Chemical Indicators of Stream Health in the Millbrook Wetlands
New Paltz, NY
Nicole Hitner, June 2008
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Abstract:
A look at the water quality of the Millbrook Stream and its tributary, referred to as Castor
Stream for the purposes of this paper, reveals the waters’ stability and overall health. The study
was conducted over a five week period beginning in early June and ending in early July;
measurements were taken on seven occasions. Classified by the New York State DEC as Class
C streams best used for fishing, these waters met state standards, with but a few exceptions. This
sampling of baseline chemical water parameters indicates the existence of a well-bolstered
wetland ecosystem worth protecting from trappers, all-terrain vehicles (ATVs), dumping, and
development.
Introduction:
According to a 2006 study conducted by Hudsonia Ltd., the Millbrook Wetland area is
the largest remaining wetland in the Village of New Paltz. Located on the northeastern side of
the village, it’s approximate boundaries lie at Shivertown Rd. to the north, North Chestnut St. to
the west, North Putt Corners Rd. to the East, and Henry W. Dubois St. to the south. The site
features two wetland ponds conjoined by a stream that feeds into the Millbrook, also known as
Tributary 13, which flows from Elting Corners on the other side of the interstate (see map 1).
Tributary 13 empties into the Wallkill River, which eventually becomes part of the Hudson
River.
The Millbrook Wetland supports a surprisingly diverse ecosystem and features several
different habitats, including the two ponds, a network of intermittent streams, marshes, braided
streams, hemlock and oak hickory forests, a vernal pool, a small oxbow lake, and grasslands.
Hudsonia reported several confirmed sightings of relatively rare species in the area.
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The beaver, a keystone species, is responsible for having shaped the Millbrook
environment into what it is today and made it livable for aquatic species. The lower of the two
wetland ponds was once a beaver lake, but illegal hunting decimated the beaver population and
forced its survivors to relocate to the higher pond. A small number of recently-felled trees
indicates continued beaver activity there. The old beaver dam has since broken and begun the
area’s transition from lake to meadow, a natural process that inevitably occurs when a beaver
family moves but has drastic effects on neighboring species.
The Millbrook Wetlands are privately owned and in the process of being developed on
the eastern side. This construction, known as Woodland Ponds, is a retirement center in the
making. Another development similar in size is slated for the western side of Castor Stream (see
map 2), sandwiching the wetland and its inhabitants between two encroaching danger zones that
not only replace the natural habitat, but introduce urban predators and various forms of pollution.
Because the streams run at a lower elevation than the two development sites, water quality
damage due to runoff and poor groundwater management is of particular concern. Polluted
waters would destroy the existing habitats and render the wetlands uninhabitable for most of the
species that currently reside there.
Purpose:
This study is meant to equip the Village of New Paltz Environmental Conservation
Commission (EnCC) with baseline water quality data to use as a basis for comparison with
future data gathered from the Millbrook Wetland streams. The parameters measured were
strictly chemical and included the following: pH, dissolved oxygen (D.O.), conductivity
(dissolved solids), alkalinity, turbidity, phosphate and nitrate nutrients, and alkalinity. Some
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Escherichia coli (e. coli) tests were run on water running under the fallen beaver dam, but
because these samples were not kept chilled between collection and incubation, the results may
be tainted and are reported here only for the sake of completion.
Methodology:
General: Overall, samples and readings were taken during AM hours. Sites were visited
from downstream to upstream so as not to disturb the stream bed and taint turbidity readings.
Dissolved oxygen, water temperature, pH, and conductivity were measured on-site while nutrient
testing, turbidity, and alkalinity were measured from water samples in a laboratory. Samples
were taken in volumes of around 200 mL in plastic bottles, opening facing upstream at middepth. The bottles were rinsed with distilled water and refrigerated before being reused for
collection. In cases when testing could not be completed directly after sample collection,
samples were frozen and later thawed to room temperature before testing.
Conductivity, pH and temperature were measured directly from the stream using a
COMBO/HANNA/pH, EC/TDS and Temperature HI 98130 measuring device and following the
device’s instructions for use.
