20250714Ex I DEQ Draft Source Water Assessment Summary Report.pdf

DRAFT
Source Water Assessm ent Sum m xy Report: BEAR CLAW SUBD (PWS#
ID1090231) WELL #1 E0010087
Introduction
Source water is untreated ground water (aquifers and springs) and surface waters (rivers, streams, and lakes)
used to supply drinking water for public water systems In Idaho there are approximately 1,960 public water
system s providing water to alm cst 1.5 m illion people. The US Environm ental Protection Agency (EPA) requires
the Idaho Departm Ent of Environm ental Quality (DEQ) to assess every public water system source (well,
spring, or surface water intake) in Idaho for its relative susceptibility to contam rants that are regulated by
the federal Safe Drinking Water Act. There are approximately 3,500 active sources in Idaho. DEQ conducts
source water assessm tints based on an inventory of potential contam inants and land uses within the
delineated source water assessm Ent area, construction of the well, sensitivity factors associated with the
drinking water source, and local aquifer characteristics. The ultim ate goal of each source water assessm Ent
is to provide data that communities can use to develop protection strategies for their drinking water sources
(source water protection).
The resources and tim eavailable to accom plish source water assessm eats are lim iced. Therefore, an in-
depth, site-specific investigation to identify each significant potential source of contam nation for every
public water system is not possible. Instead, DEQ uses com puter databases and geographic information
system (GIS) maps to produce a potential contam rant inventory that can then be verified by the system or
other stakeholders with an on-the-ground investigation. If any additional potential contam rants are
identified, the system can create a potential contam rant enhanced inventory.
The results of source water assessments should not be used as an absolute measure of risk, nor should they
be used to underm ne public confidence in the public water system .A particular susceptibility score does not
im ply any regulatory or safety violations exist or contam nation will occur. This report sum m arizes
information about public water system sin Idaho. Using or distributing the data in this report in any other
form m air inaccurately portray the data.
DEQ strongly encourages each public water system and com m unity to use its source water assessm tints,
combined with local knowledge and concerns, to develop source water protection strategies. Multiple
resources are available to help com m unities im plem art source water protection program s, including DEQ's
Source Water Protection Activity Guide and Source Water Protection Plan Tern plate.
The protection of source water involves many partners. Various governm ental entities and organizations play
a role in protecting drinking water sources in Idaho and can be a resource for protection efforts. Source
water protection activities should be coordinated with these entities to leverage resources and maximize
results. For exam ple, activities related to agricultural practices should be coordinated with the Idaho State
Departm Ent of Agriculture, Idaho Soil and Water Conservation Com m ssion, local Soil and Water Conservation
District, and Natural Resources Conservation Service. Visit the Idaho Source Water Collaborative website for
m cre inform ation on potential partners and resources.
For assistance in developing protection strategies, contact DEQ's Coeur D Alene Regional Office or the Idaho
Rural W 2ter Association.

This report was com p eted April 07, 2025. Potential contaminant information was updated on March 17,
2025. Confirmed detections noted in the susceptibility report were updated January 2019 for community and
NTNC sources active at the tim eof the update. (This could result in a change to a source's final susceptibility
ranking.)
What Was Assessed
This report evaluates BEAR CLAW SUBD (PW S# ID1090231) W ELL#1 E0010087 located in BONNER county. The
system serves approximately 70 people through 28 connections.
Defining the Source Water Assessm eit Area
The first step of a source water assessm Ent is to delineate the source water assessm Ent area. The
delineation process includes m apping the boundaries of the land area above the aquifer that could
contribute water and potential pollutants to the water supply. The delineation illustrates the portion of the
aquifer that supplies water to the well. Depending on the type of public water system (i.e., comm unity,
nontransient noncom m unity, or transient noncom m unity) and the am cunt of site-specific data available, one
of three m ethods m ay be used to delineate a ground water source: (1) a fixed 1,000 foot radius, (2) a
calculated fixed radius, or (3) a refined analytical m ethod.
For com m unity system sthat serve at least 15 service connections or 25 people year-round in their prim ary
residences (e.g., m cst cities and towns, apartm ents, and m cbile hom e parks with their own water supplies)
or nontransient noncom m unity system s that serve at least 25 of the sam a persons over 6 m cnths per year
(e.g., schools, churches, nursing hom es, and factories, and hospitals with their own water source), DEQ uses
a refined analytical m ethod approved by EPA to delineate up to three separate tim eof-travel (TOT) zones.
The TOT zones illustrate the num ber of years necessary for a particle of water or contam rant to m cve from
a specific point in the aquifer to the well. The refined analytical m ethod uses site-specific data assim elated
from a variety of sources, including well logs and hydrogeologic reports to determine the TOT zones. DEQ
m ay use a calculated fixed radius m ethod for com m unity and nontransient noncom m unity systems when site-
specific data are not available. Generalized, existing, hydrogeologic data from the major aquifer types in
Idaho, and data from the well pum prate are used in the average velocity equation to derive radii for 3-, 6-,
and 10-year TOT zones.
The following three TOT zones are m apped:
Zone I refers to the 0-3 TOT zone and is addressed by two subzones: Zone 1 A and Zone 1 B.
Zone IA refers to the sanitary setback, or the 50-foot radius around the well. The goal of this
zone is to prevent contam nation from nearby sources, particularly microbial contamination
from sewer lines, livestock, surface waters, and septic systems.
Zone IB refers to the 0-3 year TOT zone. Water in this zone takes 0-3 years to travel in the
aquifer to reach the well.
Zone 11 refers to the 3-6 year TOT zone. Water in this zone takes 3-6 years to travel in the aquifer to
reach the well.
Zone III refers to the 6-10 year TOT zone. W ater in this zone takes 6-10 years to travel in the aquifer
to reach the well.

The source water assessm Ent for WELL#1 was done using the Refined Analytical Method and is illustrated in
the m ap provided. The data used to determ ne the source water assessm Ent delineation for W ELL#1 are
included in the References section or available from DEQ upon request.
Susceptibility Analysis
The susceptibility analysis provides an estim ate of the likelihood that the water supply will becom e
contam hated. For each well, spring, or surface water intake in a public water system ,susceptibility to
contam nation is scored as high, moderate, or low. Susceptibility scores for wells take into account three
factors, which are described in m cre detail in later sections:
1. System Construction: Construction of the well being assessed.
2. Hydrologic Sensitivity: Hydrologic and geologic conditions surrounding the well.
3. Potential Contam Want Inventory(PCI)/Land Use: Potentially significant sources of contam nation
and land uses within the delineated source water assessm ant area.
Each of the factors listed above receives a score of high, m edium ,or low to reflect how susceptible the
source is to potential contam nation. Note that deriving susceptibility scores is a qualitative, screening-level
step that, in many cases, uses generalized assum ptions and best professional judgm Ent. Once corn Meted,
susceptibility scores are only updated upon request by the public water system .
PCl/land use scores and final susceptibility scores consist of four individual scores, one for each of four
categories of contam rants:
Inorganic chemicals (10C).
Volatile organic chem icals (VOC).
Synthetic organic chem icals (SOC).
Microbial contam rants
High susceptibility to one potential contam rant does not m can that the water system is at the Sam e risk for
all other potential contaminants. The susceptibility scores for WELL#1 are shown in the table below. Click
here for full susceptibility score details.
Susceptibility Scores for BEAR CLAW SUBD(PWS#ID1090231)WELL#1 E0010087
System Construction P otential Contam pant Inventory/Land Use H ydrologic Sensitivity Final Susceptibility Ranking
IOC V OC S € OC M: icrobials I OC V OC S OC M € icrobials
II4 L NN L oderate M oderate M oderate M oderate
H=High Susceptibility,M=Moderate Susceptibility, L=Low Susceptibility.System Construction refers to the well,spring,or surface water intake.
Auto High-see below.' R eport Date:4/7/2025 Click for Map C lick for details
*Auto-High Score: Four situations cause autom atic assignm Ent of a high susceptibility score: (1)any detection of a VOC or SOC, (2)
detection of an IOC at a concentration greater than the drinking water m a dm un contaminant level (MCL)set by EPA, (3)a confirmed
m icrobial detection at the drinking water source, or(4)the presence of potential contaminant sources within 50 feet of a well.
Additionally, ground water sources designated as under the direct influence of surface water(GW lAl)autom atically rank high for
m icrobial contam rants due to the inherent nature of surface water bodies as wildlife habitat and residence for various m icroorganism S.
Any of the first three situations will trigger an auto-high score because a pathway for contam nation already exists. Note that MCLs,
detections, and potential contam pants can change over tim a and are not autom atically updated in the score. Refer to the susceptibility
score details page for m ore inform ation on the contam rant source or detections resulting in an auto-high score.

System Construction Score
The first of the three factors scored in a source water assessm Ent is the system construction. System
construction refers to the construction of the well that serves as the drinking water source. The construction
of a well directly affects its ability to protect the aquifer from contam rants. System construction scores are
lower when information shows that the design and integrity of the well can help prevent potential
contam rants from reaching the aquifer. The system construction score depends on these five com ponents:
1. Com pliance with all current construction standards for public water system wells.
2. Condition of the wellhead and surface seal.
3. Placem ant of the well casing and annular seal into or through at least one continuous low
permeability geologic unit of substantial thickness (>_10 feet) reduces the risk of contam nation
to the aquifer. (Perm eability is the ability of a porous m edium ,such as rock, sedim Ent, and soil,
to transmit fluids under a hydraulic gradient; it is a m insure of the relative ease of fluid flow
under unequal pressure.)
4. Production of water from m are than 100-feet below static water level. (Static water level refers
to the level of water in a well under norm ai, no-pumping conditions.) Water drawn from deeper
portions of an aquifer is typically buffered from m cbt potential contam rants introduced at the
land surface.
5. Location of the well outside of a 100-year floodplain. (A floodplain is flat or nearly flat land
along a river or stream or in a tidal area that is covered by water during a flood. The 100-year
floodplain is the area likely to be inundated during a flood with a 1% chance of being equaled or
exceeded in any given year. DEQ uses data from the Federal Em e-gency Managem Ent Agency to
determ ne the 100-year floodplain for any given area.) Locating wells outside a floodplain can
help prevent direct contact between the wellhead and storm ,flood, or irrigation water.
Idaho Department of Water Resources' rules regulate well construction ("
Well Construction Standards Rules" [IDAPA 37.03.09]). These rules require all public water system sto also
follow DEQ's well construction standards (" Idaho Rules for Public Drinking Water System s" [IDAPA
58.01.08.510]). DEQ standards include screening requirem efts, depth of annular seal, use of a down-turned
casing vent, and casing thickness, height, and depth. Current construction standards for public water system
wells can be more stringent than standards in effect when a well was constructed, so your system
construction score m air be higher due to not m eeting current well construction standards.
Your system construction score may also be higher if adequate information about the well is not available.
Refer to the susceptibility score details page for more information about the construction of the well
assessed in this report.
Hydrologic Sensitivity Score
The second of the three factors in a source water assessm Ent is hydrologic sensitivity. Hydrologic sensitivity
considers how easily or quickly water m o✓es through the subsurface of the earth. A well's hydrologic
sensitivity score depends on the following:
1. Com position of surface soil. Soil drainage classes (defined in soil surveys published by the NRCS
in 1998), ranging from poorly drained to moderately drained, such as silt and clay, are deemed
m cre protective of ground water than m oderately to well drained soils, such as sand and gravel,
which drain faster.

2. Material in the vadose zone (the zone between the land surface and first encountered water).
Vadose zone m aterials com prised of gravel or fractured rock provide less protection from
contam nation than finer-grained sedim Entary m aterials.
3. Depth at which ground water is first encountered. All other factors being equal, a greater depth
to ground water provides greater opportunity for the attenuation of potential contam rants
through adsorption and other mechanisms.
4. Presence of a low perm cable unit (a layer of rock or sedim Ent that does not transm it water
easily, thus protecting the aquifer from contam nation). For susceptibility scoring, DEQ considers
a low permeable unit to be present if there is >50 feet of cum dative thickness of silt or clay-rich
geologic m aterials, or fine grain sedim entary interbeds within basalt settings above the bottom
of the annular seal to be protective of the aquifer.
Refer to the susceptibility score details page for m cre inform ation on the hydrologic conditions for this
source.
Potential Contam rant Inventory/Land Use Scores
The last of the three factors scored in a source water assessm Ent is the potential contam rant inventory
(PCI)/land use. A potential contaminant is defined as any facility or activity that meets these criteria:
Stores, uses, or produces, as a product or by-product, the contaminants regulated under the federal
Safe Drinking W ater Act.
Has a potential for releasing the contam rants at levels that could potentially harm drinking water
sources.
As part of each source water assessm ant, DEQ conducts an inventory of potential sources of contam nation.
The goal of the inventory is to locate and describe facilities, land uses, and environm Ental conditions that
are potential sources of ground water contamination.
The inventory is a two-step process. First, DEQ identifies and docum ants potential contam inant sources in
the source water assessm Ent area using com puter databases and GIS m aps developed by DEQ and various
state and federal agencies. Although DEQ uses the best inform ation available, DEQ does not m ake any
warranty regarding the accuracy or com pleteness of any information or data provided. For example, DEQ
m ay not be able to obtain the exact location for each potential contam rant or m ay not be notified
im m eiiately of new sites or changes to existing sites. DEQ updates PCIs when new inform ation warrants an
update. The exact date inventories are updated is found in the PCI table. Second, the public water system
receives a draft copy of the source water assessm Ent and can provide com m ants to DEQ to correct or expand
on the inventory. Although the public water system is only contacted by DEQ after the initial PCI is
conducted, the public water system can review the PCI and subm it corrections to DEQ at any time.
Com m eits can be subm itted to DEQ.
W hen agriculture is the predom inant land use within the delineation, the likelihood of agricultural
chem icals, such as fertilizers and pesticides, entering the ground water system m ay increase. This results in
m ore points assessed for the IOC and SOC categories in the 0-3 year TOT zone. Additionally, depending on the
percentage of agricultural land in each TOT, PCl/land use susceptibility scores may be influenced.
W hen the 0-3 year TOT zone intersects an area of defined ground water degradation, such as a nitrate
priority area, additional points are assigned to the PCl/land use section of the susceptibility score. Nitrate is
one of the m cst widespread ground water contam inants in Idaho. High levels of nitrate in drinking water are

