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Leaves can plug storm sewer inlets.Yard Wastes Impact the River

Storm Drain Inlets-

The River Starts Here

The City's storm drainage system is designed to efficiently carry rain and snow melt to the river and away from our streets and homes. Storm drainage inlets are the grates or openings usually located in the street near the curb.

The down side of this system is that any pollutant (garbage, chemicals, pet wastes, etc.) that is in our streets may enter the storm drainage system and ultimately, the river. There is no treatment of this water - it goes directly to the river. Yard wastes like leaves and grass clippings are Longmont's biggest problem because of the potential for blockages and localized flooding.

Another potential problem: leaves and grass clippings decompose into nutrients that can cause algal blooms in the river.

Yard Wastes

Leaves and Grass Clippings - a problem for the storm drainage system

Leaves- Curbside Leaf Pick Up and Tree Limb Diversion Center

Limbs- Curbside Limb Pick Up and Tree Limb Diversion Center

Lawn Care

Fertilizer Application

Water Conservation -irrigation audits, watering schedules, tips, Reduce Irrigation Run-Off

Link to CSU -Boulder Cooperative Extension -more information for lawns & gardens


Benefits of Composting


Boulder County's Composting Website


Leaves in the street.

Leaves and Grass Clippings

It is a violation of the Municipal Code to rake or blow leaves into the street because

it can enter the storm sewer and cause blockages and localized flooding.

Violations may result in a warning or even a fine.



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Lawn Care - Fertilizers

Most grasses only require a modest level of nitrogen for good color and controlled growth. Too much fertilizer can be harmful, promote too fast growth (more mowing required) or wash into the storm drain and pollute the river.

Boulder County's Resource Conservation suggests a good schedule to follow is fertilize once in spring, again in fall and mulch grass clippings throughout the summer.

Click here to visit CSU-Boulder Cooperative Extension website for more tips on maintaining lawns & gardens.

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Composting is the controlled, biological decomposition of organic matter, such as food and yard wastes, into humus, a soil-like material. Composting is nature's way of recycling organic waste into new soil, which can be used in gardens and landscaping.

For more information on composting:

Boulder County's Composting website


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Irrigation Run-Off

Overwatering of landscape or improperly planned drainage allows irrigation water or rain to escape your yard. Improve your landscaping by employing:

More water conservation tips available on-line.

Return to Stormwater Quality Page.

Return to Stormwater Home Page.


This page was updated August 16, 2013
City of Longmont Public Works & Natural Resources
Stormwater Quality Program