2006 O’Neil-Dunne, JPM and LA Morrissey. 2006. A GIS-Based Method for the Identification
of Candidate Riparian Buffer Zones. American Water Resources Association 2006 Spring
Specialty Conference, GIS and Water Resources IV, May 8-10, 2006, Houston, TX. Best
management practices such as riparian buffers, can significantly reduce the amount of
agricultural nonpoint source (NPS) pollution. In an effort to reduce NPS pollution in Vermont,
the Natural Resource Conservation Service (NRCS) established a program to provide financial
incentives to farmers to develop riparian buffers adjacent to their agricultural fields. The NRCS
approach involved identifying candidate agricultural fields by manually interpreting hardcopy
aerial photographs. This approach, however, does not account for geophysical factors such as
soil type, slope, land cover, and hydrology that also significantly and directly influence
agricultural runoff. A method based on the Revised Universal Soil Loss Equation (RUSLE) that
incorporates hydrologic flow modeling to identify and prioritize candidate agricultural fields for
riparian buffer development has been developed and is presented here. Implementation of the
RUSLE model within a GIS framework also provides a methodology that can be readily
extrapolated to surrounding regions in a cost effective manner. The model proved to be effective
in providing a rapid assessment of fields most likely to contribute NPS pollution to nearby
aquatic ecosystems, but was limited in its ability to accurately model hydrologic flow patterns
due to the coarse resolution of elevation data and over-simplification of the flow patterns by the
flow modeling algorithm. 2000 Papadopoulou MP, GF Pinder and GP Karatzas. 2000. Optimal
Management of a Coastal Aquifer Using Least-Cost Technology, Proceedings of the XIII
International Conference on Computational Methods in Water Resources, Vol. I, pp. 561-566,
Calgary Alberta, Canada. 1999 Abbott, MD and Stanley, RS. 1999. Modeling groundwater
recharge and flow in an upland fractured bedrock aquifer. System Dynamics Review 15(2): 163184. This article describes a system dynamics model to simulate recharge and flow mechanisms
in a fractured bedrock aquifer in northwestern Vermont. The model was constructed to aid in the
interpretation of data collected as part of a stable and radiogenic isotope study of groundwater.
Use of the model guided data collection and analysis throughout the course of the study, leading
to the derivation of equations describing temporal and spatial changes in recharge and flow
mechanisms in the study area. 1994 Borchardt, MA. 1994. Effects of flowing water on
nitrogen- and phosphorus-limited photosynthesis and optimum N:P rations by Spirogyra
fluviatilis (charophyceae). Journal of Phycology 30(30):418-430. The effects of flowing water on
net photosynthesis, dark respiration, specific growth rate, and optimum N:P ratios by Spirogyra
fluviatilis Hilse were assessed. The alga was cultivated under nitrogen or phosphorus limitation
in laboratory streams at three flow velocities: 3, 12, and 30 cm·s-1. The Droop equation
adequately described respiration and photosynthesis (PSnet) as a function of N or P cell quota
(QN or Qp). The data show that for N- or P-limited Spirogyra fluviatilis, flowing water is
physiologically costly. Generally, flowing water had little effect on respiration rates; however,
the proportion of gross photosynthesis devoted to dark respiration did increase with flow
velocity. For photosynthesis, the minimum N and P cell quotas increased with velocity, and the
theoretical PSnet maxima for N and P both appeared greatest at 12 cm·s-1. The Droop models
showed that for any given QN or Qp, PSnet, was reduced by the 30-cm·s-1 treatment. Consistent
with this finding, independent estimates of specific growth rates for P-limited S. fluviatilis in the
laboratory streams were inversely related to flow velocity when ambient PO4-3 was
undetectable. However, growth was not diminished at the fastest velocity when PO4-3 was
available for uptake. Thus, the increase in cellular phosphorus demand can be offset by flowenhanced P uptake when conditions permit; otherwise, growth will be impaired. The optimum
N:P ratios for S. fluviatilis at 3, 12, and 30 cm·s-1 were 50, 58, and 52 by atoms, respectively,
