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Modelling of the Mount Hope River watershed with BASINS-
HSPF to simulate discharges, sediment and snowpack
Juan M. Stella1*
1 Tecnológico de Monterrey, Monterrey, México
Abstract
Hydrological simulations of Mount Hope River watersheds located in northeast Connecticut,
were performed using the Unites States Environment Protection Agency (EPA) model
BASINS-HSPF (Better Assessment Science Integrating Point and Nonpoint Sources -
Hydrological Simulation Program Fortran) from 1997 to 1998. The simulation was performed
at monthly time step during one year and at sub-watershed scale. The purpose of the project
was to determine the efficacy of BASINS-HSPF in a forestry watershed for the simulation of
monthly discharges, sediments transport and snowpack. The model was calibrated using
measured discharges of the Mount Hope River and the results applied for the monthly
simulation of sediment transport and snowpack, these parameters simulated were compared
with sediment transported and snowpack calculated by another means. Some problems such
as time consuming for parameters calibration, were identified to make the model work,
besides that the results show that the model can be used for prediction of monthly discharges,
sediment transported and snow pack with a high degree of accuracy.
Keywords: BASINS-HSPF, watershed model, simulation, discharge, sediment, snowpack
Introduction
A watershed is the geographic area of land where all of the water that is under it or drains off
it goes into the same outlet, this is a drainage catchment that divides the landscape into
hydrologically defined areas, Gibson, Carlson, Simpson, Smeltzer, Gerritson, Chapra,
Heiskary, Jones and Kennedy (2000). The U.S. is divided and subdivided into successively
smaller hydrologic units which are classified in 4 levels, Regions, Sub regions, Accounting
Units, and Cataloging Units, United States Geological Survey (USGS, 2006). Watershed
models typically simulate flow and associated water quality characteristics as a series of
hydrologic and hydraulic processes, these processes include surface runoff, Parajuli and
Ouyang (2013). Urbanization can alter the hydrology of a watershed, particularly the
magnitude and frequency of storm related flooding, quantifying changes in stream flow that
result from urbanization are critical for planning and hydraulic structures systems, detention
basins, and other storm water-management facilities Zarriello (1999). Because data on storm-
runoff volume and flood flow in specific areas are commonly unavailable, and future changes
in these flow characteristics that result from urbanization cannot be measured directly,
planners and engineers have come to rely on hydrologic models for this information Zarriello
(1999).
Hydrologic models are essential and effective tools for investigating the complex nature of
processes that affect surface and subsurface hydrology, soil erosion, and the transport of
chemical pollutants in catchments and for assessing the impacts of land use changes,
agricultural activities, and best management practices on these hydrologic processes, United
states Environmental Protection Agency (USEPA, 2001). For example, major watershed
restoration efforts are under way in Illinois to reduce sediment loads and nutrient
concentrations and to improve the ecosystem along the Illinois River and its tributaries Singh,
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Knapp, Arnold and Demissie (2005). As part of restoration efforts, hydrologic models for the
Illinois River Basin are being applied and evaluated in the Illinois State Water Survey (Singh
et al. 2005). Part of the overall process in applying models for the Illinois River watershed is
a determination of which the models will perform best under varying watershed scales in
simulating hydrology, sediments, and nutrients Singh et al. (2005).
Many computer hydrologic models have been developed to simulate watershed hydrology
and water quality processes, the Hydrological Simulation Program FORTRAN (HSPF) is a
product of U.S. Environmental Protection Agency (USEPA, 2001), which is a comprehensive
model used for modeling processes related to water quantity and quality in watersheds of
various sizes and complexities Bicknell, Imhoff, Kittle, Donigian, and Johanson (2001), this
model is included within Version 3.0 of the modeling framework, referred as Better
Assessment Science Integrating Point and Nonpoint Sources- Hydrological Simulation
Program FORTRAN (BASINS-HSPF), developed by the United States Environmental
Protection Agency (USEPA, 2001).
BASINS-HSPF model uses information such as the time series of rainfall, temperature and
solar radiation; land vegetative cover characteristics such as land-use patterns; and land
management practices to simulate the processes that occur in a watershed (Bicknell et al.,
2001). The result of those simulations is a time series of the quantity and quality of runoff
from an urban or agricultural watershed such as flow rate, sediment load, and nutrient and
pesticide concentrations (Bicknell et al. 2001).
