H 2O REPORT
H2O Report is an annual publication of Beaver Water District
H2O Report is Beaver Water District's
annual water quality report. The report is an
expanded version of water quality data that BWD
provides to our customer cities. The purpose of
this report is to inform our customers about the
following:
• Where their water comes from,
• What analytical tests are conducted on their
drinking water,
• What those tests reveal about their water, and
• How those results compare to state and
federal standards.
Beaver Water District's mission is to serve
our customers in the Benton and Washington
County area by providing high quality drinking
water that meets or exceeds all federal and
state regulatory requirements in such quantities
as meets their demands and is economically
priced consistent with our quality standards. We
are a regional wholesaler of water. We sell our
water to four customer cities - Fayetteville,
Springdale, Rogers, and Bentonville. These
cities then retail water to residential, commercial, and industrial users.
Northwest Arkansas is fortunate to have
Beaver Lake as its source of water. The
Congress of the United States allocates space
within the lake to various designated users.
Beaver Water District's allocation is sufficient to
provide up to 120 million gallons of drinking water
per day, on an annual average basis. The District
makes annual payments to the U.S. government
to maintain this allocation.
Beaver Water District uses the multiple barrier approach to assure safe water. Barriers
include source water protection and monitoring,
treatment facilities, disinfection, professional
staff, water quality monitoring and consumer
education. We maintain constant communication
with our customer cities’ distribution systems to
assure adequate quantity is delivered.
"A primary task of the board of directors of
the District is to plan for the future water needs of
this region," said David Short of Bentonville, who
serves as President. "In January of 2009, we
brought on-line our renovated Steele water plant
completing our current plant expansion program.
Our maximum capacity for treatment is now 140
million gallons per day. We are poised to meet the
needs of industries or businesses that want to
relocate to Northwest Arkansas."
Should you have questions about this
report, or BWD's treatment, please contact
District staff at www.bwdh2o.org or 479-756-3651.
We welcome your calls and feedback.
Summer 2009
District's Water Meets
State & Federal Standards
By Larry Lloyd P.E., Chief Operating Officer
Safe water is the top priority for Beaver
Water District. Our water is monitored by both the
District's certified laboratory and the Arkansas
Department of Health. During 2008, for the 38th
consecutive year, the District's water quality
exceeded all state and federal standards for
drinking water.
Primary drinking water standards are established by the U.S. Environmental Protection
Agency for 87 different parameters. Parameters
include microorganisms (bacteria, viruses and
protozoa), inorganic chemicals (metals), organic
compounds, radionuclides, disinfectants, and
disinfection by-products. There are 15 secondary
standards based on aesthetic goals. For each
primary standard, a maximum contaminant level
(MCL) is established. The MCL is the highest
concentration, with a margin of safety, that can
be consumed safely. EPA regulations are
enforced in Arkansas by the Arkansas
Department of Health.
Upcoming rule changes include the Stage 2
Disinfection Byproduct Rule, to be implemented
in April 2012. The District is being proactive in
preparing for the Stage 2 DBP rule. We are working with our customer cities to help them meet
the compliance criteria.
Beaver Water District is committed to insuring
the safety of our product 100 percent of the time.
Our plant is manned by licensed operators 24
hours a day, 365 days a year. We provide on-site,
back-up electric generation and redundant treatment processes. Because of the dedication of
the staff and forward thinking of the Board, you
can be confident your drinking water is safe.
Water is routinely monitored by both the District's own
certified laboratory and the Arkansas Department of
Health laboratory. Mindi Crosswhite, featured in this photograph, is Beaver Water District's Laboratory Supervisor.
Page 2
Discussion of Water Quality Parameters
Cryptosporidium and Giardia
pH
pH is the measurement of how acidic or basic the
water is. The pH scale is from 0 to 14. A pH of less than
7.0 is acidic, while a pH of greater than 7.0 is basic. A
pH of 7.0 is considered neutral.
