Cistern at Kitsap Conservation District

 Brian Stahl from Kitsap Conservation District is hoping for rain. I stopped by the office this sunny September morning and got a tour of the Conservation District's on-site rainwater collection system. The cistern is empty at the moment and even though there isn't a cloud in the sky, Brian, is thinking about the winter rain water that will run off the building roof and fill up the 11,000 gallon tank. The water stored in the tank will flush the district building's toilets and, next summer, provide outdoor irrigation water.

11,000 gallon cistern

I immediately asked where he got such a huge tank. He told me that this rainwater collection system project started with a phone call from a small farm owner. He asked Brian if he could find a home for this good as new cistern that he couldn't use. The Conservation District offers assistance to landowners to protect natural resources, so Brian started asking around. When he got no takers, he decided to design a rainwater collection project at the office. The costs incurred fit nicely with a grant he received for rainwater collection.

filter and booster pump

This is how the project will work. The roof downspouts are all piped to a 1,500 gallon tank buried in the ground near the building. As soon as the 1,500 tank has reached its holding capacity, the rain water is pumped to the 11,000 gallon cistern.

Brian next to his electronics

 A submersible pump will send the water from the 1,500 tank to a filter.  The water will then be pumped directly to the district's irrigation system and to the building for flushing toilets. Brian is waiting for permits to connect the pipe into the building for the toilets.

Future connection to the inside toilets

 When the 1,500 gallon tank starts to drain; water from the large cistern will be gravity fed into this smaller tank to replenish the water. If the cistern becomes depleted, the toilet flushing will seamlessly revert back to well water.

If however, the huge cistern fills and overflows, the excess water will be channeled into the rain garden where the rain will make its way to the aquifer. The  rain garden has its own overflow system that has never been used.  Brian thinks this may be the year.

The rain garden closes the loop

Brian can hardly wait to watch the see-through tank gauge on the cistern fill with water. I think Brian would be glad to share his rainwater collection project with you. Contact him at the Kitsap Conservation District.

How much water to put on a new rain garden

KPUD's new Rain Garden must be kept watered until the plants are established. This could take a couple of years. This posed a question, how much water is enough? As a utility water conservation manager who is advising people to use water wisely, I needed to find out more. Marty, our hydrogeologist and I decided to approach finding out exactly how much to water scientifically and do the math.

First I had to find out how much water I was putting on the garden. I am watering with an ordinary fan type sprinkler that I got at the big box store down the road. It so happened that it's spray covers my approximately 23 square foot garden.

$9.00 sprinkler in the rain garden

 The rule of thumb is use one inch of water per week. Using a fancy sprinkler calibration system, I measured how long it took my sprinkler to water the garden this much. Homeowners can do this by doing the tuna can test.

accurate sprinkler gauge

I placed several  calibration cups through the garden. It took me a minute to figure out how this container measured only an inch, but it was pointed out by someone a little more savvy than me (Marty) that it was configured to offer a larger opening to allow the water to easily be collected.

 

calibration cups placed throughout the garden

I then turned on the sprinkler and let it run until .1 of an inch was collected. I determined that it took 20 minutes.I also determined that the sprinkler distributed pretty evenly throughout the garden. 

Marty looking at the cup measurement of .1 inch.

 Doing the math I calculated that it takes my sprinkler 3 hours and 10 minutes to get one inch to the garden!! Marty figured that multiplying the square footage of the garden by .62 gallons, It would take 328 gallons to arrive at my one inch per week.

(.62 gallons is the amount of water it takes to cover one foot of area with one inch of water.)
Alright, I decided, although letting the sprinkler run for three hours is counter-intuitive for a water conservation professional, I'll do it. Then  . . . .wait, it rained the other night. After running the sprinkler for half that time, I stopped it and got out my garden trowel.

I use a 4" garden towel to test if the soil is wet before I water

 The blade of my garden trowel is four inches. I gathered some soil from that depth.It was wet!! So, this is what I decided to do. Only run the sprinkler for 1 1/2 hours twice a week and test the soil for dampness before I water to see if it is necessary at all. Of course all bets are off if the plants are showing stress. This watering regime should keep the plants going until the winter rains take over in a month or so. I may have to continue watering another summer, but after that they will do just fine on their own.

Rain Garden Plants

Kitsap PUD has a new rain garden! I mentioned to Teresa Brooks from Kitsap Conservation District that our office needed one and it was no sooner said that done!

Teresa Brooks from Kitsap Conservation District getting ready to plant.

Rain Gardens collect rain water off of parking lots and driveways or any impervious surface. The rain garden contains a special mixture of soil that allows this water to slowly percolate into the ground rather than rush down the storm drains. Besides soil, the magic ingredient to the Rain Garden is plants.
 

Kerri Cechovic from Washington Enviroinmental Council digs right in.

Jenny Morgan, Landscape Architect from the Conservation District, designed the Garden and its plant design. She and Teresa carefully set out the 480 plants. Kerri Cechovic from the Washington Environmental Council arrived. She was soon followed by seven local volunteers to help plant.

volunteers planting the garden

The Rain Garden is designed as a depression with room for six inches of water. Planted in  this area,  are plants that like wet feet, but can tolerate completely drying out during the summer. These plants are slough sedge, small fruited bullrush, baby blue eyes and iris.

The finished rain garden

Along the outside edges are dought tolerant plants that won't need watering once established. They include rudbeckia, Nepeta Walker Low, Heuchera, Geranium Biokova and a few Spiraea Magic Carpet and some low growing Dogwoods.

Hannah, the youngest volunteer planter

 KPUD appreciates help from Teresa and Jenny from the conservation district and, especially appreciates the volunteers who came to plant  on a hot evening in September.

Teresa has a goal of 1,000 Rain Gardens in Kitsap. She even has $500 to match each homeowner's cost of building one on their property. Contact Teresa for more information.