At the time of this writing, we have just had some very wet days.

While the 2013-14 water year (water years start on Oct. 1 and end on Sept. 30 the next year) was a strange one, we had very little rain from October to January. We typically get most of our rain in late November through January.

Yearly average rainfall measured at SeaTac airport is 37.5 inches. Hansville’s Skunk Bay weather website data indicates Hansville’s annual average rainfall for the last eight years has been 25.9 inches. Variability, even in the rainiest month November, can be great.  Over the last eight years, Skunk Bay rainfall totals for November ranged from 1.45 inches just last year to 9.78 in 2006.

This water year’s conditions had left our groundwater lower than normal and some intermittent streams that normally start flowing in October did not start flowing until February. Since our streams and creeks can only support salmon and their food sources when they receive rainwater soaking in the ground, filling our wetlands, we need those rains (even if they are sometimes inconvenient). We also want rainfall to keep soaking to refill our shallow and deep aquifers to supply water for us to drink too. Thus, rain is very important to us.

The state Department of Ecology has started to get serious about helping our streams and groundwater stay full. Architects and developers are also getting on the bandwagon because the new state regulations require it, and because they are realizing that it makes good business sense. They are beginning to maximize the amount of rainwater that is “retained” on their development sites and they have found many new “green” ways to manage and dispose of that stormwater.  The days of big, fenced-in detention ponds dotting the landscape are coming to an end. Many developments and single-family homes are starting to manage their stormwater by rain gardens, bioswales, pervious pavement and even more innovative techniques.

However, some of these techniques are not new at all. One takes us back to the British Isles or Europe’s old moss houses. They are now called green roofs.

Green roofs are just like they sound — places where soil and plant on the roof’s surface absorb rain as it falls on the roof. By choosing certain types of low-growing, drought-resistant plants, the vegetation can grow and flourish on a thin layer of soil. The soil absorbs water and holds it.

While the roof requires additional strength — so it may cost more for a large building — it reduces other stormwater management costs and creates an attractive amenity in the community.

Other methods of managing stormwater available to most homeowners are rain barrels and rain gardens — the latter a constructed area with a layer of specific soils and plants that hold the water and slowly releases it to ground. Green roof and rain garden plants provide oxygen to the environment and also an amenity to look at and enjoy. If the feature is large enough, it can also assist in cooling an area around them in the summer.

— Betsy Cooper is a board member and stream monitor at Stillwaters Environmental Education Center.