Dissolved oxygen was measured in a similar fashion using a YSI 5508 D.O. Meter.
Stream discharge was measured using the following formula: Q=WDV, where Q is
stream discharge in L/s, W is the channel’s width, D is the channel’s depth, and V is it’s mean
velocity. Because the streams measured were never deeper than about 15 cm and because there
was access to only a very large flow meter, surface water velocity was used in place of the mean
velocity at various depths. Width was measured in centimeters using a measuring tape, and
depth was measured similarly at regular intervals along cross-section of the stream. Flow was
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calculated using the “ping-pong ball method:” a ping-pong ball floating on the water’s surface
was sent 3 meters downstream by the current and timed to the nearest second. Using a
proportion, this value was reduced to m/s and multiplied by the average depth and width (both
converted to meters) as the formula above indicates.
Turbidity was measured using a Hach 2100P Portable Turbidimeter and used following
the instrument’s procedures.
Phosphate and nitrate levels were measured similarly using a Hach DR/2500
Spectrophotometer following instructions outlined in the Procedures Manual.
Alkalinity was measured using a titration apparatus and alkalinity calculator supplied by
the Geology Department at SUNY New Paltz. Samples of stream water measuring 50mL in
volume were poured into 100mL beakers. Two drops of bromocresol green pH indicator and a
magnetic stir rod were added to the water and the beaker was then placed on a stir plate. With
the stir plate on, a burette was used to dispense 0.100M HCl into the beaker until the indicator
turned yellow. The concentration of HCl, volume of HCl used, and volume of water titrated
were then entered into the calculator, which gave the alkalinity as CaCO3 in g/L. This amount
was converted to mg/L to coincide with state guidelines.
E. coli samples were collected in sterile, sealed plastic tubes and incubated on 3M
Petrifilm E. coli Count Plates according to their instructions for use and following the AFNOR
Method of incubation and interpretation.
For all parameters tested in the laboratory, duplicate tests were taken from the same water
sample as the original.
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Discussion of Results:
Definition of a Class C Stream: “The best usage of Class C waters is fishing. These waters shall
be suitable for fish, shellfish, and wildlife propagation and survival. The water quality shall be
suitable for primary and secondary contact recreation, although other factors may limit the use
for these purposes.” –NYS DEC Regulations, Chapter X- Division of Water, part 701.8
Millbrook Water Quality Compared to Class C NYS DEC Standards:
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Parameter
Flow
Temperature
pH
Conductivity
(dissolved solids)
Dissolved Oxygen
Turbidity
Nitrate
Phosphate
NYS DEC
Standards
“No alternation that
will impair the
waters for their best
use.”
None, except in
cases of thermal
discharge, of which
there are no known
sources in the
Millbrook.
“Shall not be less
than 6.5 nor more
than 8.5.”
Testing Results
(Averages)
Discharge:
1: 1.38x10-3 L/s
2: 2.44x10-4 L/s
3: 2.67x10-4 L/s
4: 2.95x10-5 L/s
1: 18.7°C
2: 20.6°C
3: 19.7°C
4: 20.8°C
1: 7.35
2: 7.64
3: 7.73
4: 7.28
overall min: 7.06
overall max: 8.02
“Shall be kept as
1: 609 μS/cm
low as practicable to 2: 442 μS/cm
maintain the best
3: 692 μS/cm
usage of waters but 4: 157 μS/cm
in no case shall it
overall min: 122 μS/cm
exceed 500 mg/L
overall max: 902 μS/cm
(746 μS/cm).”
“For nontrout
1: 8.77 mg/L
waters, the
2: 8.41 mg/L
minimum daily
3: 8.69 mg/L
average shall not be 4: 5.11 mg/L
less than 5.0 mg/L,
overall min: 2.85 mg/L
and at no time shall overall max: 9.24 mg/L
the DO
concentration be
less than 4.0 mg/L.”
