My research interests include the effect of land use change on water resources and how global change affects the benefits we derive from nature.
At Stanford I work with the Natural Capital Project, focusing on the development of water models and their application to hydrological services assessments. I led the development of the nutrient and sediment retention models, and contributed to ecosystem services assessments both at the global scale and in regional studies in India, Colombia, Brazil, and the US. I also developed a particular interest in characterizing uncertainties associated with the use of decision-support tools for conservation projects.
Prior to joining the Natural Capital Project, I worked as an environmental engineer in Phnom Penh, Cambodia. I then enrolled in a PhD program at Monash University, Australia, in the field of integrated urban water management. My PhD research involved environmental monitoring and modeling work, provided practical insights into the role of stormwater management techniques in urban catchments.
Doctor of Philosophy, Monash University (2013)
PhD, Monash University, Hydrology and Environmental Engineering (2013)
MEng, Ecole Centrale Nantes, Engineering, Major in Civil & Environmental Engineering (2008)
Gretchen Daily, Postdoctoral Faculty Sponsor
Sediment delivery modeling in practice: Comparing the effects of watershed characteristics and data resolution across hydroclimatic regions.
The Science of the total environment
2017; 580: 1381-1388
Geospatial models are commonly used to quantify sediment contributions at the watershed scale. However, the sensitivity of these models to variation in hydrological and geomorphological features, in particular to land use and topography data, remains uncertain. Here, we assessed the performance of one such model, the InVEST sediment delivery model, for six sites comprising a total of 28 watersheds varying in area (6-13,500km(2)), climate (tropical, subtropical, mediterranean), topography, and land use/land cover. For each site, we compared uncalibrated and calibrated model predictions with observations and alternative models. We then performed correlation analyses between model outputs and watershed characteristics, followed by sensitivity analyses on the digital elevation model (DEM) resolution. Model performance varied across sites (overall r(2)=0.47), but estimates of the magnitude of specific sediment export were as or more accurate than global models. We found significant correlations between metrics of sediment delivery and watershed characteristics, including erosivity, suggesting that empirical relationships may ultimately be developed for ungauged watersheds. Model sensitivity to DEM resolution varied across and within sites, but did not correlate with other observed watershed variables. These results were corroborated by sensitivity analyses performed on synthetic watersheds ranging in mean slope and DEM resolution. Our study provides modelers using InVEST or similar geospatial sediment models with practical insights into model behavior and structural uncertainty: first, comparison of model predictions across regions is possible when environmental conditions differ significantly; second, local knowledge on the sediment budget is needed for calibration; and third, model outputs often show significant sensitivity to DEM resolution.
View details for DOI 10.1016/j.scitotenv.2016.12.103
View details for PubMedID 28040219
Incorporating climate change into ecosystem service assessments and decisions: a review
GLOBAL CHANGE BIOLOGY
2017; 23 (1): 28-41
Climate change is having a significant impact on ecosystem services and is likely to become increasingly important as this phenomenon intensifies. Future impacts can be difficult to assess as they often involve long timescales, dynamic systems with high uncertainties, and are typically confounded by other drivers of change. Despite a growing literature on climate change impacts on ecosystem services, no quantitative syntheses exist. Hence, we lack an overarching understanding of the impacts of climate change, how they are being assessed, and the extent to which other drivers, uncertainties, and decision making are incorporated. To address this, we systematically reviewed the peer-reviewed literature that assesses climate change impacts on ecosystem services at subglobal scales. We found that the impact of climate change on most types of services was predominantly negative (59% negative, 24% mixed, 4% neutral, 13% positive), but varied across services, drivers, and assessment methods. Although uncertainty was usually incorporated, there were substantial gaps in the sources of uncertainty included, along with the methods used to incorporate them. We found that relatively few studies integrated decision making, and even fewer studies aimed to identify solutions that were robust to uncertainty. For management or policy to ensure the delivery of ecosystem services, integrated approaches that incorporate multiple drivers of change and account for multiple sources of uncertainty are needed. This is undoubtedly a challenging task, but ignoring these complexities can result in misleading assessments of the impacts of climate change, suboptimal management outcomes, and the inefficient allocation of resources for climate adaptation.
View details for DOI 10.1111/gcb.13457
View details for Web of Science ID 000390218300004
View details for PubMedID 27507077
- Optimizing land use decision-making to sustain Brazilian agricultural profits, biodiversity and ecosystem services BIOLOGICAL CONSERVATION 2016; 204: 221-230
- Managing forest ecosystem services for hydropower production ENVIRONMENTAL SCIENCE & POLICY 2016; 61: 221-229
- Landscape configuration is the primary driver of impacts on water quality associated with agricultural expansion ENVIRONMENTAL RESEARCH LETTERS 2016; 11 (7)
- Will it rise or will it fall? Managing the complex effects of urbanization on base flow FRESHWATER SCIENCE 2016; 35 (1): 293-310
- Which baseflow metrics should be used in assessing flow regimes of urban streams? HYDROLOGICAL PROCESSES 2015; 29 (20): 4367-4378
- A new approach to modeling the sediment retention service (InVEST 3.0): Case study of the Cape Fear catchment, North Carolina, USA SCIENCE OF THE TOTAL ENVIRONMENT 2015; 524: 166-177
- Automated Chamber System to Measure Field Evapotranspiration Rates JOURNAL OF HYDROLOGIC ENGINEERING 2015; 20 (2)
Future Earth Young Scientists Conference on Integrated Science and Knowledge Co-Production for Ecosystems and Human Well-Being (vol 11, pg 11553, 2014)
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
2015; 12 (2): 2088-2089
The authors would like to add the following affiliation for Peter Søgaard Jørgensen of paper : 8 International Network of Next-Generation Ecologists, Universitetsparken 15, Building 3, Copenhagen 2100, Denmark[...].
View details for DOI 10.3390/ijerph120202088
View details for Web of Science ID 000350209800059
Sensitivity analysis of a sediment dynamics model applied in a Mediterranean river basin: Global change and management implications
SCIENCE OF THE TOTAL ENVIRONMENT
2015; 502: 602-610
Climate change and land-use change are major factors influencing sediment dynamics. Models can be used to better understand sediment production and retention by the landscape, although their interpretation is limited by large uncertainties, including model parameter uncertainties. The uncertainties related to parameter selection may be significant and need to be quantified to improve model interpretation for watershed management. In this study, we performed a sensitivity analysis of the InVEST (Integrated Valuation of Environmental Services and Tradeoffs) sediment retention model in order to determine which model parameters had the greatest influence on model outputs, and therefore require special attention during calibration. The estimation of the sediment loads in this model is based on the Universal Soil Loss Equation (USLE). The sensitivity analysis was performed in the Llobregat basin (NE Iberian Peninsula) for exported and retained sediment, which support two different ecosystem service benefits (avoided reservoir sedimentation and improved water quality). Our analysis identified the model parameters related to the natural environment as the most influential for sediment export and retention. Accordingly, small changes in variables such as the magnitude and frequency of extreme rainfall events could cause major changes in sediment dynamics, demonstrating the sensitivity of these dynamics to climate change in Mediterranean basins. Parameters directly related to human activities and decisions (such as cover management factor, C) were also influential, especially for sediment exported. The importance of these human-related parameters in the sediment export process suggests that mitigation measures have the potential to at least partially ameliorate climate-change driven changes in sediment exportation.
View details for DOI 10.1016/j.scitotenv.2014.09.074
View details for Web of Science ID 000345730800065
View details for PubMedID 25302447
- Uncertainty analysis of a spatially explicit annual water-balance model: case study of the Cape Fear basin, North Carolina HYDROLOGY AND EARTH SYSTEM SCIENCES 2015; 19 (2): 839-853
- Modelling the impact of stormwater source control infiltration techniques on catchment baseflow HYDROLOGICAL PROCESSES 2014; 28 (24): 5817-5831
- Ecosystem services: Challenges and opportunities for hydrologic modeling to support decision making WATER RESOURCES RESEARCH 2014; 50 (5): 4535-4544