by Gloria Sayler
Water is on everyone’s mind these days- usually we feel we have too much this time of year, but the sun and dry weather have inspired both wonder and concern. There have been a lot of heated discussions (and not just because of the unseasonal warmth and sun) about the issues of growth and water on our Island. I certainly share the concern about sustainable growth and protecting our water supply. But I wanted to understand the questions underlying those concerns and what data exists to answer them before I came to the conclusion that no growth is the answer (as I have heard others state).
Here are the questions I’ve heard asked:
1- We are a sole source aquifer. What does that mean?
2- How will we know if we have enough water? This question incorporates recent concerns expressed that groundwater is rapidly being depleted and that the deep-water aquifer is being tapped at a greater rate than it is being recharged . For some, this leads to a conclusion that our limited water supply prevents increased density and growth.
3 – How do we detect/watch for salt-water intrusion? The Water Conversation at City Hall last Thursday addressed them in a comprehensive and responsive manner with a panel of local and regional water experts taking questions from the audience. To watch, follow this link: http://bkat.pegcentral.com/player.php?video=9726d2261d5fb183ccab8e3eedcfee0f For handouts: http://www.bainbridgewa.gov/177/Water-Resources-Libraries
What did I learn?
- The Island Aquifer system has been designated a sole source aquifer by the EPA. However the picture of our water supply is a lot more complicated than that sounds. We have multiple layers of water (aquifers) that run across the Island. Some are very deep, others are more shallow and wells on the Island draw on different aquifers ((layers of water–bearing sediments). Some “produce” water more easily than others. Islanders get all of their water from wells – either public or private – and the wells get their water from the various aquifers. Those aquifers are recharged/replenished mainly by Island rain/snow and a small amount, for the deeper aquifers, comes from off-Island through the deep Fletcher Bay Aquifer, which continues under Port Orchard Passage and under the Kitsap Peninsula. (The USGS model report stated that approximately 95% of the recharge comes from on-Island precipitation and 5% from off-Island.) Sole source aquifer (hereafter SSA) designation applies to the entire system of aquifers. It’s important to know that this (SSA) Program focuses on water quality and provides limited protection through awareness of the vulnerability of the aquifer system to pollution and our dependence upon the system for drinking water.
- The City’s Groundwater Management Program has been monitoring Water Levels Island wide in all aquifers since 2007. The City has hired Aspect Consulting to use these recent data along with Island wide water system production data and the USGS model to, among other things, produce a “water budget “ (think of a household budget). This will allow us to track Island water so that we can better understand what happens to “our” water – what are the inputs? Where does it go?
- How will we know if we have enough? This question came up in a variety of forms. Based on current data there is no indication that we do not have enough water or that wells are running dry.
- Which aquifers are at risk of seawater intrusion? The “Conversation “ addressed this as well. Again, so far there is no indication that there is salt-water intrusion, but there may be increased chloride levels for reasons apart from saltwater intrusion. Our Groundwater Management Program has been monitoring chloride concentrations in aquifers and wells susceptible to saltwater intrusion since 2008. Aspect Consulting’s work will draw on additional data from the Kitsap Public Health District to assess for indications of potential saltwater intrusion. Aspect’s work with the USGS model will also further define each aquifer’s vulnerability to saltwater intrusion.
The answers to “how will we know” questions are what monitoring is all about. Short-term date gives some information, but it’s the data over several years that inform us as to what the patterns are and how to predict what growth will mean for our future supply. Someone asked, “Is there a reason for Islanders to conserve water?” Cami Afelbeck, the City Water Specialist, responded that water conservancy is always a good idea.
That’s the challenge to us: What can we do now to help preserve and protect our water resources – not only from depletion but also from contamination by pollutants. That will be the topic of the next blog.
If you want to follow the results of this work, the City will announce their availability through the Navigate Bainbridge mailing list. There will also be a follow-up workshop in the Fall as part of the Comp Plan update.
If you have questions for Cami Afelbeck, you can reach her at 206-780-3779, or email@example.com
For another perspective: http://rsamstag.com/downloads-2/bainbridge-island-water-issues/. Written by Randal Samstag, (disclosure – he is my husband)