CONVERSION OF FOREST TO URBAN LAND COVER: INFLUENCES ON DRINKING WATER QUALITY AND WILLINGNESS TO ACCEPT PAYMENTS FOR WATER QUALITY SERVICES Lauren D. Behnke, School of Forestry, Auburn University Dr. Graeme Lockaby, School of Forestry, Auburn University Dr. David Laband, Department of Economics, Georgia Tech University Marlon Cook, Groundwater Assessment Program, Geologic Survey of Alabama

Project Description  Objectives  Determine the effects of land use change in aquifer recharge zones on groundwater chemistry  Identify the terms and conditions under which private, non-industrial landowners within aquifer recharge zone would be willing to participate in a program that would pay them to retain and/or expand the amount of forest cover on their property.

Background  Aquifers  Source of drinking water  Infiltration in recharge zones replenish aquifer  Anthropogenic changes  Land-use change Increased forest loss Increased urbanization  Impacts on aquifer supply Increased pollutants Little known about effects /imgs/6comp.jpg

Forecasted change in the proportion of counties in urban land use (

Projection of population change (change in people per square-mile) (

Water Quality Approach  Water quality data from Utilities Board of the City of Trussville, AL from  8 wells were sampled (differed among samplings)  Analyzed water chemistry

Water Quality Approach  Recharge zones were delineated by Marlon Cook of the AL Geologic Survey  AGS provided land use/land cover data  Regression analyses were used to relate changes in impervious cover across time to water quality data

Aquifer Recharge Zone – Trussville, AL

Percent land use/land cover data Type Water Vegetation Impervious Trussville Water Quality Assessment

Results of regression analyses for water quality indices and % impervious surface Water variablesR-squarePr>F Nitrogen as nitrate * Sodium pH Total alkalinity * Calcium Chloride Magnesium Total Dissolved Solids Turbidity *significant at the 0.05 level

The relationship between percent impervious surface in the recharge zone and N-NO 3 in Trussville, AL well water

The relationship between percent impervious surface in the recharge zone and alkalinity in Trussville, AL well water

Water Quality Results  Increasing N-NO3 and declining alkalinity as impervious surface increased from 1992 to 2008  Elevated N-NO3 is generally considered to be an indicator of water quality degradation although the levels observed in the Trussville wells (0.7 mg/L) do not approach the US EPA allowable limit for drinking water

Water Quality Results  These data suggest the chemistry of the water supply for of Trussville, AL is undergoing changes due to increased urbanization within the recharge zone  Sources of N-NO 3 include lawn fertilizers, sewer and septic systems, animal waste, and atmospheric deposition from anthropogenic sources

Economic Analysis  Identify terms and conditions under which private, non-industrial landowners would participate in a program that pays them to retain and/or expand the amount of forest cover on their property  Mailed 204 surveys to individual owners of 10+ acres in Jefferson and St. Clair counties  24 returned

Economic Analysis Method of AcquisitionYears of Ownership

Economic Analysis Number of Tracts OwnedTotal Acreage Owned

Willingness to accept payment to retain forested acreage and acceptable annual payment after 1 year After 1 year

Willingness to accept payment to retain forested acreage and acceptable annual payment after 3 and 5 years After 3 years After 5 years

Cash versus tax credit as payment

Key Findings  Water Quality Findings  Levels of nitrate were below EPA critical limits; but a significant, positive relationship was found between increasing development and rising levels of nitrate in wells

Economic Findings  Landowners were willing to participate in a program:  to retain forest cover for pay  program of a short duration  relatively low payment amounts  As the desired contracting period lengthens, landowners react by:  unwilling to participate under existing payments  require higher annual, per-acre compensation  No preference between cash or a tax credit

Acknowledgements  Alabama Association of RC&D Councils, Inc.  Auburn University’s Center for Forest Sustainability  Utilities Board of the City of Trussville, AL  Alabama Geologic Survey

Questions?