**AN ASSESSMENT OF AVAILABLE DATA AND INFORMATION AND**

**POSSIBLE METHODS OF ANALYSIS OF THE WATER RESOURCES OF THE ELWHA-MORSE
WATERSHED, WASHINGTON**

U.S. Geological Survey

Water Resources Division

Tacoma, WA

March, 2000

**CONTENTS**

[Page]{.underline}

Introduction............................................................................................1

I. Water
quantity......................................................................................1

Introduction........................................................................................1

A.
Precipitation.................................................................................\...3

Needed
Information........................................................................\...4

Possible methods, needed data, and available
data.......................................4

B Surface
water...................................................................................5

Streamflow.....................................................................................5

Needed information
.......................................................................6

Possible methods, needed data, and available data
...................................7

Lakes and
Reservoirs.........................................................................9

C. Ground
water...................................................................................9

Needed
information...........................................................................9

Possible methods, needed data, and available
data......................................10

D. Interaction between ground water and surface water
...................................14

Needed
information.........................................................................14

Possible methods, needed data, and available
data......................................15

E. Water
use......................................................................................16

Needed
information.........................................................................16

Possible methods, needed data, and available
data......................................16

II.Water
Quality.....................................................................................17

Needed
information...........................................................................18

Possible methods, needed data, and available
data........................................18

III\. Habitat and instream
flows....................................................................21

Selected
references..................................................................................22

**FIGURES**

1 The hydrologic
cycle..................................................................
2

**TABLES**

1\. General summary of possible methods of analysis, data, and
information needed to

> Conduct technical assessments of the Elwha-Morse Watershed area (WRIA
> 18)

2.  Summary of precipitation and temperature at weather stations within
    the Elwha-Morse watershed

3.  Available USGS streamflow data for continuously gaged streams and
    peak flow

> measurements in the Elwha-Morse Watershed

4.  List of ID numbers, streams, and locations of miscellaneous stream
    flow

> measurements made by the U.S. Geological Survey, beginning 1898, for
> the
>
> Elwha-Morse Watershed

5.  List of miscellaneous stream-flow measurements in the Elwha-Morse
    Watershed,

> made by U.S. Geological Survey

6.  Selected well data from the USGS database for wells located in the
    Elwha-Morse

> Watershed

7.  Summary of well data obtained from the Elwha River Morse Creek web
    page

8.  Available water quality data for streams in the Elwha-Morse
    Watershed

9\. Available USGS water quality data for ground water in the
Elwha-Morse Watershed

**AN ASSESSMENT OF AVAILABLE DATA AND INFORMATION AND**

**POSSIBLE METHODS OF ANALYSIS OF THE WATER RESOURCES OF THE ELWHA-MORSE
WATERSHED, WASHINGTON**

**INTRODUCTION**

The Water Resource Inventory Area (WRIA) 18 Planning Unit is developing
a watershed plan to maintain reliable supplies of clean water for
population and economic growth and a healthy aquatic habitat, based on
the State of Washington's Watershed Management Act (RCW 90.82/ ESHB
2514). Water-resource and related data and information are needed to
develop the plan and will also be needed for making water-resource
management decisions for the study area when the dams on the Elwha River
are removed.

The objectives of this document are to briefly describe data and
information needed to assess the water resources of the Elwha-Morse
watershed, to summarize available hydrologic data and data gaps, and to
describe possible methods of analysis to obtain the needed data and
information. This document is organized by the four watershed components
in ESHB 2514---water quantity, water quality, habitat, and instream
flows. In ESHB 2514, technical assessments are required for water
quantity, and assessments are optional for the other three components.
The emphasis of this document, therefore, is on water quantity, but
there is also some information on the other compo­nents. A web page that
contains information on available and data was developed for this study
and its url is *\[to be determined\].*

**WATER QUANTITY**

**[Introduction]{.underline}**

The objectives of the water-quantity component of ESHB 2514 are to
estimate the amount of water present in a WRIA (both areally and
temporally) and the amount of that water available for appropriation.
Such appropriation could include water use by the public, by com­mercial
interests, or for wildlife (instream flows for fish).

Water present in a watershed is located in surface water, ground water,
and the transition zone between surface water and ground water. Surface
water includes streams and lakes, ground water includes the water in
saturated pore spaces of underground material, and the transition zone
includes water in soils and material between the soil and ground water.
The key to estimating water present in a watershed is to understand that
water is constantly moving through the water­shed. The hydrologic cycle
depicts this movement (fig. 1).

1

![](media/image1.wmf){width="6.707638888888889in"
height="5.371527777777778in"}

Figure 1.\-- The hydrologic cycle.

A convenient beginning of the hydrologic cycle is precipitation, which
is the sole source of water to a watershed. If precipitation is
rainfall, it will run off on the land surface or in the shallow
sub­surface to streams or lakes, or it will infiltrate land surface and
become ground-water recharge. If precipitation is snowfall, it will
accumulate on the ground surface and eventually melt and follow the same
fate as rainfall. Ground water will move from recharge areas to
discharge into streams, lakes, or other such surface-water bodies as the
Strait of Juan de Fuca. Evapotranspiration is a net loss of water from
the watershed, and it includes evaporation from surface-water bodies and
bare soil, transpiration from vegetation, and evaporation from
intercepted rainfall or snowfall. During the movement of water through a
watershed, the water is, although constanly moveing may be considered,
temporarily stored in streams, lakes, soils, ground water, and snowpack.

The water-quantity section of this document describes some possible
methods of analysis and data and information needed to estimate the
amount of surface water and ground water present in a watershed. It also
explains methods of estimating amounts of precipitation and the
interac­tion between ground water and surface water.

The areal distribution of water in a WRIA can be estimated by dividing a
watershed into different subbasins and then computing the amount of
water in each component of the hydrologic cycle for each subbasin. The
temporal distribution of water can be estimated by computing amounts of
water for different time periods. For example, the seasonal distribution
of streamflow can be shown by computing average streamflows for each
month of a year.

The amount of water available for appropriation in a WRIA or subbasin
depends on the amount of water present, the interaction between ground
water and surface water, exist­ing water rights, actual water use,
existing or proposed minimum instream flows, anticipated future
water-use needs, and acceptable changes to water movement and storage.
Although these are all factors need to consider in assigning future
water rights, it is not the purpose of this document to explain how to
incorporate all these factors in an analysis. A recent publication by
the Washing­ton State Department of Ecology (1998), \"Report of the
technical advisory committee on the cap­ture of surface water by wells\"
contains a good discussion of the methods that can be used to estimate
the amount of ground water available for appropriation.

This document describes possible methods to estimate most components of
the water resources of a watershed. These methods range from simple
interpolation methods to empirical or statistical methods to complex
numerical models. The choice of which method to use will depend on the
complexity of the hydrologic system, the needed accuracy, and the
available funds. A general summary of these methods of analysis, data,
and information needed to assess the water resources of WRIA 18 is
listed in table 1.

