Amit Batabyal (p), Hamid Beladi

Michelle Talal

We exploit the public good attributes of Ganges water pollution cleanup and theoretically analyze an aggregate economy of two cities---Kanpur and Varanasi---through which the Ganges flows. Our specific objective is to study whether water pollution cleanup in these two cities ought to be provided in a centralized or in a decentralized manner. We first determine the efficient cleanup amounts that maximize the aggregate surplus from making the Ganges cleaner in the two cities. Second, we compute the optimal amount of water pollution cleanup in the two cities in a decentralized regime in which spending on cleanup is financed by a uniform tax on the city residents. Third, we ascertain the optimal amount of water pollution cleanup in the two cities in a centralized regime subject to equal provision of cleanup and cost sharing. Fourth, we show that if the two cities have the same preference for pollution cleanup then centralization is preferable to decentralization as long as there is a spillover from pollution cleanup. Finally, we show that if the two cities have dissimilar preferences for pollution cleanup then centralization is preferable to decentralization as long as the spillover exceeds a certain threshold.

Katsuhiro Sakurai (p), Hiroyuki Shibusawa, Ilkka Jokinen, Matti Lehtonen

Amit Batabyal

The objective of this study is to estimate the emission coefficients of water pollutants from point and non-point sources. The emission coefficients are needed for simulation and model analysis of water environment policy evaluation in Finland. Point sources refer to sources of water pollutant emissions from socio-economic activities, while non-point sources refer to sources of water pollutant emissions from land use. First, we attempt to quantify the relationship between socio-economic activities and water pollutant emissions in Finland. Socio-economic activities refer to production of several industrial sectors and household consumption, which discharge water pollutants. Finland, the target area of this study, has a land area of about 338,000 km2, more than 70% of which is covered by forests and semi-natural areas. Nearly 90% of the land, including wetlands and water bodies, is in natural environments. Emissions of water pollutants from land use, including these natural environments, are also estimated. Helsinki, the capital and largest city, is located in the southernmost part of the country, facing the Gulf of Finland, and has a population of 665,058 (2023). The economic activities of these cities result in the discharge of some water pollutants, including total nitrogen and total phosphorus. In addition, parts of Finland face the Baltic Sea, and water pollutants generated by land area activities flow into the sea through rivers. The Baltic Sea and other surrounding sea areas in Finland are still evaluated as eutrophic sea areas. In order to improve the water quality of Finland's inland waters and surrounding sea areas, it is necessary to clarify the structure of water pollutant emission from point sources and non-point sources, and to evaluate water environment policies through model simulation analysis using emission coefficients.

Michelle Talal (p), Shiri Zemah Shamir, Michal Gruntman

Katsuhiro Sakurai

Nature in cities provides essential ecosystem services and increases human health and wellbeing. Ecosystem-based management is an important approach for managing urban green/blue spaces, and understanding the value that people place on urban nature can help to improve planning and management, promote urban nature investments, and enhance ecosystem services to create more equitable, sustainable cities. Previous studies aimed to determine the value that people place on urban nature, but many were limited in that they were from the perspective of conservation rather than utilization of environmental resources and did not integrate on-site urban nature site characteristics with the ecosystem services and nature preferences of urban residents. In our interdisciplinary study, we investigated urban residents’ valuation of urban nature site visits (i.e., using the Contingent Valuation Method) using publicly available geospatial data of on-site environmental features with a web-based survey of residents and their ecosystem services attitudes, nature preferences, and demographics. In our case study of Tel Aviv-Yafo, we developed a multiple linear regression model to determine residents’ valuation of urban nature site visits and its association with these variables. We also compared visitor and non-visitor preferences and their desired future improvements for urban nature sites. We found that a higher willingness to pay (WTP) to visit urban nature sites was positively associated with ecosystem services such as relaxation opportunities, lower air temperatures, and biodiversity, which have important management implications that can help to meet both social and environmental management goals in urban ecosystems. Overall, participants gave relatively high preference ratings for various green and blue components of urban nature sites, but our model showed mixed results for these features in terms of their valuation, implying that some participants may not feel a monetary obligation towards paying for urban nature components which are perceived as meant to be openly accessible and free. Even so, both visitors and non-visitors indicated that improving existing urban nature sites was important (83% and 85%, respectively), followed by creating new sites (62% and 49%, respectively). In recognizing the great value that urban residents place on urban nature, we recommend that managers/planners work collaboratively with diverse stakeholders to integrate values for urban ecosystem services and preferences into participatory environmental decision-making. Urban ecosystem management should include improvements that incorporate aspects highly valued by residents and a range of green and blue components to promote human and environmental health.