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 thyeager@pa.gov