The importance of BASINS-HSPF come of the fact that is a comprehensive, continuous
model designed to simulate catchment hydrology and the associated water quality Duru
(1999). BASINS-HSPF system is designed so that the various simulation and utility modules
can be used conveniently, either individually or in group with a top-down approach that
emphasize structured design Dellman, Ruiz, Manwaring and Nelson (2002).
BASINS-HSPF considers a wide range of parameters that impact on hydrology and water
quality, therefore for Duru (1999) the application of the model could be wide. Evaluation of
BASINS-HSPF that is essentially equivalent to calibration of its parameters is, therefore, an
important effort toward understanding the model and bringing it into practical application
Duru (1999).
Dellman et al. (2002) considered that with the growing need to monitor the environment, it
became apparent that a method for rapid analysis of those effects was needed, BASINS-
HSPF is an analytical tool that apply mathematical models designed to simulate watershed
hydrology and water quality for both conventional and toxic organic pollutants in natural and
urban systems and predict possible environmental problems in the watershed (Dellman et al.
2002).
BASINS-HSPF model incorporates the watershed-scale Agricultural Runoff Model (ARM)
and Non-Point Source (NPS) models into a basin-scale analysis framework that includes
pollutant transport and transformation in stream channels (Bicknell et al. 2001). This set of
modules arranged in a hierarchical structure that must include a methodic data management
component, which permit the continuous simulation of a comprehensive range of hydrologic
and water-quality processes (Bicknell et al. 2001).
The objective of this study is to model the Mount Hope River catchment applying BASINS-
HSPF hydrologic model, calibrate the parameters of the model in such way that the simulated
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monthly discharges match the observed discharges, and then apply BASINS-HSPF to
simulate sediment transported and snowpack, and compare the results with sediment
transported and snowpack calculated by other means.
Methods
Description of the study site
The Mount Hope river is tributary of the Thames River (Figure 1) has a total length of 23 km,
and the drainage area at the United States Geological Service (USGS 2005) gage # 01121000
is 74,0 km2 and is located close to the town of Warrenville in the northeast of the state of
Connecticut, New England Region, northeast of USA. The discharges gage datum is 102,3
meters above sea level National Geodetic Vertical Datum of 1929 (NG5D29) (USGS 2005).
a
0 25 5012.5 Kilometers
b
0 5 102.5 Kilometers
c
0 1 20.5 Kilometers
Figure 1: a) The west branch of the Thames River watershed (Mount Hope river is tributary
of Thames River) in black color in the state of Connecticut. b) The east branch of
the Thames river watershed with the Mount Hope river watershed in black color
and the Agronomy Farm site (black star). c) Mount Hope river watershed, and the
gage discharge site (black star).
Table 1, shows the vegetative cover of the Mount Hope River basin, where the percentages of
land use in the watershed are based on 1990 Land Use and Land Cover data calculated by
Bighinatti (2005).
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Table 1: Attributes of Mount Hope River Basin (Bighinatti, 2005)
Monthly data for testing BASINS-HSPF were obtained for the years 1997 and 1998,
discharge data for the Mount Hope River were obtained from the USGS gage # 01121000, at
Warrenville (USGS, 2005). The discharge attributes are based on data from United States
Geological Survey website from 1941 to 2003 (USGS, 2005), the lowest recorded lowest
seven day average flow that occurs (on average) once every ten years (7Q10) in the Mount
Hope River at Warrenville was 0.011 m3/s on 1957, minimum discharge 0.071 m
3/s in 1958,
maximum discharge 6.853 m3/s on 1974, median discharge 0.425 m
3/s and mean discharge
0.850 m3/s (USGS, 2005).
Precipitation, potential ET, potential surface evaporation, air temperature, dew point
temperature, wind speed, and solar radiation data were obtained from the University of
Connecticut, Agronomy Farm located at 41°47'42" N and 72°13'42" W approximately 11,26
km from the Mount Hope gage (Figure 1). Table 2 summarizes the monthly mean values of
air temperature, humidity, solar radiation and precipitation in the Mount Hope River
watershed from 1958 to 2003.
Table 2: Monthly mean values of air temperature, humidity, solar radiation and precipitation
in the Mount Hope River watershed.