**[Precipitation]{.underline}**

Precipitation is the source of all water in the Elwha-Morse watershed
because all of the rivers or streams originate entirely within the
watershed and it is unlikely that there is substatial ground-water flow
into the area from adjacent watersheds. Precipitation generally falls as
rain in the lowlands and as snow and rain in the uplands of the
watershed. Estimating the areal and temporal distribution of
pre­cipitation is an important starting point for partitioning the amount
of water that moves to surface water or to ground water.

3

Precipitation varies considerably across the Elwha-Morse watershed
because of the large

differ­ences in elevation and the orographic effects of the topography
and elevation on storms that move across the watershed. The temporal
distribution is typical of western Washington, with most of the
precipitation falling in the fall, winter, and spring.

**Precipitation: Needed Information**

The areal and temporal distribution of precipitation needs to be defined
for the Elwha-Morse watershed. Defining the areal distribution is
important because it varies largely across the watershed. For
water-quantity planning, the temporal distribution is typically
estimated on an average annual or an average monthly basis. Average
annual precipitation provides an estimate of the typical total amount of
source water for the watershed. Average monthly precipitation will show
the seasonal distribution of precipitation. Daily values of
precipitation may need to be esti­mated if hydrologic water-budget
modeling of the watershed is planned in the future.

**Precipitation: Possible Methods, Needed Data, and Available Data**

There are two current and one discontinued National Weather Service
stations in the Elwha- Morse watershed (table 2). All three stations
have a sufficient number of years of record to define charac­teristics
such as average annual and monthly precipitation. Port Angeles has 124
years of record, Elwha Ranger Station has 58 years, and the discontinued
station at Lake Sutherland has 38 years.

All of the weather stations are located in the lowland areas where there
is the least amount of pre­cipitation. Precipitation in the mountainous
areas far exceeds that falling on the lowlands, but this amount is
poorly known because of the lack of data in the largely inaccessible
Olympic Moun­tains. The National Resources Conservation Service (NRCS),
in cooperation with the U.S. Environ­mental Protection Agency,
established a snow-data-collection site in the Elwha-Morse watershed in
1999. This site, named "Waterhole" and located at an elevation of 5,000
feet, will col­lect valuable data on precipitation, snow accumulation,
temperature, and other meteorological data.

The most accurate currently available estimate of average annual and
monthly precipitation for the entire Elwha-Morse watershed is from the
PRISM method (Oregon Climate Service, accessed 1999 at
[http://www.ocs.orst.edu]{.underline} ). This method is a spatial
statistical procedure that distributes point measurements of average
monthly precipitation (weather station data) to a regular grid
superimposed on the study area. PRISM is uniquely suited to regions with
mountainous terrain, where precipitation increases with altitude,
because it uses elevations and slope orientations of the weather
stations and grid points derived from a digital elevation model.

4

Although the PRISM estimates of average precipitation are available for
the Elwha-Morse water­shed, a much more detailed characterization of
precipitation would be attainable if precipitation data were collected
at higher altitudes. The new NRCS snow-data-collection site will collect
valu­able data; however, more data sites are needed to develop a more
accurate estimate of the variation of average annual and monthly
precipietation for the area. Unfortunately, collection of accurate
precipita­tion data at high altitudes, where a large portion of the total
precipitation falls as snow, is difficult, costly, and prone to error.
Precipitation gages placed in such locations almost invariably
undercollect snowfall due to wind and "coning\" on the gages
(Christopher Daly, Oregon State University, personal commun., 1993).
Therefore, the optimal locations for additional precipita­tion gages are
at altitudes below permanent winter snowpack at about 2,500 to 3,000
feet but above about 1,000 feet. Five or more, with even aerial
disribution in the study are, weighing-bucket precipitation gages, with
electronic data loggers, could be installed throughout the Elwha-Morse
watershed, at altitudes between about 1,000 and 2,500 feet.

**[Surface Water]{.underline}**

Surface water in the Elwha-Morse watershed is found in streams, lakes,
and wetlands. The quantity of water in streams varies considerably
during a year according to the input of precipitation and snowmelt
runoff. The quantity of water in lakes, reservoirs, and wetlands which
generally function to store surface water, is less variable during a
year than in streams, and it varies according to the inflow from streams
and the outflow from dams.

**Streamflow**

Streamflow is a result of several processes in the hydrologic cycle
(fig. 1). Rainfall or snowmelt runs off over land surface and quickly
becomes streamflow. A second and slower response to rainfall and
snowmelt is shallow subsurface runoff of water that moves into streams.
Ground-water discharge, the third component of streamflow, is more
sustained and less variable in quantity than the two types of runoff.

The separation of streamflow into its components of runoff and
ground-water discharge is not needed for many water-quantity planning
purposes. However, understanding those components can be important,
though, if ground-water/surface-water interactions are significant.
Those interactions will be discussed in the following section titled
"Interactions between ground water and surface water."

5

**[Streamflow: Needed Information]{.underline}**

Estimates of the areal and temporal distribution of streamflow are
needed to plan for the efficient and wise use of the surface-water
resources. Areal distribution is typically estimated by dividing the
study area into subbasins and estimating the amount of streamflow for
each subbasin. Tem­poral distribution can be estimated by computing

statistics that describe the average amount of flows for a given time
period and the variability of flows over time.

Many statistics can be used to characterize the temporal distribution of
streamflow. The follow­ing statistics are some of the more common indices
that can be used for water-quantity planning.

1\) AVERAGE ANNUAL FLOW - this statistic describes the total amount of
water that flows in a stream in an average year. It is useful for gross
estimates of water quantity.

2\) AVERAGE MONTHLY FLOWS -- these statistics are useful to show how
stream­flows vary seasonally. Average flows can be computed for each
month in the year. In the Elwha-Morse watershed, streamflows are
typically high in the winter and spring and low in the late summer and
fall. It is often important to know this sea­sonal distribution,
especially the low flows in the summer and fall when demand for water is
high by the public and agriculture and minimum levels of flow are needed
by fish.

3\) VARIABILITY OF FLOWS -- water-quantity planning should take into
account the expected variabilty of flows in addition to the average
flows described in statistics (1) and (2). Three statistics can be used
to characterize the variability of flows.

A\) STANDARD DEVIATION OF FLOWS -- this statistic describes the
vari­ability of flows about an average value. Thus, a standard deviation
could be computed for an average monthly flow or the average annual
flow. Streams with smaller standard deviations would have less variation
from year to year and would thus be more reliable for planning purposes.

6

B\) PROBABILITIES OF LOW FLOWS -- these statistics describe the flows
for a specified time period that are expected not to be exceeded in the
future. A typ­ical low-flow probability is the 7-day, 10-year flow. The
annual minimum 7-day average flow is expected to be equal to or less
than that value once every 10 years. Or there is a 10 percent chance
that the annual minimum 7-day aver­age flow would be equal to or less
than that value in any year. Any time peri­ods can be selected to compute
a probability of low flows.

