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Introduction

Hāpua are a type of non-estuarine river mouth lagoon, common in New Zealand, which form where gravel-bed rivers emerge onto high wave energy micro/meso-tidal coasts. Hāpua are separated from the ocean by a mixed sand and gravel beach barrier, through which a highly dynamic outlet channel generally flows. Hāpua outlet channel rapidly change in length, width and position in response to sediment transport by fluvial flows and waves.

HapuaMod is a morphodynamic model of hāpua evolution. The model is driven by timeseries inputs of river flow, wave conditions and sea level (i.e. tides). HapuaMod was developed following research to develop a conceptual model of hāpua behaviour based on monitoring of the Hurunui hāpua in North Canterbury, New Zealand, described by Measures et al. (2020).

HapuaMod is being developed by Richard Measures, as part of PhD research funded by NIWA's Environmental Flows research program.

Contents

How the model works

1. Overview
2. 1D river hydrodynamics and morphology
3. 1-Line shoreline model
4. Wave overtopping/overwashing
5. Inter-model connectivity
6. Complexities of the outlet channel and lagoon
7. Limitations

How to run HapuaMod

1. Requirements (dependencies)
2. Model configuration
3. Running models
4. Model outputs
5. Animating results

Model development

1. Introduction to using the HapuaMod GitHub repository
2. Directory structure
3. Automated testing

Other notes/details

1. Notes on logic rules in mor.updateMorphology