Month Air temperature Humidity Radiation Precipitation
[oC] [%] [W/m] [mm]
January -3 92 24 96
February -1 89 57 88
March 2 86 72 113
April 8 83 105 115
May 14 78 179 101
June 19 75 244 113
July 22 77 218 97
August 21 73 215 104
September 17 74 170 117
October 11 81 97 116
November 6 67 89 116
December -1 70 63 106
Land Use in the Watershed Value Unit
Barren Land 1.4 [%]
Forest 84.4 [%]
Non-forested Vegetation 8.3 [%]
Open Water 2.1 [%]
Urban 2.8 [%]
Wetland 1.0 [%]
Stratified Drift 4.2 [%]
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A USGS digital elevation model (DEM) layer and a predigitized stream network data layer
from the National Hydrography Dataset (NHD) were used to setup BASINS-HSPF in the
Mount Hope River watershed (USGS, 2005). A digitized soil information layer from the
Natural Resources Conservation Service-State Soil Geographic Database (NRCS-STATSGO)
soil database and land use-land cover data layer from the Unites States Geological Service-
Geographic Information Retrieval and Analysis System (USGS-GIRAS) database were used
for further sub classification of areas in the watershed (USGS, 2005).
BASINS-HSPF model application in the Mount Hope River watershed
Based on its topography and existing stream network, the Mont Hope River watershed was
divided into 12 smaller, hydrologically connected sub watersheds and associated stream
reaches using the automatic delineation tool GIS interface.
Each sub watershed of the Mount Hope River watershed was partitioned into pervious and
impervious areas based on land uses such as urban, agriculture, forest, barren, and
wetland/water areas. Since BASINS-HSPF did not automatically create segments based on
soil types, the dominant soil (Hydrologic Soil Group B) was assumed to be representative of
the Mount Hope River watershed soil conditions, such an approach has been used in some
previous BASINS-HSPF studies (Donigian et al. 1984) and Jones and Winterstein (2000).
Because major hydrologic differences occur between pervious and impervious land use types
and since forest is the major pervious land use in the Mount Hope River watershed, all
pervious land segments in the model were assigned the same hydrologic parameters. The
storage routing scheme was used for channel routing. The function tables (FTABLES) were
not modified, and the default volume-discharge relationship was used as calculated by the
model based on DEM and NHD data.
The Muskingum routing scheme was used for channel routing and the Soil Conservation
Service (SCS) curve number method was used for runoff simulation; thus, only the daily
precipitation and maximum and minimum air temperature data were input from the climate
station.
The entire Mount Hope River watershed was assumed to be totally forested in character so
that the IMPLND module was not applicable. Thus, only the parameters required to operate
PERLND and RCHRES modules for runoff simulation were calibrated.
During the calibration process in this study Bicknell et al. (1996) specifies the numerical
range of BASINS-HSPF model parameters and Donigian and Davis (1978) provides general
evaluation guidelines for setting numerical values of the parameters. Furthermore, Donigian,
Imhoff, Bicknell and Kittl. (1984) describes the entire application process of BASINS-HSPF,
to demonstrate the decisions, procedures, and results involved in a typical application.
Furthermore Donigian, Beyerlein, Davis and Crawford (1977) present a thorough discussion
of the parameters in the application of the BASINS-HSPF to agricultural watersheds in
Georgia and Michigan. Initial parameter values in this study were nominated by integrating
information from the above sources with information from earlier BASINS-HSPF related
experiences such as provided by Moore, Matheny, Tyre, Sabatini and Klaine (1988) and
Chew, Moore, and Smith (1991).
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The parameters and the ranges within which their values were varied were selected based on
other BASINS-HSPF evaluation studies, specifically Chew et al. (1991); Jones and
Winterstein (2000) and the BASINS Technical Note 6 (USEPA, 2001).
The descriptive equations used to represent these processes in BASINS-HSPF operation are
given by Bicknell et al. (1996) and the parameters required to execute BASINS-HSPF model
for sediment simulation can be grouped under the four categories: watershed, meteorological,
hydrological, and sediment are given by Wang, Duru, Hjelmfelt, Qiu and Thompson (1999).
The SNOW module simulates snowmelt contributions from the land surface derived from the
fall, accumulation, and melting of snow. This module is necessary for a complete hydrologic
package since much of the runoff, particularly in the northern half of the United States, is
directly related to snow conditions. Two options are available for modeling the processes
involved in snow accumulation and melt on a land segment: an energy balance and a degree-
day approach. The energy balance approach is based on work by the US Corps of Engineers
(USACE, 1956), Anderson and Crawford (1964), and Anderson (1968). Empirical
relationships are employed when physical relationships are not well understood. The snow
algorithms use meteorological data to: determine whether precipitation occurs as rain or
snow; simulate an energy balance for the snow pack; determine the effect of the heat fluxes
on the snow pack, and; calculate the resulting melt that reaches the land surface.
