Drinking Water 101

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Drinking Water 101
Groundwater Basics Dennis Nelson
Source Water Assessments/Protection Amy Parmenter
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Groundwater Basics

• Where does ground-water come from?
• How does ground-water occur?
• How does ground-water move and how fast does it
  travel?
• How susceptible is groundwater to contamination?

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Important Groundwater Facts

• Groundwater originates from precipitation
  sinking into the ground from the surface to the
  water table.
• Groundwater occurs in the open spaces between
  silt, sand and gravel particles or in natural
  fractures in rocks (not underground rivers or
  lakes).
• Groundwater moves from where the water table is
  high to where it is low.
• How fast it moves depends on the slope of the
  water table and the aquifer permeability.
• Groundwater is susceptible to contamination from
  surface activities.

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Origin of Groundwater
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Types of Aquifers

• Unconfined
• Shallow
• Local Recharge
• Water Table
• Susceptible
• Confined
• Deeper
• Confining Layer
• Distant Recharge
• Water under pressure
• Less susceptible

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Local vs. Distant Recharge
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Groundwater Movement
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Groundwater Flow Direction
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The Nature of Aquifers and Groundwater Movement
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Source of Information Well Logs

• What are the geologic materials and where do they
  occur?
• Where is the first water?
• Compare static water level with level of
  water-bearing zone
• Confined vs. Unconfined aquifer?

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Unconfined vs. Confined AquifersWhat does the
well log tell us?
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Seasonal Water LevelsWinter
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Seasonal Water Levels Summer
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Groundwater and Surface Water Reactions
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Streams and Groundwater
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Hydrographs and Base Flow
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Lakes and Groundwater Lakes may
receive Groundwater, Discharge to ground- Water,
or both
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Pumping wells Close to Streams Drawing in
surface Water? How much pumped
How long pumped
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Potential for Groundwater Contamination

• Soil and subsurface materials as filtering
  mechanism
• Particulates (Pt)
• Dissolved (Ds)
• Bacteria (Bc)
• Chemical processes affect dissolved constituents
  Organic (Or) vs. Nitrate (NO3)

Or
Pt
Bc
Ds
NO3
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Potential for Groundwater Contamination Aquifer
Sensitivity

• Hydrogeologic
• Soil (b, K, Org. C)
• Vadose (b, K)
• Depth to aquifer
• Avail. H2O
• Chemical Specific
• Solubility
• Sorption tendency
• Persistance (T 1/2)

Soil
Vadose
Aquifer
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Aquifer Sensitivity

• Nature of vadose zone
• Permeability of material is highly variable
• Approximate travel time across 20 vertical feet
  under saturated conditions
• Also aquifer character, old wells, depth to
  aquifer, rainfall,etc.

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Groundwater Contamination
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Seasonal Compositional Variations

• Seasonal Differences within a single well
• Recharge related
• Infiltration of nitrate from a nitrate source (A)
• Dilution of contaminated aquifer (B)
• Significant Variations
• Up to 100 have been observed, e.g., lt10 to gt20
  mg/L

B
A
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Seasonal Pumping Variations

• In winter months, dashed lines, groundwater flow,
  and therefore the capture zone of a domestic well
  may differ from that during irrigation season
  when large-capacity wells alter the flow pattern.

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Between Wells Variability

• Recharge and/or source related
• Wells screened in different aquifers
• Wells screened at different depths in the same
  aquifer

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Important Groundwater Facts

• Groundwater originates from precipitation
  sinking into the ground from the surface to the
  water table.
• Groundwater occurs in the open spaces between
  silt, sand and gravel particles or in natural
  fractures in rocks (not underground rivers or
  lakes).
• Groundwater moves from where the water table is
  high to where it is low.
• How fast it moves depends on the slope of the
  water table and the aquifer permeability.
• Groundwater is susceptible to contamination

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Drinking Water 101
Groundwater Basics Dennis Nelson
Source Water Assessments/Protection Amy Parmenter
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Oregon Source Water Assessments

• Mandated by 1996 Amendments to the Safe Drinking
  Water Act
• Applies to all federally-defined public water
  systems community, nontransient noncommunity and
  transient noncommunity
• Goal encourage implementation of protection
  measures in order to
• Insure the quality of future drinking water
  sources
• Minimize the cost of future treatment costs

