Transcript Nonpoint Sources of Pollution

An Introduction to NC’s
Water Quality Program
and
*Nonpoint Source Pollution
Division of Water Quality
WQ Planning Branch
NC Department of
Environment and Natural
Resources
* Also known as Runoff Pollution
Overview of Presentation
•
•
•
•
•
•
•
Growth issues in NC Affecting NPS Pollution
Introduction to the DWQ’s WQ Program
Primary Goals of the WQ Program
Major Sources of Pollution (Point/NPS)
Impacts of Pollution on Water Quality
How do We Measure Water Quality?
How is the WQ in North Carolina?
North Carolina’s water resources are
abundant and diverse
But the face of NC is changing
Population
(Millions)
NC Population Growth (16702000)
8
7
6
5
4
3
2
1
0
1670 1700 1750 1800 1850 1900 1950 2000
Year
NC’s population has been doubling every 50 years for the past 200 years!
What will be the impact of 8 million more people by 2050?
NC Land Cover Changes 1982-97
(acres x 1000)
18000
16000
1982
14000
1997
% Changes
Agric. -13.4%
Forest -6.9%
Urban +88.1%
12000
10000
8000
6000
4000
2000
0
Agric.
Forest
Develop.
Source: USDA NRCS
National Resources
Inventory (1997)
The NC Division of
Water Quality plays
an important role in
protecting water
quality
DWQ is…
Known primarily as a
regulatory agency, but…
DWQ Permitting Programs
•Discharge permits
•Nondischarge permits
•Wetlands permits
•Riparian buffer protection
•Others
We also do biological
investigations,
Predictive Computer Modeling,
Water quality monitoring and
chemistry lab analyses,
Planning,
•Basinwide Planning
•Stream classifications
•Rule development
And
enforcement of
water quality
laws
Primary Goal of NC’s Water
Quality Program
Protect and Restore uses of North
Carolina’s surface waters.
Uses include:
Fishing and
Swimming
Water Supply
and...
High Quality Waters (HQW) and
Outstanding Resource Waters (ORW)
Major Sources of
Pollution
Point Sources and
Nonpoint Sources
Point Sources of Pollution
Comes from a pipe, discrete point or ditch. Generally
associated with a wastewater discharge but includes
urban or industrial stormwater discharges
*Nonpoint Sources of Pollution
Pollution reaching(NPS)
waterways from rainfall runoff,
atmospheric deposition and groundwater flow.
Impacts result from cumulative effects of many
small activities. (*Also known as Runoff
Pollution)
NPS/Runoff Pollution
Land Development
If not done properly, this can result in:
• Increased
Imperviousness
• Increased
Pollutants
• Increased Runoff
• Impacts to Stream
Banks
• Erosion/Sediment
ation
NPS/Runoff Pollution
Construction and
Grading
The major runoff pollution pollutant is
sedimentation. Sediment control
measures need to be properly designed,
installed and maintained until the site
is stabilized.
Problems can also result fro
improperly handling fuel and chemicals
at construction sites.
Urban stormwater
A major impact is runoff from impervious
surfaces which erodes streams and destroys
aquatic habitat is the major impact from
urban stormwater. Urban runoff also
carries high fecal coliform levels from pet
and wildlife wastes, fertilizer and
pesticides from yards and landscaped
areas, auto-related pollutants such as oil,
grease, and abraded tire material, and
pollutants contained in
atmospheric deposition.
NPS/Runoff Pollution
Agriculture
Impacts come from cropland and
animal operations. Common
pollutants are sediment, nutrients and
fecal coliform bacteria (animal
operations). Agriculture is the leading
source of nonpoint source pollution in
NC although it should be noted that
this impact is shrinking as ag land is
converted to development and as
sediment control measures such as notill farming become more widespread.
NPS/Runoff Pollution
NPS/Runoff Pollution
Land disposal of wastewater
This includes onsite wastewater systems (e.g., septic systems), spray
irrigation, sludge disposal and landfills.
NPS/Runoff Pollution
Silviculture (Forestry)
Forest cover is generally excellent for protection of water quality. However,
water quality problems can occur from improper harvesting techniques such
as clearing next to streams and not using adequate BMPs for sediment
control . In eastern NC, ditching, which changes the nature hydrology, also
adversely impacts water quality by increasing the rate of runoff
NPS/Runoff Pollution
Atmospheric Deposition
The atmosphere is a significant source of water pollution. This includes
acid rain, nitrogen compounds (which come from cars, industry and
animal operations and contribute to nutrient overenrichment and algal
blooms) and mercury (which has resulted in fish consumption advisories
across NC , particularly in the Coastal Plain).