C\) AVERAGE FLOWS DURING DIFFERENT CLIMATE REGIMES -- Recent work on
climate has identified two regimes that affect world-wide weather
pat­terns and have strong associations with weather in the Pacific
Northwest. The El Nino regime is typically cold and dry in the winter,
and the La Nina regime is typically warm and wet in the winter.
Streamflow statistics could be com­puted from historical streamflow
records for both these climate patterns, and a water-resource planner
could use those characteristics to plan for water use during those two
regimes.

**[Streamflow: Possible Methods, Needed Data, and Available
Data]{.underline}**

Depending on the available data, the characterization of streamflow
using statistics can be done using two basic approaches. If the stream
of interest has a gaged site with a continuous record of streamflow, the
statistics can be computed directly from the gaged record. If the stream
has no gaged record, a regionalization or simulation method can be used
to estimate the statistics for the ungaged site.

In the Elwha-Morse watershed, there are only two streams with continuous
gaging-station records--the Elwha River, with one current site and two
discontinued sites, and Morse Creek, with one discontinued site (table
3). The Elwha River above Lake Mills (station number 12044900) has 3
years of record (discontinued), the Elwha River below Glines Canyon Dam
(12045500) has 84 years, the Elwha River below diversion near Port
angeles ( station number 12046500) has two years of record
(discontinued) and Morse Creek (12047300) has 10 years
(discontinued).Most of this stream flow data is contained in a water
resource data report for Clallam County (Drost, 1986).

The reliability of streamflow statistics improves with the length of
record of streamflow data. The USGS generally does not publish
statistics for streams with periods of record less than 10 years because
it is uncertain if a short record represents the true long-term
streamflow characteristics of the site. Based on this criterion, only
the Elwha River below Glines Canyon Dam and Morse Creek sites have
sufficient periods of record to compute reliable statistics. The 84
years of record at the Elwha site provides a solid

7

sample to produce reliable streamflow statistics; however, the 10 years
of record at the Morse Creek site barely fits into the criteria for
publishing statistics, so statistics for that site should be used with
caution. Streamflow at the Elwha site is slightly regulated by the dam,
but adjustments can be made for storage in the lake, and reliable
estimates can be made for statistics of natural flows.

Because no other streams in the Elwha-Morse watershed have gaged data,
regionalization or simulation methods must be used. There are many
regionalization methods, ranging from simple ratios to multiple
regression methods (table 1, surface water methods A2a to A2d). An
example of a simulation method is a process-based numerical watershed
model (table 1). In this type of model, all the processes in the
hydro­logic cycle that affect streamflow (precpitation, runoff,
evapotranspiration, ground-water recharge and discharge) are simulated.

There are two existing reports that use or present regionalization
methods for estimating stream­flow statistics at ungaged sites. Amand and
Orsborn (1987) evaluated streamflow on the Olympic Peninsula, and that
report provides methods for estimating various statistics at ungaged
sites. The methods are based on streamflow data from 20 gaging-station
records on the entire Olympic Pen­insula, and the records are from
drainage areas larger than 10 square miles. These methods, there­fore,
could be used in the Elwha-Morse watershed for streams with drainage
areas larger than 10 square miles, but should not be used for the
smaller drainage areas of less than 10 square miles. These
correlation-type analyses are only valid for sites within the range of
variables used to develop them.

Haushild and LaFrance (1978) estimated the probability of low flows for
many streams on the Olympic Peninsula using streamflow data through
1973. The 7-day low flows for recurrence intervals of 2, 5, 10, and 20
years are available for the Elwha River below Glines Canyon Dam, Morse
Creek, Tumwater Creek, and Ennis Creek. Average monthly flows for July,
August, and September are also available for those streams.

New regionalization or simulation methods need to be developed to
estimate streamflow statistics for all the other small ungaged streams
in the Elwha-Morse watershed, including tributaries to the Elwha River.
Many miscellaneous streamflow measurements have been made in the
watershed, and these can be used to help develop new regional methods
(tables 4 and 5). Table 1 presents sev­eral regionalization or simulation
methods for ungaged sites. Statistical method (multiple regression,
table 1, surface water, methods A2b and A2c) is commonly used, and its
accuracy depends on the number of available gaging-station records in
and near the study area, the length of the gaging-station records, and
the amount of the variation in streamflow that can be explained by the
basin and climatic characteristics used as explanatory variables. The
sim­ulation method (watershed model, table 1, surface water, method A2d)
is difficult to construct, and its accuracy also depends largely on the
same factors as the statistical method. An advantage to the simulation
method is it can be used to evaluate the effects of changes in land use
on runoff.

8

**Surface Water: Lakes and Reservoirs**

Surface water is stored in lakes and reservoirs. If a dam is present at
a lake or reservoir the amount of storage can be regulated for
withdrawals or for power generation by diverting water through
generators.

There are two reservoirs on the Elwha River, Lake Mills, and Lake
Aldwell. The dams on these reservoirs are used to generate electricity.
To compute the amount of water stored in the reser­voirs, the stage of
the reservoir is measured and area-depth-volume relations are used to
compute volume. Although there are many small lakes and ponds in the
Elwha-Morse watershed, the total vol­ume of water stored in these lakes
is insignificant compared to streamflow.

**[Ground Water]{.underline}**

Ground water includes the water in the saturated pore spaces of
underground material. Ground water underlying a specific area can be
recharged by infiltration and percolation of precipitation, subsurface
flow from outside area, seepage from streams, or infiltration and
percolation of uncon­sumed irrigation water. Most of the recharge in the
Elwha-Morse watershed is from precipitation, probably with some small
local amounts by seepage from streams. Ground water moves slowly from
recharge areas to discharge areas. The rate of movement can vary
considerably from frac­tions of feet per day up to several feet per day.
Discharge areas for ground water in the Elwha-Morse watershed include
lakes,springs, streams, wetlands, and the Strait of Juan de Fuca.

Most of the ground water in the Elwha-Morse watershed is in the
unconsolidated glacial materials between the Olympic Mountains and the
Strait of Juan de Fuca. Very little water is found in the bedrock
materials, where only fractures contain and transmit appreciable amounts
of water.

**Ground Water: Needed Information**

To estimate the amount of ground water in the Elwha-Morse watershed and
to understand the effects of ground-water withdrawals on the
ground-water system and streams, much data and information are needed
about the ground-water system.

The boundaries of the ground-water system need to be defined. Lateral
boundaries include rela­tively impermeable materials such as bedrock and
saltwater boundaries (the Strait of Juan de Fuca). Upper and lower
boundaries include a lower bedrock surface and an upper surface such as
the water table. Internal boundaries of a ground-water system are the
top and bottom surfaces of aquifers and confining beds. These boundaries
influence the amount of recharge, the directions and rates of
ground-water flow, and the amount of discharge.

