dynatopmodel {dynatopmodel}R Documentation

Implementation of the Dynamic TOPMODEL hydrological model.

Description

A native R implementation and enhancement of Dynamic TOPMODEL, an extension to the semi-distributed hydrological model TOPMODEL. It includes some digital terrain analysis functions for discretisation of catchments by topographic indexes and other geo-referenced layers containing relevant landscape data.

TOPMODEL (Beven & Kirkby, 1979) is a well-established and widely used hydrological model that implements a spatial aggregation strategy ("discretisation") in order to reduce its computational demands. Hydrological similar areas identified by the discretisation procedure are referred to as hydrological response units (HRUs). Beven and Freer (2001) introduced a "dynamic" variant that addressed some of the limitations of the original TOPMODEL but which retained its computational and parametric efficiency. In particular, the original assumption of a quasi-steady water table was replaced by time-dependent kinematic routing between and within HRUs. This allows a more flexible discretisation approach, whereby any type of landscape data can be used to identify the HRUs.

With the introduction of a single new parameter SDmax specifying the maximum storage deficit before downslope flow out of a HRU ceases, variable upslope drainage areas can be simulated. This allows application to arid catchments subject to seasonal drying of upslope areas.

The 2001 version was implemented in FORTRAN and it, and its source code, have not been made generally available. It has been applied in a number of studies (see Metcalfe et al, 2015). A modified version with chemical stores attached to each HRU was implemented by Page et al. (2007) and applied to modelling the Cl signal in the Hafren, Mid-Wales. This new version, described in detail in Metcalfe et al. (2015), retains the core dynamics of the FORTRAN implementation but makes use of data storage and vectorisation features of the R language to allow efficient scaling of the problem domain. This version was utilised by Metcalfe et al. (2017) to supply hillslope runoff to a new hydraulic channel routing model for evaluation of the effectiveness of arrays of in-channel barriers on mitigating flood risk.

A new, semi-distributed surface routing algorithm has been introduced in this version. This allows examination of surface storages as they move downslope and specification of different effective velocities throughout each unit. It also allows for a modified routing matrix that can reflect situations where the surface flow pathways differ from the topography. These could be used to simulate a unit associated with one or more surface features designed to intercept storm runoff, such as excavated ponds or bunds (see Hankin et al., 2016, 2017; Metcalfe, 2017).

The preprocessing routines supplied incorporate handling of geo-referenced spatial data to allows it to integrate with modern GIS through industry-standard file formats, such as GEOTiff and ESRI Shapefiles.

References

Beven, K. J. and M. J. Kirkby (1979). A physically based variable contributing area model of basin hydrology. Hydrol. Sci. Bull 24(1): 43-69.

Beven, K. J. and J. Freer (2001). A Dynamic TOPMODEL. Hydrological Processes 15(10): 1993-2011.

Hankin, B., Craigen I., Chappell, N., Metcalfe, P., Page, T. (2016). The Rivers Trust Life-IP Natural Course Project: Strategic Investigation of Natural Flood Management in Cumbria.Technical Report. Available at http://naturalcourse.co.uk/uploads/2017/04/2016s4667-Rivers-Trust-Life-IP-NFM-Opportunities-Technical-Report-v8.0.pdf. Rivers Trust, Callington, Cornwall, UK.

Hankin, B., Metcalfe, P., Johnson, D., Chappell, N., Page, T., Craigen, I., Lamb, R., Beven, K. (2017). Strategies for Testing the Impact of Natural Flood Risk Management Measures. In Hromadka, T. & Rao, P. (eds). Flood Risk Management. InTech, Czech Republic. ISBN 978-953-51-5526-3.

Metcalfe, P. (2017). Development of a modelling framework for integrated flood risk management (Doctoral dissertation). Lancaster University, UK.

Metcalfe, P., Beven, K., & Freer, J. (2015). Dynamic TOPMODEL: a new implementation in R and its sensitivity to time and space steps. Environmental Modelling & Software, 72, 155-172.

Metcalfe, P., Beven, K., Hankin, B., & Lamb, R. (2017). A modelling framework for evaluation of the hydrological impacts of nature?based approaches to flood risk management, with application to in-channel interventions across a 29 km2 scale catchment in the United Kingdom. Hydrological Processes, 31(9), 1734-1748.

Page, T., Beven, K. J., Freer, J., & Neal, C. (2007). Modelling the chloride signal at Plynlimon, Wales, using a modified dynamic TOPMODEL incorporating conservative chemical mixing (with uncertainty). Hydrological Processes, 21(3), 292-307.

See Also

discretise

run.dtm


[Package dynatopmodel version 1.2.1 Index]