safe drinking water program surface water identification protocol...
TRANSCRIPT
Safe Drinking Water Program
Surface Water Identification Protocol
(SWIP)
May 17, 2016
Tom Yeager, P.G.
• SWIP is used to determine if groundwater sources are directly influenced by surface water.
• GUDI – Groundwater Under Direct Influence
PA Safe Drinking Water Program
SWIP is designed to protect PUBLIC HEALTH
Section 109.202 of the Safe Drinking Water Regulations states that…
“A public water system shall provide adequate treatment to reliably protect users from the adverse health effects of microbiological contaminants, including pathogenic bacteria, viruses and protozoan cysts.”
*Does not assess adverse
impacts/quantity issues
PA Safe Drinking Water Program
• Giardia lamblia (Giardiasis)
• Criptosporidium
parvum
(Cryptosporidiosis)
Resistant to disinfection
Outbreaks
Must Filter (SW & GUDI)
Why is SWIP important?
Section 109.1 defines GUDI as…
“Any water beneath the surface of the ground with the presence of insects or other macroorganisms, algae, organic debris or large diameter pathogens such as Giardia lamblia and Crytosporidium, or significant and relatively rapid shifts in water characteristics such as turbidity, temperature, conductivity or pH which closely correlate to climatological or surface water conditions ”
Groundwater Under Direct Influence (GUDI)
SWIP consists of three stages:
Screening to determine questionable sources Wells-aquifer geology, water level and proximity to
surface water Springs and infiltration galleries-automatically
questionable
Special six-month monitoring on questionable sources
Microscopic Particulate Analysis (MPA) for final surface influence determination
Surface Water Identification Protocol
IS THE WELL LOCATED…
□YES □NO in a carbonate aquifer with static
water elevation <or=100 feet below ground level?
□YES □NO in an unconfined aquifer with static
water elevation <or=50 feet below ground level?
SWIP Screening Criteria
IS THE WELL LOCATED…
□YES □NO in a confined aquifer which is
located <or=50 feet below ground level?
□YES □NO <or=200 feet from a surface water
body? (Does not apply to confined or unconfined with SWL>100 ft bgl)
SWIP Screening Criteria – Continued:
Well = YES, What’s next?
Submit a SWIP Monitoring Plan for Approval
Reviewed and approved by Regional Geologist Monitoring should commence within 3 months of
approval
Surface Water Identification Protocol
SWIP Monitoring Plan Guidelines
SWIP Monitoring Plan Guidelines
Water system must take a daily raw water sample from the approved sampling point for:
turbidity, pH, specific conductance and temperature
Daily measurements – pumping rate and water level
Weekly total coliform and E. coli sampling (certified laboratory)
SWIP Sampling
• Precipitation-Daily recordings (National Weather Service-975 Gauges)
• If local rain gauge is not available (<20 miles) operator must install and maintain one
Climatological and Surface Water Monitoring
• Local Surface Water conditions-Daily recordings of stage or flow
• Typically utilize USGS Gauge or install staff gauge
Climatological and Surface Water Monitoring
SWIP – Monthly Reporting
Evaluate the relationship between PRECIPITATION and the pH, temp., cond. and Turbidity
Correlation Analysis: five day averages run through a multiple regression model
Model generates a strength of correlation: -.40 to +.40 Weak Relationship
-.40 to -.75 and +.40 to+.75 Moderate Relationship -.75 to -1.00 and +.75 to +1.00 Strong Relationship
SWIP Statistical Analysis
MPA-What do we look for?
MPA-What do we look for?
• MPA-identification, sizing and population estimates of microorganisms and organic or inorganic debris found in water
• Minimum 300 gallons
• One micrometer filter
Microscopic Particulate Analysis (MPA)
MPA-What do we look for?
WELL CONSTRUCTION-VERY IMPORTANT!
HIGH RISK GUDI WELLS
WELL CONSTRUCTION DEFICIANCIES
HIGH RISK GUDI WELLS
SWIP Cases – Can be re-evaluated at any time based on water quality changes
LIMESTONE – CONSTANTLY CHANGING
LIMESTONE – Complex System
HIGH RISK GUDI WELLS
Must provide permanent filtration treatment facilities
Abandon the unfiltered source
Utilize a backup source
Interconnect with another water supplier
Drill a new well
What if my well is GUDI?
HIGH RISK GUDI WELLS
HIGH RISK GUDI WELLS
Summary
• Prevent outbreaks/Protect Public Health • Adverse Impacts identified by aquifer
test/permitting evaluation • Just because a well passes SWIP does not mean you
are off the hook for a pass-by flow requirement • Conditions change – Have a reliable back-up source!
DEP SC Region – SWIP Contacts
Tom Yeager, P.G. Safe Drinking Water Program PA DEP South-central Region
717.705.4949 [email protected]