Academic Appointments


  • Research Engineer, Stanford Woods Institute for the Environment

All Publications


  • Global expansion of sustainable irrigation limited by water storage. Proceedings of the National Academy of Sciences of the United States of America Schmitt, R. J., Rosa, L., Daily, G. C. 2022; 119 (47): e2214291119

    Abstract

    Providing affordable and nutritious food to a growing and increasingly affluent global population requires multifaceted approaches to target supply and demand aspects. On the supply side, expanding irrigation is key to increase future food production, yet associated needs for storing water and implications of providing that water storage, remain unknown. Here, we quantify biophysical potentials for storage-fed sustainable irrigation-irrigation that neither depletes freshwater resources nor expands croplands but requires water to be stored before use-and study implications for food security and infrastructure. We find that water storage is crucial for future food systems because 460 km3/yr of sustainable blue water, enough to grow food for 1.15 billion people, can only be used for irrigation after storage. Even if all identified future dams were to contribute water to irrigation, water stored in dammed reservoirs could only supply 209 ± 50 km3/yr to irrigation and grow food for 631 ± 145 million people. In the face of this gap and the major socioecologic externalities from future dams, our results highlight limits of gray infrastructure for future irrigation and urge to increase irrigation efficiency, change to less water-intensive cropping systems, and deploy alternative storage solutions at scale.

    View details for DOI 10.1073/pnas.2214291119

    View details for PubMedID 36375068

  • Modeling multiple ecosystem services and beneficiaries of riparian reforestation in Costa Rica ECOSYSTEM SERVICES Langhans, K. E., Schmitt, R. P., Chaplin-Kramer, R., Anderson, C. B., Vargas Bolanos, C., Vargas Cabezas, F., Dirzo, R., Goldstein, J. A., Horangic, T., Miller Granados, C., Powell, T. M., Smith, J. R., Alvarado Quesada, I., Umana Quesada, A., Monge Vargas, R., Wolny, S., Daily, G. C. 2022; 57
  • Floating solar power: evaluate trade-offs NATURE Almeida, R. M., Schmitt, R., Grodsky, S. M., Flecker, A. S., Gomes, C. P., Zhao, L., Liu, H., Barros, N., Kelman, R., McIntyre, P. B. 2022; 606 (7913): 246-249

    View details for Web of Science ID 000807557600013

    View details for PubMedID 35672509

  • Strategic planning of hydropower development: balancing benefits and socioenvironmental costs CURRENT OPINION IN ENVIRONMENTAL SUSTAINABILITY Almeida, R. M., Schmitt, R. P., Castelletti, A., Flecker, A. S., Harou, J. J., Heilpern, S. A., Kittner, N., Kondolf, G., Opperman, J. J., Shi, Q., Gomes, C. P., McIntyre, P. B. 2022; 56
  • Restoring Rivers and Floodplains for Habitat and Flood Risk Reduction: Experiences in Multi-Benefit Floodplain Management From California and Germany FRONTIERS IN ENVIRONMENTAL SCIENCE Serra-Llobet, A., Jaehnig, S. C., Geist, J., Kondolf, G., Damm, C., Scholz, M., Lund, J., Opperman, J. J., Yarnell, S. M., Pawley, A., Shader, E., Cain, J., Zingraff-Hamed, A., Grantham, T. E., Eisenstein, W., Schmitt, R. 2022; 9
  • Nature-based solutions for flood risk reduction: A probabilistic modeling framework ONE EARTH Lallemant, D., Hamel, P., Balbi, M., Lim, T., Schmitt, R., Win, S. 2021; 4 (9): 1310-1321
  • Sediment transport at the network scale and its link to channel morphology in the braided Vjosa River system EARTH SURFACE PROCESSES AND LANDFORMS Bizzi, S., Tangi, M., Schmitt, R. P., Pitlick, J., Piegay, H., Castelletti, A. 2021

    View details for DOI 10.1002/esp.5225

    View details for Web of Science ID 000696075900001

  • Strategic basin and delta planning increases the resilience of the Mekong Delta under future uncertainty PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Schmitt, R. P., Giuliani, M., Bizzi, S., Kondolf, G. M., Daily, G. C., Castelletti, A. 2021; 118 (36)

    Abstract

    The climate resilience of river deltas is threatened by rising sea levels, accelerated land subsidence, and reduced sediment supply from contributing river basins. Yet, these uncertain and rapidly changing threats are rarely considered in conjunction. Here we provide an integrated assessment, on basin and delta scales, to identify key planning levers for increasing the climate resilience of the Mekong Delta. We find, first, that 23 to 90% of this unusually productive delta might fall below sea level by 2100, with the large uncertainty driven mainly by future management of groundwater pumping and associated land subsidence. Second, maintaining sediment supply from the basin is crucial under all scenarios for maintaining delta land and enhancing the climate resilience of the system. We then use a bottom-up approach to identify basin development scenarios that are compatible with maintaining sediment supply at current levels. This analysis highlights, third, that strategic placement of hydropower dams will be more important for maintaining sediment supply than either projected increases in sediment yields or improved sediment management at individual dams. Our results demonstrate 1) the need for integrated planning across basin and delta scales, 2) the role of river sediment management as a nature-based solution to increase delta resilience, and 3) global benefits from strategic basin management to maintain resilient deltas, especially under uncertain and changing conditions.

