Derek Vollmer

Changing the Course of Rivers in an Asian City: Linking Landscapes to Human Benefits through Iterative Modeling and Design†

Concerns over water scarcity, climate change, and environmental health risks have prompted some Asian cities to invest in river rehabilitation, but deciding on the end goals of rehabilitation is a complex undertaking. We propose a multidisciplinary framework linking riparian landscape change to human well-being, providing information relevant to decision makers, in a format that facilitates stakeholder involvement. We illustrate this through a case study of the densely settled, environmentally degraded, and flood prone Ciliwung River flowing through metropolitan Jakarta, Indonesia. Our methodology attempts to respond to this complexity through an iterative approach, strongly based on conceptualization and mathematical modeling. Nested hydrologic, hydrodynamic, and water quality models provide outputs at catchment-, corridor-, and localized site-scales. Advanced 3-D landscape modeling is used for procedural design and precise visualization of proposed changes and their impacts, as predicted by the mathematical models. Finally, participatory planning and design methods allow us to obtain critical stakeholder feedback in shaping a socially acceptable approach. Our framework aims at demonstrating that a change in paradigm in river rehabilitation is possible, and providing future scenarios that balance concerns over flooding, water quality, and ecology, with the realities of a rapidly growing megacity.

Determining Demand for Riparian Ecosystem Services: A Spatially Explicit Discrete Choice Experiment in Jakarta, Indonesia

The demand for urban river rehabilitation can be measured through stated preference surveys such as choice experiments, providing information on the welfare estimates of a particular approach. We deploy such a technique in the context of plans to rehabilitate a major river in Jakarta, Indonesia. The current plan focuses on widening and canalizing the downstream segment of the river, but we hypothesize that residents would demand (and thus be willing to pay for) additional components of an ecological rehabilitation program in the form of riverside park space and upstream forest conservation outside of the city. We develop a spatially-explicit discrete choice experiment in which households register their preferences for channel widening, park space, forest conservation, and a monthly fee to fund the rehabilitation. Using mixed logit models we find significant and substantial demand for both park space and forest conservation, with a lower bound on the total willingness to pay (WTP) of greater than US

Changing the course of rivers in Asian cities: Linking riparian landscapes to human benefits through iterative modeling and design

4 million per year for park space and nearly US

Changing the course of rivers in an Asian city: Linking landscapes to human benefits through iterative modeling and design: Linking Landscapes to Human Benefits through Iterative Modeling and Design

6 million per year to support reforestation in the upper catchment. These estimates are based on households within the catchment, but we find that demand did not seem to decay with distance so the upper bound on total WTP could be substantially higher. We also find that household income level has a strong effect on marginal WTP for forest conservation, minimal effect on marginal WTP for park space, and that location along the river influenced WTP for park space and channel widening. This provides further evidence that there is substantial demand for river rehabilitation in developing world cities, and that choice experiments can provide information relevant to land use planning.

Understanding the value of urban riparian corridors: Considerations in planning for cultural services along an Indonesian river

Concerns over water scarcity, climate change, and environmental health risks have prompted some Asian cities to invest in river rehabilitation, but deciding on the end goals of rehabilitation is a complex undertaking. We propose a multidisciplinary framework linking riparian landscape change to human well-being, providing information relevant to decision makers, in a format that facilitates stakeholder involvement. We illustrate this through a case study of the densely settled, environmentally degraded, and flood prone Ciliwung River flowing through metropolitan Jakarta, Indonesia. Our methodology attempts to respond to this complexity through an iterative approach, strongly based on conceptualization and mathematical modeling. Nested hydrologic, hydrodynamic, and water quality models provide outputs at catchment-, corridor-, and localized site-scales. Advanced 3-D landscape modeling is used for procedural design and precise visualization of proposed changes and their impacts, as predicted by the mathematical models. Finally, participatory planning and design methods allow us to obtain critical stakeholder feedback in shaping a socially acceptable approach. Our framework aims at demonstrating that a change in paradigm in river rehabilitation is possible, and providing future scenarios that balance concerns over flooding, water quality, and ecology, with the realities of a rapidly growing megacity.

Rivers as municipal infrastructure: Demand for environmental services in informal settlements along an Indonesian river

Concerns over water scarcity, climate change, and environmental health risks have prompted some Asian cities to invest in river rehabilitation, but deciding on the end goals of rehabilitation is a complex undertaking. We propose a multidisciplinary framework linking riparian landscape change to human well-being, providing information relevant to decision makers, in a format that facilitates stakeholder involvement. We illustrate this through a case study of the densely settled, environmentally degraded, and flood prone Ciliwung River flowing through metropolitan Jakarta, Indonesia. Our methodology attempts to respond to this complexity through an iterative approach, strongly based on conceptualization and mathematical modeling. Nested hydrologic, hydrodynamic, and water quality models provide outputs at catchment-, corridor-, and localized site-scales. Advanced 3-D landscape modeling is used for procedural design and precise visualization of proposed changes and their impacts, as predicted by the mathematical models. Finally, participatory planning and design methods allow us to obtain critical stakeholder feedback in shaping a socially acceptable approach. Our framework aims at demonstrating that a change in paradigm in river rehabilitation is possible, and providing future scenarios that balance concerns over flooding, water quality, and ecology, with the realities of a rapidly growing megacity.