Article 32 · Land & Farm Design
Swales, Trenches, and Ponds: What to Consider Before You Dig
Questions to answer about catchment, soil, slope, overflow, safety and maintenance before constructing earthworks or water bodies.
A trench is easy to draw on a farm plan. Understanding where its water will come from - and where it will go when full - takes more work.
At Bholi, water availability is a serious constraint. That makes careful assessment more important, not less.
Start with the purpose
Feature Intended role Key question
Infiltration swale Intercept and spread runoff so Can the soil safely receive that it can enter the soil water here?
Drainage trench Convey excess water to a Where will it discharge without
suitable outlet causing harm?
Infiltration trench Store water temporarily within Are soil, groundwater and
an assessed infiltration system nearby structures suitable?
Farm pond Store water for a defined use Is there enough suitable
inflow, and can storage be maintained safely?
These features are not interchangeable. A low point is not automatically a safe pond site, and a trench does not automatically recharge useful groundwater.
Before earthmoving, assess
- Slope, soil layers, infiltration and slope stability.
- Runoff catchment and extreme-rainfall flows.
- Groundwater and water-quality concerns.
- Buildings, utilities, access and neighbouring land.
- Inlets, outlets, overflow routes and maintenance.
- Safe access and protection around open water.
No single slope percentage or soil label establishes safety. Even a gentle slope can conceal unsuitable conditions.
Observe rainfall from safe locations and retain your notes. Do not dig first and decide the overflow route afterwards. Permanent works need appropriate site-specific technical assessment.