The second snowmelt method uses a temperature index, or "degree-day" approach. Most
processes from the snow algorithms are employed; however, snowmelt due to atmospheric
heat exchange is calculated using the air temperature and an empirical degree-day factor.
This approach minimizes the requirements for meteorological data to precipitation and air
temperature. The reader is referred to Rango and Martinec (1995) for a summary of the
degree-day method. SNOW may require six meteorological time series for each land segment
simulated, depending on the option chosen. They are:
A value from each of these time series is input to SNOW at the start of each simulation
interval. However, some of the meteorological time series are only used intermittently for
calculating rates. One such example is the calculation of the potential rate of evaporation
from the snow pack.
Air temperature is used to determine whether precipitation is falling as rain or as snow. The
critical temperature TSNOW may be automatically adjusted upward by up to one degree in
unsaturated conditions, based on the dew point. This adjustment is optional when using the
temperature index method, and is made only if the input dew point time series is supplied
(Bicknell et al., 2001).
Sediment transport calculation
Mtalo, Killingtveit and Ndomba (2008) in their research presented a sediment rating curve
given by Equation 1 is a regression line with coefficients chosen for a rising flow condition
for the Mount Hope application with square-r equal to 0.63.
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bQa*ansportSedimentTr [1]
Where:
Q Observed discharges
a 0.2286
b 2.2271
Snow Water Equivalent (Snowpack) calculation
The Snow water equivalent (SWE) was calculated applying Maidment (1993) methodology,
using the relationship between surface air temperature and water density curve and the
relationship between SWE water density and depth of water (Equation 2).
SS ρ*d*0.01SWE [2]
Where:
SWE Snow Water Equivalent
ds Water depth
ρS Water density
Statistical analysis
The simulated stream discharges, sediment transported and snowpack for the years 1997 and
1998 along the Mount Hope River were compared with observed stream water temperatures
and calculated sediment transported and snowpack using the Nash - Sutcliffe model of
efficiency (Nash and Sutcliffe 1970) given by Equation 3 and linear regression.
n
1i
2
i
n
1i
2
ii
)OO(
)SO(
1NS [3]
Where:
Oi Observed discharges
O Mean of observed discharges
Si Simulated discharges
n Number of steps modeled
Nash–Sutcliffe efficiencies can range from −∞ to 1. An efficiency of 1 corresponds to a
perfect match between simulated and observed data, therefore that the model is very accurate.
An efficiency of 0 indicates that the model predictions are as accurate as the mean of the
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observed data, an efficiency less than 0 occurs when the observed mean is a better predictor
than the simulated, Nash and Sutcliffe (1970).
Results and Discussion
Hydrologic calibration
The hydrologic components of BASINS-HSPF were calibrated to fit the observed daily
discharge data for one year period from October 1997 to September 1998. Initial values of the
model parameters were varied iteratively within a reasonable range during the calibration
runs until the maximum coefficient of determination square-r between observed and
simulated discharges data was obtained.
Figure 2, shows the observed and simulated monthly discharges at the Mount Hope River
from October 1997 to September 1998. The model showed a high sensitivity to the variations
in the intensity of the rain but failed to achieve a close value of the observed peak discharge
in event in March 1997 with one peak discharge of 5.5 m3/s for the observed and 3.4 m
3/s for
simulated and other event in June 1998 with almost the same peak discharges, 3.7 m3/s for
the observed and 3.6 m3/s for the simulated peak discharges. The shape of the concentration
and recession curves of the simulated events follows the trends of the observed discharges.
Figure 2: Monthly observed and simulated discharges at the Mount Hope River from October
1997 to September 1998.
Figure 3, shows the monthly the calculated and simulated sediment transported at the Mount
Hope River from October 1997 to September 1998. The model shows a high sensitivity to the
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variations in the intensity of the discharges and achieve similar values for the sediment
transported event in March 1998 with sediment transported of 113 mg/l for the calculated and
129 mg/l for simulated. The shape of the concentration and recession curves of the simulated
events follows the trends of the calculated sediment transported.
Figure 3: Monthly calculated and simulated sediment transported at the Mount Hope River
from October 1997 to September 1998.
