Degree Type


Date of Award


Degree Name

Doctor of Philosophy



First Advisor

Joe P. Colletti

Second Advisor

Richard C. Schultz


Like many agricultural states, Iowa is facing a serious threat from non-point source (NPS) pollution in the water resources. The dispersed NPS pollution mixes with soil particles from uplands and is deposited in bottom lands where the pollutants can enter the aquatic environments of streams, ponds, and lakes. Sediment from the erosion of agricultural lands is the most significant source of NPS pollution in many parts of the state. All of these pollutants create various problems in the surface, subsurface, and ground water resources. One of the suggested methods to arrest this situation is the introduction of a Vegetative Buffer Strip (VBS) along with other conservation measures. A VBS can consist of perennial grasses, shrubs, and tree species, all with vigorous growth characteristics, and all purposefully established parallel to waterways along one or both banks. The objectives of the VBS and other measures, is to capture localized erosion and to filter nutrients, sediments and other chemical pollutants from agricultural runoff;The purpose of this study is to measure the benefits of environmental improvements through VBS and other management practices as perceived by residents of the watershed. For a wide variety of environmental resources and quasi-public goods, such as water, the absence of markets makes it extremely difficult to establish a monetary value for access to those commodities. Whenever events or a proposed change in policy affects the quality or availability of these nonmarket goods, either explicit or implicit cost benefit analysis often must be undertaken. Therefore, the contingent valuation (CV) methodology, which is based on underlying economic theory to measure welfare change, was used for this purpose. This procedure assumes that there is a market for clean water through VBS and other measures, and then using a survey approach, asks individuals what they would be willing to pay for clean water. The estimated average annual WTP for surface water was 49 and the ground water was \80. WTP values reported in many similar studies suggests that the value lies between 30 and \60.



Digital Repository @ Iowa State University,

Copyright Owner

Premachandra Mathuwansa Wattage



Proquest ID


File Format


File Size

198 pages