Water, water everywhere...
June 9, 2008 · Updated 5:06 PM
Groundwater, streams the focus of environmental conference.
No one can say it doesnt rain enough. Hydrologists just wish they knew how to get more of it back into the ground.
The water-naive may think Bainbridge replenishes its drinking water from sources other than precipitation. Not so.
We really need to keep water on the island, said Stephanie Moret, water resources specialist for the city. Theres been this idea that water comes from the Olympic Peninsula, but theres no evidence of this.
The fourth-annual Bainbridge Island Environmental Conference took up the topic of water and watersheds, long an issue championed by conference co-sponsor the Association of Bainbridge Communities and in direct alignment with the Bainbridge Island Land Trust, whose work preserves areas for water to infiltrate the soil.
The conferences 100 participants learned that groundwater aquifers from which Bainbridge gets its drinking water are recharged by precipitation. However, the amount of water infiltrating into the groundwater system is diminished by evaporation and run off. Water collecting in storm drains runs off into Puget Sound and out of the groundwater system.
Water issues frequently bump against development of land, which creates more water consumers and more pavement directing water to the sewage system which dumps out to sea, instead of going back into the ground.
Low impact development is the philosophy Moret promoted for the capture, storage, and safe release of water.
Keynote speaker Kristina Hill of the University of Washingtons Department of Landscape Architecture kicked off the conference by sharing new methods that promote spongifying, to keep water on the land so it can get back to aquifers.
Hill presented Street Edge Alternatives, a method to reduce impervious surfaces and stormwater runoff.
SEA streets, she said, are high on one side instead bulging in the middle, directing rainwater into a wide side strip of native plant vegetation with a swale to catch and hold storm water. Curvilinear streets and the vegetation strip slow the runoff, and the swale lets the water collect and infiltrate back into the soil.
She described an SEA street as having a garden-like feel from the vegetation along one edge. Another bonus of an SEA, Hill said, is the low cost for stormwater infrastructure along such streets.
Hill recommended a strategy of looking at where money is already allocated for new or redevelopment projects. These are low-hanging fruit, ideal for spongifying the landscape on Bainbridge Island.
Individual homeowners can spongify, too, by shrinking lawn sizes and putting in perennial beddings.
First-time conference attendee Dallas Shaffer said discussion of groundwater made her think about the health of her own well.
It really makes me look at my lawn and how I take care of it, and the alternatives to the way I do it now, she said.
Exactly how is Bainbridge Island doing in terms of water?
Russ Prior, senior hydrologist at Pacific Groundwater Group, said that with the average person using 132 gallons a day, Bainbridges current population of about 20,000 people manages to go through about 2,985 acre feet of water each year, from aquifers at various depths.
Averaged over the whole island, a recent report estimates that about 13 inches of water a year percolates through the soil, equaling a recharge of 19,000 acre feet meaning Bainbridge residents use up 16 percent of recharge each year.
But not all the water is there for human consumption. The recharge first replenishes the upper aquifers, which also flow laterally to provide flow for streams. Water pressure in aquifers also keeps salt water at bay and out of the water supply. A diminished flow of water replenishes successively deeper aquifers.
Douglas Dow, senior hydrologist at the engineering firm of Robinson and Noble, spoke on Bainbridge Islands water resources, saying that Bainbridge Island draws about one-third of its water from the deepest Fletcher Bay Aquifer, which is about 15 square miles and is probably recharging less than 1 inch of water each year.
The deep aquifer cant sustain this level of drawing without changing things, Dow said.
When the water level becomes worrisome, a well may be closed off for a while as the city did in 1994-95.
With what the water level records are indicating, were pretty comfortable that we can support the current population and the foreseeable future, said Martin Sebren, hydrogeologist for Kitsap Public Utility District.
But well all start getting nervous if all the new growth in Kitsap is in Bainbridge and we have to supply 50,000 people.
Knowing how many people Bainbridges water resources can support is a matter of having data. All speakers emphasized the need for more monitoring.
Mike Bonoff, a wetland scientist, referred to a water study done on Vashon Island that led to downzoning because it showed there was not enough water to support proposed growth.
Moret says the city is slowly working towards having better data for the next time an in-depth water assessment is done on Bainbridge, including having a monitoring system and a more detailed geological map for better equipment placement.
Everything is speculation until you have data, Moret said. Historically (the water) has not been monitored. Each year we ask for money to build off the last thing we did.
The second half of the conference was spent discussing the importance of maintaining watersheds by making their consideration a part of development and also being aware of how development in a watershed affects wildlife habitats.
Various local environmental and neighborhood groups then updated attendees on their recent projects and issues.
Deborah Vann, city councilwoman and chair of its land use committee, urged people to email the council their concerns or actively participate in the current updates of the critical areas ordinance and comprehensive plan.
Weve learned a lot of things at the conference, but we need more input from people, Vann said. My concern is that people havent been actively participating in those in the past.
Im asking for people to educate themselves on whats going on and to participate to make sure were getting their input early in the process.
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Find the City of Bainbridge Islands Level II Assessment (December 2000) at www.kpud.org (click on Reference Documents).
For more information on the Street Edge Alternative Project, see www.cityofseattle.net/util/SEAstreets/.