Leaks and Opportunities

Yesterday we had a welcome preview of summer weather: sunny and mildly warm, with light wind. Coastal summers are typically dry from mid-June to mid-October, just the opposite of our sodden winters.

This year, after four years on our property, my plan is to finally design and build at least the start of a gravity-fed, rainwater-collected drip system for my vegetable garden. I have been planning it (in my mind) since we bought the place, and now it's time to get my hands wet.

The house in background, provides opportunity for gravity feed to garden

The contour of our property is ideally suited for this project. Our house sits above the garden, which is literally "sunken" about 6 feet below the grade of our foundation. Closer to the garden grade, but slightly higher and directly adjacent, is the garage and attached lean-to greenhouse. And our chicken coop wraps neatly around a small building used for storage and processing produce in season, we call the "fruit room."

The soil in the most of my front and side-yard landscape retains moisture (in our relatively cool summers) so that a weekly watering is enough. And because these areas are largely planted with shrubs and well mulched, I prefer to hand-water the shrub beds so I can have a look at everything.

Another good reason on the coast for overhead watering, at least occasionally: salt fog. A local nurseryman reminded me of this fact, in late summer we get little rain and regular morning fog which is laden with salt from the ocean. This salty mist deposits a crust on everything (check your windshield in August) including plants.  So occasional overhead watering is a good thing on the coast, to give the plants a rinse.

The needs in my vegetable garden are different; anyone growing food knows the water requirements are generally greater than landscaped shrub beds. In the past couple years I have experimented with scheduling and found watering every third day to be just right. I plant closely in raised beds and add lots of organic matter to the soil, and the "sunken" location of the garden helps to reduce moisture loss. I want to avoid wasting water on pathways, and reduce the constant threat of fungal disease from too much moisture.  So the obvious answer is drip irrigation, and lucky me, I came across a deal on emitter tubing last fall.

Coop wraps around 'fruit room'

My irrigation plan as of this writing:

Chicken coop: supply water to the birds by installing a filtered diverter from the fruit room gutters into their 5-gallon bucket waterer, already installed, which includes "nipples" to reduce water waste and keeps it clean.

Greenhouse: install a 2-barrel collector just outside the door, collecting water from the greenhouse roof. This will allow me to shut off the outside water supply to the greenhouse sink that causes freeze-anxiety in winter, due to the fact the building is not heated. The barrel storage will provide plenty for filling watering cans to maintain plants in the greenhouse and outside cold frame nearby.

House to garden:  install a large water storage for gathering water off the house, and gravity-feed to garden drip system. Garden beds will be arranged with in-line drip emitter tubing, supplied by a poly main line that can be connected to the filtered tank. When water supplies are low, the drip system can be alternately connected to the city water supply from our existing garden hose-bib.

The first task is to repair our outside water line that I had to cut last fall. As usual, we had a spike in water use around late summer/early fall, due to little rainfall and high garden production. We got the usual notice from the city, to point out our higher-than-normal usage. We didn't actually worry until November, when we noticed the previous bill had not declined... but actually increased. Uh-oh.

Searching for the leak was no easy task, and after checking everything in the house and digging up every outside connection (including the water meter), we guessed the leak was underground and cut the line between house and garden.  Wouldn't you know, that wasn't it...grrr.  Finally we located a mystery valve under the house (!) leading to another outside line, shut it off and voila!  The meter stopped turning.

So now that drier weather has returned... we get to do some repair work.

Other resources: 
Peaceful Valley Farm Supply's short video on drip irrigation (beginners).
Supplier of drip irrigation, including several starter kits and parts.

Coastal Rain Gardens

Spring bulbs in rain garden

A little over a year ago, I wrote about dealing with our heavy rainfall on the coast of Oregon and mentioned in that post the idea of "rain gardens."  Then last summer I had the opportunity to attend a workshop hosted by Oregon State University on this topic, and wanted to share this idea a little further with readers.

The basic idea of a rain garden addresses this problem: too much of our heavy rainfall comes all at once in a large "event," and rushes across impermeable surfaces like roofs, sidewalks, parking lots and driveways, then flows directly into the storm sewers (or nearby water bodies) without any filtration.  When this happens, lots of pollutants including fertilizers and motor oil are swept along with the water, requiring treatment if they make it to the sewer system, or just polluting the water bodies if it flows there directly.

If instead we create a mechanism to slow down the water flow, and cause it to slowly drain through layers of soil, plants and rock, it is much cleaner by the time it gets to its final destination and reduces our need for storm sewer treatment capacity.

