Surface Water Topics

Rain Storms!
The weather in the Pacific Northwest during our 2021-2022 winter has been described as an "atmospheric river".  We saw pictures and even ourselves witnessed rivers flooding or nearly flooding nearby areas, streets full of water, and roadways actually being washed away. 

Runoff is surface water that flows from one area to another.  During rain storms, that runoff starts from where the rain lands and flows downhill however it can.

When it starts raining, even a small city of Mill Creek's size can produce and accumulate a lot of runoff water quickly.  The city is about 4.7 square miles in area (nearly 3,000 acres or nearly 130 million square feet!).  Even the grassy and other vegetated areas in Mill Creek do not absorb all the rain right where it lands. 

All that runoff that needs to be controlled and helped to flow down to North Creek.  Our combination of public and private stormwater pipes and facilities help with that, along with our natural streams like Penny Creek.

Even with nearly 3,600 street storm drains in the city to collect runoff, and nearly that same number of additional drains located in parking lots similar areas, it is common for water to pond up and not drain away quickly.  Hard surfaces like streets and driveways are particularly prone to this ponding.

What can I do?

Before the next storm?
1. City crews continue to sweeping our streets as the leaves continue to fall.  However, as storms become longer and more frequent, those same crews are called upon to address emergency storm response activities.  It gets more and more difficult to keep streets swept. 

Continue to check street and other storm drains near your home or business.  Use a rake to keep them free of leaves, broken branches, and other debris.  Dispose of the debris with your yard waste.  Sweep debris safely from the sidewalk or street shoulder and do not stand in the street!

2.  Check any drainage structures, including your roof gutters, on your property.  Make sure no leaves or debris are blocking and water can flow as freely as possible.

3.  Leaves, broken branches, and other debris clump up when wet, and can really slow runoff water flow down (especially in street gutters and parking lots!).  This happens even if the clumps seem small when dry. 

Watch for clumps. Use a rake to scoop up the clumps and debris and dispose with your yard waste.  Sweep debris safely from the sidewalk or street shoulder and do not stand in the street!

4.  Check your basement and yard sump pumps, if you have them, and make sure they are working.  If they run on electricity, consider a battery backup power supply.  Avoid using generators!

5.  Move chemicals such as paint, cleaners, or fertilizers to storage locations off the floor.  Store in waterproof containers when possible.

6.  Move cloth items such as blankets, towels, or lawn furniture cushions off floor areas where they may get wet.  If they do get wet, move them to a dry location to dry out as soon as possible. Both of these are important for avoiding mold or rot that may be unhealthy.

7.  Prepare for power outages! Have a home emergency kit (flashlights, batteries, etc.). Have a plan for recharging cell phones and similar electronic devices in case case the power is out.  Make sure you have (and can find in the dark) the needed chargers and cords.  Avoid using generators!

During a storm?
1.  Watch for ponding water in your street and yard.  Avoid walking or driving in areas of ponding.

2.  If you must drive through ponded water, avoid driving through deep-looking areas and slow down.

3.  If water does get into your home or building, unplug electric appliances that may end up in the water.  Do no attempt to unplug electric appliances already in flood water.

4.  As much as possible, stay indoors and avoid walking or driving (especially at night).

After the next storm?
1. Inspect your home and yard.  Look for downed or damaged trees.  Look for signs of roof damage.  If you have above-ground electrical or similar utility lines, look for damaged or disconnected lines.

2.  Look for eroded or ground disturbance sliding, particularly on slopes in or adjacent to your property.

3.  Clean up and dispose of all storm debris promptly.

4.  Mop and dry building interiors as soon as possible.  Put cloth items that get wet, including towels used to mop up water, in areas where they can dry promptly.

An image saying Contact Us
Angela Bolton
Surface Water Program Coordinator
Phone: 425-921-5752
Email: [email protected]
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