9

The hydraulic properties of the aquifers and confining beds need to be
defined because these properties control the amount of water in storage,
the rate of ground-water movement, and the effects of withdrawals on the
ground-water system.

Water-level maps for the aquifers and confining beds are important
because they show the rate and direction of ground-water flow. In
addition, the depth to ground water is important data because the deeper
it is to the water level of an aquifer, the greater the cost of pumping
that water to the surface for use.

Groundwater recharge and discharge need to be defined to estimate how
much water moves through the sys­tem in a given time period. Discharge
includes natural ground-water discharge and withdrawals from wells. The
amount of decline in ground-water levels and the reduction in
streamflows caused by ground-water withdrawals are related to areas and
amounts of recharge and discharge.

**Ground water: Possible Methods, Needed Data, and Available Data**

A ground-water system can be defined with several different methods,
depending on the available data, degree of accuracy required, and the
scale of the study area. Often, a considerable amount of data needs to
be collected and analyzed before an adequate definition can be made.

Ground-water data and information for the Elwha-Morse watershed are
meager. Two computer databases contain some characteristics about wells
in the study area, but many of these wells have not had their locations
field checked, and little analysis has been done (tables 6 and 7). The
USGS well database contains 268 wells and 168 of those wells have been
field checked. The Clallam County well database contains 445 wells and
an unknown number of those wells were field checked. Because many of the
same wells are in both databases, a first step in a ground-water study
would be to compare the databases and determine which wells are in both
databases. An unknown number of wells in the Elwha-Morse watershed are
not in these databases.

The most recent and comprehensive published ground-water information for
the Elwha-Morse watershed is contained in a water-resources data report
for Clallam County (Drost, 1986). That report collected and compiled
ground-water, surface-water, and water-quality data, and conducted a
cursory analysis of the data. That analysis included an evaluation of
water-resource conditions, identification of areas of water-quality
problems, and identification of any water shortages. The analysis was
intended only for a regional water-resources assessment of Clallam
County. No assessments were made to determine any of the ground-water
information described in the previous section -- ground-water
boundaries, hydraulic properties, recharge and discharge, or water-level
maps.

10

A characterization of the Port Angeles watershed was conducted by the
Clallam County Planning Division, Puget sound cooperative River Basin
Team, and the city of Port Angeles (Clallam County and others, 19993)
which includes information on geology, soils, water resources, and water
quality.

The thickness of unconsolidated deposits in the Elwha-Morse watershed
was determined as part of a regional study of the entire Puget Sound
area (Jones, 1996). This study provides a useful starting point for
assessing depth to bedrock and the ground-water boundaries. Because of
its regional scale, however, any detailed assessment of ground water in
the Elwha-Morse watershed would require a refinement of this map using
lithologic information from wells and geophysical data.

A geologic map developed for the entire Olympic Peninsula (Tabor and
Cady, 1978) is available for an initial rough characterization of the
surficial hydrogeology of the Elwha-Morse watershed. Any detailed
assessments of ground water, however, would require more information on
the surf­icial geology.

A typical complete assessment of ground water would include the
following steps: (1) assembling and analyzing all existing ground-water
data and information, (2) determining what new data are needed to
provide the information described in the "needed information" section of
this ground-water section, (3) collecting the data, (4) analyzing
existing and new data; and (5) constructing and cali­brating a numerical
ground-water model to synthesize the information and to evaluate effects
of increasing or decreasing ground-water use on the ground-water system.

Steps (1) and (2) have been completed for the Elwha-Morse watershed, and
the data are included in this document and tables. There are some
existing well data, but very little interpretation of the data. Steps
(3) through (5) would be conducted for a complete assessment of ground
water. The level of detail and scope of this assessment would depend on
the needed accuracy and scale. The following description of steps (3)
through (5) is for a moderate level of detail and scale.

A field inventory of wells (step 3) would be conducted to obtain
accurate locations, to measure water levels, to verify construction
characteristics, and to collect water-quality samples. These
well-inventory data, along with the lithologic and pumpage information
from well reports, pro­vide information to determine the ground-water
boundaries, hydraulic properties, and water-level maps (step 4). The
number of wells selected for inventory controls the level of detail and
scale for this part of the assessment.

Ground-water boundaries could be defined using the lithologic
information from inventoried wells, a map of the thickness of
unconsolidated deposits (Jones, 1996), and any available geo­physical
data. Products of this assessment would be hydrogeologic cross sections,
and maps of the thickness and top altitude of aquifers and confining
beds.

11

This effort should be concentrated on the areas of unconsolidated
deposits north of the foothills and the Olympic Mountains. There is only
a small amount of ground water in

the bedrock of the foothills and the Olympic Mountains, and defining
ground-water boundaries there would be problematic and not worthwhile.

Hydraulic properties of aquifers can be estimated from the
specific-capacity tests that are usually reported on drillers' logs.
Although values derived using this information are only approximate, the
use of specific-capacity data is a practical means of determining
hydraulic conductivity and transmissivity for the Elwha-Morse watershed.
Hydraulic characteristics of the confining beds are more difficult to
determine because wells are rarely finished in them. Generally, the
vertical hydraulic conductivity and thickness of a confining bed are
most important in controlling ground-water movement because flow is
usually significant only across the confining bed. In practice, the
vertical conductance (which is proportional to the average vertical
conductivity divided by the thickness) of a confining bed is estimated
from the lithologic information for the confining bed and further
refined during the calibration of a three-dimensional ground-water
model.

Water-level maps need to be constructed for each mapped aquifer. For a
first approximation, the water levels measured during the well inventory
could be used to construct maps. For more accu­rate maps, a network of
representative wells would be selected from the inventoried wells.
Ini­tially, water levels would be measured at two

different times (in addition to when the initial site inventory was
made): once when water levels are near a seasonal low and once when they
are near a seasonal high. A smaller subset of wells would be measured on
a bimonthly basis.\
\
The water-level maps have many uses. For example, directions of lateral
ground-water flow in the aquifers could be established, and when used in
conjunction with mapped distributions of transmissivities, flow
quantities can be roughly estimated. Additionally, areas of downward and
upward ground-water movement between aquifers could be established. A
knowledge of water-level differences between aquifers is necessary to
quantify the amounts of water moving between aquifers and thus quantify
the amounts of recharge to the lower aquifers. Water-level maps also can
help in defining the aquifers. A significant difference in water levels
at different depths in an area usually indicates separate aquifers;
water-level information would be used in conjunction with the lithologic
information from drillers' logs to help delineate the aquifers.
Knowledge of water levels near shorelines is especially critical. For
example, where water levels are near sea level, ground-water pumpage may
cause seawater intrusion. On the other hand, in shoreline areas of high
water levels, it may be desirable to limit well depths such that their
bottoms are above sea level by an amount greater than the zone of
diffusion so that it reduces the possibility of seawater intrusion into
such wells. (Existing deeper wells, however, would still be vulnerable.)

