Week 10 - Catchment & Soil ErosionOverview

Question 1

Describe the Hydrological Cycle and how it relates to the atmospheric processes

Answer 1

Hydrological cycle is the sequence of conditions through which water passes from vapor in the atmosphere through precipitation upon land or water surfaces and ultimately back into the atmosphere as a result of evaporation and transpiration.

The atmospheric circulation (6-cell model) and ocean currents cause uneven spatial and temporal distribution of precipitation over the Earth’s surface:

High amounts of rain in certain locations (refer to ITCZ) other areas where dry. This setups different environments for outputs and inputs of flows

Question 2

Define the term ‘catchment’ and outline the four main natural assets that catchments provide

Answer 2

• Topographically defined (e.g. hills/mountains) area of land where water drains “down” to a stream then to a common outlet, e.g. from mountains/hills to major river or the sea
• Catchment “contains” the water and land and therefore treated as a biosystem
• Boundaries = drainage divides
  What are the four main natural assets of catchments?
  1. Water
  Catchment processes:
• input of water
• Hillslope processes: infilitration, interception, throughfall, overland flow, throughflow, percolation (the way water moves through the landscape in the catchment, studying lets us know how to measure and manage)
• Subsurface processes: ground water (water table, permeability, water-table, aquifers)

2. Soil
   - Result of catchment processes (inputs, flows, storages and outputs)
   - Controls on ecological processes, and agricultural production
   - Varies seasonally with changes in inputs, outputs and storages:
3. Biota
4. Atmosphere

Question 3

Explain the key hillslope, surface and subsurface hydrological processes operating in the catchment

Answer 3

What is fluvial processes? - Overland flow (hillslope processes) & Streamflow (river processes)
What are the four main natural assets of catchments?
1. Water
Catchment processes: input of water
Hillslope processes: infilitration, interception, throughfall, overland flow, throughflow, percolation (the way water moves through the landscape in the catchment, studying lets us know how to measure and manage)
Subsurface processes: ground water (water table, permeability, water-table, aquifers)

Question 4

Describe, for a temperate climate, the seasonal changes in soil water resources

Question 5

Explain how catchment hydrographs can change when land cover is altered

Question 6

Explain the process of Integrated Catchment Management and outline the key components of Regional Catchment Strategies

Question 7

Describe some key soil characteristics and agro-ecological landscapes in Victoria and other global examples

Answer 7

Agroecological zone is areas with the same conditions of rainfall, soils and geology

Question 8

Distinguish between soil health and soil quality

Answer 8

Soil health is the continued capacity of a soil to function as a vital living system, within ecosystem and land use boundaries, to sustain biological productivity, maintain the quality of air and water environments, and promote plant, animal and human health
• Contrast quality with health
• Both have a ‘fit for purpose’ component
• Resilience

Soil quality The capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation