Strategic Overview of Rivers & Catchments: Geomorphology & River Management

Conference

This programme has been designed to identify a framework to raise awareness, learning and development pathways and ultimately drive recruitment and attraction strategies to assure river management expertise for the future

Date & Time

2-day workshop – Wellington

14 & 15 February 2023

Day one: classroom

Day two: field trip, Waikanae

Cost

Cost – $900.00

Council Staff – $200.00 discount

Rivers Group - 10% discount

Please mention discount when making the booking

Where to register

Email Rachael Armstrong - Rachael.Armstrong@hbrc.govt.nz

Outline

Key Learning Objectives/Outcomes

Familiarity with key principles in fluvial geomorphology and their application to various river management situations (e.g., catchment (and regional) planning, sediment flux issues, relation to flood hazards).

Key themes

Management issues for which geomorphic insight is fundamental:

  • Work with the river (nature-based solutions) – respect diversity, work with process
  • Determine what is realistically achievable
  • Be proactive, precautionary, pre-emptive – tackle threatening processes
  • Risk management
  • Integrated Catchment Management
  • Active and passive practices (including the do-nothing option) – hard versus soft engineering practices … Role of maintenance (weed management)
  • Flood management/protection versus ‘living with a living river’
  • Managing river erosion
  • Using sediment budgets to manage sedimentation issues (including sand/gravel extraction)

Spatial Dimensions of geomorphologically-informed river management

Catchment

  • Fundamental geomorphic unit
  • Longitudinal profile – source, transfer accumulation zones
  • Network relationships (tributary-trunk stream pattern, flux)
  • Connectivity relationships

Channel planform: Braided, wandering gravel-bed, active meandering passive meandering, discontinuous watercourse (wetland/swamp)

Channel geometry

  • Downstream and at-a-station hydraulic geometry
  • Size and shape

Geomorphic units

  • Erosional and depositional forms (and process relations)
  • Channel (instream) and floodplain
  • Assemblages – and approach to analysis of morphodynamics, condition, recovery (Fryirs & Brierley, 2021)

Bed material size

  • Bedrock, Boulder/cobble, gravel-bed, sand-bed, fine-grained
  • Bedload, mixed load, suspended load

Temporal dimensions of geomorphologically-informed river management

Timescale: Geologic, geomorphic, engineering

Magnitude-frequency relations

Equilibrium versus non-linear relations

Legacy effect (landscape memory)

Processes of geomorphic river adjustment

  • Balance of impelling and resisting forces
  • Stream power, shear stress
  • Resistance elements – role of riparian vegetation, wood, ecosystem engineers
  • Entrainment, transport, deposition (Hjulstrom curve)
  • Sediment transport – Bedload, suspended load, solution load
  • Aggradation/degradation regime – Lane Balance

Evolutionary trajectory of rivers (and recovery potential)

  • Relating character and behaviour (capacity for adjustment/range of variability) to evolutionary trajectory
  • Scoping (modeling) prospective river futures to determine what is realistically achievable in management

Geomorphology and river health (condition)

What do we measure where, how and why?

What do we measure against?

Geomorphic relations to Māori conceptualisations of rivers

A living river ethos, mauri, mana, ora

How geomorphology can support river management (indicative only – set up follow up specialist courses)

Scoping river futures - Proactive and precautionary approaches to Visioning & Catchment Planning

Concern for treatment response

Geoethical considerations – concerns for social and environmental justice

  • Risk management
  • Integrated Catchment Management
  • Active and passive practices (including the do-nothing option) – hard versus soft engineering practices … Role of maintenance (weed management)
  • Flood management/protection versus ‘living with a living river’
  • Managing river erosion
  • Using sediment budgets to manage sedimentation issues (including sand/gravel extraction)

Presenters

Ian Fuller, Gary Brierley, Jon Tunnicliffe