12

Subsequent water-level measurements should be taken periodically at the
same time of year (i.e., late spring about once every 5 to 7 years) in
order to identify areas of ground-water deple­tion or potential
depletion. Care should be taken to use the same set of wells each time
inasmuch as is feasible.

Estimates of the amount and distribution of ground-water recharge are
necessary for quantifying the ground-water resource and for assessing
the potential effects of ground-water withdrawals on the aquifers and on
the perennial streams. Recharge is dependent upon the seasonal
distribution of precipitation, temperature, humidity, and wind speed;
the plant community and rooting depths; the moisture-holding capacity of
the soil in the root zone; and the vertical hydraulic conductivity of
the material below the root zone.

A large part of the Elwha-Morse watershed within the Olympic National
Park is underlain by rel­atively impermeable bedrock. These generally
mountainous areas receive large amounts of pre­cipitation and, therefore,
have the potential for large amounts of recharge. However, recharge in
these areas is probably limited by the water-bearing and transmission
properties of the bedrock rather than by precipitation amounts or
soil-moisture characteristics.

There are several methods available to estimate recharge (table 1,
ground water, methods A1 to A6). These methods range from a simple water
accounting method (Thornwaite method), to statistical methods, to
numerical mod­els. The choice of which method to use will depend on
available data, needed accuracy, and available funds. For the
Elwha-Morse watershed, a statistical method (regression equations)
developed recently for a ground-water study of the Sequim-Dungeness area
could be used to esti­mate average annual recharge (Thomas and others,
1999). The regression equations are applica­ble to the unconsolidated
deposits of the Elwha-Morse watershed because the two study areas have
similar climate, soils, vegetation, and hydrogeology. The data needed
for the regression equa­tions are average annual precipitation, soils,
and land-surface slope.

Natural ground-water discharge is difficult to estimate. Most of the
ground-water discharge from the unconsolidated deposits in the
Elwha-Morse watershed flows into the Strait of Juan de Fuca. This
discharge cannot be directly measured. The discharge could be estimated
using Darcy's Law, water-level gradients, hydraulic conductivity, and
thicknesses and widths of aquifers. Methods for estimating discharge to
streams are discussed in the following section "Interaction between
ground water and surface water." Withdrawals from wells can be estimated
and this is discussed in the section titled "Water Use."

Ground-water flow models (step 5), when properly constructed and
utilized, provide the only means available for quantifying ground-water
budgets and fully assessing the effects of increas­ing (or decreasing)
ground-water usage on the ground-water system. To a certain extent, they
can also be used to quantify changes in streamflow that may accompany
changes in ground-water pumpage or changes in recharge (due to
land-cover changes, for example).

13

The most widely used and accepted computer code for ground-water
modeling is the USGS MODFLOW model (McDonald and Harbaugh, 1988). It is
a finite-difference model that simu­lates flow in three dimensions. It
contains a series of highly independent subroutines or \"modules\" that
simulate specific hydrologic features, such as flow to and from rivers
from the aquifers and evapotranspiration from a shallow water table.
Layers can be simulated as confined, unconfined, or convertible from one
to the other as a function of potentiometric head (water level)

The data needed for constructing and calibrating a ground-water model
include all the data and information determined for steps (1) through
(4) of the "typical" ground-water assessment -- ground-water boundaries,
hydraulic properties, water-level maps, recharge, and discharge. The
development of a ground-water model is an excellent vehicle for
highlighting shortcomings in the available data and also in uncovering
flaws in the conceptual model (perceptions about the pro­cesses operating
within the system) developed for a study area. Once a reliable model is
devel­oped, it is the best available method for assessing effects of
ground-water withdrawals.

**[Interaction Between Ground Water and Surface Water]{.underline}**

The movement of water between ground water and surface water is an
important and complex interaction that can have impacts on water
planning and fish habitat. In some areas, water moves from ground water
into streams (ground-water discharge), and in other areas, water moves
from surface water into ground water (ground-water recharge). Streamflow
in many streams during late summer and early fall is largely maintained
by ground-water discharge. Significant with­drawals of ground water may
lower streamflows if the withdrawals intercept ground water that would
have discharged to a stream or if the withdrawals are large enough to
cause water to flow from streams into the ground water.

**Interaction: Needed Information**

Five major components of ground-water/surface-water interaction need to
be defined: (1) areas of significant interaction, (2) water-level
elevations of surface water and nearby ground water (water-level
gradient), (3) amount of flow between ground water and surface water,
(4) properties of the stre­ambed and nearby aquifer, and (5) the effects
of ground-water withdrawals on streamflows.

It is important to estimate the areas of ground-water/surface-water
interactions. For example, streams flowing over bedrock will probably
have a small interaction, but streams flowing over permeable sands and
gravels will have a large interaction. The

14

water-level elevations of surface water and nearby ground water need to
be defined because they indicate the direction of flow as water moves
from higher water levels to lower levels. The amount of flow between
ground water and surface water may be a large part of the ground-water
budget or a large part of streamflows in late sum­mer and early fall. The
properties of the streambed and nearby aquifer need to be defined to
understand the interaction process. These properties include the
hydraulic conductivity and thick­ness of the streambed and aquifer,
storage properties of the aquifer, recharge to the aquifer, and the
hydrologic boundaries of the aquifer. The effects of ground-water
withdrawals on streamflow are important to define for understanding the
effects of existing withdrawals and for allocating new water rights.

**Interaction: Possible Methods, Needed Data, and Available Data**

The interaction between ground water and surface water is complex and
difficult to define. Areas and directions of flow are fairly
straightforward to estimate, but it is difficult to estimate the amounts
of flow and the effects of ground-water withdrawals on streamflow.

There is limited available data on the interaction between ground water
and surface water in the Elwha-Morse watershed. The ground-water-level
information in the USGS and Clallam County computer databases might be
useful for some rough analyses of the

interaction. If complex water­shed models or ground-water flow models are
used, only some of the needed data for these mod­els is available.
Therefore, any analysis beyond a rough approximation would require
collection and analysis of new data.

Several methods to estimate the interaction between ground water and
surface water are described in table 1. The areas of significant
interaction can be estimated using (1) detailed maps of ground-water
levels that show directions of ground-water flow and (2) measurements of
water-level elevations in the streams and nearby aquifers that show
gradients and directions of flow.

Areas of interaction and amounts of flow can be estimated using
seepage-run data. Streamflow measurements are made, simotaineously (or
as close as possible), at several sites along a stream and the
difference in flow between each site can be assumed to be ground-water
discharge or recharge.

Watershed and ground-water models simulate the interaction between
ground water and surface water. These models require large amounts of
data and require much time to construct. However, they are the best
means for evaluating the interaction because they account for all the
major fac­tors affecting the interaction. Watershed models simplify the
ground-water component, and ground-water models simplify the
surface-water component. If the goal of a study is to estimate the
effect of ground-water withdrawals on streamflow, a ground-water model
is the best model to use.