Hardness and Alkalinity
Hardness in water is caused by the presence of
calcium and magnesium ions. Hard water can cause an
increase in soap and detergent usage and increase
mineral deposits (scaling) in hot water tanks and
plumbing systems. Soft water doesn't require as much
soap to work up a lather; however, if the water is too
soft you will have trouble rinsing the soap off and may
be left with a slimy feeling. The 2008 average hardness
of the water distributed by Beaver Water District was 61
parts per million (ppm) which is moderately hard
according to the table below.
Water Hardness Scale
Grains Per Gallon
less than 1.0
1.0 - 3.5
3.5 - 7.0
7.0 - 10.5
over 10.5
Milligrams Per Liter (mg/l)
or Parts Per Million (ppm)
less than 17.1
17.1 - 60
60 - 120
120 - 180
over 180
Classification
Soft
Slightly Hard
Moderately Hard
Hard
Very Hard
Alkalinity is the quantitative capacity of water to
neutralize an acid; that is, the measure of how much
acid can be added to a liquid without causing a significant pH change. Hardness and alkalinity are often
talked about together because many chemical substances contribute to both hardness and alkalinity.
Coliform
Coliforms are a group of non-pathogenic bacteria that are naturally present in the environment, as
well as in feces. Total Coliforms indicate if other potentially harmful bacteria may be present.
Turbidity
Turbidity is a measure of the cloudiness of water.
It is used to indicate water quality and filtration effectiveness (e.g., whether disease-causing organisms are
present). Higher turbidity levels are often associated
with higher levels of disease-causing microorganisms.
Trihalomethanes and Haloacetic Acids
Disinfection byproducts are compounds that are
formed when disinfectants like chlorine combine with
organic matter. Trihalomethanes (THMs) and
Haloacetic Acids (HAA5) are two classes of these
byproducts that are regulated because of potential
negative health effects and have limits established by
the Environmental Protection Agency (EPA) of 80 ppb
and 60 ppb respectively.
Total Organic Carbon (TOC)
Total Organic Carbon (TOC) is a measure of the
organic content in the water. TOC is used as a "precursor"
for DBP formation. TOC samples can be analyzed more
quickly and are less costly to run than THM and HAAs.
Cryptosporidium and Giardia are microscopic
parasites that are resistant to chlorine disinfection.
They cause gastrointestinal illness including nausea,
vomiting, and diarrhea. These microorganisms can be
transmitted through ingestion of infected water; recreational waters like fountains and water parks are common sources of outbreaks.
Chlorophyll_a
Chlorophyll a is a specific type of chlorophyll present
in all types of algae. Chlorophyll a is an indicator of the trophic status or concentration of algae in a water body. Higher
concentrations indicate increased algae growth in the water.
Nutrients
Nutrients are elements or chemicals essential to
life. Nitrogen and phosphorus are the principal nutrients
of concern for water quality. When nutrients become
excessive, algal biomass increases and this contributes
to increased turbidity, reduced aesthetic quality of water,
and potential water treatment difficulties.
