Border-Dyke Irrigation Overview

Name:

Date:

📚 Part 1: WALT & Multiple Choice

WALT (We Are Learning To): describe how border-dyke (flood) irrigation works, compare it with modern spray systems, and identify key benefits and problems.

Success criteria: I can define border-dyke irrigation, list two advantages and two limitations, calculate simple water volumes for a paddock, and sketch a border-dyke cross-section.

Dyslexia-friendly reading options: Read instructions aloud with a partner, use a ruler to track lines, highlight key words (border, dyke, efficiency), and work in short 10–15 minute blocks.

1. What is border-dyke (flood) irrigation?

A surface method using earth borders to hold water on slopes

A type of spray irrigation using sprinklers

A sub-surface drip system

A pumped centre-pivot system

2. Historically, border-dyke irrigation was widely used in the Canterbury plains because:

The land was flat and fields were partitioned by earth borders

It required expensive modern pumps

It only worked in steep, rocky country

It was the most water-efficient option available

3. Compared with modern spray systems, border-dyke irrigation is:

More efficient at delivering water evenly

Less efficient due to higher losses from runoff and evaporation

Identical in efficiency

Better for irregular-shaped small paddocks

4. Check all that apply: Common problems associated with border-dyke irrigation include:

Waterlogging of soil

Increased evaporation and seepage losses

Reduced need for earth borders and maintenance

Risk of salinity or nutrient runoff

✏️ Part 2: Short Answers & Activities

5. In one sentence, explain why many farmers in Canterbury are switching from border-dyke to spray irrigation.

6. List two advantages and two limitations of border-dyke irrigation.

7. Calculation: A 1 hectare paddock receives 10 mm of water from a single flood event. How many cubic metres of water is that? Show your working.

(Hint: 1 hectare = 10,000 m²; 10 mm = 0.01 m)

8. Sketch a simple cross-section showing a border-dyke, flow direction, and where the water sits on the paddock. Label the dyke and the flow. Record this sketch on the following page.

Differentiation strategies: Provide sentence starters for learners who need support (e.g. "Border-dykes are used to..."). Allow oral answers or a paired-read option. Give advanced students extra data for calculations.

Extension activity: Research one modern spray irrigation method and write a short comparison (2–3 sentences) explaining why it may be preferred over border-dyke irrigation.