Basic Dry Weather Field

Screening WorkshopCity of Arlington Environmental Management

Alexandria Edwards

Today’s Discussion

Background Info

Permit Requirements

Regional Protocol

Sampling Pregame

BREAK

Monitoring Procedures

Test & Observations

Kit Demonstrations

LUNCH ☺

Field Screening (outside)

Comparing Programs & Case Studies

Final Comments & Evaluation

Illicit Discharge:

40 CFR 122.26 (b)(2)

defines an illicit discharge

as any discharge to an MS4

that is not composed

entirely of stormwater,

except allowable

discharges pursuant to an

NPDES permit, including

those resulting from fire

fighting activities.

4 Key Points to Remember about Illicit

Discharges

1) A storm drain that has measurable flow during dry weather containing

pollutants and/or pathogens is considered an illicit discharge. A storm drain with

measurable flow but containing no pollutants is simply considered a discharge.

Ex) Groundwater infiltration

4 Key Points to Remember about Illicit Discharges

2) Each illicit discharge has a

unique frequency, composition and

mode of entry in the storm drain

system.

Frequency → don’t occur every

day

Composition → paint, SSO,

chlorinated water (swimming

pool, water main break)

Mode of Entry → dumping, SSO,

illicit connection

4 Key Points to Remember about Illicit

Discharges

3) Illicit discharges are frequently caused when the sanitary sewer system

interacts with the storm drain system through overflow or illicit connection.

4 Key Points to Remember about Illicit

Discharges

4) Accidental or Purposeful

Dry Weather Screening – Permit Requirements

National requirements – CWA / NPDES

TEXAS specific:

ALL MS4’s Required by Texas Commission on Environmental Quality (TCEQ) to

obtain a Texas Pollution Discharge Elimination System (TPDES) permit from the

TCEQ to discharge stormwater to “surface waters in the State”

Permit Requirements cities with a population greater than 100,000 were ((or

large MS4’s”.)

Requirements:

Apply for individual permits with specific dry weather screening

requirements

Must address these in their annual report to TCEQ

small MS4s were issued a TPDES general permit by the

TCEQ (also known as a Phase 2 MS4 permit)

IDDE

Illicit Discharge Detection and Elimination Program.

TPDES permit required for phase 1 and level 4 phase 2 cities.

TXR040000.

Phase 1: All outfalls must be screened at least once per permit term.

Phase 2: Source investigation and elimination upon detection of an

illicit discharge.

Level 4 Phase 2: Prioritize problem areas for field screening and

implement by end of permit term.

Regional Protocol

Developed by NCTCOG under the direction of

the Regional Stormwater Management

Coordinating Council (RSWMCC)

Creates a consistent method for IDDE

Promotes consistency throughout the region

Increases impact of program

Creates consistent quality control

Getting Ready to Sample

How to Detect Illicit Discharges

Dry weather screening is a field test method for inspecting

stormwater drainage areas to help locate and identify harmful and

illicit discharges to a municipal stormwater system.

Inspecting a storm drainage system during dry weather is an effective

way to find illicit discharges since there should not be any water

flowing during dry weather.

FIND → FIX → PREVENT

A sampling kit can be used to test for

these parameters:

Copper

Chlorine

Ammonia-nitrogen

Detergents

Conductivity

Turbidity

Temperature

pH

*** By running these tests, field personnel can identify potential pollutants which can then help locate the source of the illicit discharges.

Locating Your Sites

Locate your sites

GPS

GIS, if already available

Other maps

Plan your route

**Make absolutely certain that you

obtain permission from the

landowner before entering any

private property.

GPS and Map Survey Method

GPS (Global Positioning System)

Accurate, easy to use, rapid positioning

Useful when there’s not a map available

Map Survey

Maps have streets, blocks, contours

Less accurate; more likely to miss small discharge pipes

Global Positioning System

(GPS) Survey Method

Read manufacturer’s instructions on how to initialize your GPS before first use

Allow GPS to receive satellite signals for about 5 to 10 minutes

This will allow it to download all relevant data in the area

Avoid standing near things that could block signal

Buildings, hills, rock formations, trees, heavy vegetation and bridges can affect the signal received from satellite

Hold unit at arms length, level with shoulder, so your body does not interfere with signal quality

Record point as close as you can to the outfall

Key is labeled with a check-mark or star

After field work is performed, data from GPS should be downloaded into computer for a mapping program

Map Survey

Method

MAPSCO

Readily available

Easy to use in locating streets and reference points in grid system

U.S. Geological Survey (USGS) topographic maps (Scale of 1:24,000) to conduct outfall inventories

Low equipment cost, however, accuracy can be questionable in areas

Map Survey Method

MAPSCO Street block numbers

Zip codes

City/county names

Points if interest (airports, golf

courses)

USGS Elevation contours

Symbols to identify man-made

features (shading to represent

forested or urbanized areas)

Latitude & longitude

Community or city names

Highways & major streets

Preparing to Sample

Gather all information if possible

Outfall shape

Material

Size

Watershed Basin

X,Y coordinates

Address description

Field observations on the ORI

The ORI is designed to

record basic characteristics:

• Individual storm drain

outfalls

• Evaluate suspect outfalls

• Assess the severity of

illicit discharge problems

in a community

The ORI results can then be

used to help guide future

outfall monitoring and

discharge prevention

efforts.

