Forests and water
|Authors:||Graeme Lockaby, Chelsea Nagy, James M. Vose, Chelcy R. Ford, Ge Sun, Steve McNulty, Pete Caldwell, Erika Cohen, Jennifer Moore Myers|
|Station:||Southern Research Station|
|Source:||In: Wear, David N.; Greis, John G., eds. 2013. The Southern Forest Futures Project: technical report. Gen. Tech. Rep. SRS-GTR-178. Asheville, NC: USDA-Forest Service, Southern Research Station. 309-339.|
- Forest conversion to agriculture or urban use consistently causes increased discharge, peak flow, and velocity of streams. Subregional differences in hydrologic responses to urbanization are substantial.
- Sediment, water chemistry indices, pathogens, and other substances often become more concentrated after forest conversion. If the conversion is to an urban use, the resulting additional increases in discharge and concentrations will produce even higher loads.
- Although physiographic characteristics such as slope and soil texture play key roles in hydrologic and sediment responses to land use conversion, land use (rather than physiography) is the primary driver of water chemistry responses.
- Conversion of forest land to urban uses may decrease the supply of water available for human consumption and increase potential threats to human health.
- Increases in urbanization by 2060 in the Appalachians, Piedmont, and Coastal Plain will increase imperviousness and further reduce hydrologic stability and water quality indices in the headwaters of several major river basins and in small watersheds along the Atlantic Ocean and Gulf of Mexico.
- On average, water supply model projections indicate that water stress due to the combined effects of population and land use change will increase in the South by 10 percent by 2050.
- Water stress will likely increase significantly by 2050 under all four climate change scenarios, largely because higher temperatures will result in more water loss by evapotranspiration and because of decreased precipitation in some areas.
- Approximately 5,000 miles of southern coastline are highly vulnerable to sea level rise.