Topics in Water and Wastewater Management
Friday, Jan. 5, 2018 2:30 PM - 4:30 PM
- Chair: Lea-Rachel Kosnik, University of Missouri-St. Louis
Reducing Watershed Pollution through Dynamic Stormwater Retention using Green Roofs
AbstractThis study evaluates the impact and performance of different green roof systems to manage and control stormwater runoff to prevent watershed pollution over the short and long term in the greater Milwaukee WI MSA. A hybrid internet and mail-based stated-preference conjoint choice experiment was administered to residents of the Milwaukee MSA in order to ascertain the public benefits value of green roof infrastructure. 508 responses were obtained from 7000 mailed surveys, as well as an additional 501 responses from a professionally administered internet-based panel. This study contributes to the literature on the public and private net benefits of green roofs in two novel ways. First, the value of dynamic stormwater retention facilitated through the use of “smart” green roofs with access to real-time weather data versus traditional extensive green roofs and grey infrastructure investment is estimated. Second, the full range of public benefits associated with green roofs, including improved air quality, water quality, biodiversity, and urban heat island effects are estimated. Estimation of all of these public values, allows for determination of the optimal public subsidy for supporting green roofs as a component of decentralized stormwater management in municipalities.
Household Preferences for Environmental Assets: Testing for the Importance of the Frequency, Severity and Scope of Reductions in Water Quality
AbstractWater quality indices are constructed as a means of summarizing and communicating the multifaceted nature of water quality and aquatic ecosystem health. The Canadian Council of Ministers of the Environment (CCME) has adopted an index based on the severity, frequency, and scope of water impairment (i.e. instances when water quality objectives are exceeded). An important feature, and potential shortcoming, of this approach is that the three attributes of water quality are weighted equally. If households, however, weight these attributes differently, then the index’s ability to convey information to the public may be weakened. We examine this issue using a choice experiment (CE) implemented in Shawnigan Lake, British Columbia, Canada. Shawnigan Lake is home to several thousand full-time residents and serves as a popular summer vacation destination. Activities associated with residential development, seasonal recreation, and commercial forestry have led to small but measurable declines in the lake’s water quality. For the CE, respondents were told about a hypothetical water quality protection program that would mitigate the upward trend in phosphorous levels and its negative impacts (e.g. reduced recreational benefits, diminished aesthetic). Specifically, the protection program would mitigate the number of days when phosphorous levels exceed the provincial objective during summer months, the number of days when phosphorous levels exceed the provincial objective during non-summer months, and the amount of shoreline with reduced water quality. Responses to the CE are modeled using latent class techniques, which indicated the presence of two equally sized preference classes. The two classes have dramatically different preferences, but both benefit from the hypothetical water quality protection program. Evidence on the weighting of index components is inconclusive but generally supports the use of equal weights in CCME water quality index. Results also add to the scare number of water quality valuation studies conducted within a Canadian context.
A Retrospective Benefit Cost Analysis on the Elwha River Restoration Project
AbstractIn 1992 Congress passed The Elwha River Ecosystem and Fisheries Restoration Act, with the goal of “full restoration of the Elwha River ecosystem and native anadromous fisheries.” As part of that act, the federal government was required to produce a benefit cost analysis on dam removal of the Elwha and Glines Canyon dams, which was published in 1994. This paper revisits that initial 1994 benefit cost analysis; background on its methods and assumptions is given, comparisons are made to current state-of-the-art techniques in benefit cost analysis, and an ex post benefit cost analysis of the project is conducted for comparison purposes. We find that the cost and scope of the project exceeded original expectations, the cost of the foregone electricity generation was less than expected and that anticipated recreational and fisheries benefits were both delayed, and lower, than expected. Further, issues such as the value of hatchery-spawned versus wild anadromous fish seem not to have been anticipated in the original analysis, highlighting the fact that in doing an ex-ante analysis, researchers must expect that unexpected factors may influence the ex-post results of any project.
- H0 - General
- Q2 - Renewable Resources and Conservation