15

**[Water Use]{.underline}**

Water-use data are necessary for water-resources management decisions
and for projections of the adequacy of the finite water resource. Water
is used for public supply, domestic supply, agricul­ture, commercial and
industrial activities, fish hatcheries, and so forth. This section
describes water use as withdrawals of surface water and ground water.
There is also instream use of water for fish habitat, but that is not
discussed in this section.

**Water Use: Needed Information**

Amounts and locations of both surface- and ground-water withdrawals need
to be quantified. Categories of water usage also should be known so that
consumptive use can be estimated and the reuse potential of return flows
can be assessed. For example, irrigation return flows may be
con­taminated by pesticides and fertilizers and have little reuse
potential, whereas water from a thermoelectric plant that only increases
water temperature will have greater reuse potential. Locations, amounts,
and prior-use categories of return flows should therefore also be
quantified.

**Water Use: Possible Methods, Needed Data, and Available Data**

Currently, various types of water-use data are collected by several
different State and local agen­cies, but no Washington State agency
maintains comprehensive water-use statistics. The Water Resources
Division of the USGS in Tacoma, Washington, maintains a water-use data
base for the state and has published a few statewide water-use
statistics at 5-year intervals from 1965 through 1975 (Dion and Lum,
1977; Parker, 1971; Laird and Walters, 1967). Since the last of these
stud­ies, however, the USGS has updated the information in the data base
once every 5 years mainly by pro-rating the older water-use compilations
according to changes in published census and industrial-activity
statistics. Data for these 5-year updates are contained in a USGS
computer database http://wa.water.usgs.gov/otherdata.html. Because of
the approximately 25-year period since the last comprehensive
com­pilation of water-use statistics, information in this data base
should not be relied upon for accurate water-use statistics for the
Elwha-Morse watershed.

A comprehensive water-use survey could be conducted for the Elwha-Morse
watershed as follows. All Group A public supply systems (greater than 15
connec­tions) within the Elwha-Morse watershed would be contacted and
asked to provide monthly with­drawal values for each surface-water,
ground-water, and transferred source of supply. Transferred water, water
obtained from other suppliers, needs to be known so that

16

overestimates of water withdrawn from actual sources are not made.
Locations and withdrawal rates of each well and surface-water source of
supply would be obtained. Areas served by each supplieer would be maped.
In addition, the depth and aquifer of each pumped interval would be
identified for each well. The amounts delivered by each public supply
system would be tallied according to domestic (permanent and part-time),
industrial, com­mercial, irrigation, thermoelectric, mining, livestock,
and sewage treatment use categories. All public supplies are supposed to
be registered with the Washington State Department of Health, which and
would be the primary source of names, addresses, and telephone numbers
for these systems.\
\
Many industrial and commercial establishments, irrigators, and other
large users of water are self-supplied. Those that use more than 5,000
gallons per day (gpd) of ground water are required by law to submit an
application to Washinton Departement of Ecology (WDOE) to withdraw a
specified amount of water. All surface-water users, regardless of
amount, are also required to apply for a water right. Because the water
right granted may exceed the amount actually used, all owners of water
rights would be contacted for actual consumption data. The same types of
information would be collected as for the public supply systems.

Amounts and distribution of water used by small public water systems
(Group B) and by individ­ual domestic wells are most efficiently
determined from population distribution statistics and per capita (or
per household) consumption rates. Local domestic consumption rates can
be computed from the Group A public supply domestic delivery data.

**[WATER QUALITY]{.underline}**

The objectives of the water-quality component of ESHB 2514 are to
determine the quality of sur­face water and ground water in a WRIA, to
determine the degree to which legally established water-quality
standards are being met, and to assess the causes of any water-quality
problems. This document briefly describes some possible methods of
analysis and data and information needed to assess the water quality of
WRIA 18.

The quality of water is largely determined by the types and amounts of
constituents dissolved in the water and by characteristics or properties
that these substances give to the water. The natural types of
constituents and their concentrations in surface water depend on the
composition of pre­cipitation and the biological and chemical reactions
at land surface and in soils. The natural qual­ity of ground water
depends on the same factors as surface water plus the mineral
composition of aquifers and confining beds and the residence time of the
ground water. The overall quality of surface water and ground water
depends on the natural factors plus any introduction of contaminents
from domestic, urban, industrial, forestry, and agricultural activities.

17

**Water Quality: Needed Information**

To determine the quality of surface water and ground water and to assess
causes of any water-quality problems, determinations of water chemistry
are needed and the amount and distribution of contaminents introduced
from human activity need to be estimated. The areal distribution of
water quality can be estimated by evaluating a sufficient number of
water-quality samples from surface water and ground water throughout the
Elwha-Morse watershed. The temporal distribution of water quality can be
estimated by evaluating samples collected at the same location over
months and years. The influence of human activity can be evaluated by
comparing water quality to the estimated amount and distribution of
contamintents introduced by humans.

**Water Quality: Possible Methods, Needed Data, and Available Data**

Water quality is measured by collecting water samples and analyzing for
the concentrations of chemical,physical and biological constituents in a
laboratory. Then assessments of water quality are often done by
com­paring these concentrations to water-quality standards established by
the Environmental Protec­tion Agency and the State of Washington. The
assessment of causes of water-quality problems is difficult, because
there are often multiple causes of high concentrations of a particular
constituent, and chemical reactions between constituents further
complicates the assessment.

An assessment of the water quality in WRIA 18 would start with the
evaluation of existing data. Tables 8 and 9 show some of the
water-quality data available from the USGS and Washington State
Department of Ecology. Drost (1986) conducted a cursory evaluation of
the quality of sur­face water and ground water in Clallam County.

Summaries of the data are only given for the entire County and most
samples were collected from the Sequim-Dungeness area east of the
Elwha-Morse watershed. Drost (1986) did not find any major water-quality
problems. Most of the minor problems were a result of natural conditions
such as high iron and manganese concen­trations.

Public-supply purveyors are required to analyze and report the quality
of their water supplies to the state While was not in the scope of this
study to assemble and analyze that data, the Washington State Department
of Health data base is a valuable source of data.

Don Haring of the Washington Conservation Commission recently completed
a study of limiting factors for fish habitat (Haring, 1999). The report
documenting that study evaluated some aspects of water qual­ity for the
Elwha-Morse watershed.

Most of the surface water and ground water in the Elwha-Morse watershed
probably has good quality, so a comprehensive study of water quality
across the entire watershed is not needed. A one-time synoptic
data-collection effort would probably be worthwhile. Then a monitoring
net­work should be established based on results of the synoptic study.

