Proposal for Additional Resources from Dept of Ecology Grant
from Climate Change Technical Committee
Draft 3/13/07
Background
This proposal outlines three activities that the Climate Change Technical Committee is
recommending for further study from the Coordinating Committee. This work would be
initiated in 2007, but would likely not be completed entirely until 2008. A majority of
this work will be to respond directly to requests made by the Water Demand and Water
Supply Technical Committees. A portion of this work will be devoted to enhancing the
distribution of the data that are being generated.
On February 28, 2007, Dr Richard Palmer, the technical lead for the Climate Change
Technical Committee, received a letter from Don Wright addressing four areas of interest
to the Water Demand and Water Supply Technical Committees. The four questions
posed were:

“Using the same information that is use to predict the inflows to the service water
supplies, what would be the effect of climate change be on the region’s ground
water supplies? As you are aware ground water provides a significant course of
municipal water supply within the study area, with utilities using both shallow
and deeper aquifers.

What will be the effects of climate change on temperature during the months May
through October? These months represent the time when the majority of outdoor
water use occurs and changes in temperature may affect municipal water demand.

What will be the effects of climate change on precipitation during the months
May through October? These months represent the time when the majority of
outdoor water use occurs and changes in temperature may affect municipal water
demand.

What will the effects of climate change be on cloud cover during the months of
May through October? Anecdotal reports have suggested that climate change will
result in a more “marine” climate in the summer which might include increases in
cloudy days or morning clouds. These months represent the time when the
majority of outdoor water use occurs and when changes in temperature may affect
municipal water demand.”
The Climate Change Technical Committee has already begun to address specifically
bullets 2 and 3 above. This information will be generated for current conditions and for
three other decadal periods in the future (2025, 2050, and 2075). This information will
be made available to all members of the Regional Planning Process.
The Climate Change Technical Committee is also very interested in bullets 1 and 4, but
the answers to these questions were not part of the original funding for the committee.
Proposed Activities
The Climate Change Technical Committee is seeking additional funding from the
Coordinating Committee to perform three tasks:
1. Evaluating Macro-scale Impacts of Climate Change on Groundwater Resources in the
Puget Sound
2. Evaluating the Potential Impacts of Climate Change on Cloud Cover in the Puget
Sound Region
3. Enhancing the Delivery of Climate Impact Data
These activities will be conducted by researchers at the University of Washington.
Activity 1 – Evaluating Macro-scale Impacts of Climate Change on Groundwater
Resources in the Puget Sound
A primary goal of the Climate Change Technical Committee is to determine the impacts
of climate change on the water resources of the Puget Sound. Thus far, these activities
have been directed at estimating the impacts of climate change on future temperatures,
precipitation, and surface water flows. Climate change impact studies have addressed
this type of issue since the mid-1990s. Another important question is: What will be the
likely impacts of climate change on groundwater resources? This question has not been
directly answered for this region for a variety of reasons, including:
1. Groundwater modeling, particularly the storage and movement of deep
groundwater, is a more complex undertaking than surface water modeling,
2. The data required to create calibrated groundwater models does not exist
for many sub-basins in the Puget Sound,
3. The interactions between precipitation, streamflow, and groundwater
recharge are dependent upon site specific parameters, and
4. Currently, there is no comprehensive, regional groundwater model of the
Puget Sound.
The lack of calibrated groundwater models in the region is unfortunate because there is a
great interest in the role that groundwater may play in the future as the impacts of climate
change on surface water unfold.
The Climate Change Technical Committee recommends addressing this issue by
performing an initial evaluation of the potential impacts of climate change on
groundwater resources in the Puget Sound. This effort will evaluate the potential benefits
of a more comprehensive study by performing four tasks:
Climate Change Technical Committee Proposal
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a) Literature Review
An assessment of the peer-reviewed literature will be performed to determine
the extent of literature that exists on the impacts of climate change on
groundwater. Initial reviews indicate that research has been performed in the
southwest of the US, in California, in British Columbia, and in Eastern
Canada. These research efforts have been at a localized watershed scale and
at large, river basin scales. The literature review will focus on the techniques
that have been used and the general finding of these studies.
b) Simple Hydrologic Balance of Selected Puget Sound Watersheds
A simple assessment of changes in groundwater recharge will be made to
estimate the change in overall hydrologic balance (evapotranspiration, runoff,
and flow into the subsurface). This will be addressed in two ways. First, for a
small number of selected watersheds, DHSVM, the hydrology model used to
estimate the impacts of climate change on surface flows, will be used to
examine the watershed balance for current and future conditions. Second, the
Deep Percolation Model, developed by the USGS, will be used to form
general statements about the possible impacts of groundwater in lowland
areas. The Deep Percolation Model is available from the USGS and estimates
on a daily time-step the long-term average groundwater recharge from
precipitation. It has been developed to simulate the recharge of groundwater
for large areas with variable weather, soils, geological features, and land uses.
c) Simple Framework for Bracketing the Range of Impacts to Groundwater
Using the output from b) above, and other simplified groundwater balance
models, a procedure for estimating the range of likely impacts to groundwater
will be created. The goal of this framework is to provide a consistent set of
assumptions and relationships between the hydrologic components that will
allow for an initial estimate of the impacts of climate change on groundwater.
d) Summary Report
A report will be generated that summarizes the findings of the study of
groundwater listed above. The report will serve both as a review and provide
lessons learned. It will also provide guidance on the potential value of more
extensive studies of the impacts of climate change on groundwater in the
region.
Activity Cost: $12,500
Activity 2 - Potential Impacts of Climate Change on Cloud Cover in the Puget
Sound Region
In the Puget Sound, the maritime climate has significant impacts on the maximum and
minimum temperatures. During the summer, the presence of clouds often moderates late
Climate Change Technical Committee Proposal
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morning temperatures, and the daily high can be impacted by the extent of cloud cover.
It has been proposed that warmer temperatures in the future may exaggerate either the
amount of cloud cover or the number of days that cloud cover is significant.
These hypotheses will be investigated by an examination of a number of weather stations
in the Puget Sound. An evaluation of the number of cloudy days and the extent of cloud
cover will be performed during the periods of traditional high water demands (the
summer months) to determine whether there is a statistically significant trend over the
past half century.
In addition, an evaluation will be made of the number of cloudy days and the extent of
cloud cover as a function of regional temperature during those periods in the past that are
likely to be similar to those forecasted for the future. Specifically, a number of summers
in which temperatures were above average for a series of weeks will be investigated to
determine if those periods have a higher number of cloudy days and increased cloud
extent than average summers.
Activity Cost: $10,000 - $12,500
Activity 3 - Enhancing the Delivery of Climate Impact Data
It is anticipated that the Water Supply and Demand Committees, as well as the
Coordinating Committee, will have future questions related to the data used to evaluate
climate change in the future. The Climate Change Technical Committee is in the process
of developing a database to contain this information and a website to aid in its
distribution. However, the funding of this activity will be exhausted before it is likely to
be used by many in the planning process. The Climate Change Technical Committee
would like to reserve a small amount of money to ensure that the website can be updated,
modified, and enhanced as needed in the future and that it serves as a clearinghouse for
information related to climate change in the Puget Sound. To this end, the Committee is
requesting support on an hourly, as needed basis up to a specified limit, to modify the
data sets and website as needed to meet the needs of other committees.
Activity Costs: not to exceed $5,000.
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