Publications - Water
Global multi-pollutant modelling of water quality: scientific challenges and future directions.
Strokal M, Spanier JE, Kroeze C, Koelmans AA, Flörke M, Franssen W, et al. (2019)
Assessing global water quality issues requires a multi-pollutant modelling approach. We discuss scientific challenges and future directions for such modeling. Multi-pollutant river models need to integrate information on sources of pollutants such as plastic debris, nutrients, chemicals, pathogens, their effects and possible solutions. In this paper, we first explain what we consider multi-pollutant modelling. Second, we discuss scientific challenges in multi-pollutant modelling relating to consistent model inputs, modelling approaches and model evaluation. Next, we illustrate the potential of global multi-pollutant modelling for hotspot analyses. We show hotspots of river pollution with microplastics, nutrients, triclosan and Cryptosporidium in many sub-basins of Europe, North America and South Asia. Finally, we reflect on future directions for multi-pollutant modelling, and for linking model results to policy-making.
- Assessing global water quality issues requires a multi-pollutant modelling approach.
- Challenges relate to consistent inputs, multi-pollutant modelling approaches and model evaluation.
- Our illustrative example shows hotspots of river pollution with multiple pollutants.
- Multi-pollutant models are highly policy relevant.
How to model algal blooms in any lake on earth
Janssen, Annette B.G. ; Janse, Jan H. ; Beusen, Arthur H.W. ; Chang, Manqi ; Harrison, John A. ; Huttunen, Inese ; Kong, Xiangzhen ; Rost, Jasmijn ; Teurlincx, Sven ; Troost, Tineke A. ; Wijk, Dianneke van; Mooij, Wolf M. (2019).
Algal blooms increasingly threaten lake and reservoir water quality at the global scale, caused by ongoing climate change and nutrient loading. To anticipate these algal blooms, models to project future algal blooms worldwide are required. Here we present the state-of-the-art in algal projection modelling and explore the requirements of an ideal algal projection model. Based on this, we identify current challenges and opportunities for such model development. Since most building blocks are present, we foresee that algal projection models for any lake on earth can be developed in the near future. Finally, we think that algal bloom projection models at a global scale will provide a valuable contribution to global policymaking, in particular with respect to SDG 6 (clean water and sanitation).
- Reaching SDG 6 requires algal projection models applicable at a global scale.
- There are currently no algal projection models similar to the ideal model.
- Scientific challenges relate to spatial scales, data availability and uncertainty.
- Recent developments provide opportunities for further development.
- Global algal projection models will be highly relevant to global policymaking.
Liberalizing rural-to-urban construction land transfers in China: Distribution effects
Tan, R., R. Wang and N. Heerink. (2019)
China’s land market is characterized by a dual urban-rural system, with the government in control of rural-urban land transfers. In recent years, different types of pilot projects have been implemented to experiment with liberalizing markets for rural-urban construction land transfers. The objective of this study is to gain insights into the distributional effects of three different types of land liberalization rules by making a comparative analysis of three pilot projects carried out under each of these liberalization rules. We find that transfers facing more liberalized rules result in higher shares of land revenue flowing to the rural sector and thereby reduce the ruralurban income gap. But direct transfers between rural and urban land users also contribute to growing income inequality within the rural sector, as households living in urban fringes benefit relatively more from such transfers. A tradable quota system can reduce the impact of location on the price of land, and thereby contribute to a more equal distribution of the revenues of rural-urban land transfers within the rural sector.
- We assess the distributional effects of three different liberalization rules for rural-urban construction land transfers.
- We compare the outcomes of pilot projects carried out under each of these three liberalization rules.
- Transfers facing more liberalized rules result in higher shares of land revenue flowing to the rural sector.
- A tradable quota system can reduce the impact of location and contribute to a more equal rural income distribution.
