Using swales to manage flooding and drought

 

Swales - what are they?

Managing water flow is essential to good farming practices. Water is the lifeblood of your land, after all. Swales are a very old technique for managing water flow. They are designed to slow down the rush of water and allow it to spread over a larger area, thus reducing bogginess, erosion and land slippage during heavy rain. They also guard against drought by keeping moisture in the soil for longer.

Swales are easy to construct and are entirely individual, depending upon the slope of your land, the water source, where it flows, how fast, and where you want it to flow.

Above is our 'chain of ponds' swales system of three swales, dug on the lower side of our big dam. Before we made them, the water rushed down to the river in the valley below, carving a deep gully, beside which the land was often dry. The first pond is slightly lower than the dam, the next lower still and so on. Water flows from one to the other, under the ground. (We have grassed spaces between them).

Do swales rob river systems of their flow?

No. Swales only slow the progress of the water. Eventually, all water flows to the rivers then the oceans. We just make use of it for longer. Ultimately the use of swales improves pasture, improves soil microbiology, helps protect against drought, reduces the risk of flooding and boggy land, and most importantly, reduces erosion and land slippage.

 

So how are they constructed?

We use the tractor, specifically the front end loader, to dig trenches on the lower side of a dam where soil erosion is worst. If the land is steep, you might want to construct a chain of ponds.

 

Swales instead of watering troughs

We also dig smaller swales as watering holes in areas where the reeds grow, indicating ground water is available. At the top of the hill this isn't possible, so we have raintank water pumped to troughs, but lower down on the property we have springs and boggy areas, so this works well.

How our land has benefitted from swales

Using swales means Nature does the watering for you! Here are some of the benefits we now enjoy:

1. We don't have to irrigate in summer
2. Boggy land drains away during heavy rains
3. Pasture diversity is possible with a constant supply of water as different seeds germinate at different times of the year
   
4. the water has even spread uphill, to cover land above the level of the swale! An area that was too dry to grow much is now lush and green
5. Bird life has exploded in these areas! The swales create their own little habitat.
   

So, I hope you'll consider swales as part of your land management. Saves on sprinklers and diesel to run the pumps!