    View details for DOI 10.1073/pnas.2026127118

    View details for Web of Science ID 000705126700014

    View details for PubMedID 34475204

    View details for PubMedCentralID PMC8433524

  • Joint strategic energy and river basin planning to reduce dam impacts on rivers in Myanmar ENVIRONMENTAL RESEARCH LETTERS Schmitt, R. P., Kittner, N., Kondolf, G., Kammen, D. M. 2021; 16 (5)
  • Modeling seasonal water yield for landscape management: Applications in Peru and Myanmar. Journal of environmental management Hamel, P., Valencia, J., Schmitt, R., Shrestha, M., Piman, T., Sharp, R. P., Francesconi, W., Guswa, A. J. 2020; 270: 110792

    Abstract

    A common objective of watershed management programs is to secure water supply, especially during the dry season. To develop such programs in contexts of low data and resource availability, program managers need tools to understand the effect of landscape management on the seasonal water balance. However, the performance of simple, parsimonious models is poorly understood. Here, we examine the behavior of a geospatial tool, developed to map monthly water budgets and baseflow contributions and forming part of the InVEST (integrated valuation of ecosystem services and trade-offs) software suite. The model uses monthly climate, topography, and land-use data to compute spatial indices of groundwater recharge, baseflow, and quickflow. We illustrate the model application in two large basins in Peru and Myanmar, where we compare results with observed data and alternative hydrologic models. We show that the spatial distribution of baseflow contributions correlated well with an established model in the Peruvian basin (r2=0.81at the parcel scale). In Myanmar, the model shows an overall satisfactory performance for representing month to month variation (Nash-Sutcliffe-Efficiency 0.6-0.8); however, errors are scale dependent highlighting limitations in representing processes in large basins. Our study highlights modeling challenges, in particular trade-offs between model complexity and accuracy, and illustrates the role that parsimonious models can play to support watershed management programs.

    View details for DOI 10.1016/j.jenvman.2020.110792

    View details for PubMedID 32721288

  • Impacts of current and future large dams on the geographic range connectivity of freshwater fish worldwide. Proceedings of the National Academy of Sciences of the United States of America Barbarossa, V. n., Schmitt, R. J., Huijbregts, M. A., Zarfl, C. n., King, H. n., Schipper, A. M. 2020

    Abstract

    Dams contribute to water security, energy supply, and flood protection but also fragment habitats of freshwater species. Yet, a global species-level assessment of dam-induced fragmentation is lacking. Here, we assessed the degree of fragmentation of the occurrence ranges of ∼10,000 lotic fish species worldwide due to ∼40,000 existing large dams and ∼3,700 additional future large hydropower dams. Per river basin, we quantified a connectivity index (CI) for each fish species by combining its occurrence range with a high-resolution hydrography and the locations of the dams. Ranges of nondiadromous fish species were more fragmented (less connected) (CI = 73 ± 28%; mean ± SD) than ranges of diadromous species (CI = 86 ± 19%). Current levels of fragmentation were highest in the United States, Europe, South Africa, India, and China. Increases in fragmentation due to future dams were especially high in the tropics, with declines in CI of ∼20 to 40 percentage points on average across the species in the Amazon, Niger, Congo, Salween, and Mekong basins. Our assessment can guide river management at multiple scales and in various domains, including strategic hydropower planning, identification of species and basins at risk, and prioritization of restoration measures, such as dam removal and construction of fish bypasses.

    View details for DOI 10.1073/pnas.1912776117

    View details for PubMedID 32015125

  • The CASCADE toolbox for analyzing river sediment connectivity and management ENVIRONMENTAL MODELLING & SOFTWARE Tangi, M., Schmitt, R., Bizzi, S., Castelletti, A. 2019; 119: 400–406
  • Deploy diverse renewables to save tropical rivers NATURE Schmitt, R. P., Kittner, N., Kondolf, G., Kammen, D. M. 2019; 569 (7756): 330–32

    View details for Web of Science ID 000468123700020

    View details for PubMedID 31092945