when calculated for PSnet= 0. The optimum ratios were inversely related to PSnet and decreased
to approximately 20 when PSnet was near maximum. The potential for flowing water to mediate
nutrient partitioning among lotic algae by altering growth rates and optimum nutrient ratios is
discussed. Borchardt, MA, Hoffman, JP, and Cook, PW. 1994. Phosphorus uptake kinetics of
Spirogyra fluviatilis Charophyceae in flowing water. Journal of Phycology 30(3):403-417. The
inorganic phosphorus (Pi) uptake kinetics of Spirogyra fluviatilis Hilse were examined as a
function of phosphorus cell quota (QP) and flow velocity in a laboratory stream apparatus. Shortterm uptake and the acclimation of the uptake mechanism to flow were measured by the
disappearance of Pi pulses in a recirculating flow cell. Short-term Pi uptake was biphasic. When
the alga was P-deficient, Phase 1 and 2 half-saturation constants and maximum uptake rates were
11.0 and 47.2 µg P·L-1 and 473 and 803 µg P·g dry wt-1 h-1, respectively. Flowing water
altered short-term uptake when the alga was P-deficient, but not when it was P-replete. When QP
was less than 0.21%, increases in flow velocity from 3 to 15 cm·s-1 enhanced uptake with
maximum uptake for any Pi pulse at 12 and 15 cm·s-1. At 22 and 30 cm·s-1, uptake was reduced
by 12% or more relative to the maxima. If, however, the alga was cultivated at 22 and 30 cm·s-1
and short-term Pi uptake was measured at 12 cm·s-1, uptake was on average 33% greater than
when the alga was cultivated at the latter velocity. Apparently, the alga could adjust short-term
uptake to compensate for the suboptimal conditions of the faster velocities. Long-term Pi uptake
and net phosphorus efflux were estimated by a non-steady state application of the Droop
equation. Long-term uptake of very low Pi concentrations was not reduced by fast flowing water.
Instead, uptake increased proportionately with flow velocity. Maximum phosphorus efflux from
S. fluviatilis was 3% of cellular P per hour and occurred when QP was greater than 0.2%. At
lower QP, the hourly efflux rate was typically less than 1%. Flowing water did not greatly
enhance efflux, although when Pi was undetectable, efflux did tend to increase slightly with
velocity. The data show that the effects of flowing water on Pi uptake were varied and not
always beneficial. If the effects of flowing water on nutrient acquisition by other lotic algae are
similarly varied and complex, flow may be an important determinant of nutrient partitioning
among benthic algae in streams. 1993 Douglas, WC, McIntosh, A, Clausen, JC. 1993. Toxicity
of sediments containing atrazine and carbofuran to larvae of the midge Chironomus tentans.
Enviromental Toxicology and Chemistry 12(5):847-853. Field and laboratory tests were
conducted to determine the 10-d toxicity of atrazine and carbofuran to larvae of the midge
Chironomus tentans. The pesticides were first spiked onto a clean control sediment, and the
midges were exposed to atrazine, carbofuran, or mixtures of both compounds. Laboratory
toxicity tests with carbofuran yielded LC50s of 20.5 µg/kg bound to sediment and 11.8 µg/L
dissolved in interstitial water. Slight but statistically significant toxicity was detected at the
highest tested concentration of atrazine (9,000 µg/kg, bound). Toxic interaction between the two
pesticides was assessed using all possible combinations of four concentrations of both pesticides
spiked onto clean sediments. Analysis of variance was used to determine if greater than or less
than additive effects occurred when both pesticides were present. No toxic interaction between
atrazine and carbofuran was detected. Based on laboratory findings, it was predicted that edgeof-field runoff could be toxic to midge larvae if concentrations of carbofuran exceeded 5 µg/kg.
To test these predictions, actual edge-of-field runoff was collected from a cornfield receiving
atrazine and carbofuran at recommended rates and the suspended sediments used in a toxicity
test. Edge-of-field runoff containing carbofuran at 186 µg/kg was acutely toxic to midge larvae.
1992 Duchovnay A, JW Reid, A McIntosh. 1992. Thermocyclops crassus (Crustacea: Copepoda)
present in North America: a new record from Lake Champlain. J. Great Lakes Res. 18: 415-419.