“No increase that
1: 5.68 NTU
will cause a
2: 8.68 NTU
substantial visible
3: 5.54 NTU
contrast to natural
4: 7.90 NTU
conditions.”
overall min: 2.07 NTU
overall max: 24.8 NTU
10,000 μg/L
1: 0.40 mg/L
(10 mg/L)*
2: 0.26 mg/L
3: 0.52 mg/L
*This applies to
4: less than 0.2 mg/L
class A, A-S, AA,
overall min: “undetectable”
AA-S, and GA
overall max: 0.7 mg/L
waters. Nitrogen
standards for class C
waters are: “None in
amounts that will
result in growths of
algae, weeds and
slimes that will
impair the waters to
their best usages.”
Orthophosphate
1: 0.50 mg/L
Standard
Met?
Based on
comparison.
Does not
apply.
Yes.
No. Site 3
consistently
breaching
limit.
T
he
No. On two
occasions,
Site 4 read
less than 4.0
mg/L. Daily
averages
were not
recorded.
two
situ
atio
ns
indi
Based on
comparison.
cate
d
abo
Based on
comparison.
ve
in
whi
ch
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Based on
the water does not comply with set standards are 1) Site 3 concerning conductivity, and 2) Site 4
being low on dissolved oxygen. Site 3, as indicated on the map, is the Millbrook branch that has
not yet merged with water draining from the wetland. The high amount of dissolved solids must
then be attributed to conditions outside of the Village of New Paltz and would require not only
further investigation, but communication with neighboring townships to resolve. Site 4 is where
Castor Stream drains from the upper pond, less than three meters from it’s edge, at only a trickle.
Here there lives little more than scum, but as the water gathers speed and begin tumbling over
rocks, its D.O. levels increase to healthy life-sustaining levels. This may be the natural
development of the stream and therefore no cause for concern.
All other parameters either meet their standards or are “based on comparison,” meaning
further information over time is needed to determine what is “normal” for a given stream.
“Normalcy,” however, may be a difficult thing to define for an area transitioning from wetland to
meadow.
The E. coli test results, as aforementioned, are unusable because samples were left unrefrigerated for approximately one hour between collection and incubation. This error in
procedure may have allowed bacteria to multiply before incubation, making the population seem
greater than it actually was in the stream. Also, in the case of the total coliforms, samples were
only collected on three occasions, failing to meet the five examination per month requirement.
Conclusion:
From the data gathered, the Millbrook and Castor Stream appear to be in good overall
health. Study of water quality in the Upper and Lower Ponds would complement this study and
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offer further baseline data with which to make comparisons. A macroinvertebrates study would
provide further information concerning streams’ health.
Monitoring the Millbrook Wetlands’ water condition over the next several months, and
perhaps the next few years, could potentially unearth a trend showing the effects of nearby
development on the stream habitats. It is necessary that emerging problems be identified early
on so that steps to prevent damage to the area may be taken.
Attachments:
Raw data for this report and Figures 1 through 9, analytical graphs and charts.
Note: the parameters in red on the graphs and charts represent values taken from the NYS
DEC.
References:
Behar, Sharon and Martha Cheo, et al. Hudson Basin River Watch Guidance Document. New
York: River Network, June 2000.
Chapter X: Division of Water. NYS Department of Environmental Conservation. 11 Aug. 2008.
Regulation and Enforcement. <http://www.dec.ny.gov/regs/2485.html>
Castor Canadensis: American Beaver. Animal Diversity Web. 11 August 2008. Information.
<http://animaldiversity.ummz.umich.edu/site/accounts/information/Castor_canadensis.ht
ml>
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Chowdhury, Shalfiul: Hydrogeology Professor at SUNY New Paltz. Personal correspondence.
June-July 2008.
Jakim, Dave: Co-chair of Village of New Paltz EnCC. Personal correspondence. April-July
2008.
Stevens, Gretchen. Wetlands in the Village of New Paltz, Ulster County, New York: Report to
the Village of New Paltz. Annandale, NY: Hudsonia Ltd., October 2006.
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