Southeast Metro Stormwater Authority

Southeast Metro Stormwater Authority Since 2006, SEMSWA has provided stormwater management services for drainage and flood control facili

The SEMSWA Board of Directors will consider a fee increase at its next Board Meeting, which is scheduled at 1:30 pm on W...
09/03/2026

The SEMSWA Board of Directors will consider a fee increase at its next Board Meeting, which is scheduled at 1:30 pm on Wednesday, September 16, 2026.

The agenda for the board meeting will be posted on SEMSWA’s website on September 14, 2026.

To learn more about how stormwater fees are used, please visit the Annual Stormwater Fee page on our website. (link below)

https://www.semswa.org/annual-stormwater-fee

As residents of unincorporated Arapahoe County or the City of Centennial, you are eligible for Flood Insurance backed by...
08/26/2026

As residents of unincorporated Arapahoe County or the City of Centennial, you are eligible for Flood Insurance backed by the National Flood Insurance Program (NFIP).

Flood insurance is sold by local insurance agents. If your insurance company doesn’t sell flood insurance, you can go to floodsmart.gov to search for a flood insurance provider in your state.

Flood insurance may be required if your home is in a FEMA floodplain. Not sure if you’re in a floodplain? Start by searching your address on FEMA’s website https://msc.fema.gov/portal/search. Residents of City of Centennial and Arapahoe County can contact SEMSWA for flood hazard information on our website’s Contact Us page at semswa.org.

GIS is more than a map. When a utility line bores through a storm sewer pipe, GIS helps SEMSWA locate the problem, inves...
08/21/2026

GIS is more than a map. When a utility line bores through a storm sewer pipe, GIS helps SEMSWA locate the problem, investigate the damage, and guide repairs.

Not every stormwater issue is visible from the surface, which is why mapping, inspection technology, and field investigations are essential tools for protecting our underground infrastructure.

It starts with the map. Nearly every project at SEMSWA begins with GIS, whether we're reviewing a new development, plann...
08/13/2026

It starts with the map.

Nearly every project at SEMSWA begins with GIS, whether we're reviewing a new development, planning a capital improvement project, or scheduling routine maintenance.

Before work begins, GIS helps us locate stormwater infrastructure, understand site conditions, plan inspections, and coordinate field activities. Accurate mapping gives us a better understanding of what lies underground and helps us identify areas that may need attention before problems occur.

GIS is more than a map. It's a critical tool that helps SEMSWA make informed decisions, improve efficiency, and protect our community from flooding.

Follow along in our GIS series as we explore how mapping helps identify work, uncover underlying issues, and better understand flood risk throughout the watershed.

Do you ever come across basins such as these and wonder what they are used for? An Extended Detention Basin (EDB), also ...
08/06/2026

Do you ever come across basins such as these and wonder what they are used for? An Extended Detention Basin (EDB), also referred to more simply as a "detention pond", is a basin designed to provide temporary storage of stormwater runoff. Detention ponds utilize structures called forebays, trickle channels, and a slow-release outlet structure designed to control the flow of water and facilitate pollutant removal and flood control.

As new development or redevelopment occurs, pervious areas (fields or undeveloped lots) are often replaced with impervious surfaces (such as rooftops and parking lots). This means more water runs off the area that previously soaked into the ground. To manage the higher runoff volumes and pollutant loads (picked up as water runs across roads and parking lots), SEMSWA requires stormwater quality facilities to be installed on all applicable development projects. Detention ponds are among the most commonly used stormwater quality facilities in our service area.

Learn more about stormwater management at semswa.org

SEMSWA’s Request for Qualifications is out. All related information will be posted on SEMSWA's website. The process will...
08/03/2026

SEMSWA’s Request for Qualifications is out. All related information will be posted on SEMSWA's website. The process will begin at 5 pm on August 03, 2026. Email questions to [email protected] or check our website for more information.

07/31/2026

Turf Conversion Update — From Construction to Establishment 🌱

A few months ago, this area was traditional Kentucky bluegrass. Since then, we've removed turf, constructed a new water quality swale, installed stormwater conveyance features, amended soils, and prepared the site for long-term success.

Today, the main swale is largely complete.

Recent work included planting shrubs and maple trees, installing Dog Tuff grass plugs and buffalo grass, placing landscape boulders, completing the irrigation system, and installing protective fencing to help keep wildlife from damaging young vegetation. These plantings and landscape features were part of the original vision for the project and are now beginning to take shape. The landscape plan included a variety of native and water-wise grasses, shrubs, and trees to support both water conservation and stormwater management objectives.

The boulders placed near the downstream end of the swale will help slow water movement and encourage temporary ponding before runoff leaves the system, complementing the stormwater functions built throughout the project. The completed landscape also includes Buffalo Grass and Dog Tuff grass areas, along with maple trees and diverse shrub plantings.

With the swale now substantially complete, crews are shifting their attention to enhancements around SEMSWA's demonstration garden and areas adjacent to the office building. While these improvements are a smaller part of the overall project, they will help extend the water-wise landscaping theme throughout the campus.

The transformation is becoming easier to see with every update, and we're excited to watch the vegetation establish and mature in the coming seasons.

SEMSWA invites you to view the new Flood Hazard Area Delineation (FHAD) for Willow Creek Tributaries.Creeks included in ...
07/24/2026

SEMSWA invites you to view the new Flood Hazard Area Delineation (FHAD) for Willow Creek Tributaries.

Creeks included in this study are Acres Green Tributary, Fox Hill Park Tributary, Homestead Tributary, Homestead Farms Tributary, Jamison Tributary, Kettle Tributary, Phillips Tributary, Spring Creek Tributary, Trenton Outfall Tributary, West Spring Creek, and Willow Creek East Tributary.

Protect what proves who you are. Keep things like your passport safe, dry, and ready—store it in a waterproof bin before...
07/21/2026

Protect what proves who you are. Keep things like your passport safe, dry, and ready—store it in a waterproof bin before a flood.

Ever wonder where your stormwater fees go?From runoff to reinvestment, see how every step supports cleaner, safer waterw...
07/16/2026

Ever wonder where your stormwater fees go?

From runoff to reinvestment, see how every step supports cleaner, safer waterways. Visit www.semswa.org to learn more.

Address

Centennial, CO
80015-80016, 80111-80112, 80121-80122, 80161 (PO BOX)

Opening Hours

Monday 8am - 4:30pm
Tuesday 8am - 4:30pm
Wednesday 8am - 4:30pm
Thursday 8am - 4:30pm
Friday 8am - 4:30pm

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