The cyclopoid copepod Thermocyclops crassus was collected in Missisquoi Bay, Lake
Champlain, Vermont, U.S.A., in May and August 1991. Since this is the first confirmed record
of the species in North America, the population is considered to be introduced. Thermocyclops
crassus is widespread in temperate and tropical Eurasia and Africa, but, in the Americas, has
been collected previously only in Costa Rica. It is planktonic and thermophilic, with a preference
for eutrophic waters Shellinger, GR and Clausen, JC. 1992. Vegetative filter treatment of dairy
barnyard runoff in cold regions. Journal of Environmental Quality 21(1):40-45. A vegetative
filter strip was installed to treat barnyard runoff from an active dairy farm in Vermont. Runoff
from a concrete surfaced barnyard flowed through a detention pond, then onto a vegetative filter
strip measuring 22.9 m by 7.6 m with a 2% slope. The water input and surface and subsurface
outputs for the strip were continuously monitored from December 1984 through May 1986. Of
the total barnyard runoff entering the strip, 65% left as surface runoff and 27% was measured as
subsurface outflow. The average hydraulic loading rate was 14.7 cm wk-1 and the average
overland flow detention time was 15 min. The filter strip did not significantly (P < 0.05) reduce
solids, P, N and bacteria concentrations in the surface output. Over the period of study the mass
retention was 33% total suspended solids, 12% total P and 18% total Kjeldahl N. Mass retention
was highest during the growing season and was poorest during snowmelt periods. It was
concluded that poor filter strip performance was due to an excessive hydraulic loading rate
resulting in an inadequate detention time for proper treatment. A preferential flow path from the
level lip spreader to the subsurface drain tiles may have contributed to the poor subsurface
treatment performance. Watzin, MC. 1992. A research and monitoring agenda for Lake
Champlain : proceedings of a workshop, December 17-19, 1991, Burlington, Vermont. Lake
Champlain Basin Program technical report 1. 1991 Brynn, DJ and Clausen, JC. 1991.
Postharvest assessment of Vermont's acceptable silvicultural management practices and water
quality impacts. Northern Journal of Applied Forestry 8(4):140-144. Seventy-eight recently
completed timber harvesting operations in Vermont were evaluated for Acceptable Management
Practice (AMP) compliance, soil erosion extent, and water quality impacts using a systematic,
one-day examination of each site. Evaluations of water quality impacts and soil erosion were
conducted on the portions of the transportation network and streams that could be most heavily
affected by the timber harvesting operation. Increased stream sedimentation was observed on
46% of the operations with streams. Woody debris impacts occurred on 65% of the operations
with streams. AMP compliance was over 90% for protective strip maintenance and stream
avoidance, but soil erosion control practices on truck roads and skid trails commonly failed to
meet AMP recommendations. Soil erosion was very limited on truck roads, skid trails, and log
landings. Although the Vermont operations often only partially complied with the AMPs,
minimal soil erosion and water quality impacts were observed. Kirn, RA and LaBar, GW. 1991.
Stepped-oblique midwater trawling as an assessment technique for rainbow smelt. North
American Journal of Fisheries Management 11:167-176. Discrete-depth midwater trawling for
rainbow smelt Osmerus mordax at night in Lake Champlain USA revealed a delayed vertical
migration of smaller fish and size partitioning verticially within the water column. These
behavioral observations led to the development and evaluation of a nighttime stepped-oblique
midwater trawling technique. This latter method proved effective in obtaining large catches of
rainbow smelt (mean catch per unit of effort CPUE, 215-655 fish/55-min trawl) and provided
estimated of relative abundance with reasonable precision (CPUE .+-. 13-50% from June through
October), as well as estimates of length and age distributions unbiased by vertical migration
behavior. 1990 Clausen, JC and Johnson, GD. 1990. Lake level Influences on sediment and
nutrient retention in a lakeside wetland. Journal of Environmental Quality 19(1):83-88. Lake
levels, sediment and nutrient retention, and flows were studied in a 180-ha wetland adjacent to
Lake Champlain, VT, to assess the role of lake levels on sediment and nutrient retention within
the wetland. This wetland received both point and nonpoint sources of nutrients. Input, output,
and within-wetland water samples were collected at 15 sites, and flows were measured nine
times in 1983 at lake levels varying over 2 m. The ratio of wetland inflow to outflow was related
to changes in lake levels. During spring, the concentrations of total suspended solids, total P, and
total Kjeldahl N throughout the wetland were lower than during summer and fall periods.
