1. Recreation Demand Using Physical Measures of Water Quality Kevin Egan, Joseph Herriges, and Catherine Kling Department of Economics Center for Agricultural and Rural Development John Downing Department of Ecology, Evolution and Organisimal Biology Department of Ecology, Evolution and Organisimal Biology Iowa State University R830818

2. Linking Recreational Values to Physical Water Quality  Regulatory considerations, such as TMDL standards, require developing physical water quality standards.  Yet the linkage between the physical measures of water quality and the values associated with water resources is poorly understood.  Recreation demand models have found water quality matters, but have typically had to rely on limited measures, such as Catch rates (e.g., Chen, Lupi, and Hoehn, 1999), Catch rates (e.g., Chen, Lupi, and Hoehn, 1999), Toxin levels (Phaneuf, Kling and Herriges, 2000), or Toxin levels (Phaneuf, Kling and Herriges, 2000), or Water quality indicators (Parsons, Helm, and Bondelid, 2003) Water quality indicators (Parsons, Helm, and Bondelid, 2003)  Understanding the linkage between physical attributes and water quality values is important to setting water quality standards setting water quality standards prioritizing restoration efforts prioritizing restoration efforts

3. Iowa Lakes Valuation Project  Collaborative project involving economists and ecologists studying Iowa lakes Builds off of existing 5 year study of the ecological conditions of 132 lakes in Iowa (2000-2004) Builds off of existing 5 year study of the ecological conditions of 132 lakes in Iowa (2000-2004)  EPA Star grant augments work begun with Iowa DNR funding and CARD support – 4 year project  A four-year panel data set of survey responses will be collected involving Actual trip behavior and future expected trips, years 2001-2006 Actual trip behavior and future expected trips, years 2001-2006 2 nd through 4 th year survey will contain water quality scenarios measuring WTP for quality improvements 2 nd through 4 th year survey will contain water quality scenarios measuring WTP for quality improvements Knowledge and perceptions regarding lake quality Knowledge and perceptions regarding lake quality

4. Clear Lake - Cerro Gordo County - Data from Summer 2002 Parameter 6/10/027/15/028/12/02 Mean of Three Sampling Events 2002 Mean of Three Sampling Events 2001 Mean of Three Sampling Events 2000 Secchi Disc Depth (m) 0.81.00.50.80.7 0.4 Chlorophyll (  g/l) 2528383071 31 NH 3 +NH 4 + -N (  g/l) 164152202173535 1125 NH 3 -N (un-ionized) (  g/l) 2222312577 48 NO 3 +NO 2 -N (mg/l) 0.220.210.170.200.24 0.17 Total Nitrogen (mg/l as N) 1.211.191.251.221.83 1.97 Total Phosphorus (  g/l as P) 57399062103 129 PO 4 -P (  g/l) <3<3<3<365 -- SiO 2 -Si (mg/l) <1611613 16 pH 8.58.48.58.58.5 7.4 Alkalinity (mg/l) 158158156157129 149 Total Suspended Solids (mg/l) 17.713.322.217.728.1 47.4 Inorganic Suspended Solids (mg/l) 7.34.39.06.910.6 19.0 Volatile Suspended Solids (mg/l) 10.39.013.210.817.4 28.5 Dissolved Organic Carbon (mg/l) ----12.4---- -- Cyanobacteria (mg/l) 16.2328.756.8133.911.425.9 Total bacteria (mg/l) 36.8331.3 59.8 142.614.537.1

5. Baseline Survey  First of four mail surveys  8000 Iowa residents selected at random  Survey collected trip data for 132 lakes trip data for 132 lakes 2001 and 2002 actual trips2001 and 2002 actual trips 2003 anticipated trips2003 anticipated trips attitudes regarding lake quality attitudes regarding lake quality Socio-demographic data Socio-demographic data  62.1% response rate

7. Figure 2: Average number of day trips 62.8% of Iowa households took at least one trip

8. Summary Statistics Table 2. Lake Characteristics Summary Statistics VariableMean Std. Dev. MinimumMaximum Day Trips per Individual 6.6810.46052 Price135.7929.4794.12239.30 Acres672.202,120.301019,000 Log(Acres)4.811.692.309.85 Ramp0.860.3501 Wake0.660.4701 Handicap Facilities 0.390.4901 State Park 0.390.4901

9. Summary Statistics Table 3. Physical Water Quality Summary Statistics VariableMean Std. Dev. MinimumMaximum Secchi Depth (m) 1.170.920.095.67 Chlorophyll (ug/l) 40.9338.022.45182.92 NH 3 +NH 4 (ug/l) 292.15158.5772955.34 NO 3 +NO 2 (mg/l) 1.202.540.0714.13 Total Nitrogen (mg/l) 2.202.520.5513.37 Total Phosphorus (ug/l) 105.6580.6117.10452.55 Silicon (mg/l) 4.563.240.9516.31 pH8.500.337.7610.03 Alkalinity (mg/l) 141.8040.9873.83286.17 Inorganic SS (mg/l) 9.4317.870.57177.60 Volatile SS (mg/l) 9.357.931.6449.87