Unregulated Constituents - Monitored by ADH and BWD *
Physical and Chemical Parameters
Units
Alkalinity (Phenolphthalein) *
ppm as CaCO3
Alkalinity (Total) *
ppm as CaCO3
Calcium *
ppm as Ca
Range of Results
ppm as Ca
Conductivity *
uS/cm
Hardness (Total) *
ppm as CaCO3
Range of Results
ppm as CaCO3
Magnesium
ppm as Mg
Nickel
ppm
Potassium
ppm
Silica *
ppm as SiO2
Sodium
ppm
BWD
ND
58 (avg)
24.4 (avg)
12.8-32.4
186 (avg)
61 (avg)
34-89
2.31
ND
ND
3.5 (avg)
8.09
Unregulated Volatile Organic Chemicals - Monitored by ADH
Parameter
Units
BWD
Bromobenzene
ppb
ND
Bromochloromethane (Chlorobromomethane)
ppb
ND
Bromodichloromethane
ppb
5.42
Bromoform
ppb
ND
Bromomethane
ppb
ND
n-Butylbenzene
ppb
ND
sec-Butylbenzene
ppb
ND
tert-Butylbenzene
ppb
ND
Chloroethane (Ethyl Chloride)
ppb
ND
Chloroform
ppb
13.8
Chloromethane
ppb
ND
2-Chlorotoluene
ppb
ND
4-Chlorotoluene
ppb
ND
Dibromochloromethane
ppb
1.11
1,2-Dibromo-3-chloropropane (DBCP)
ppb
ND
1,2-Dibromoethane
ppb
ND
Dibromomethane (Methylene Bromide)
ppb
ND
1,3-Dichlorobenzene
ppb
ND
Dichlorodifluoromethane
ppb
ND
1,1-Dichloroethane
ppb
ND
1,3-Dichloropropane
ppb
ND
2,2-Dichloropropane
ppb
ND
1,1-Dichloropropene
ppb
ND
cis-1,3-Dichloropropene
ppb
ND
trans-1,3-Dichloropropene
ppb
ND
Hexachlorobutadiene
ppb
ND
Isopropylbenzene
ppb
ND
p-Isopropyltoluene
ppb
ND
Methyl tertiary butyl ether (MTBE)
ppb
ND
Naphthalene
ppb
ND
n-Propylbenzene
ppb
ND
1,1,1,2-Tetrachloroethane
ppb
ND
1,1,2,2-Tetrachloroethane
ppb
ND
1,2,3-Trichlorobenzene
ppb
ND
Trichlorofluoromethane
ppb
ND
1,2,3-Trichloropropane
ppb
ND
1,2,4-Trimethylbenzene
ppb
ND
1,3,5-Trimethylbenze
ppb
ND
Page 3
2008 State of the Lake
PRIMARY STANDARDS - Health Related and Mandated by U.S. EPA & ADH
Disinfectant
Units
MCLG
MCL
BWD
Total Residual Chlorine* (Average)
ppm
4.0
4.0
1.23
Range of Results
ppm
1.04-1.49
Clarity
Units
MCLG
MCL
BWD
>0.3 NTU in
Turbidity * (Treated Finished Water)
>5% of samples
Highest yearly sample result
NTU
n/a
0.15
or any 1
Average NTU
NTU
0.10
sample>1 NTU
Lowest % of samples meeting limit
%
100
Microbiological
Units
MCLG
MCL
BWD
Total Coliform Bacteria
P/A
0
1/month
0
Fecal Coliform or Escherichia coli
P/A
0
0
0
Inorganic Chemicals
Units
MCLG
MCL
BWD
Antimony
ppb
6
6
ND
Arsenic
ppb
n/a
10
ND
Asbestos
MFL
7
7
Waiver
Barium
ppm
2
2
0.0259
Beryllium
ppb
4
4
ND
Cadmium
ppb
5
5
ND
Chromium
ppb
100
100
ND
Copper
ppm
1.3
AL=1.3
ND
Cyanide
ppb
200
200
ND
Fluoride (Average)
ppm
4.0
4.0
0.85
Range of Results
ppm
0.71-0.98
Lead
ppb
0
AL=15
ND
Mercury
ppb
2
2
ND
Nitrate + Nitrite (as N) - Average
ppm
10
10
0.26
Selenium
ppb
50
50
ND
Thallium
ppb
0.5
2
ND
Volatile Organic Contaminants (VOC’s) - Regulated
Total Trihalomethanes (TTHMs)
Highest Running Annual Average
Range of quarterly samples
Haloacetic Acids 5 (HAA5)
Highest Running Annual Average
Range of quarterly samples
Benzene
Carbon Tetrachloride
Chlorobenzene
o-Dichlorobenzene (1,2-Dichlorobenzene)
p-Dichlorobenzene (1,4-Dichlorobenzene)
1,2-Dichloroethane
1,1-Dichloroethene (1,1-Dichloroethylene)
cis-1,2-Dichloroethene (cis-1,2-Dichloroethylene)
trans-1,2-Dichloroethene (…-Dichloroethylene)
Dichloromethane (Methylene Chloride)
1,2-Dichloropropane
Ethylbenzene
Styrene
Tetrachloroethene (Tetrachloroethylene)
Toluene
1,2,4-Trichlorobenzene
1,1,1-Trichloroethane
1,1,2-Trichloroethane
Trichloroethene (Trichloroethylene)
Vinyl Chloride