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Drinking Water Protection Process for Public
Water Systems (PWS)
DHS and DEQ contact PWS GPS intake or well and
request PWS assistance
Activate community citizens, gather input, select
a few strategies for protecting the source area
DELINEATION of the source area or Drinking Water
Protection Area
INVENTORY for Potential Sources of
Contamination per guidance
Source Water ASSESSMENT phase
OPTIONAL Consider writing a Drinking Water
Protection Plan and gaining certification from DEQ
Drinking Water PROTECTION phase
Determine SUSCEPTIBILITY to contamination
IMPLEMENT the strategies to prevent contamination
SOURCE WATER ASSESSMENT REPORT Sent to PWS
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OregonSource Water Assessments

• GW - 948 systems (community and nontransient
  noncommunity)
• SW - 142 systems
• Total full assessments - 1090
• TNCs - 1046 systems

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Procedure for mapping of Surface Water DWP Area

• Compiled base map with USGS topographic maps
  edge-matched
• Used 5th-field HUC Oregon Sub-basins to delineate
  watershed if available
• Completed mapping on GIS base map (up to state
  boundaries)

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Sensitive Areas for SW

• Characteristics
• Setbacks 1000 from centerline of water body,
  includes all perennials
• High soil erosion potential (NRCS)
• High permeability soils (alluvials mapped by
  USGS)
• High runoff potential (Class D soils)
• Landslide hazard areas

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Oregon drinking water source areas for surface
water intakes
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What weve learned from surface water assessments

• Surface Water DWPAs include multiple PWSs
• Surface Water DWPAs contain many different
  stakeholders
• Headwaters of a lot of DWPAs are in forested land

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Procedures for Delineation Groundwater

• Identify that part of the aquifer that supplies
  water to the well or spring
• Site-specific parameters
• Radius a function of time
• Project to the
• surface

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Procedures for Delineating Groundwater Sources

• Dependent on population, number of wells and
  hydrogeologic setting
• lt500 and single well calculated fixed radius
  (volume calculation) 63
• lt500, multiple wells enhanced calculated fixed
  radius 4
• gt500 analytical model 22
• Complex hydrologic boundaries analytic element
  or numerical method 5
• Springs hydrogeologic mapping 6
• Transient NC systems outreach area - 1115

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Drinking Water Protection Areas Oakhill School
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Multiple Well Delineation
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Adding Groundwater Flow
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Drinking Water Protection Areas Junction City
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Hydrogeologic Mapping
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Oregon Drinking Water Protection Areas from
Groundwater Sources
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What weve learned from groundwater assessments

• 347 (55) of our CWSs have at least one source
  that rates as highly sensitive
• General categories of highly sensitive
• Chemical detection at the source
• Coliform from the source
• Aquifer character
• Ease in which water can move from the surface to
  the aquifer
• Well construction

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What weve learned highly sensitive aquifer

• Aquifer Character/Ease of Movement
• Many systems use shallow unconfined aquifer
• 255 (39) CWSs have 392 sources lt100 feet
• 144 (22) CWSs have 209 sources lt50 feet
• 58 (9) CWSs have a high infiltration potential

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What weve learned highly sensitive well
construction

• 116 (24) community water systems have no well
  report for at least one source
• Older than 1960?
• Cannot evaluate well construction
• 171 (35) additional CWSs have sources with
  inadequate well construction
• Casing seal

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Inadequate Well Construction
Water

• Too small of annular space
• Incorrect method of emplacement
• Incorrect materials, e.g., drill cuttings
• Insufficient sealant to fill annular space
• Inadequate depth to isolate or protect aquifer

Slab
Casing Seal
Casing/Liner
Bore Hole
Screen/Perforation
Pump
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What weve learned future rule implementation

• Groundwater under the direct influence
  (noncommunity systems)
• 245 systems need to be evaluated others
  eliminated by assessment
• Groundwater Rule (hydrogeologic assessment)
• 211 CWSs are highly sensitive and have coliform
  sources within 2-year time-of-travel

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Drinking Water Protection Process for Public
Water Systems (PWS)
DHS and DEQ contact PWS GPS intake or well and
request PWS assistance
Activate community citizens, gather input, select
a few strategies for protecting the source area
DELINEATION of the source area or Drinking Water
Protection Area
INVENTORY for Potential Sources of
Contamination per guidance
Source Water ASSESSMENT phase
OPTIONAL Consider writing a Drinking Water
Protection Plan and gaining certification from DEQ
Drinking Water PROTECTION phase
Determine SUSCEPTIBILITY to contamination
IMPLEMENT the strategies to prevent contamination
SOURCE WATER ASSESSMENT REPORT Sent to PWS
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Potential contaminant source

• a location where there is any activity having the
  potential to release one or more contaminants
  into water at a concentration of concern
• Database queries (14), field locating in
  sensitive areas, PWS consultations
• 96 separate categories of PCSs
• As of 7/05, over 15,300 PCS locations have been
  identified
• focus must be on HIGHER risks

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Important points about the SWA Inventory

• listed potential sources not all inclusive
• contaminants of concern SDWA
• potential sources store/uses/produces levels
  that could contaminate PWS sufficient
  likelihood of release
• not all listed sources were inventoried
• microbes within 2-yr. TOT
• watersheds gt100 sq. miles sensitive area focus
• not all listed sources pose actual high risk
• worst-case assumptions for POTENTIAL
• not all inventoried sources need managing
• screen out lower risks focus only on higher
  ones

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Oregons SWA Inventory ResultsSurface Water
SystemsHighest Potential Risks in Sensitive Areas
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Oregons SWA Inventory ResultsGroundwater
Systems Highest Potential Risks in 2-yr TOT
(wells) Zone 1 (springs)
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Drinking Water Protection Process for Public
Water Systems (PWS)
DHS and DEQ contact PWS GPS intake or well and
request PWS assistance
Activate community citizens, gather input, select
a few strategies for protecting the source area
DELINEATION of the source area or Drinking Water
Protection Area
INVENTORY for Potential Sources of
Contamination per guidance
Source Water ASSESSMENT phase
OPTIONAL Consider writing a Drinking Water
Protection Plan and gaining certification from DEQ
Drinking Water PROTECTION phase
Determine SUSCEPTIBILITY to contamination
IMPLEMENT the strategies to prevent contamination
SOURCE WATER ASSESSMENT REPORT Sent to PWS
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Drinking Water Protection Process for Public
Water Systems (PWS)
DHS and DEQ contact PWS GPS intake or well and
request PWS assistance
Activate community citizens, gather input, select
a few strategies for protecting the source area
DELINEATION of the source area or Drinking Water
Protection Area
INVENTORY for Potential Sources of
Contamination per guidance
Source Water ASSESSMENT phase
OPTIONAL Consider writing a Drinking Water
Protection Plan and gaining certification from DEQ
Drinking Water PROTECTION phase
Determine SUSCEPTIBILITY to contamination
IMPLEMENT the strategies to prevent contamination
SOURCE WATER ASSESSMENT REPORT Sent to PWS
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Knowledge of Risks Promotes Resource Protection

• Facilitates better community planning
• Cost effective
• Expensive to treat or replace
• Better public health/economic health
• Protect property values
• Preserve economic growth potential
• Increased public understanding of DW resource and
  responsibility to protect it

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Reasons to Protect the Source

• Population increase
• Increased water needs
• Increased threats to watershed health
• Water infrastructure is aging
• Water Quality standards are tightening
• Emerging pollutants of concern
• Limited funds for treatment upgrades
• Security Issues

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Discrete land use areas help focus risk reduction
activities

• Residential
• household hazardous wastes
• septic system maintenance
• stormwater management
• Commercial / Industrial
• pollution prevention TA
• mentoring/partnerships
• Agricultural
• improved irrigation practices
• nutrient/pesticide BMP
• Forest
• reduce road densities
• sediment control
• pesticide BMPs

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Purpose of Management Plan or pollution
prevention measures

• REDUCTION of contamination risks, not
  elimination
• encouragement of community-based decisions on
  how to implement plan
• increased public understanding of drinking
  water resource and responsibility to protect it
• recognition of good-neighbor businesses,
  farmers, etc.

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Why is citizen involvement so critical to
drinking water protection?

• The largest percentage of pollution in Oregon
  comes from sources not regulated by permits, so
  we must engage individual citizens in the
  communities
• Some of the most effective prevention tools will
  be individual actions by landowners and
  unregulated sources
• We must promote water quality protection through
  effective education and outreach materials

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Drinking Water ProtectionChallenges

• DWP time-consuming involves many players. PWS
  staff time/capability is often limited
• Most PWSs dont have jurisdiction over their
  entire DWPA
• Easier to fund/justify treatment (reactive) vs.
  protection (proactive)
• Common misconceptions
• Required water testing is enough
• Detections below the MCL not a risk
• Think protection is covered in emergency
  response/vulnerability planning/plan review

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Drinking Water ProtectionChallenges

• DWP is an unknown process to most PWSs
• PWS hesitate to tell consumers there is a risk
• Lack of data to support protection (detection
  levels, focus is on MCL concentration, risk not
  known for synergistic effects)
• More common misconceptions
• Protection means excluding land uses
• Polluter pays right?
• Water systems with low risk assume no risk
• Area immediately adjacent to well is all that
  matters

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Drinking Water ProtectionOpportunities

• Completed SWAs provide a tremendous amount of
  information
• GIS resources can be used by other
  agencies/organizations
• DEQ programs, Counties, Cities, USFS, BLM, ODOT,
  OERS
• Adds to Multi-Barrier approach
• DWP planning is complementary to proper system
  operation, treatment and emergency response
  planning
• Can be used to set local priorities
• Staff finally available to provide TA

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Funds Available

• Source Water Protection Grants
• C or non-profit NC systems w/SWA
• 200,000 in 2007
• Up to 20,000/PWS/year
• Eligible Activities that reduce risk of
  contamination of DW source
• Not eligible OM of system/treatment
• Regional or local projects
• Scoring system

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Drinking Water ProtectionNext Steps - DHS

• Implementation of Drinking Water Protection
  Strategies groundwater systems
• Assess new systems (since June 99)
• Finish TNC assessments (175 need site visits)
• Review delineations every 5 years
• Update modified systems

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Drinking Water ProtectionNext Steps - DHS

• Coordinate remaining assessments and review with
  sanitary surveys
• 646 groundwater sanitary surveys due this year
  174 CWS, 58 NTNC, 412 TNC
• Region 1 194 systems
• Region 2 253 systems
• Region 3 199 systems

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DHS Implementation Strategies

• Focus on community systems with local governments
  (including Boards)
• Prioritize based on interest, risks, sensitivity
• Increased public involvement
• Encourage regional strategy development
• Large system with embedded small sys
• Involve local planning authorities
• Integrate SWAs in land use planning
• Communication
• Follow-up letters/surveys, workshops, factsheets,
  etc.

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Drinking Water ProtectionNext Steps - DEQ

• Get the word out conferences, program/agency
  meetings, watershed councils
• Coordinate more with OAWU/RCAC
• Prepare written implementation tools
  factsheets, handouts, DWPP template

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Drinking Water ProtectionNext Steps - DEQ

• Integrate into CWA and watershed approach
• Coordinate/Leverage other programs and agencies
• Transfer data lists of high risk PCS to other
  programs for potential prioritization (ex DEQ
  programs like tanks, WWTP, ODF-private
  forestlands)
• Work to integrate DWP into policy priority for
  agencies (ex County planning, USFS, BLM, ODOT,
  ODA, SWCD, Watershed councils)

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Emerging IssuesPotential focus ?

• Pharmaceuticals in Oregon waters
• USGS data
• Treatment effectiveness?
• Focused collection events, TA
• Microbial sources within 2-year time-of-travel of
  public supply wells
• PWS detections as priorities for protection
  technical assistance
• Rural schools
• Others ?

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What we need from county staff

• PWS changes on Source Info Pg
• Water usage
• New/modified well (including irrigation?)
• GPS locations of new wells
• Datum (WGS 84, NAD 27)
• TNC special projects (see handouts)

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For More Information

• Dennis Nelson DHS GW Coordinator
• [phone] x21
• Dennis.O.Nelson_at_state.or.us