Wetland outlet concentrations decreased with rising lake levels. When wetland inflows exceeded
outflow, there was a net mass retention of total suspended solids, total P, and total Kjeldahl N.
Exports from the wetland decreased as lake level increased. The sediment and nutrient treatment
capacity of this lakeside wetland appeared to be dominated by hydrologic influences. Davis,
LS, Hoffman, JP, and Cook, PW. 1990. Production and nutrient accumulation by periphyton in a
wastewater tretment facility. Journal of Phycology 26(4):617-623. Five growth experiments were
conducted over a 15-month period to quantify biomass, seasonal growth rates, and production of
a periphyton community in the secondary clarifier of a wastewater treatment plant. A maximum
periphyton biomass of 130 g·m-2 (ash-free dry weight) was achieved during fall. Growth rates of
approximately 0.23·d-1 (from chlorophyll a) were observed during spring, summer and fall.
Winter values were also high (0.20·d-1). Maximum production was approximately 22 g·m-2·d-1
during spring. Periphyton phosphorus and nitrogen content was variable ranging from 0.4–2.4
and 4.4–15.1%, respectively. Estimated maximum removal rates of both nutrients were high (up
to ~ 160 mg P·m-2·d-1 and ~ 1900 mg N·m-2·d-1). High productivity and nutrient removal rates
in this lotic hypereutrophic ecosystem may warrant further investigation of periphyton as a
tertiary biological wastewater treatment in cold climates. Davis, LS, Hoffman, JP, and Cook,
PW. 1990. Seasonal succession of algal periphyton from a wastewater treatment facility. Journal
of Phycology 26(4):611-617. Attached algal populations were sampled at weekly or biweekly to
characterize successional changes in the secondary clarifiers of a wastewater treatment plant.
Three communities were compared from areas of slow, medium and rapid current velocities. In
general, the algae resembled those reported for other hypereutrophic flowing water. Of the
twenty-three algae recorded, Stigeoclonium, Oedogonium, Oscillatoria, Lyngbya, and
Pleurocapsa were dominant at some point in the 15 month sampling period. Nutrient
concentrations were consistently high (N = 1.1–21.4 mg·L-1; P = 0.1–10.4 mg·L-1); therefore,
changes in temporal distribution of algae were probably dependent on seasonal changes in light
and temperature. Colonization of artificial substrates was also observed. Small unicellular algae
were the first autotrophs to attach and these were followed by larger filamentous forms. DS
Ross, and RJ Bartlett. 1990. Effects of Extraction Methods and Sample Storage on Properties of
Solutions Obtained from Forested Spodosols. Journal of Environmental Quality 19(1):108-113.
Soil solutions obtained by three methods from Spodosols at a high-elevation, forested study site
were compared. Solutions were extracted by miscible displacement, by centrifugation, and by
compressing a soil-packed syringe. Analyses of pH, inorganic anions, total and reactive Al, and
organic C showed few differences between miscible displacement and the syringe-pressure
methods. However, centrifugation at a relative centrifugal force (RCF) of 9700 m s-2
consistently produced solutions with significantly higher pH and F- content than did the other
methods. Differences after centrifugation also were found in Cl-, NO-3, SO2-4, but Al, but less
frequently. Effect of soil storage time on solutions obtained using the syringe-pressure technique
was studied. Both Oa and Bhs horizon samples showed large increases in solution NO-3 after 24
h of storage at 3°C. During 36 d of storage, NO-3 levels increased by as much as 10-fold and
were accompanied by pH decreases. Measurements in solutions obtained from samples that had
been frozen for 36 d were higher than in the original solutions, except for NO-3 and pH. Changes
with freezing appeared to be related to large increases in soluble organic C. Our results suggest
that soil solution samples should be obtained very quickly after sampling of soils and that highspeed centrifuge techniques may give erroneous results. The syringe-pressure method is
relatively rapid, simple, and easily performed in the field. However, it may not be practical under
dry conditions. 1989 Clausen, JC and Meals, DW. 1989. Water quality achievable with
agricultural best management practices. Journal of Soil and Water Conservation 44(6):593-596.
