We conducted a PUB (predictions in ungauged basins) experiment looking at hydrology and crop dynamics in the semi-arid rural Mod catchment in India. The experiment is led by the motivation a) to develop a coupled eco-hydrological model capable to analyse land use strategies concerning crop water need, erosion protection, crop yield and resistivity against droughts and floods, and b) to assess the feasibility of a strategy to collect the necessary data in a data scarce region.

Our experiment combines parsimonious data assessment and eco-hydrological model coupling at the lower mesoscale. Linking bottom-up sampling of functionally representative soil classes and top-down regionalisation based on spectral properties of the same resulted in a comprehensive distributed data basis for the model. A clear focus on the dominating processes and the catena as organising landscape element in the given environmental setting enabled this.

We employ WASA (model of Water Availability in Semi-Arid environments) for uncalibrated process-based water balance modelling and integrate a crop simulation subroutine based on SWAP (Soil Water Atmosphere Plant model) in order to account for crop dynamics, feedbacks and yield estimation.

While we find the data assessment strategy and the hydrological model application largely feasible through its awareness to scale, processes and model concepts, the simulation of feedbacks with crops turned out problematic. Contributing to the PUB issue, more general conclusions are drawn concerning spatially distributed structural information and uncalibrated modelling.