Field Trips and Guest Lecture

Question 1

Discuss the following issue: As precipitation deficits during the growing season get larger in Belgium, we are faced with river levels that are too low in summers. That is also the case for the Meuse river. Does the Kinrooi irrigation scheme (with water from the CIRO pumping station) contribute to that problem? Please discuss. There is no correct or wrong answer here. What is needed is a good reasoning.

Answer 1

= Precipitation Deficits: The first aspect to consider is the increasing precipitation deficits during the growing season in Belgium. If the precipitation deficits are so large, the Kinrooi irrigation scheme may have negligible effects. In this case, the low river levels are mainly a result of insufficient rainfall rather than excessive water extraction.
- Water Withdrawal/ farmer water demand: The next step is to evaluate the amount of water being withdrawn from the CIRO pumping station for the Kinrooi irrigation scheme. If the withdrawal is significant compared to the river’s natural flow and exceeds the river’s capacity to replenish itself, it could contribute to the problem of low river levels. Factors to consider include the volume of water withdrawn, the frequency of withdrawal, and the overall impact on the river’s water balance.

Question 2

Explain how irrigation with a hose reel and raingun is performed (what does the farmer have to do? How does the equipment function?) What are advantages and disadvantages?

Answer 2

• The hose reel houses the irrigation hose. It is designed to wind and unwind the hose smoothly and efficiently. The hose carries water from the water source to the raingun (high pressure sprinkler). Rain gun can shoot 40 m distance or further with larger systems
• Farmers should position the hose reel and raingun in the needed area and adjust the sprinkler pressure based on crop needs. Monitor the process and ensure that the water distribution is sufficient for the crops.
• Advantage:
  > Flexibility - can move around
  > Wide coverage - raingun
• Disadvantage
  > Initial costs
  > Energy requirements - requires a reliable power source to pump water to gun but turning of raingun does not require energy
  > Labour - farmer has to drive to the field and move hose reel

Question 3

Explain how farmers use drip irrigation in pear production in Belgium in order to maximize the financial return

Answer 3

• Drip irrigation delivers water directly to root zone - minimises water loss through evaporation or runoff = more efficient water use = better crop yield and quality for volume of water applied
• Using soil and plant sensors, moisture content is monitored and input into a model routinely. The model then gives the farmers an optimised irrigation schedule based on predicted meteorological conditions. With drip irrigation the farmers can apply irrigation only when needed and less labour required from the farmer (don’t need to go into field)

Question 4

Briefly explain how the Kinrooi irrigation system scheme works (water source, pumping infrastructure, water distribution system, for what purposes do the farmers use the water, what arrangement is there for when the farmer can take off water and who pays for the maintenance of the system?)

Answer 4

Large reservoir of water supplied by surface, ground water and from leaching from the fields which are situated higher than the reservoir. Farmers can take water when they need, whenever they want. Pay a certain amount per volume of water which takes into account maintenance of the system. 4 large pumps for summer and 4 smaller pumps for winter - water is still needed to feed the cattle, washing etc `

Question 5

Explain which are the typical steps in an irrigation design project as explained by the SHER project engineer?

Answer 5

• Diagnostic: prepare project, check and update available data, field visit, stakeholder meeting
• Feasibility study:
  > topography, soil study, land use, agro-socio-economic characterization (also includes data availability)
  > Economic analysis
• Development options
  > Consider topography to irrigate by gravity
  » Presence of significant slopes in the area, ignore areas with no or minor slopes
• Design study: structures design, cost, plan production
• Tender documents: administrative documents, selection of building company, technical specifications (materials, equipment required), unit price sheet
• Monitoring and control of the works