Strategic basin and delta planning increases the resilience of the Mekong Delta under future uncertainty

# Geospatial data and analysis results for:

Schmitt R. J. P., Giuliani, M., Bizzi, S., Kondolf, G. M., Daily, G. C., Castelletti, A. (2021). Strategic basin and delta planning increases the resilience of the Mekong Delta under future uncertainty (accepted for publication in the Proceedings of the National Academy of Sciences). 

# Prepared by R. Schmitt ([e-mail]), July 2021. 

# 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 the 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, to 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 sediment management at individual dams. Our results demonstrate (1) the needs 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.

# Contents:
Mekong_Basin_geomorphic provinces.gpkg: location of geomorphic provinces and the associated sediment load. Digtized and modified from Kondolf et al., 2014
Schmitt_et_al_PNAS_2020-26127P.m: Script demonstrating the robust analysis and the derivation of decision surfaces (e.g., Fig. 3, f, g and Figure 4)
Data PNAS_2020-26127P.mat: Resimulation data (i.e., sediment yield and dam sediment trapping multipliers and the response in terms of sediment delivery to the delta)