Farm Dams for Water Storage: The Complete Walkthrough

This guide covers farm dams for water storage, rated a hard task, typically taking days of earthworks.

This is the expanded version of our farm dams for water storage guide, for anyone who wants the full detail rather than just the quick-reference card.

Captures and stores runoff

A farm dam captures surface runoff from its catchment area and stores it for stock or irrigation use — this is a different and generally more straightforward proposition than damming a flowing watercourse for power, though it still typically requires approval.

Before You Start

Worth paying attention to:

• A suitable site with adequate natural catchment and appropriate soil (clay content for a sealed dam)
• Earthmoving machinery (usually contracted)
• Water licensing/approval from your state authority — check before any construction
• A spillway design to safely handle overflow in heavy rain

Step by Step

Keep these points in mind:

• 1. Check water licensing requirements with your state authority — most farm dams require some form of approval, especially above a certain size.
• 2. Assess the site for catchment area, soil suitability (clay content for sealing), and safe spillway location.
• 3. Engage a suitably experienced contractor for earthworks, particularly for wall construction and spillway design.
• 4. Construct with a properly engineered spillway to handle overflow safely — this is the single most common failure point in poorly built dams.
• 5. Fence if needed to manage stock access and protect water quality and dam walls from erosion.

Troubleshooting

Worth paying attention to:

• Dam not holding water — often insufficient clay content in the soil; may need a clay liner or bentonite treatment.
• Wall erosion or failure risk — usually inadequate spillway capacity for heavy rain events; this is a genuine safety issue requiring professional assessment.
• Poor water quality — often from stock having direct access; consider fencing with a separate trough system fed from the dam.
• Regulatory issues discovered after construction — always confirm approval requirements before starting earthworks, since retrofitting compliance is far more difficult and costly.

Keeping It Going

Best time — construct during the dry season when the site is accessible and dry for earthworks. Duration — a properly built dam is a long-term, multi-decade asset with appropriate maintenance. Maintenance — regular inspection of walls and spillway, particularly after heavy rain events. Signs of success — a dam holding water reliably through dry periods, with a spillway that's never been tested to its limit in a way that causes concern.

For the condensed printable version, head to the main guide page linked below.

→ View the printable A4 guide for farm dams for water storage