data on drainage costs and gross and net rates of return were calculated, a 

 region in west-central Minnesota and a region in south-central Minnesota. The 

 publication of analyses of the same data in three different places is partly 

 justified by the rarity with which data on drainage costs has been presented in 

 the literature on wetlands. The data analyzed in the three studies was obtained 

 from a survey instrument; the sample size (35 respondents) was, unfortunately, 

 remarkably small. Leitch and Kerestes ([49]) reported that many farmers who were 

 rumored to have recently drained wetlands refused to respond to the survey. 



One important policy implication that is bought to the fore in this paper 

 is that the rate of return on nearly half the drainage investment projects in 

 the west-central Minnesota study area had a net present value that was less than 

 the average present value yielded by participation in one of the U.S. Fish and 

 Wildlife Service's preservation programs. Payment levels in the programs are 

 geared to foregone earnings from drainage, so the calculations of foregone 

 earnings have significant policy implications. However, the fact that the 

 respondents chose to drain rather than enroll their wetland acreage in a 

 preservation program suggests that nonpecuniary benefits may provide a more 

 important incentive for drainage activity than the Service realizes. 



Leitch cites a study that indicates that the U.S. Fish and Wildlife Service 

 paid an average of $847 per hectare for easement leases in the west-central 

 Minnesota study area in 1980. The west-central Minnesota study area was composed 

 of two subareas, a northern and a southern area. One reason for this division 

 was that the pattern of output differed sharply between the two regions. Average 

 net returns to ditch drainage in the northern subarea was $529 per hectare before 

 taxes, using a 15-year life of investment and 8% discount rate; in the southern 

 subarea, they were $1,499 per hectare. Average, before tax, discounted return 

 (8% discount rate) to tile drainage investment in the southern subarea was $583. 

 In the northern subarea it was negative (-$388 at 8% discount rate). General 

 (or supplemental) field drainage is popular among southern Minnesota and Iowa 

 farmers. These projects (multi-farm) drain excess moisture and enhance 

 productivity from croplands; they also drain water from wetlands. The 

 respondents were asked to estimate the profitability of general field drainage 

 for their wetlands, but it was clearly a somewhat artificial issue from the 

 farmer's perspective. The discounted (8% discount rate) net before tax return 

 to general field drainage in the south-central Minnesota study area for wetlands 

 was $2,193 per hectare. For removal of excess soil moisture it was only $635 

 per hectare. 



65. Turner, R.K., D. Dent, and R.D. Hay. 1983. Valuation of the environmental 

 impact of wetland flood protection and drainage schemes. Environment and 

 ' Planning 15(7) :871-888. 



One of the most widely appreciated alleged beneficial functions performed 

 by riparian corridor and coastal wetlands is flood control. The Yare Barrier 

 Proposal in Norfolk, England, is a large wetlands conversion and flood control 

 project. Flood control enhancement would be provided by a tidal surge barrier 

 (a drop gate) near the mouth of the River Yare, together with improvements to 

 existing floodwalls on the Rivers Bure, Waveney, and Yare. The flood protection 

 enhancement project would provide protection from freshwater and seawater 

 flooding and North Sea tidal surges for the extensive low-lying regions of the 



50 



