Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Integrating soil data into hydrological models – results of a user survey

Joseph Pollacco, October, 2014

Objectives of survey

The objective of this survey was to establish the current and future needs of hydrological model users to assess: (a) the advantages of developing a spatial hydrological model platform that can model movement of water in the landscape (lateral flow), and (b) the best usage of the available spatialised soil data such as S-map.

The long-term objective is to implement a flexible and user-friendly catchment-scale hydrological modelling platform. The proposed platform will enable users to easily plug-and-play their module of interest that relies on hydrological output, at a particular scale and time step. For example, the outputs could be used to compute contaminant transport, sediment yield, N and P leaching, irrigation water demand, etc.

The following questions were investigated:

What models using hydrological inputs are being used in New Zealand and what are future modelling needs?

  • What soil information is required to meet these modelling needs?
  • What software should the hydrological modelling platform use?
  • What automatic optimisation software should be used?
  • Survey participants

Figure 1 . Affiliations of survey participants.
Survey participants

The survey was completed by 50 users of hydrological models, including researchers and consultants from both the public and private sector.

Figure 3 . Hydrological output of interest.
Unsaturated zone modelling

The survey shows that the main scale of interest is at the catchment scale, and on terrain <15°. These slopes include the intensively managed agricultural land.

Figure 11 . Soil databases currently used in hydrological modelling (multiple choices accepted).
Use of soil databases in hydrological modelling

S-map and the Fundamental Soil Layers are the most widely used soil databases.

Figure 14 . Importance of automatic calibration tool boxes.
Optimisation and sensitivity analysis

A majority of responses (73%) show an interest in having a powerful calibration (inverse modelling) tool.

Figure 10 . Participants’ ranking of importance of lateral flow (multiple choices accepted).
Recommended hydrological modelling platform and future contribution

40% of survey participants indicated their willingness to be involved in a collaborative development of a new hydrological modelling platform.

Figure 6 . Terrain of interest (multiple answers accepted).

The survey was completed by a range of researchers and consultants, half of whom are active modellers, while the others are users of established models. This demonstrates the importance of the proposed hydrological model platform being made accessible to users with a limited knowledge of programming.