Figure 4, shows the monthly the calculated and simulated sediment transported at the Mount
Hope River from October 1997 to September 1998. The model shows a high sensitivity to the
variations in the temperature and achieve similar values for the snowpack accumulated event
in December1997 with a snowpack of 77.3 mm for the calculated and 86.2 mml for
simulated. The shape of the concentration and recession curves of the simulated events
follows the trends of the calculated snowpack.
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Figure 4: Monthly calculated and simulated snowpack at the Mount Hope River from
October 1997 to September 1998.
Parameters and statistical analysis
Table 3 shows the linear regression slope and square-r, and Nash – Sutcliffe coefficient (NS)
between the simulated and observed discharges, sediment transported and snowpack.
Table 3: Linear regression slope and square-r, and NS for discharges, sediment and
snowpack.
Discharges Sediment transported Snowpack
Square-r 0.78 0.78 0.76
NS 0.72 0.77 0.62
slope 0.59 0.83 0.76
Table 4 shows the peaks obtained between simulated and observed-calculated discharges,
sediment and snowpack.
Table 4: Peaks between simulated and observed-calculated discharges, sediment and
snowpack.
Discharges Sediment transported Snowpack
Simulated 3.4 129 86
Observed-Calculated 5.5 113 77
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The simulation performed applying BASINS-HSPF at the Mount Hope River from October
1997 to September 1998, shows a high degree of accuracy between simulated and observed
discharges and simulated and calculated sediment transported and snowpack.
The results after calibration between the simulated and observed discharges performed a
square-r over 0.78 and Nash – Sutcliffe coefficient over 0.72. The trend line for the simulated
discharges shows that the model underestimated the discharges, with a slope of 0.59.
The results after calibration between the simulated and observed sediment transported
performed a square-r over 0.78 and Nash – Sutcliffe coefficient over 0.77. The trend line
between the simulated and calculated sediment transported shows that the model predicts
accurately the sediment transported, with a slope over 0.83.
The results after calibration between the simulated and observed snowpack performed a
square-r over 0.76 and Nash – Sutcliffe coefficient over 0.62. The trend line between the
simulated and calculated snowpack shows that the model predicts accurately the sediment
transported, with a slope over 0.76.
Conclusions
The hydrologic simulation model BASINS-HSPF is one of the most commonly used
hydrologic models, due to its complexity BASINS-HSPF requires extensive data input for an
accurate simulation. The agreement between simulated and observed monthly discharges,
sediment transported and snowpack was good with a square-r coefficient of 0.76 and Nash –
Sutcliffe coefficient over 0.62.
Modeling field activities with BASINS-HSPF is very difficult because the variables and the
data that determine the magnitude of discharges and other parameters are difficult to find and
have control when the BASINS-HSPF files are prepared. The discharges generated by
BASINS-HSPF model follow the trend of discharge observed in monthly simulation. The
snow and sediment simulated by BASINS-HSPF couldn’t be compared with observed data,
because there were not, but the trend of this simulation and the calculated values have a high
degree of relationship.
References
1) Anderson, E.A., and N.H. Crawford. 1964. The Synthesis of Continuous Snowmelt
Runoff Hydrographs on a Digital Computer. Technical Report 36. Department of
Civil Engineering, Stanford University, Stanford, California, 103 p.
2) Anderson, E.A. 1968. Development and Testing of Snow Pack Energy Balance
Equations, Water Resources Research, 4(1): 19-37.
3) Bicknell, B.R., Imhoff, J.C., Kittle, J.L., Jr., Donigian, A.S., Jr. and Johanson, R.C.
2001. Hydrological Simulation Program -- FORTRAN, User's manual for Release 12.
U.S. Environmental Protection Agency, EPA/600/R-97/080, Environmental Research
Laboratory, Athens, GA.
4) Bighinatti, S.J. 2005. Investigations of flow-duration curves and application to
estimating discharge on ungauged streams. Master Thesis. Storrs, University of
Connecticut.
Page 12
American Journal of Engineering, Science and Technology (AJEST) Volume 5, 2020
12
5) Chew, Y. C., L.W. Moore, and R. H. Smith. 1991. Hydrological Simulation of
Tennessee=s North Reelfoot Creek Watershed. Res. Jour. Water Pollut. Control Fed.
63(10).