associated with adverse health effects. Therefore, DEQ designates areas with degraded ground water quality
due to nitrate as nitrate priority areas with the goal of developing and im plem anting m anagem Ent strategies
with local stakeholders to im prove ground water quality.
Understanding Potential Contam rant Source Inform ation
The presence of a potential source of contam nation m eans that the potential for contam nation exists due
to the nature of the business, industry, or operation. A release is less likely to occur from a potential source
of contam nation, when the facility or landowner uses best m anagem Ent practices to manage the potential
contam nant. Many potential sources of contam nation are regulated at the federal or state level, or both, to
reduce the risk of release. Therefore, when businesses, facilities, or properties are identified as potential
contam Want sources, it does not m ean that they are violating any local, state, or federal environm anal law
or regulation.
The table below lists the potential contaminants for WELL#1 public water system .The public water system
is not located within a nitrate priority area.
PW S Nam e: BEAR CLAW SUBD (PW S# ID1090231)
Source Number: E0010087
Source Name, WELL#1
Potential Contaminants:
Export to Excel
TOT Description of Potential Contaminant Source 1,4 Potential Contaminant(s) N ame Data Source Z Updated Date s
0-3 year j Surface Water S ite specific G IS 3 /17/2025
0-3 year Major And Minor Roads
3-6 year [ Surface Water
3-6 year Mine Site
3-6 year Major And Minor Roads
6-10 Surface Water S e ite specific W st Fork Blue Creek G IS 3 /17/2025
year
6 10 Major And Minor Roads I OC,VOC,SOC,Microbe G IS 3 /17/2025
year
Footnotes:
1. The GIS datasets used to identify potential contaminants are gathered from various state and federal agencies and are
updated on different intervals.
2. During the first phase of the PCI, known as the prim ary contaminant inventory, DEQ staff use GIS datasets and aerial photos
to identify and docum ant potential contam rant sources within the water system t source water assessm ant delineation.
During the second phase of the PCI, known as the enhanced inventory, potential contam inants not already identified
through GIS (e.g., septic system s, business sites, and land use activities)can be added to the PCI.
3. Date Updated refers to the m cst recent date each potential contam inant was last verified within the GIS datasets. PCIs are
updated when new information warrants an update. Potential contaminants identified through aerial photos or enhanced
inventories are updated less often.
4. Restriction of Liability for GIS Data: Neither the State of Idaho nor DEQ, nor any of their em pioyees m ake any warranty,
express or im Oied, or assume any legal liability or responsibility for the accuracy, com pleteness or usefulness of any
information or data provided. Metadata are provided for all datasets, and no data should be used without first reading and
understanding its Lim nations.The data could include technical inaccuracies or typographical errors. DEQ m ay update,
m odify, or revise the data used at any tim e, without notice.

*TOT = tim eof travel zone
IOC = inorganic chemical, VOC = volatile organic chemical, SOC = synthetic organic chemical
Refer to the susceptibility score details page for m cre inform ation about the potential contam rants and
land use within this delineation.
Conclusion
Local com m unities can use the inform ation gathered through the assessm ant process to create a broader
source water protection program to address current problem sand prevent future threats to the quality of
their drinking water supplies. Preventing contaminants from entering the public water system source can
m nim to health risks, expanded drinking water m cnitoring requirem ants, additional water treatm Ent
requirem ants, or expensive environm vital cleanup activities. For assistance developing protection
strategies, contact DEQs Coeur D Alene Regional Office or the Idaho Rural Water Association. Also consider
the following resources:
Idaho Source Water Protection W dbsite
Idaho Source Water Protection Activities Guide
Idaho Source Water Protection Planning Tool
www.protectthesource.org
List of Acronyms and Abbreviations/Glossary
List of Acronyms and Abbreviated/Glossary
References
ID1090231 Bear Claw Subdivision Wdl 1 SWAModeling Report FY2013.pdf
ID1090231 Bear Claw Subdivision W dl 1 Re-Model SWAModeling Report FY2025(2).pdf
M ap
The public water system is not located within a nitrate priority area.
Click here for dynam is m ap.
To save the map or legend right click on the images below and select save as.
(This m ap m ay take several seconds to load.We appreciate your patience.)

AL
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a®
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Map Legend
r-
I County Boundaries Streets (100k)
--
l Deep Injection Well
O Source Location Highway
cl Shallow Injection Well
Source Water Delineations Time of Travel (TOT) Limited Access
3 Year TOT NPDES Location
6 Year TOT © RCRA Site Local Road
C3 10 Year TOT & Drain Location Major Road
C3 Surface Water Buffer iI Road Salt Location Other Roads
C:3 Fixed Radius
Watershed Boundary 3t Mine Site Ti Ramp
� Tier II(formerly CAMEO)
Potential Contaminants Inventory Locations Trail
._ Sewage Drainfields
� Brownfield Site 4WD
A CERCLA Site Tunnels and Drains
Toxics Release Inventory Site Railroad Hydrography
General Waste Site Phosphate Mine Lakes
AL UST/LUST Site Water Reuse Area Streams
n Dairy Wastewater Lagoon
■ Feedlot Pesticide Management Area
f Managed Aquifer Recharge Site
Landfill
1DEQ GIS May 2019

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