18

Constituents for analysis in all synoptic samples include field
measurements such as temperature, dissolved oxygen, specific
conductance, and pH; common ions; nutrients; and bacte­ria. Constituents
that could be determined in a subset of samples include trace metals and
syn­thetic organic compounds (including pesticides). A minimum
water-quality monitoring network would consist of the periodic
collection of samples for the analyses of nitrate, chloride, and
bacte­ria. An expanded program could include analyses for concentrations
of common ions, trace ele­ments, and synthetic organic compounds. Samples
would be collected from the areas of potential contamination from
various activities. Seawater intrusion is a concern for wells near the
Strait of Juan de Fuca, so a monitoring network of wells within a couple
miles of the shoreline could be established to analyze for chloride,
which is a good indicator of seawater intrusion.

The assessment of causes of water-quality problems includes the analysis
of water samples and the evaluation of human activity that introduces
contamintnts. Water-quality problems can result from six major sources:

1\) Agriculture, forestry, and domestic gardening:

> Fertilizers and pesticides are used in commercial agriculture,
> forestry, and for domestic lawns and gardening. Most commonly,
> application of fertilizers and pesticides, and seep­age and runoff from
> barnyard wastes may result in contamination by various nitrogen
> species, pesticides and associated compounds, chloride, bacteria, and
> viruses. Other forms of contamination, such as sulfate, sodium,
> potassium, and phosphorous, are not as frequently observed.
>
> The transport and transformation of pesticides is complex. Pesticides
> can undergo biodegradation, photolysis, hydrolysis, and oxidation, and
> the products of these reac­tions may be as toxic as the original
> pesticide. Carriers and solvents of the pesticides can also be
> contaminants.
>
> Bacterial and viral contamination from barnyard wastes depends on the
> survival rates of the many different types of organisms as they are
> transported to streams and aqui­fers. Survival rates depend upon such
> factors as water temperature, rate of transport, and filtration
> properties of the soil. Levels of fecal coliform and fecal
> streptococci bacteria are used as indicators of bacterial
> contamination. Specific indicators of viral contamination are not
> widely used because the presence of fecal bacterias also indi­cates the
> possible presence of viruses.

2\) Household wastes and septic systems:

> Septic systems are used wherever central sewer systems are not
> available. Drain­fields spread the liquid portion of household effluent
> over large areas
>
> 19
>
> where it then flows downward through the unsaturated zone, eventually
> reaching the water table. In densely populated areas, seepage from
> drainfields can be an appreciable part of the total ground-water
> recharge. As with barnyard wastes, contaminants consist primarily of
> nitrates along with the lesser quantities of sodium, potassium,
> sulfate, chloride, phos­phorous, ammonia, and bacteria.

3\) Roadside spraying:

Herbicides are used to inhibit growth of vegetation along road
shoulders. Typically, in western Washington, 2,4-dichlorophenoxy acetic
acid and glyphosate (Roundup) are used and have been found in ground
water (j. Barbash and Resek, 1996)

4\) Industrial and commercial activities:

> Industrial and commercial activities are minimal in the Elwha-Morse
> watershed; however, certain commercial establishments that are a
> potential source of contamina­tion are common to most populated areas.
> Service stations may be sources of com­pounds from fuel and oil such as
> benzene, toluene, and xylene. Dry cleaners and paint shops may be
> sources of solvents such as 1,1,1-trichloroethane and trichloroet­hene.
> Solvents, along with metals such as chromium, copper, zinc, and lead,
> can come from electronic, machine, and automotive repair shops.
> Shipping, manufactur­ing, food processing, and road and parking lot
> runoff can also be sources of these chemicals. Polychlorinated
> biphenyls in surface water sediments may be caused by hydroelectric
> facilities where they were once used for transformers and other
> electrical equipment.

5\) Natural sources:

While usually not considered contaminants, dissolved solids in natural
water usually result from the solution of minerals in the soil and
aquifers. The major dissolved sol­ids constituents depend upon many
factors, but generally include calcium, magne­sium, sodium, potassium,
bicarbonate, sulfate, chloride, nitrate, and silica. Other constituents
that generally occur in lower concentrations include carbonate,
fluoride, and metals such as iron and manganese. Except for silica, the
dissolved solids are ions, which is why the specific conductance of a
water sample is an excellent mea­sure of the total dissolved-solids
content. Generally, dissolved solids do not pose health problems but may
have detrimental effects related to taste, hardness, and staining.

20

Trace elements are present in natural waters at much lower
concentrations than the major constituents listed above. Some trace
elements can present health problems. EPA has adopted drinking water
standards for arsenic, barium, cadmium, chromium, copper, lead, mercury,
selenium, silver, and zinc. These naturally occurring trace ele­ments can
sometimes exceed EPA standards, and various industries can also cause
trace element contamination.

6\) Seawater intrusion:

> Under natural conditions, water levels in a coastal aquifer are higher
> than sea level and decrease toward the coast. The movement of fresh
> ground water along this gra­dient is seaward. When the freshwater
> gradient is decreased or reversed, such as by the pumping of nearshore
> wells, the seaward flow of freshwater is decreased, and the front of
> seawater (the zone of diffusion) begins to move landward. In
> situations where artesian (confined) aquifers extend seaward and are
> in contact with the sea only at a considerable distance from the
> coast, the aquifers could undergo intrusion without resulting in the
> appearance of seawater in coastal wells for many decades.

**[HABITAT AND INSTREAM FLOWS]{.underline}**

The assessment of habitat and instream flows is an important part of a
water-resources assessment and is a suggested component of ESHB 2514.
These two elements were not in the scope of this assesment. Don Haring's
recent study of limiting factors provides much of the data and
informa­tion needed for this assessment.

21

**SELECTED REFERENCES**

See the Elwha River---Morse Creek web page for a complete list of
references for the study area.

Amerman, K.S., and Orsborn, J.F., 1987, An analysis of streamflows on
the Olympic Peninsula: Albrook Hydraulics Laboratory, Department of
Civil and Environmental Engineering, Washington State University,
Pullman, Washington, unpaged.

Barbash, J.E., and Resek E.A., 1996, Pesticides in ground water
ditribution, trends and governing factors:Ann Arbor Press, Inc, 588 p.

Bauer, H.H., and Vaccaro, J.J., 1987, Documentation of a deep
percolation model for estimating ground-water recharge: U.S. Geological
Survey Open-File Report 86-536, 180 p.

Bauer, H.H., and Mastin, M.C., 1997, Recharge from precipitation in
three small glacial-till-man­tled catchments in the Puget Sound lowland,
Washington: U.S. Geological Survey Water Resources Investigations Report
96-4219, 119 p.

Bortleson, G.C., N.P. Dion, McConnell J.B., and Nelson, L.M., 1976,
Reconnaissance data on lakes in Washington volume 1: U.S. Geological
Survey Water-Suppply Bullitin 43, 248 p.

Clallam County, 1993, Port Angeles regional watershed Clallam County,
prepared for Port Angeles Watershed Management Committee: Port Angeles,
Wash., Clallam County, unpagiated.

