Ask Mariah: How Farmers Manage Water in the Spring

By: Mariah Roberts

Spring is here at last. The wet weather that inspired the term “April showers” is upon us. But excessive rain can spell trouble for landowners— especially when it comes to agricultural land. 

This time of year, I often get the question: how do farmers and landowners manage these heavy rains?

Let’s start with why. Why should we care to manage rain and water on land?

The short answer is: pollutants on land can end up in our lakes.

Consider an incident that occurred in the spring of 2017 on a local farm. Heavy rains caused significant gullies that carried sediment onto residential properties and into Chapman Lake.

Excess nutrients from fertilizers and manure make that runoff even more damaging, triggering algae and weed growth that disrupts entire ecosystems.

Eroding fields don’t just hurt farmers — they hurt everyone downstream.

So how can farmers and landowners prevent these rain-related mishaps?

It all starts with the soil

Topsoil contains the most nutrients and organic matter for crop growth. And if not protected, it will be carried away by rain.

The first step to good water management is healthy soil structure. When soil is in good shape, water can soak in rather than run off — a process called infiltration. The better the infiltration, the less erosion. 

Here are some of the most common practices farmers use to make that happen:

Cover Crops

During the off-season, cover crops are planted; however, they aren’t intended for harvest. These plants are meant to be a sort of placeholder— keeping topsoil in place, building soil biology, and improving water infiltration until it’s time to plant the main crop. They also prevent soil from crusting over, and in the spring, they absorb excess water before it can run toward the lakes.

Tile Drainage

Beneath many farm fields runs a large, yet invisible system: a network of perforated plastic pipes called tile drains. These pipes collect excess water that soaks through the soil and move it away from the field.

Tile drainage prevents fields from becoming waterlogged.

Tile is super effective for moving water away, but does nothing to filter/clean it.

That’s why tile systems are often paired with treatment practices that filter out pollutants.

Bioreactors

These may sound technical, but the concept is simple. The most commonly used is the Denitrifying Bioreactor, which filters water through an underground bed of wood chips before it leaves the field. Those woodchips feed naturally occurring microbes that convert nitrates into harmless nitrogen gas, which is then released into the atmosphere.

No chemicals, no machines- just amazing biology!

Blind Inlets

At the location where water collects and enters the underground tile system, there needs to be some sort of opening. Traditional pipe risers work, but they are cumbersome for farmers to work around with large equipment.

Blind inlets (A.K.A. French drains) offer an alternative: a buried bed of coarse stone and/or sand that filters water as it seeps down into the tile drainage system.

So, not only are they more practical for farmers, but they are also effective at protecting water quality.

Grassed Waterways and Filter/Buffer Strips

Even with strong subsurface water management, some water and sediment will still run off toward the edges of a field. Grassed waterways and filter strips are the last line of defense. Grassed waterways are shaped channels that safely convey concentrated water through fields to prevent erosion, while filter strips are broad, shallow, flat strips of vegetation that filter pollutants from runoff before it reaches water bodies.

Before and after TWF partnered with a farmer to install a grassed waterway:

When farmers commit to these practices, they sacrifice a strip of land that could be used for more crops. That’s a real cost. When farmers do it anyway, it’s worth recognizing— because those simple grass borders are working hard to protect every lake downstream.

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Investing in any of these conservation practices is a big commitment for farmers. The Watershed Foundation is so proud to partner with local farmers to make them happen.