Marinas and
Recreational
Boating
Runoff pollution comes primarily from paved
areas and service yards, oil and gas leakage,
and improper disposal of human wastes.
NPS/Runoff Pollution
NPS/Runoff Pollution
Mining
What are the Impacts of
Nonpoint Source Pollution
on Water Quality?
Algae Blooms
and Aquatic
Weeds
Comes from an excess of nutrients such
as nitrogen and phosphorus from both
point and nonpoint sources
Fish kills
(most often resulting from low dissolved oxygen associated with algal
blooms and/or hot weather)
Habitat
degradation
Mostly a nonpoint source problem resulting
from improperly performed land disturbing
activities (such as construction, farming and
forestry which allow excessive sediment
runoff) and post development stormwater
runoff in urban areas (which increases the
flow of stormwater and erodes stream
channels)
Closed shellfish waters
Caused by pathogen contamination as indicated by high levels of fecal coliform
bacteria. The bacteria come mostly from runoff in developed areas containing
wildlife and pet wastes. Can also come from leaking sewer systems and pump
stations, improper sewage treatment, failing septic systems and improperly
handled farm animal wastes.
Unsafe swimming conditions
Results from pathogen contamination as evidenced by elevated levels of fecal
coliform bacteria. Can come from a variety of sources including wildlife and pet
wastes, leaking sewer systems and pump stations, improper sewage treatment,
failing septic systems and improperly handled farm animal wastes.
How Do We Measure
Water Quality?
Biological and chemical water
quality testing is done by DWQ as shown in the
following slides to determine whether waters are
supporting the intended uses
Benthic Macroinvertebrate
Sampling
This technique utilizes the varying
pollutant sensitivities among different
aquatic organisms, such as aquatic
insect larvae, as a water quality indicator
Assessing the types and numbers of
species gives an indication of water
quality.
Fish community
and tissue
sampling
Assessing the numbers, diversity
and health of fish communities is
another way to assess water
quality. Tissues of fish are also
sampled to determine whether
they are safe to eat.
Ambient Water
Quality
Monitoring
Chemical water quality
sampling is performed
monthly at almost 400
stations around the state in
streams, lakes and salt
waters. Many parameters are
studied such as pH, metals,
bacteria, dissolved oxygen
and others. This sampling
helps DWQ determine water
trends and problem areas.
Water
Chemistr
y
DWQ’s lab analyzes
ambient and other water
quality samples.
Oxygen demand
from bottom
sediments
Wastewater treatment plants discharge
pollutants known as oxygen-consuming
wastes. This includes organic matter
that decomposes in the water column
and takes up dissolved oxygen needed
by other aquatic life.
Divers place devices on the bottom of
selected waterways to measure the
amount of dissolved oxygen removed
from the water column by bottomdwelling bacteria and through chemical
processes. This information is used by
computer modelers to determine the
level of treatment required at wastewater treatment plants to protect the
waters and aquatic life.
How is the water quality
in North Carolina?
*Most streams are in good shape
...but 16.4% are impaired, or not supporting their uses
Supporting
Impaired
16.4%
83.6%
*Based on monitored streams
Major Causes of Imp.:
• Habitat Degradation
(stream erosion and
sedimentation)
• Fecal Coliforms
• Low dissolved Oxygen
• Turbidity
Includes approximately
2000 miles of
impaired streams that
need to be restored
Source: 1998-99 305(b) Report
Impaired Stream Miles by Source
(Top five sources)
1400
Runoff Pollution
1200
Point Source
1000
800
600
400
200
0
Agriculture Urban SW
Source: 1998-99 305(b) report
Point S
Constuct.
Hydromod.
*Saltwater Use Support Ratings
Only 4% of all 1,997,375 acres of coastal waters
in NC are impaired. Sources of impairment
by %:
• 41% Fecal Col. Bacteria (Shellfish Closures)
• 9% Dissolved oxygen
• 51% Chlorophyl a (nutrient problem)
(Note: because of overlap,
%s do not add to 100%)
Source: 1998-99 305(b) Report
For further
information
contact:
Alan Clark
NC Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
919-733-5083 x570
[email protected]