Nutrient losses to surface waters in Hai He basin: A case study of Guanting reservoir and Baiyangdian lake
Yang, Jing ; Strokal, Maryna ; Kroeze, Carolien ; Wang, Mengru ; Wang, Jingfei ; Wu, Yihong ; Bai, Zhaohai ; Ma, Lin (2019)
Hai He basin is located in the densely populated North China Plain that is providing food to more than 100 million people. The fast developing agriculture and urbanization in Hai He basin have resulted in discharging nutrient-rich wastewater into lakes and reservoirs, leading to eutrophication and water scarcity such as in Guanting reservoir and Baiyangdian lake. In this study we analyzed future trends in nutrient inputs into Guanting reservoir and Baiyangdian lake by applying the MARINA (Model to Assess River Inputs of Nutrients to seAs) model. We analyzed trends between 2012 and 2050 for a business-as-usual scenario (SSP3) and a scenario based on Current Environmental Policies (CEP). In addition, we assessed future impacts of two important events on river export of nutrients: the 2022 Olympic Winter Games in the Guanting basin (OLY scenario), and the development of Xiong’an in the Baiyangdian basin (URB scenario). Finally, we assumed implementation of advanced technologies to reduce nutrients in rivers (OLY+ and URB+). Our study has five main findings. First, nutrients in Guanting reservoir and Baiyangdian lake were mainly from agriculture in 2012. Second, nutrient export doubles between 2012 and 2050 in SSP3. Third, effective implementation of current environmental policies could reduce the future pollution to levels below that in 2012. Fourth, improved sewage systems associated with the 2022 Winter Olympic Games could not reduce nutrient pollution effectively in Guanting reservoir, indicating that reducing nutrient losses from agriculture may be more effective to improve water quality than urban waste water treatment. Fifth, urbanization in the Baiyangdian basin may increase river export of nutrients to the lake by 28-43% compared to the CEP scenario (URB scenario). Highly effective waste treatment is needed not only in Xiong’an but also in surrounding areas to ensure the availability of clean water (URB+ scenario). Our results could improve our understanding of nutrient management for specific lakes and reservoirs, and highly relevant for policy making for effective environmental policies.
- Nutrients in Guanting reservoir and Baiyangdian lake were mainly from agriculture in 2012.
- Between 2012 and 2050 nutrient pollution in the lake and reservoir may double.
- Current environmental policies in China may reduce pollution to below 2012 levels.
- To further improve water in Guanting, pollution control in agriculture is needed.
- To further improve water in Baiyangdian, reduced pollution from sewage in Xiong’an surrounding areas is needed.
Does property rights integrity improve tenure security? Evidence from China’s forest reform
Zhou, Y., X. Ma, D. Ji, N. Heerink, X. Shi and H. Liu. (2018)
The purpose of this paper is to examine the impact of land property rights integrity, subdivided into use rights, mortgage rights, and transfer rights, on household perceptions of long-term tenure security in China. To this end, we establish a theoretical framework that links China’s collective forest tenure reforms undertaken since 2003 to property rights integrity and two sources of tenure (in)security based on property rights theory: forestland reallocation and expropriation. Probit models are applied in the empirical analysis to household data collected in Jiangxi province in 2011 and 2013. The results indicate that household perceptions of tenure insecurity resulting from forestland reallocation expectations are affected by transfer rights, whereas household perceptions of insecurity resulting from forestland expropriation expectations are not affected by forestland rights. We thus suggest that it is crucial for policymakers to identify the sources of local property rights insecurity before they take steps to strengthen land tenure security. This paper contributes to the available literature on the relationship between property rights integrity and tenure security by identifying different sources of tenure insecurity, emphasizing the effect of property rights integrity on long-term tenure security, and taking into account the potential endogeneity problem.
How do land rental markets affect household income? Evidence from rural Jiangsu, P.R. China
Zhang, L., S. Feng, N. Heerink, F. Qu and A. Kuyvenhoven. (2018).
The development of land rental markets in developing countries attracts much attention, but little is known about its impact on household income. This study empirically examines the effects of land rental decisions of farm households on their income and income components, i.e. farm, off-farm and transfer income, taking into account potential endogeneity of land rental decisions. Rural household survey data for 1080 households in 128 villages in Jiangsu Province, China are used to estimate these effects. Quantile regressions are used to examine to what extent effects differ between income groups. Results indicate that lessor households surprisingly obtain lower total income as compared to autarkic households. Among the lessee households, who gain on average from land rentals, the lower income groups obtain the largest total income gains. As to the sources of income, no significant differences in off-farm income between transacting households (i.e. lessee or lessor households) and autarkic households are found while differences in farm income between transacting households are as expected. Transfer income of lessor households is significantly lower than that of autarkic households. We explain these findings from some typical features of the rural land rental market in China and discuss the policy implications.
- We examine the effects of land rentals on farm household income and income components.
- Household survey data for 1080 households in Jiangsu Province, China are used to estimate these effects.
- Among the lessee households, the poorest income groups show the largest income gains.
- Lessor households surprisingly do not gain from land rentals.
- We argue that collective land rentals to large-scale operating units explain the findings for lessor households.