially, yet we do not know whether the pattern of such removals comports with principles of environmental justice. This exploratory study investigates the spatial pattern of dam removals across the United States to ascertain whether there were any geographic areas where the probability of removal was correlated with the racial or ethnic composition of the environs. We analyze dam removals since 2010 using national data on existing dams, removed dams, and demographics. We estimate multivariate probability models of dam removal stratified by census region and dam ownership to pinpoint contexts where significant spatial-racial patterns occur that cannot be attributed to dam characteristics. Our exploration reveals only a few such contexts. After controlling for dam purpose, construction type, age, and height, the probability of a dam being removed since 2010 is positively associated with the proportion of nearby White residents for dams owned by local or state governments in the South. The probability of removal is negatively associated with the proportion of nearby White residents for dams owned privately or by state or local governments in the West. Future case studies should probe these contexts of clear spatial–racial patterns from an environmental justice perspective.

Key Words:

• census tracts
• dam removal
• disparate impact
• GIS
• race

Disclosure Statement

No potential conflict of interest was reported by the authors.

Notes

1 The vast body of research on watershed restoration has been collected in the National River Restoration Science Synthesis (U.S. Geological Survey 2021) and reviewed in Bernhardt et al. (2005), Kondolf et al. (2007), Holifield and Schuelke (2015), Sneddon, Barraud, and Germaine (2017), and Morandi, Cottet, and Piegay (2022).

2 Two case studies of river restoration efforts, one in Pennsylvania (Moran 2010) and one on the central California coast (Sanford et al. 2018) found that these initiatives were less likely to be undertaken in communities of color. Unfortunately for our purposes, neither initiative involved dam removal.

3 Because USGS-DRIP contains no information about dam construction type and is often missing information about dam ownership and purpose, we supplemented this information to the extent feasible through Google searches.

4 The vast majority of observations in AR-DRD and USGS-DRIP do not have the identification number that permits linkage with the USACE-NID; see Table A.1.

5 See https://nid.usace.army.mil/#/what-is-nid/closer-look.

6 Although a dam could potentially span multiple census tracts (e.g., a dam across a river constituting the tract boundary), we used the one census tract identified by spatial coordinates.

7 Our tests assume unequal variance in the two groups.

8 Dam age and height, and the proportion of non-Hispanic Whites in the dam’s census tract are all normalized (i.e., converted to variables with M = 0, SD = 1) to make estimated coefficient magnitudes more comparable.

9 Of course, substantial unexplained variation remains, indicating that there are omitted predictors and considerable idiosyncrasies related to dam removal, a point we return to in our caveats section.

10 Table A.2 provides descriptive statistics for the ownership of removed dams, by region.

11 These percentages are based only on observations with complete information on all variables used in the regression; see Table A.2.

12 These percentages are based only on observations with complete information on all variables used in the regression; see Table A.2.

Additional information

Notes on contributors

Joshua C. Galster

JOSHUA C. GALSTER is an Associate Arofessor in the Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ 07043. E-mail: [email protected]. His research interests include geomorphology, hydrology, and GIScience.

George C. Galster

GEORGE C. GALSTER is the Clarence Hilberry Professor of Urban Affairs and Distinguished Professor, Emeritus, Department of Urban Studies and Planning, Wayne State University, Detroit, MI 48202. E-mail: [email protected]. His research interests include housing, neighborhoods, and inequality of opportunity.