About Stormwater

What is Stormwater?

Stormwater - It's not just rainwater turned loose.

Where did the water go?Stormwater is generally rain and melting snow that runs off surfaces that cannot readily absorb water. These surfaces include rooftops, pavement, compacted gravel lots, and even frozen ground. As it flows towards receiving waters such as streams, lakes, rivers or infiltrates down into the aquifer it picks up pollutants. These pollutants are such things as sediments, airborne dust, pet waste, oil, grease, fertilizers, chemicals, litter and whatever else we have left on the ground or poured down our drains and grates that can be carried or dissolved in water. Stormwater pollution is caused by all of us. Some of it can be treated. Most of it must simply be prevented.

What are stormwater problems?

Stormwater runoff causes pollution, erosion and flooding problems. These problems occur because we altered the land and changed the way that water moves through the landscape.

What causes flooding problems?

As Redmond grows and we build more rooftops, driveways, streets and other hard or impervious surfaces, the land's capacity to soak up and carry away excess water decreases. As a result, conditions that might result in a flood once every 100 years in an undeveloped area can cause flooding every four or five years after development has covered the land with impervious surfaces.

What causes pollution problems?

As water from rain and melting snow runs across these hard surfaces and over lawns and gardens they pick up pollutants such as sediments, pet waste, oil, grease, pesticides, and fertilizers. Stormwater carries these contaminants to our streams, rivers, lakes, wetlands and our aquifer. More and dirtier stormwater runs off each year, but we have fewer and fewer options to deal with it. Since individual contributions to stormwater are small, it is hard to believe that we really impact the quality and quantity of stormwater entering our water systems. The cumulative and long-term effects have a substantial impact to the health of our waterways.

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What can be done about the problems?

Fortunately, something can be done to keep stormwater flooding and pollution problems from becoming worse. We can:

  • educate ourselves about how our actions affect the quality of water, and what we can do to improve water quality
  • limit the use of chemicals at home and at work to reduce the risk of them being released into the environment
  • avoid washing cars or pressure washing driveways in areas that drain to stormwater facilities or to streams
  • pick up pet waste before it can wash off our lawns into waterways
  • plan and construct stormwater systems that work to remove some contaminants before they pollute our surface waters or our groundwater resources
  • acquire and protect natural waterways and their buffers where they still exist or can be rehabilitated
  • look for opportunities to build "soft" structures such as ponds, swales or wetlands to work with existing or "hard" structures, such as pipes and concrete channels, or high tech treatment systems
  • consider low impact development techniques like rain gardens, porous pavement, and rainwater harvesting that aim to restore the water balance of a site to predevelopment conditions
  • plant a tree to soak up rainwater, filter pollutants, shade impervious areas to keep runoff cooler
  • revise current stormwater regulations to address our comprehensive stormwater needs
  • enhance and enforce existing ordinances to make sure property owners consider the effects of stormwater before, during and after development of their land
  • plan carefully to create solutions before problems become too great
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What's being done now?

The City has been divided into 68 drainage areas – or watersheds – for study. We are taking a detailed look at each watershed to determine the best way to handle stormwater from existing and future development. Watershed plans will enable us to make better choices about how to plan, maintain, and construct our drainage systems so they can better meet the community's many needs.

We are improving the way we maintain ponds, swales, catch basins, drywells, ditches and culverts. We are mapping the location of each stormwater facility, monitoring their condition and tracking the time it takes to maintain them. This will help us determine which ones are working well, which ones aren't and which ones we need to replace immediately to save money.

When you have a stormwater concern in your neighborhood, please submit a Report a Concern request, or call the stormwater utility to find out what can be done. We use your requests to help us determine which facilities need to be replaced or repaired.

Contact:  425-556-2800 or info@redmond.gov

We are informing the public about drainage systems, how they function and how to take care of them. This will help reduce threats to water quality and prevent flooding problems.

Stormwater funds are paying, through the Stormwater CIP Program and the Neighborhood Drainage CIP Program, for construction by City crews and by contractors of projects to repair or rehabilitate failed stormwater facilities and construct new regional facilities to better manage stormwater throughout the City. Stream restoration efforts to repair eroded areas, restore fish habitat, and enhance stream buffers are examples of other Capital Improvements projects funded by the Stormwater Utility. 

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