As KPUD water educator, I am frequently asked; “Are
we going to run out of water?”; “Is there
going to be enough groundwater for our future?”
KPUD measures aquifer levels and stream flows and tracks precipitation
though out Kitsap County. Our collected data indicates that we are not going to
run out of water anytime soon. However, it became clear to us that a larger
more comprehensive study is warranted. This is why water purveyors located on
the Kitsap Peninsula contracted with the United States Geologic Survey to
build a characterization and numerical simulation model of the water resources
of the peninsula. We refer to this modeling
as the Ground Water Model. This model will ultimately give us a static picture
of what our water resources look like under average conditions and will
also be able to be manipulated to show how any unexpected change, such as
population growth or reduced rain fall will affect our groundwater supplies.
Wendy Welch and Mark Savoca, both hydrologists from USGS, gave
us an update on the project at the February WaterPAK meeting. The area being modeled consists of 700 acres,
mostly in Kitsap County. The area is mostly bordered by water. USGS is on track midway in what will be a five year project. A web site
has been set up that will contain the data and results of the study. After hearing the update, I can appreciate the
time it is taking to build this model.
The skeleton of the project
Wendy outlined how she has nearly completed building a cross section of the hydrogeology of the peninsula. Wendy has looked at data from the well logs of 2,200 wells. She is sifting through 9,599 items and creating a database from the relevant information. This has to be done by hand. What a feat!!! From this data, she has isolated eleven hydrological units. This is a lot of layers and a lot of wells. By looking at this picture, we will be able to see where and at what depth are good water bearing materials and where they are absent.
Wendy outlined how she has nearly completed building a cross section of the hydrogeology of the peninsula. Wendy has looked at data from the well logs of 2,200 wells. She is sifting through 9,599 items and creating a database from the relevant information. This has to be done by hand. What a feat!!! From this data, she has isolated eleven hydrological units. This is a lot of layers and a lot of wells. By looking at this picture, we will be able to see where and at what depth are good water bearing materials and where they are absent.
Well levels
Water levels in 70 wells have monitored for the past two years. These wells are dispersed evenly throughout the peninsula and have been chosen to represent water levels in shallow, medium an deep aquifers. Most of these wells are domestic wells that are not being used or are used very minimally. Any fluctuations observed will be natural occurring and not caused through heavy withdrawal. The hydrograph of how water levels changed over the past two years is complete and will be published on the website.
Water levels in 70 wells have monitored for the past two years. These wells are dispersed evenly throughout the peninsula and have been chosen to represent water levels in shallow, medium an deep aquifers. Most of these wells are domestic wells that are not being used or are used very minimally. Any fluctuations observed will be natural occurring and not caused through heavy withdrawal. The hydrograph of how water levels changed over the past two years is complete and will be published on the website.
Stream base flows
One key point to the groundwater model is the relationship of surface water and groundwater. Streams in Kitsap have been monitored to determine a base flow discharge of groundwater to streams. The base flow measurements take place in late summer or early fall when runoff is at its lowest. At this time, the flow in the stream can be attributed to groundwater release.
One key point to the groundwater model is the relationship of surface water and groundwater. Streams in Kitsap have been monitored to determine a base flow discharge of groundwater to streams. The base flow measurements take place in late summer or early fall when runoff is at its lowest. At this time, the flow in the stream can be attributed to groundwater release.
Recharge
The modelers received accurate gridded precipitation information that enabled them to map how much rain falls on each portion of the test area. The map is overlaid with land use information and geologic data. Putting together these factors, they can assess how much inflow or recharge the peninsula is receiving. For example, their data reflects that on average the recharge for the year 2000 was 24 inches. It was pointed out that this infiltration rate does not reflect water received from septic systems and possible leaky distribution pipes.
The modelers received accurate gridded precipitation information that enabled them to map how much rain falls on each portion of the test area. The map is overlaid with land use information and geologic data. Putting together these factors, they can assess how much inflow or recharge the peninsula is receiving. For example, their data reflects that on average the recharge for the year 2000 was 24 inches. It was pointed out that this infiltration rate does not reflect water received from septic systems and possible leaky distribution pipes.
All of this data is put together, assigned numerical values and magically turned into a model that will give us the groundwater
picture here in Kitsap. The model will help answer the question of how much water we have and
will allow resource managers to better plan for the future.
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