Flagstone set into a permeable rock/sand base
provides additional area for infiltration

So the rain garden is simply a designed area which intentionally collects water that might otherwise flow from your downspouts to the storm drain, or across a large paved area, and directs it to an attractive planted feature which can contain the likely amount of water from a single "event" and let it filter through slowly.

"Stream" catches water from center
downspout & sidewalk

Benefits of the rain garden obviously include improved water quality and a reduction in the need/cost of storm water treatment.  Other less obvious benefits to the homeowner might include a very attractive landscape feature including grasses, shrubs and flowering perennials; wildlife habitat when using carefully chosen native species; turning a difficult area of the yard into a useful landscape feature; and preserving your structures from additional erosion or mud-splash by directing the flow elsewhere.

Commercial rain garden installation

A terrific guide is available from Oregon State University (free) to help homeowners, builders and landscapers  design rain gardens into their ecologically-friendly landscapes.  This guide is very thorough including design specifications and plant lists, so I'm providing here some photos of local examples.  The tiny residential rain garden is in my front yard, installed last fall.  The larger, commercial project is located at our new fire station and the garden is about 3 years old.

Note the curb cuts which allow parking
lot to drain into rain garden

Looking north: varied planting includes
Oregon grape, purple-osier willow, vine maple and rushes

Further reading--

Water Runs Downhill

We are challenged by water on the central coast of Oregon.

In the summer, at the height of our growing season, it can be downright scarce. At that time of year, it's plain that the lack of planning for adequate water-- given our wind and sandy soil-- is to blame for many gardening failures.

But in January... oh yes and November, December, February, March etc... it's the opposite. We receive some of the highest rainfall counts in Oregon, 70-90 inches. Cascade Head, only 10 miles north of Lincoln City where I live, receives around 100 inches per year. By comparison, Portland receives merely 37-40 inches. Gives you some idea of what is considered "normal rainfall" on the central coast.

So what happens to all that water? Certainly the vast majority ends up in our rivers, streams and eventually the ocean. But it has to get there first... which gets me to the point of this post's title. Many homeowners here just don't plan for where the deluge is going to go, and what damage or benefit it may leave in its path.

One of the most obvious and lasting effects is on our soil. High rainfall totals equal acidic soils. Did you ever wonder why our soils west of the Cascades are "acid" and those east of the mountains are "alkaline" or less acidic? The falling rain leaches minerals like calcium and magnesium. In order to make our soils more palatable to the widest array of plants therefore may require annual applications of lime to boost the pH level. This is generally recommended for vegetables and lawns, and many other herbaceous plants.

The soil is likewise compacted by the constant falling rain, if it's exposed throughout winter. Protecting unplanted areas with mulches (bark, compost, straw) will make a huge difference come springtime. If the area is to be planted in spring/summer, simply pull back the mulch and compost it. In areas that you don't want lawn or shrubs, consider planting groundcovers in place of the annual chore of mulching. Many are low-maintenance and will thrive without extra water in summer. See my earlier post for some recommended spring-blooming groundcovers.

Drainage is no joking matter here. Take a good look at the slope of your property, locate your downspouts and storm drains. Now, where is the water going? Newer homes may have connected the downspouts to a storm sewer connection, but we have seen many that just drain out next to the house, across your treasured plant's roots, washing away bark and soil. The bigger the roof, the more water diverted, and the more potential damage. If you are not handy, consider asking a landscape contractor to look at whether you need French drains or other means to handle runoff.

When planning areas of hardscape (walkways, driveways) homeowners should consider permeable surfaces instead of concrete or blacktop. Selecting concrete pavers on a gravel foundation for your driveway, or even just using gravel as the drive surface, can help to keep vast amounts of water out of our storm sewers and improve groundwater by slower filtering as it moves through layers of rock and soil.

A personal pet-peeve of mine is bark on top of weedcloth, on steep slopes. The first time it rains hard, here comes your 3 inches of barkdust rolling down into the driveway, leaving ugly swathes of uncovered plastic fabric. Yuck. Again, this is a situation for groundcovers. Plant a dense selection and enjoy the view as they fill in; the added benefit is in preventing soil erosion from your steep slope. Plant roots hold soil in place better than anything else.

Obviously this is a big topic, and I am just scratching the surface. Let this be a gentle reminder to plan for rainy winter storms when you have the chance in summer. Happy New Year!

An update: OSU SeaGrant has posted a terrific resource guide for planning/planting "rain gardens." This could provide a beautiful and lasting solution to many homeowners' runoff problems.