Greater emphasis has been placed on controlling nonpoint sources of pollution; however, the
quality of water achieved by implementing best management practices (BMPs) remains
uncertain. Water quality in runof from agricultural areas under best management was compared
with water quality standards, where appropriate, and with other measures of treated water,
thereby defining the water quality achievable by using best management practices. f i e study
draws upon results obtained from 7 years of water quality monitoring in the LaPlatte River and
St. Albans Bay watersheds in kmont of BMPs implemented for manure management, barnyard
rune$ and milkhouse wastes. These studies include long-term stream monitoring for sediment
and nutrient concentration and load, as well as intensive evaluation of the treatment efectiveness
of certain BMPs, such as vegetated filter strips and manure storage, on concentration and export
of sediment, nutrients, and bacteria. Results indicate that BMPs may be highly effective in
reducing pollutant concentrations and loads, but runof may continue to exceed water quality
criteria. Further development of BMPs is needed to improve the water quality achievable.
Schwer, CB and Clausen, JC. 1989. Vegetative filter treatment of dairy milkhouse wastewater.
1989. Journal of Environmental Quality 18(4):446-451. A vegetated filter strip constructed to
treat milkhouse wastewater from a Vermont dairy farm was evaluated to determine its
effectiveness in reducing solids, P and N concentrations and exports in surface and subsurface
flow. The liquid waste was applied twice daily via a level lip spreader at a rate of 2.94 cm/wk on
a vegetated loam soil having a 2% slope. The flow and concentrations of inputs and surface and
subsurface outputs were continuously monitored during the 2-yr study. The strip significantly (P
< 0.01) reduced solids, P, and N on a concentration basis, and retained 95% solids, 89% P, and
92% N on a mass basis. Retention was the greatest during the growing season and the poorest
during snowmelt periods. Concentrations in subsurface outputs were greater than in surface
runoff and over 75% of the mass export was in subsurface flow. Comparisons of this study with
values reported in the literature suggests that hydraulic loading rate governs the effectiveness of
filter strip treatment. 1984 Ratsep, AI and Sjogren, RE. 1984. Assay for biologicaly available
phosphorus using proteolytic Aeromonas hydrophila. Freshwater Biology14:423-429.
1. A simple and inexpensive assay was developed to determine the amount of biologically
available phosphorus (BAP) present in freshwater.
2. BAP was measured by using Aeromonas hydrophila in a proteolytic assay system in which the
release of the chromogen from an insoluble azure dye derivative of hide powder (HPA) was
determined spectrophotometrically. The time necessary to hydrolyse 50% of the HPA was found
to be directly dependent on the amount of BAP present. BAP within the range 2–250 μg 1−1
phosphate-phosphorus was detected.
3. Our data suggest that the application of this assay for the measurement of BAP in freshwater
offers the potential of monitoring the biological response of a freshwater ecosystem to
phosphorus.
1983 Hopkins, RB and Clausen, JC. 1983. Land use monitoring and assessment for nonpoint
source pollution control. Perspectives on Nonpoint Source Pollution, Proceedings of a National
Conference, Kansas City MO. May 19-22, 1985. Environmental Protection Agency, 1985. p 2529. Varying soil characteristics, land use patterns, the relative timing of agricultural practices,
and hydrologic events complicate quantifying relationship between agricultural land use and
surface water quality. In two Vermont watersheds where the effects of best management practice
(BMP) implementation on water quality are continuously monitored, land use and agricultural
activities are being monitored on a field-by-field level. The land use data are entered in a
computerized Geographic Information System (GIS), and the results mapped. Correlation and
stepwise regression techniques related weekly land use activities for one subwatershed to surface
water quality. Comparisons of water quality to agricultural land use were based on proximity to
surface drainage and whether activities had occurred on runoff-producing zones. Manure
application on Soil Hydrologic Group D was significantly related to stream total phosphorus
concentration (r = 0.62) when manure was accumulated between runoff events. A predictive
equation developed explained 55% of the variation in total phosphorus concentration. GIS offers
the potential to inventory critical sources of nonpoint source pollution and identify changes in
water quality from agricultural land use and BMP's. 1981 Ciali, CP and Manning, RE. 1981.
