Water in the Native World: Hydrological Impacts of Future Land Use and Climate Change in the Lumbee River Watershed and Implications for Ecosystems and Indigenous Communities

In the coming decades, the southeastern US will likely experience substantial shifts in land use due to population growth, food and energy production, and other factors. In the same period, climate change is expected to alter ecohydrological processes in terrestrial landscapes while contributing to further land use change. Increasingly, these changes will challenge the ability of the region's freshwater resources to support natural ecosystems and human communities. The impacts of land use and climate change on water are of particular concern to rural indigenous communities of the southeastern US. For these communities, the cultural significance of land and water, together with historical legacies of discrimination, marginalization and other factors, combine to create unique vulnerabilities to environmental change. Assessments of land use and climate impacts on water resources of the southeastern US tend to focus on quantity and quality concerns of large cities or on waters of special economic concern (e.g. estuaries and coastal fisheries). The potential impacts of land use and climate change on American Indian communities are largely overlooked or unknown. With this in mind, we used a semi-distributed hydrological model (SWAT) to assess impacts of climate and land use change on streamflow regimes in the Lumbee (aka Lumber) River, North Carolina (USA). This coastal plain blackwater river is a significant natural and cultural resource for indigenous people of the Lumbee Tribe, and its watershed, containing extensive riparian wetlands and agriculture-dominated uplands, is home to more than 30,000 tribal citizens. We ran SWAT with statistically downscaled output from four general circulation models (GCMs) for the mid-21st century (RCP8.5 scenario), together with a mid-century land use scenario from the US Forest Service's Southern Forest Futures Project. We used these inputs to simulate daily streamflows on the Lumbee River for the 2040-2060 period with uncertainty estimates derived from multiple GCMs and ensemble parameter sets. We compare simulated fluxes for the 2040-2060 period to a historical baseline of observed data and discuss implications of shifting flow regimes for the river, for its adjacent wetland and agricultural ecosystems, and for the related concerns of the Lumbee people.