6) Dellman, P. N., Ruiz, C. E., Manwaring, C. T., and Nelson, E. J. 2002. Watershed
Modeling System Hydrological Simulation Program; Watershed Model User
Documentation and Tutorial (No. ERDC/EL-SR-02-1). Engineer Research and
Development Center Vicksburg MS Environmental Lab.
7) Donigian, A. S., D. C. Beyerlein, H. R. Davis, and N. H. Crawford. 1977. Agricultural
Runoff Management (ARM) Model Version 11: Refinement and Testing, U. S.
Environmental Protection Agency, Environmental Research Laboratory, Athens,
Georgia.
8) Donigian, A. S. and H. H. Davis. 1978. User’s Manual for Agricultural Runoff
Management (ARM) Model EPA-600/3-78-080. U. S. Environmental Protection
Agency, Environmental Research Laboratory, Athens, Georgia.
9) Donigian, A. S., J. C. Imhoff, B. R. Bicknell, and J. K. Kittl. 1984. Application Guide
for Hydrological Simulation Program - FORTRAN (HSPF), EPA-600/3-84-065, U. S.
Environmental Protection Agency, Environmental Research Laboratory, Athens,
Georgia.
10) Duru, J. O. 1999. Evaluating HSPF for simulating sediment yield from a Claypan
agricultural watershed in Central Missouri. The Society for Engineering in
Agricultural, Forest, and Biological Systems. In International Meeting (pp. 18-21).
11) Gibson, G.R., R. Carlson, J. Simpson, E. Smeltzer, J. Gerritson, S. Chapra, S.
Heiskary, J. Jones, R. Kennedy. 2000. Nutrient criteria technical guidance manual:
lakes and reservoirs (EPA-822-B00-001). U.S. Environmental Protection Agency,
Washington, D.C.
12) Jones, P.M. and T.A. Winterstein. 2000. Characterization of Rainfall-Runoff
Response and Estimation of the Effect of Wetland Restoration on Runoff, Herone
Lake Basin, Southwestern Minnesota, 1991-97. USGS, WRIR 00-4095. Mounds
View, Minnesota.
13) Maidment, D.R. 1993. Handbook of Hydrology. Mc Graw-Hill, Inc., 1424 p., New
York.
14) Moore, W., H. Matheny, T. Tyre, D. Sabatini, and S. J. Klaine. 1988. Agricultural
runoff modeling in a small west Tennessee watershed. Research Journal Water
Pollution Control Federation 60(2): 242-249.
15) Mtalo, F. W., Killingtveit, Å., & Ndomba, P. M. 2008. Developing an Excellent
Sediment Rating Curve from One Hydrological Year Sampling Programme Data:
Approach. Journal of Urban and Environmental Engineering, 2(1), 21-27.
16) Parajuli, P. B., and Ouyang, Y. 2013. Watershed-scale hydrological modeling
methods and applications. INTECH Open Access Publisher.
17) Rango, A., and Martinec, J. 1995. Revisiting the degree‐day method for snowmelt
computations. Journal of the American Water Resources Association, 31(4): 657-669.
Page 13
American Journal of Engineering, Science and Technology (AJEST) Volume 5, 2020
13
18) Singh, J., Knapp, H. V., Arnold, J. G. and Demissie, M. 2005. Hydrological modeling
of the iroquois river watershed using HSPF and SWAT. Journal of the American
Water Resources Association, 41(2): 343-360.
19) U.S. Army Corps of Engineers (USACE). 1956. Snow Hydrology, Summary Report
of the Snow Investigations, North Pacific Division. Portland, Oregon, 437p.
20) U.S. Environmental Protection Agency (USEPA). 2001. BASINS-HSPF Version 3.1,
User's Manual. EPA-823-B-01-001, Washington, D.C.
21) United States Geological Survey (USGS). 2005. Daily Streamflow for Connecticut.
http://waterdata.usgs.gov/nwis/nwisman/?site_no=01121000&agency_cd=USGS
22) United States Geological Survey (USGS). 2006. http://water.usgs.gov/ GIS/huc.html
23) Wang, M., Duru, J. O., Hjelmfelt, A. T., Qiu, Z., and Thompson, A. 1999.
Hydrological Simulation of a Claypan Watershed Using HSPF.
http://www.fse.missouri.edu/home/hjelmfelta/Publications_files/PDF/seattleasce.pdf
24) Zarriello, P. J. 1999. Watershed modeling approach to assessing the hydrologic effects
of future development in the Ninemile Creek Basin, Onondaga County, New York.
US Department of the Interior, US Geological Survey.