Date, time, coordinates, watershed, weather

Open/closed, material, shape, flow, size

Measure of flow, temperature, pH, ammonia

Odor, color, turbidity, floatables

Damage, deposits, stains, growth, benthic growth

Severity of illicit discharge, Overall rating of outfall

Scheduling your Screenings

Do not sample within 48 hours of a rain event

(>0.1”)

Visit the site twice in a 24hr period

Keep at least 4 hours between visits

Vary time and day of the week when

sampling

Follow-up sampling should be at roughly the

same time of day

Check the

Weather

Cannot sample within 48 hours of a rain event >0.1”

Water.weather.gov/precip

Prepare accordingly

Bring lots of water in the summer

Wear warm clothes in the winter

You may be out for a while

Site Safety

Wear appropriate PPE

Reflective vest and nitrile gloves

Park off the road if possible

Turn on light bar and other safety lights

Use traffic cones

Avoid high water

Have something between you and traffic

Use your truck as a traffic barrier

Don’t take unnecessary risks

You may not have immediate help

Sampling Safety

Familiarize yourself with test procedures

Read SDS for the chemicals you use

Protect yourself and equipment

Avoid contact with eyes, mouth, nose, skin

Use PPE (gloves, eye protection)

Use tube caps, not fingers, when mixing reagents

Hold droppers vertically when dispensing drops

Thoroughly rinse test tubes before and after sampling – triple rinse

Avoid direct sunlight

Protect chemicals & equipment from extremely high or low temperatures

Safely dispose of waste chemicals in the field

Animals/Insects

to Look Out For:

Venomous Snakes

Poisonous Spiders

Feral Hogs

Fire ants, wasps, honeybees

Cottonmouth

Rattlesnake

Texas Coral Snake

Brown Recluse

Black Widow

Feral Hogs

Plants to Look

Out For:

Poison Ivy

Poison Oak

Briars

Poison Sumac

BriarsPoison Ivy

Winter Poison Ivy

Poison Sumac

Poison Oak

Equipment list

Thermometer

pH meter

Conductivity meter

Storm drain test kit (copper, chlorine, phenols, detergents)

Ammonia-Nitrogen test kit

PPE (gloves and eyewear)

Waste container

DI water

Tape measure

Camera

Paper towels or rags

Field Testing Equipment

LaMotte Colorimeter LaMotte Storm Drain Kit

Field Testing Equipment

YSI Pro 2030Hach HQ 40D

Field Testing Equipment

YSI ProDSS

Suggested Sampling Sequence

1. pH meter calibration (& other meters – conductivity, D.O., etc.)

2. Initial site observations: trash, sewage, surface scum, etc.

3. Air temperature

4. Physical observations: flow, color, turbidity, odor, oil sheen

5. Water temperature

6. pH

7. Detergent

8. Phenols

9. Ammonia-Nitrogen

10. Copper

11. Chlorine

12. Conductivity

Initial Outfall Visit

Get as much information as possible since you’re already there

Shape

Dimensions

Material

Land use

Coordinates (latitude/longitude)

Flow severity (if applicable)

Describe the location so anyone can get there

Be very detailed!

Physical Observations

Trash

Subjective – make a decision and stick with it to keep consistent

Sewage

Scum

Algae and bio foam are not scum

Hydro sheen

Oil – rainbow hue, forms back together when disturbed

Biofilm – No rainbow hue, forms a sheet-like film that breaks if disturbed

Physical Observations

Physical Observations

Physical Observations

Air temperature

Keep thermometer out of direct sunlight

Water temperature

Color

Be general (clear, brown, green)

Odor

Refer to odor table

Notes and

Observations

How NOT to Take Pictures

How TO Take Pictures

Sampling Methods

Sampling containers

Sample bottle

Sample pole (dipper)

Bucket/Van Dorn

Sampling Methods

Discharge grab

Sample flows directly into container

Surface water grab

Take the sample below the surface

Bucket/Van Dorn grab

Lower bucket gently

Do not disturb bottom sediment

Always triple rinse containers

Approach site and dispose of sample water downstream

Questions?