Xylenes, Total
Radionuclides
Gross Alpha
Gross Beta
RA-226
RA-228
Units
MCLG
MCL
BWD
ppb
N/A
80
64
33-106
ppb
N/A
60
ppb
ppb
ppb
ppb
ppb
ppb
ppb
ppb
ppb
ppb
ppb
ppb
ppb
ppb
ppm
ppb
ppb
ppb
ppb
ppb
ppm
0
0
100
600
75
0
7
70
100
0
0
700
100
0
1
70
200
3
0
0
10
5
5
100
600
75
5
7
70
100
5
5
700
100
5
1
70
200
5
5
2
10
41
17-74.8
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Units
MCLG
MCL
PCi/Liter
0
15
PCi/Liter
0
50
PCi/Liter
0
5
PCi/Liter
0
Combined
BWD
ND
ND
ND
ND
SECONDARY STANDARDS - Aesthetic Standards Recommended by EPA & ADH
Physical Parameters
Units
MCLG
BWD
Apparent Color
units
15
0
pH * (Average)
units
6.5 - 8.5
8.2
Inorganic Chemicals
Units
MCLG
BWD
Aluminum
ppm
0.05 - 0.2
ND
Chloride
ppm
250
9
Corrosivity * (Average)
SI
Non-corrosive
-0.32
Langelier Saturation Index
Iron
ppm
0.3
ND
Manganese
ppm
0.05
ND
Silver
ppm
0.1
ND
Sulfate
ppm
250
27.4
Total Dissolved Solids
ppm
500
109
Zinc
ppm
5
ND
By Robert Morgan, Ph.D., Manager of
Environmental Quality
Water quality in Beaver Lake is
correlated to inflow from the tributaries,
and 2008 was no exception. Total rainfall
for the year at Drake Field in Fayetteville
was 56.87 inches, 11 inches above average. Average rainfall, however, does not
tell the full story.
Rainfall in 2008 was highlighted by
three major events. On March 18, more
than 4.6 inches fell in a single day, causing major flooding in Beaver Lake's tributaries. Beaver Lake filled to the top of the
flood pool. At Beaver Dam, the flood
gates were opened March 19 and 20.
From April 8-10, another 3.6 inches fell at
Drake Field. With the lake already full, the
flood gates were opened for a second
time April 10 and remained open until
April 12. The result of these two floods
was a massive influx of sediment and
nutrients. Those pollutants were carried
much further down lake than normal.
Finally, in September, Hurricane Ike blew
through the region, dropping another 4.6
inches of rain. The other anomaly of precipitation in 2008 was that there was an
unusually wet summer.
The lake surface started the year
in the conservation pool at 1113.45 feet,
mean sea level. Peak surface water elevation occurred April 10 at 1132.18, 2.18
feet above the top of the flood pool. At
the end of the year, the water surface
was back down into the conservation
pool, at 1120.39 feet.
The impact of the flood events is
demonstrated in water quality. The U.S.
Geological Survey, in a cooperative program with Beaver Water District, monitors lake water quality six times a year at
a site near our intake. From data collected two meters below the surface, we can
see that in 2008 the lake was markedly
cooler than the average of the previous
seven years. The dissolved oxygen concentration in the epilimnion (the surface
layer of the lake) was slightly higher at
9.9 milligram per liter (mg/l) compared to
the average of 8.2. Organic matter in the
lake, as measured by total organic carbon, increased from the average of 3.0
mg/l up to 3.3 mg/l. Most of this increase
was particulate. The average dissolved
organic carbon actually decreased from
3.0 to 2.5 mg/l. The increase in organic
matter is also seen in the algae content
as measured by chlorophyll a. The
seven-year geometric mean was 4.0
parts per billion compared to 6.2 parts in
2008. Taste and odor events in 2008
were less severe than in previous years.