Daly, C., Neilson, R.P., and Phillips, D.L., undated, A digital
topographic model for distributing precipitation over mountainous
terrain: U.S. Environmental Protection Agency, Environ­mental Research
Laboratory, Corvallis, Oregon, 44 p.

Daniels, P.D., Fritz, S.J., and Leap, D.I., 1991, Estimating recharge
rates through unsaturated gla­cial till by tritium tracing: Ground Water,
January-February, 1991, v. 29, no. 1, p. 26- 34.

Dinicola, R.S., 1990, Characterization and simulation of rainfall-runoff
relations for headwater basins in western King and Snohomish Counties,
Washington: U.S. Geological Survey Water-Resources Investigations Report
89-4052, 52 p.

22

Dion, N.P., and Lum, W.E., 1977, Municipal, industrial, and irrigation
water use in Washington, 1975: U.S. Geological Survey Open-File Report
77-308, 34 p.

Dion, N.P., and Sumioka, S.S., 1984, Seawater intrusion into coastal
aquifers in Washington, 1978: Washington State Department of Ecology
Water-Supply Bulletin 56, 13 p.

Drost, B.W., 1986, Water resources of Clallam County, Washington: Phase
I Report: U.S. Geo­logical Survey Water-Resources Investigations Report
83-4227, 263 p.

Dungeness-Quilcene Water Resource Pilot Planning Project Regional
Planning Group, 1993, Dungeness-Quilcene Water Resource Pilot Planning
Project Scoping Document, 28 p.

Eylar, T., Anderson, C., and Blair, M., 1990, Streamflow and
ground-water level records for southwest Washington 1976 to 1989:
Washington State Department of Ecology, 463 p.

Forbes, R.B., and CH~2~M Hill, 1993, Preliminary assessment of seawater
intrusion in coastal water wells in Clallam and Jefferson
Counties\--draft report, 35 p.

Haring, D., 1999, Salmon and Steelheed habitat limiting factors, water
resource inventory area 18, Washington State Conservation Commission,
202 p.

Haushild, W.L., and LaFrance, D.E., 1978, Low-flow characteristics of
streams on the Olympic Peninsula, Washington: U.S. Geological Survey
Open-File Report 77-812, 25 p.

Hirsch, R.M., Alley, W.M., and Wilbur, W.G., 1988, Concepts for a
national water-quality assessment program: U.S. Geological Circular
1021, 42 p.

Jones, M.A., 1996, Thickness of unconsolidated deposits in the Puget
Sound lowland, Washing­ton and British Columbia: U.S. Geological Survey
Water-Resources Investigations Report 94-4133, one plate.

Knott, J.F., and Olimpio, J.C., 1986, Estimation of recharge rates to
the sand and gravel aquifer using environmental tritium, Nantucket
Island, Massachusetts: U.S. Geological Survey Water-Supply Paper 2297,
26 p.

Laird, L.B., and Walters, K.L., 1967, Municipal, industrial, and
irrigation water use in Washing­ton, 1965: U.S. Geological Survey
Open-File Report (unnumbered), 13 p.

23

McDonald, M.G., and Harbaugh, A.W., 1988, A modular three-dimensional
finite-difference ground-water flow model, Book Chapter A1: Techniques
of Water-Resources Investiga­tions of the U.S. Geological Survey.

McFarland, C.R., 1983, Oil and gas exploration in Washington, 1900-1982:
State of Washington. Department of Natural Resources, Division of
Geology and Earth Resources, Information Circular 75, 119 p.

Parker, G.G., Jr., 1971, Municipal, industrial, and irrigation water use
in Washington, 1970: U.S. Geological Survey Open-File Report
(unnumbered), 21 p.

Phillips, E.L., 1966, Washington climate for these counties: Northeast
Clallam, northeast Jeffer­son, Island, San Juan, Skagit, Snohomish and
Whatcom; E.M. 2626, Cooperative Exten­sion Service, College of
Agriculture, Washington State University, 64 p.

Pollock, D.W., 1989, Documentation of computer programs to compute and
display pathlines using results from the U.S. Geological Survey Modular
Three-Dimensional Finite- Differ­ence Ground-Water Model: U.S. Geological
Survey, Open-File Report 89-381, 188 p.

Soule, A., 1992, Sequim-Dungeness groundwater monitoring quality
assurance project plan: Cla­llam County, Washington, Department of
Community Development Water Quality Office, 28 p.

State of Washington, Department of Conservation, 1964, Miscellaneous
streamflow measure­ments in the state of Washington, 1880 to January
1961: Water-Supply Bulletin 23, 292 p.

State of Washington, Office of Financial Management, 1991, Washington
State 1991 data book, 306 p.

Tabor, R.W., and Cady, W.M., 1978, Geologic map of the Olympic
Peninsula, Washington: U.S. Geological Survey, Miscellaneous
Investigations Series, Map I-994.

Tabor, R.W., Yeats, R.S., and Sorensen, M.L., 1972, Geologic map of the
Mount Angeles quad­rangle, Clallam and Jefferson Counties, Washington:
U.S. Geological Survey Quadrangle Map GQ-958, scale 1:62,000, 1 sheet.

Thomas, B.E., Goodman, L.A., and Olsen, T.D., 1999, Hydrogeologic
assessment of the Squim- Dungeness area, Clallam County, Washington:
U.S. Geological Survey Water Resources Investigations Report 99-4048,
165 p.

24

U.S. Department of Agriculture, 1965, Mean annual precipitation,
1930-57, State of Washington: Portland, Oregon, U.S. Soil Conservation
Service Map M-4430.

U.S. Environmental Protection Agency, 1984, Hydrologic simulation
program - FORTRAN (HSPF): Users manual for release 8.0:
EPA-600/3-84-066, Environmental Research Lab­oratory, 767 p.

U.S. Environmental Protection Agency, 1987, Use of pesticides in
vulnerable groundwaters of Washington State: EPA 910/9-87-169, EPA
Region 10 Pesticides Section.

U.S. National Oceanic and Atmospheric Administration, 1992,
Climatological data annual sum­mary, Washington 1991, volume 95, number
13.

Veatch, F.M., 1964, Miscellaneous stream-flow measurements in the state
of Washington, 1890 to January, 1961: U.S. Geological Survey
Water-Supply Bullitin No. 23, 292 p.

Walters, K.L., 1971, Reconnaissance of sea-water intrusion along coastal
Reassignment, 1966- 68: State of Washington, Department of Ecology,
Water-Supply Bulletin No. 32, 208 p.

Western Regional Climate Center, accessed January 4, 2000 at

<http://www.wrcc.dri.edu/index.html>.

Williams, J.R., and Riis, S.A., 1989, Miscellaneous streamflow
measurements in the state of Washington, January 1961 to September 1985:
U.S. Geological Survey Open-File Report 89-380, 382 p.

25