10. Modeling Issues  Randomly divided sample into three segments: Specification Specification Estimation Estimation Prediction Prediction  Modeling approach: repeated mixed logit  Specification considerations Inclusion/exclusion of specific water quality measures Inclusion/exclusion of specific water quality measures functional form (e.g., linear, quadratic or logarithmic) functional form (e.g., linear, quadratic or logarithmic) random versus fixed parameters random versus fixed parameters

11. Repeated Mixed Logit Conditional on the parameter vector,, the probability of observing that Individual i chooses alternative j on choice occasion t follows the standard logit form: The corresponding unconditional probability,, is obtained by integrating over an assumed probability density function for the assuming i.i.d. so that

12. Specification

13. Coefficient Results Variable Using 6 Physical WQ measures Secchi Depth 0.87 Chlorophyll 0.61 Total Nitrogen -0.15 Total Phosphorus -2.51 Inorganic SS -0.73 Volatile SS -0.20 Variable Using 6 physical WQ measures MeanDispersion Income-0.06 Male-5.79 Age-0.35 Age 2 -0.0004 School-2.61 Household-2.50 Price-0.48 Log(Acres)4.383.75 Ramp11.1418.86 State Park 3.8314.86 Facilities0.8014.40 Wake2.4310.48 -12.242.44

14. Comparing Water Quality across Lakes West Okoboji Lake Averages of the nine focus lakes Secchi Depth (m) 5.671.23 Chlorophyll2.6340.13 Total Nitrogen 0.863.64 Total Phosphorus 21.2891.11 Inorganic Suspended Solids 1.009.52 Volatile Suspended Solids 1.798.42 Medians of the non-impaired lakes Averages of the 65 impaired lakes 0.900.70 6.5556.76 1.102.77 43.87153.70 5.4220.42 3.6215.49

15. Silver Lake

16. West Okoboji Lake

17. Willingness to Pay Estimates Average Annual WTP Nine focus lakes improved to West Okboboji Sixty-five impaired lakes improved to the median of the non- impaired lakes Per Iowa household for all Iowa households Predicted Trips (8.0 currently) $11.86 $13,675,685 8.3 $10.23 $11,799,261 8.2

18. Lakes with the Highest Valued Improvements Lake On EPA’s Impaired Waters List Annual WTP Secchi Depth (m) Total Phosphorus (ug.l) Total Annual 2002 Day Trips Average Travel Cost Coralville Lake Yes0.8204457,000$106 Saylorville Lake No0.7101600,000$97 Red Rock Lake No1.599284,000$112 Storm Lake Yes0.589232,000$157 Trumbull Lake Yes0.145320,000$168 Lake Darling Yes0.322663,000$124 Black Hawk Lake Yes0.919399,000$138 Badger Creek Lake Yes0.629063,000$104 Rathbun Lake No0.944248,000$139 Hannen Lake No1.322741,000$101 Average across all lakes $300,0001.210683,000$136 $10,600,000 $6,000,000 $3,700,000 $1,100,000 $900,000 $800,000 $600,000 $500,000 Willingness to Pay Estimates

19. Figure 8: Lake zones 1 5 4 7 10 2 8 6 3 9

20. Conclusions  Recreator’s trip behavior is responsive to physical measures of Water Quality Better water clarity increases recreational trips Better water clarity increases recreational trips Nutrients decrease recreational trips Nutrients decrease recreational trips  Allows consumer surplus measures to directly be linked to physical water quality improvements Iowans value more highly a few lakes with superior water quality over all recreational lakes at an adequate level Iowans value more highly a few lakes with superior water quality over all recreational lakes at an adequate level  Findings allow prioritization for clean-up activities to generate the greatest recreation benefits for a given expenditure Rank which lakes and in what order and most efficient levels of improvement Rank which lakes and in what order and most efficient levels of improvement

21. Next Stages of Project  2003 Survey gathered A second year of trip data A second year of trip data Perceptions data regarding water quality Perceptions data regarding water quality Stated preference data regarding water quality improvements Stated preference data regarding water quality improvements  2004 Survey is currently in development

24. Water Quality Perceptions Full SampleWater ContactNon Water Contact Corr.p-valueCorr.p-valueCorr.p-value Day Trip Per Capita0.250.000.260.00-0.100.24 Secchi Depth0.420.000.430.000.13 Chlorophyll-0.300.00-0.290.00-0.160.08 NH3+NH4-0.240.01-0.230.01-0.110.20 NO3NO2-0.040.67-0.030.75-0.150.09 Total Nitrogen-0.190.03-0.180.04-0.200.02 Total Phosphorus-0.330.00-0.320.00-0.250.00 Silicon-0.400.00-0.390.00-0.270.00 pH-0.090.29-0.100.230.030.75 Alkalinity-0.200.02-0.210.02-0.130.13 ISS-0.330.00-0.340.00-0.100.26 VSS-0.380.00-0.380.00-0.150.10