Lake water quality is quite variable. Long-term trends are more valuable than a single year's events. The
most significant trend in Beaver at this
time is slowly increasing total organic
carbon. Organic matter can become
problematic when it is disinfected
because of the production of regulated
disinfection by-products.
Page 4
From Beaver Lake to Your Tap!
centrifuge where centrifugal force
(1.) Source Water:
is used to dewater the solids and
Raw water is pumped
produce cakelike solids.
from Beaver Lake and
(9.) Solids Disposal: Solids
travels about two miles
are removed
through large pipes to the
from
the
treatment plant near
facility and
Lowell. The District's
either land
Source Water Protection
(1.) Rusty Tate,
applied or
Program routinely moniEnvironmental Technician,
landfilled.
monitors source water quality tors source water quality
(10.)
in Beaver Lake and its
in Beaver Lake.
tributaries.
(8.) Mike Yeager, Disinfection:
(2.)
Flash
Mix Water Operator, pulls Water is disa solids sample from infected with
Process: Aluminum sulfate
the centrifuge.
chlorine.
(alum) is rapidly mixed into
Before
the raw water. This
(9.) Solids are
c i t i e s removed from the
process
coagulates
began facility and landfilled
(brings together) suspendor land applied.
r o u ed particles with the alum.
tinely
(3.)
Flocculation
(2.) Dean Ward, Stacy
disinfecting water, thouCheevers, Kelly Payne & Basins: During slow mixFrank Blowers observe the ing, charged particles
sands of people died annuflash mix process.
ally from waterborne disstick together to form
"floc." The flocculation 10-Bill Catt & Jim Johnson, eases such as cholera,
process grows particles Instrument Technicians, cali- typhoid fever, dysentery and
into larger, heavier parti- brate chlorine analyzer which hepatitis A. Disinfection
cles so that they will set- measures disinfectant level. ensures that dangerous
microbes are killed. Chlorinetle out of the water as
based disinfectants are most commonly used because
sediment.
they are very effective. Chlorine(4.) Sedimentation
based disinfectants also provide
Basins: Water goes to
(3.) Kelly Payne & Frank sedimentation
residual protection against biobasins
Blowers, Maintenance
logical contamination in the water
where clay, silt, and algae
Mechanics, maintain
distribution system.
particles settle to
flocculators.
This is a critical step
the
bottom.
to assure our water
Sedimentation occurs with
is safe all the way to
the help of gravity.
the consumer's tap.
(5.) Filtration: Water
(11.) Drinking
passes through filters conwater samples are
taining several feet of media
collected and tested
(sand, anthracite, and garnumerous
times
net) for a final cleaning prior
each day in our
to disinfection. Filtration
(11.) Roger
onsite
labs
to
removes the remaining parHuddleston, Water
ticles from the water. Those (5.) Damon Hoops, ensure consistent Operator, testing a
particles may include silt, Electrician, pulling drinking water quality,
water sample.
(4.) Frank Blowers & natural organic matter, iron wire on the filter and online analyzers
Kelly Payne,
continuously monitor the water for adeand
manganese,
and
deck.
Maintenance
quate disinfection and clarity.
Mechanics, work on microorganisms. Filtration
(12.) Clearwells: Clean, pure
a scraper at the sedi- clarifies water and also
water is pumped into distribution
improves the effectiveness of disinfecmentation basin.
systems that carry it to users
tion.
throughout Northwest Arkansas.
(6.) Backwashing:
Filters are cleaned by
backwashing with treated
water.
(7.) Solids Handling:
Backwash water and sedimentation blowdown dis(6.) Kelly Payne & Frank charge to a solids hanBlowers, Maintenance
dling facility where the
Mechanics, change
oil on a backwash pump. solids are further thick- (7.) Dennis Wright,
ened and clean water is Centrifuge Operator,
recovered and discharged back to the lake.
samples sludge
(12.) Kelly Payne & Frank Blowers,
(8.) Centrifuge: Polymer is added to the thickdepth
Maintenance Mechanics, service a
ened solids from solids handling before it enters the
at the clarifier.
pump on top of the clearwell.