Recreation and River Type: Social-Environmental Relationships Recreation use was studied on a
diverse state river system to test the hypothesis that recreation use patterns vary systematically
by river type. River segments were classified into representative river types through application
of a two-reid classification system. The first classification factor, generalized geomorphology,
defines and groups the dominant resource bases of which rivers are comprised. The second
classification factor, cultural setting, defines the land use and settlement patterns in which each
river type is found. Significant differences were found among resulting river types with respect
to the nature and intensity of recreation activity, desired use density, and user perceived
problems and conflicts. Management recommendations were developed, based on study findings,
for each river type. It is concluded that when both environmental attributes and cultural setting
are taken into account, regularities appear with respect to the way in which river resources are
used and perceived by recreationists. Further exploration and expansion of such recreationresource relationships to other activities and environments may hold substantial implications for
the allocation and management of outdoor recreation resources. Sjogren, RE and Gibson, MJ.
1981. Bacterial survival in a dilute environment. Applied Environmental Microbiology
41(6):1331-1336. Bacteria were isolated from lake water, and their ability to remain viable in a
dilute, nutrient-deficient environment was tested by a method that permits suspension of test
bacteria between two appressed microporous membranes in an aqueous environment. This
approach permitted separation of the lake isolates into two categories. Members of the tribe
Klebsielleae were shown to have a prolonged survival rate of 40% or better after 24 h, whereas
nonsurvivors were not viable for much longer than 24 h. These nonsurvivors belonged to the
genera Acinetobacter, Aeromonas, Alcaligenes, Erwinia, Escherichia, Flavobacterium, and
Pseudomonas. Differences in ribonuclease and adenosine triphosphatase levels between
Escherichia coli (nonsurvivor) and Klebsiella (survivor) cells were detected. At pH 7.5, stressed
E. coli cells contained 14% of the adenosine triphosphatase activity detected in the control,
whereas at pH 5.5, in the presence of calcium ions, these same cells contained 50% of the control
adenosine triphosphatase levels. At pH 7.2, E. coli cells were strongly inhibited by an adenosine
triphosphatase inhibitor, bathophenanthroline (88%); oligomycin (64%); and the proton
ionophore carbonyl- cyanide-m-chlorophenyl hydrazone (67%). Both sodium azide and
valinomycin were only moderately inhibitory (15 and 28%, respectively). Although the ability to
scavenge internal endogenous reserves seems important, we postulate that certain enteric bacteria
are capable of utilizing acidic conditions (pH 5.5) as an electrochemical gradient to generate
necessary high-energy intermediates for prolongation of survival beyond that possible in
environments of near-neutraL pH. Sjogren, RE and Port, J. 1981. Heavy metal-antibiotic
resistant bacteria in a lake recreational area. Water, Air, and Soil Pollution 15:29-44. We
undertook this study to determine the impact of urbanization on the microbial content of waters
of a major recreational area of Lake Champlain. We followed changes in the numbers of total
coliforms, fecal coliforms, fecal streptococci, and ascertained resistance of coliforms to heavy
metals and antibiotics. We determined the distribution of these bacterial indicators of pollution
by examining water and sediment samples. We also surveyed changes in physical parameters
such as pH, temperature, turbidity, and wind direction to evaluate their effect on the examined
aquatic microbial population. The level of all standard microbial indices of pollution frequently
exceeded acceptable levels for recreational waters. Sediment samples indicated prolonged
deposition of microbial pollutants, but efforts to demonstrate their release from sediment by
dislocation and resuspension were inconclusive. We confirmed the presence of a population of
heavy-metal and antibiotic-resistant coliforms isolated from harbor waters. Eighty-four percent
of the total coliforms isolated from harbor water samples were resistant to one or more
antibiotics and 96% were resistant to two or more heavy metals. The presence of these antibiotic
resistant properties in coliforms, as well as elevated fecal coliform and fecal streptococci counts
in both water and sediment samples, suggests to us that the bay is polluted by human fecal
matter. This pollution probably emanates from south harbor sources and affects the shores of the
major northern bathing area. It constitutes a potential hazard to public health because of the
geophysical nature of the harbor and the location of the pollution source.