Question

What roles do forests and forested wetlands play in producing and protecting water resources in the South and how might future land management and land use change affect these roles?

Issues

• Describe the relationship between forests and water timing, flow and quality.
• Discuss how forest conversion and loss affects these relationships.
• Describe the implications of intensive forest management for water.
• Discuss the roles of forested wetlands and riparian areas in protecting water quality, and describe potential implications of their conversion and loss.
• Discuss the implications for increased demand and interactions with forest conversion, drought, and climate change.
• Describe the known effects of impoundment construction on forests and associated resources.

Subregional Issues

• Effects of Hemlock loss on riparian ecosystems (App-Cumb)
• Effects of wetland loss on wastewater assimilation (Coastal Plain)
• Effects of wetland loss on storm mitigation (Coastal Plain)
• Effects of changes in forests on water quality and quantity, in particular resulting from and affecting urban areas. (Piedmont)
• Restoration of riparian buffer strips and artificial wetlands (MAV)
• Nutrient sequestration and the Gulf Hypoxic Zone (MAV)
• Loss or gain of connectivity between river and floodplain (MAV)
• Projections of water quantity between 90^th and 105^th meridian (Mid South)

Meta-Issue Managers

Graeme Lockaby, Auburn University and James M. Vose, Southern Research Station, USDA Forest Service

Methods of Analysis

Describe the relationships between forests and the timing, quality, and quantity of water.
These relationships have been described in detail in many publications and recent syntheses (e.g., the National Research Council Report 2008). We will draw on some of the most recent work conducted by Lockaby as part of an Eastwide synthesis of forest-water relationship in collaboration with Dr. Paul Barten at University of Massachusetts.

Discuss how forest conversion and loss affects these relationships.
We will compare and contrast variation in water resources (quality, quantity, and timing) across a range of land uses (i.e., forest, urban, agriculture) in the South. We will draw on some of the most recent work conducted by Lockaby as part of an Eastwide synthesis of forest-water relationship in collaboration with Dr. Paul Barten at University of Massachusetts.

Discuss the roles of forested wetlands and riparian areas in protecting water resources, and describe potential implications of their conversion and loss.
We will draw on existing literature to briefly describe the role of riparian wetlands as filters for pollutants in surface waters and in maintaining stable flows. The effect of land use changes on direct losses of wetlands as well as the impact of those changes on downstream hydrographs and, subsequently, decreased connectivity between terrestrial and aquatic systems will be postulated and summarized. We will use this information to estimate the net effect of changing land use and climate on the protective functions afforded by riparian wetlands in regard to surface water quality and quantity.

Describe the implications of intensive forest management on water resources.
For implications for water quality, we will review existing literature and utilize a recent synthesis of the effectiveness of BMP's conducted by Anderson and Lockaby as part of a project assessing BMP effectiveness in the South. For water quantity, we will summarize results from experimental watersheds and other measurement methods (e.g., sapflow) to examine impacts of intensive forestry and the quantity and timing of water resources.

Discuss the implications for increased demand and interactions with forest conversion and drought.
We will adapt the modeling approach develop by Ge Sun et al. (JAWRA 44(6):1441-1457) to assess how the combination of increased demand, changing forest cover, and increased drought frequency will impact water resources in the South. Areas that are projected to be most impacted will be identified and displayed graphically.

Describe the effects of impoundment construction on forests, downstream wetland and riparian ecosystems, and other associated resources.
We will quantify the volume of surface water that will be required to satisfy water demand for all uses in the next 30 years, then estimate the acreage of land required to impound (and the associated watershed size required to keep it full) that volume of water on a state-by-state basis. We will then provide an estimate of the loss of forest habitat and future management options, as well as an assessment of how altered flow regimes impact downstream aquatic and riparian wetland ecosystems.

Data and Information Sources

• Previous studies
• USGS Streamflow Gauges
• Land Cover Maps (current and projected)

Products

(1) maps of areas where the combination of projected changes in forest cover and increased demand are likely to result in water shortages (with and without drought), (2) maps of areas where projected changes in forest cover are likely to impact water quality (3) maps of wetland and riparian areas most vulnerable (and with the highest impact if lost) to forest conversion.

Cooperators

Steve McNulty and Ge Sun, USDA Forest Service Southern Global Change Program; Dr. Paul Barten, University of Massachusetts; Dr. Yanli Zhang, S.F. Austin University.