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Mowing Patterns

Grass plays an important role in your stormwater facility by filtering pollutants. Alternate mowing patterns and keep off wet soils to prevent ruts from forming, which can lead to channeling and costly overhauls. Keeping your grass healthy and maintained helps protect water quality in your local stream. It also helps keep your stormwater facility in compliance and looking good.

mowing a stormwater facility
Alternating mowing patterns and staying off wet
ground can help prevent ruts from forming.





Where to find it:

You’ll find grass in swales, infiltration basins and along the edges of ponds.

When to maintain it:

Mow throughout the year to keep grass 3 to 6” high. Do not mow if ground is very wet.

What you'll need:

  • PPE (gloves, eye and ear protection)
  • mower - push or riding mower
  • blower or rake

Tools you'll need: 

mowing tools

Mow this way one time:

mowing a swale widthwise
Alternate between mowing across the width of
the swale one time and the length next.

Next time mow this way:

mowing a swale lengthwise
Alternate between mowing the length of the
swale and the width.

Step 1

When the swale is not excessively wet, mow
grass to 3-6" high.

mowing a swale widthwise

Step 2

Keep grass on swale side slopes below
12" high.

mowing the side slopes of a swale

Step 3

Use a blower or rake to remove grass clippings
from the swale bottom.

 blowing grass from a swale bottom

Step 4

Next time you mow, go in a different direction to
prevent ruts from forming.

mowing a swale lengthwise

Printable maintenance card

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mowing patterms COVER.jpg


Stormwater facilities where mowing pattern practices should be used: 

BiofiltrationSwale sm sq.jpg


Note: swales are commonly part of other facilities such as detention ponds and infiltration basins.