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Landscape Maintenance S-9
Description
Proper landscape maintenance, including
maintenance of vegetated stormwater
BMPs, is important to reduce nutrient
and chemical loading to the storm drain
system, reduce nuisance flows and
standing water in stormwater BMPs, and
maintain healthy vegetation that helps
minimize erosion. Additionally, when
landscapes and vegetated BMPs are overirrigated,
the ground remains saturated
and capacity to infiltrate runoff is
reduced.
Appropriate Uses
Appropriate lawn care practices are
applicable to residential, commercial,
municipal, and some industrial operations.
Practice Guidelines 1
Photograph LM-1. Over-irrigation and overspray can wash fertilizers
and lawn chemicals into the storm drain system. These flows can
comingle with storm runoff and cause nuisance flow conditions in
stormwater BMPs. Photo courtesy of the City of Westminster.
Practice guidelines for a healthy lawn that reduces pollution during both wet and dry weather conditions
include a combination of practices such as mowing, aeration, fertilization, and irrigation. Also, see the
Pesticide, Herbicide, and Fertilizer Usage BMP for information on proper use of these chemicals and
Integrated Pest Management (IPM) strategies.
Lawn Mowing and Grass Clipping Waste Disposal
• Keep lawn clippings and debris out of gutters. When blowing walkways or mowing lawns, direct
equipment so that the clippings blow back onto the lawn rather than into the street, or collect
clippings blown onto the street and properly dispose of them.
• Mulch-mowing turfgrass at a height of 2.5 to 3 inches helps turfgrass develop deeper root systems.
No more than one-third of the grass blade should be removed in a single mowing. Mulched grass
clippings can return roughly 25 to 30% of the needed nitrogen that grass requires to be healthy,
thereby reducing fertilizer requirements. Avoid throwing grass clippings onto streets and sidewalks
to reduce nutrient pollution to surface waterbodies.
• Minimize thatch development by mowing at appropriate frequencies and heights for the grass type,
avoiding overwatering, preventing over fertilization, and aerating the turf.
1 These practice guidelines have been adapted from the GreenCO Best Management Practices for the
Conservation and Protection of Water Quality in Colorado: Moving Toward Sustainability (GreenCO
and WWE 2008). See this manual for additional detail and references.
November 2010 Urban Drainage and Flood Control District LM-1
Urban Storm Drainage Criteria Manual Volume 3